Data from the

NATIONAL HEALTH SURVEY

AgeatMenarche

UnitedStates

A discussion of current age at menarche (onset of menstruation) of

American women, and analysis of variations in age at menarche

associated with race, region, family income, population size of place

of residence, educational level, height, weight, and skinfold thickness, as estimated from three cross-sectional programs of the Health

Examination Survey conducted during the period 1960 to 1970.

DHEW Publication No. (HRA) 74-1615

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

Public Health Service

Series 11

Number 133

Health Resources Administration

National Center for Health Statistics

Rockville, Md. November 1973
Series 11 reports present findings from the National Health Examination

Survey, which obtains data through direct examination, tests, and measurements of samples of the U.S. population. Reports 1 through 38 relate

to the adult program, Cycle I of the Health Examination Survey. The

present report is one of a number of reports of findings from the children and youth programs, Cycles II and 111of the Health Examination

Survey. These latter reports from Cycles II and III are being published

in Series 11 but are numbered consecutively beginning with 101. It is

hoped this will guide users to the data in which they are interested.

Vital and Health Statistics-Series 1 l-No. 133

For sale by the Superintendent of Documents, U.S. Government Printing Office, Wssbington, D.C. 20402- PrIco 66 cents
NATIONAL CENTER FOR HEALTH STATISTICS

EDWARD B. PERRIN, Ph. D., Acting Director

PHILIP S. LAWRENCE,SC.D., Deputy Director

GAIL F. FISHER, Assistant Director for Health Statistics Development

WALT R. SIMMONS, M.A., Assistant Director for Research and Scientific Development

JOHN J. HANLON, M.D., Medical A&isqr

JAMES E. KELLY, D. D. S., Dental Advisor

EDWARD E. MINTY, Executive Officer

ALICE HAYWOOD, kformation Officer

DIVISION OF HEALTH EXAMINATION STATISTICS

ARTHUR J. McDOWELL, Director

GARRIE J. LOSEE, Deputy Director

PETER V. V. HAMILL, M.D., Medical Advisor, Children and Youth F’ropams

HENRY W. MILLER, Chief Operations and Quality Control Branch

JEAN ROBERTS, Chiej Medical Statistics Branch

COOPERATION OF THE BUREAU OF THE CENSUS

In accordance with specifications established by the National

Health Survey, the Bureau of the Census, under a contractual

agreement, participated in the design and selection of the sample,

and carried out the first stage of the field interviewing and certain

parts of the statistical processing.

Vital and Health Statistics-Series 11-No. 133

DHEW Publication No. (HRA) 74-1615 “

Library of Congress (2talog &rd Number 73-600229
FOREWORD

The Health Examination Survey, a major program of the National

Center for Health Statistics, collects, analyzes, and publishes health

information gathered by direct examinations, laboratory tests, and

other measurements. The survey is conducted as a series of separate

cross-sectional programs, each based on a stratified, multistage probability sample of a specific segment of the civilian noninstitutionalized

population of the United States.

The basic functions of the survey programs are to provide national

estimates of distributions of physical, physiological, and psychological

characteristics within the population, prevalence of selected conditions,

and analyses of the interrelationships among demographic, socioeconomic, and health-related conditions. Such estimates along with

appropriate sampling variances are published in this series of reports

and disseminated nationally.

Since 1963 the National Center for Health Statistics, recognizing

the value of wider exploitation of the data being accumulated in the programs of the Health Examination Survey, has called upon competent

scientists outside the Center for the preparation of a number of reports. This report represents the most recent of these collaborative

efforts. On the basis of preliminary discussions between staff of the

Division of Health Examination Statistics and Dr. Brian MacMahon of

the School of Public Health, Harvard University, the scope and general

approach of this report were determined. Initial data tapes and related

information requested by Dr. MacMahon were provided by James Baird,

formerly with the Division. Liaison for the Center was the responsibility of Garrie J. Losee, Deputy Director of the Division of Health

Examination Statistics. Substantial contributions in preparing the manuscript for publication, including the preparation of final tabulations and

appendices and revision of preliminary drafts were provided by James

V. ScanIon and Wesley L. Schaible of the Division Staff.

Arthur J. McDowell, Director

Division of Health Examination

Statistics

...

Ill
CONTENTS

Introduction ----------------------------------------------------------

Method ---------------------------------------------------------------

Sources of Information ----------------------------------------------

Methods of Analysis ------------------------------------------------

Results --------------------------------------------------------------

Current Menstrual Status --------------------------------------------

History of Age of Menarche ------------------------------------------

Discussion -----------------------------------------------------------

References -----------------------------------------------------------

List of Detailed Tables ------------------------------------------------

Appendix I. Questionnaire Items onMenarche --------------------------

Cycle I------------------------------------------------------------

Cycle II-----------------------------------------------------------

Cycle III-----------------------------------------------------------

Appendix II. Technical Notes -----------------------------------------

Survey Design ------------------------------------------------------

Standard Errors ----------------------------------------------------

Logistic Curves ----------------------------------------------------

Appendix III. Demographic Terms -------------------------------------

1

1

1

2

2

2

3

5

7

9

23

23

23

23

25

25

25

26

28
SYMBOLS

Data not available ------------------------

Category not applicable -------------------

Quantity zero ----------------------------

Quantity more than O but less than 0.05 -----

Figure does not meet standards of

reliability orprecision ------------------

---

. . .

0.0

*
AGE AT MENARCHE

Brian MacMahon, M.D., l+ofesso?’, Department of -Epidemiology,

School of Public Health, Havviwd Univwsity

INTRODUCTION

In this report information from the Health Examination Survey is used to estimate current age

at menarche (onset of menstruation) of women in

the LTnitedStates and to examine the data for differences in age at menarche among subsets of the

population and for changes in age at menarche over

time.

As a major program of the National Center for

Health Statistics the Health Examination Survey

collects and analyzes information gathered by direct physical examinations, tests, and measurements performed on probability samples of the

L1.S. population. ”Supplementary health and social

information is also collected by means of several

questionnaires. The survey is conducted as a

series of separate, cross-sectional programs referred to as “cycles.” Each cycle is limited to

some specific segment of the U.S. population and to

certain aspects of the health of that segment. During the period 1960-1970 three separate cycles

have heen completed. Information from all three

cycles is used in this report. In the first cycle,

which focused on adults, female respondents completed a questionnaire in which they were asked

whether or not their menstrual periods had begun

and if so, at what age. In Cycles II and III, which

dealt with 6- through 11-year-olds and 12-

through Ii’-year -olds, respectively, information

on menorche used in this report was supplied by

the p;lrents.

METHOD

Sources of Information

I“he questions on menstrual status for each

cycle are shown in appendix I. The nature of the

samples is detailed in previous publications 1-.7

mxl summarized in appendix II. Sample frequencicw of females for each cycle along with estimates

of thu populations represented are shown in table

1 according to race and age. The survey designs

are described briefly below:

Cycle 1. The sample of Cycle I of the Health

Examination Survey (HES) was selected to

represent the civilian noninstitutional population of adults in the United States 18 through

79 years of age. I Survey operations took

place during the years 1960-1962.~ The response rate was approximately 86 percent.

Among those examined were 3,581 women,

who because of the sample design and estimation procedures and adjustment for nonresponse, may be considered representative

of the approximately 58 million women in

that age range at the time of the survey. Information on menarche was not available for

about 1 percent of the women examined in

Cycle I.

Cycles II and III. The data from Cycles II and

III of the Health Examination Survey are combined in this report to yield estimates of current age at menarche for the female civilian

noninstitutionalized population of the United

States aged 6 through 17 years. The sample

for Cycle II was designed to provide health

information for the population of 6- through

11-year -olds, and survey operations were

conducted from 1963 through 1965. ‘]”4 Cycle

III focused on youths 12 through 17 years of

age, and survey operations took place during

the years 1966-1970.; The response rate for

Cycle H was 96 percent and that for Cycle III

was 90 percent.

In Cycle II, 3,487 girls were examined. The

sample design, survey operation, and response

results have been described in earlier reports. ‘]’4

Findings for these examinees may be considered

representative of the approximately 11.7 million

girls 6 through 11 years old in the noninstition1
alized population of the United States at the time

of the survey. Cycle III included 3,223 girls, representing a population of about 11.2 million girls

12 through 17 years of age at the time of the survey. The plan and operation of this survey of

youths have been described previously: In sum,

Cycles H and 111included 6,710 girls in the age

range of 6 through 17 years, representing a population of approximately 23 million. Responses to

the questions on menstrual status were not available for about 3 percent of the girls 6 through 17

years old.

In this report the age recorded for each sample person was the age at last birthday on the date

the questionnaire was completed.

Methods of Analysis

The samples for all three cycles of the Health

Examination Survey were selected by complex

multistage procedures. For each individual in each

sample a statistical “weight” was subsequently

assigned. This weight is the reciprocal of the probability of selection of that individual, based on a

comparison of representation of individuals with

specified demographic characteristics in the sample and in the total United States noninstitutional

population (appendix H).

Unless otherwise specified, all descriptive

statistics presented in this report have utilized

this weight. The statistics therefore reflect characteristics as estimated for the U.S. population

rather than for the samples. For example, in computing mean age at menarche the value reported

by each individual is multiplied by the statistical

weight assigned to that individual.

Since the estimates shown in this report are

based on samples of the population rather than the

entire population, they are subject to sampling

error. Standard errors of the estimates are presented in the detailed tables and discussed in appendix H. The standard errors were computed by

a half-sample pseudoreplication technique which

takes into account the complex design of the samples.

A further word on the sample designs for

Cycles 11 and 111is appropriate. Because of both

operational considerations and the desire to obtain

longitudinal data, over 30 percent of the youths

comprising the Cycle III sample had also participated as children in Cycle II. It was assumed

that this overlap had no appreciable effect on the

findings presented in this report.

As stated earlier, information on menstrual

status was not available for almut 1percent of the

women in Cycle I and for about 3 percent of the

girls in Cycles II and III. Women and girls for

whom no information on menstrual status was

available were excluded from this analysis. It

was assumed in effect that the responses of this

small number of women would be essentially the

same as those for whom responses were available.

For the adult women of Cycle I the only relevant measure of age at menarche is the mean age

at which the event was reported to have occurred.

This measure is subject to the usual random and

nonrandom variability associated with anamnestic

data. However, the samples of Cycles II and 111

are distributed throughout the age range during

which menarche occurs. Relevant parameters

therefore include the percentages of girls at

various ages whose parent or guardian reported

that the girl’s menstrual periods had begun. As

noted in appendix II, these percentages—at least

in the years 11 through 14—give good fits to logistic curves from which estimates of the median

age at menarche and its confidence limits can be

derived. These data probably provide the more

accurate estimate of age at menarche in the United

States at the present time and are presented

next in this report; data from Cycle I are than

presented. primarily to examine for differences

in mean age at menarche among subgroups of the

population and for changes in mean age at menarche over time.

RESULTS

Current Menstrual Status

In table A and in table 2 the percentages of

girls whose menstrual periods had begun, as estimated from Cycles H and 111of the Health Examination Survey, are shown according to age at the

time of the survey and race. The data for the

population 10 through 15 years old are illustrated

in figure 1, together with a fitted logistic curve.

The observed values lie close to the computed

logistic function in which the median age at menarche is 12.77 years and the slope 1.S3. A description of the logistic function is presented in

appendix II. In comparing the percentages in table

A with those in figure 1, it should be noted that

2
100 —

m —

~ 60 —

m

<

1-

Z

E

u

% 40

— Fined logisticcuwe

o —

X Observedpercentage

o I

10 11 12 13 14 15 16

AGE IN YEARS

—

Figure 1. Percentage of girls whose menstrual periods had

started and fitted logistic curve, by age: United States.

age shown intable Areferstoageat last birthday.

In computing the constants of the logistic and

plotting the values in figure 1, it has been assumed

that girls whose age at last birthday was x have

a mean age of x -t 0.5 years.

Table A shows that at all ages between 10 and

15 years the percentage of black girls whose

periods had begun is higher than that in the white

population. The difference is most striking at the

younger ages. For example, among 11- year-old

girls almost twice as many black as white girls

were menstruating. This earlier menarche in

black girls is also seen in table 3, which gives the

constants of logistic curves fitted to the data for

demographic subgroups of the population. For

reasons stated in appendix II, these values are

estimated only from the data for girls aged 11

through 14 years. Overall, the median age at menarche is 12.80 ‘years for white girls and 12.52 for

black girls. The racial difference is seen within

categories of family income, population size of

place of residence, and all geographic regions except the South.

Other differences seen in table 3 are not remarkable. There @ no consistent trend in median

age at menarche with family income or population

size of area of residence. Variation by region

Table A. Percentage of girls whose menstrual periods had started, by race and

age: United States

6-17 years --

+

43.2

6-9 years ---------

10 years ----------

11 years ----------

12 years ----------

13 years ----------

14 years ----------

15 years ----------

16-17 yeara -------

.0.2

1.2

12.8

43.3

73.2

91.7

98.3

99.7

JMte Black

1

=4===

11.6 21.3

41.7 51.2

72.9 74.1

91.4 93.5

98.2 98.7

99.6 100.0

lAge at last birthday.

~Includes data for “other races, ” which

are not shown separately.

among white girls is small, with medians ranging

from12.69 yearsin the Southto 12.90 in the Midwest. As indicatedin table 3 the numberof black

girls in certain subgroups of the sample is too

small to provide reliable estimates of median

age at menarche.

History of Age a+ Menarche

Mean ages at menarche as reported by women 18-79 years of age in Cycle I of the Health

Examination Survey are given in table 4. In the

data for all races and in those for white women,

a trend towards older mean age at menarche with

increasing age at time of the survey is evident.

No such trend is seen for black women. Consideration of the trend among white women suggests

that there are three broad age groups— 18-34

years, 35-54 year% and 55-79 years—within which

smaller age groups are reasonably homogeneous.

Subsequent tabulations are therefore presented

for each of these three broad groups. The means

and standard deviations of reported age at menarche are shown by race and broad age group in

table B.

Women in the age group 18-34 years reported

a mean age at menarche (12.76 years) similar to

that computed from data on the current menstrual

status of girls aged 10-15(12.77 years). However,

3
Table B.

age at

Cycle I

vey, by

States

Mean and standard deviation of

menarche reported by women in

of the Health Examination Surrace and broad age group United

Race and age

All races

18-79 years--

18-34 years --------

35-54 years --------

55-79 years --------

. White

18-79 years--

18-34 years --------

35-54 years --------

55-79 years --------

Black

18-79 years--

18-34 years --------

34-54 years --------

55-79 years --------

lean age

at

nenarche

13.08

12.76

13.06

13.53

13.09

12.73

13*O7

13.56

12.94

12.85

12 ● 93

13.10

Standard

deviation

1.576

1.411

1.512

1.753

1.563

1.386

1.481

1.746

1.622

1.534

1.658

1.690

the means shown in table 4 and tableB are the

simple means oftheages reportedbyrespondents.

It could be that women who reported that their

menarche occurred at agexwere reporting their

age at last birthday when the event occurred and

that they were, on average, actually x+O.5. Perhaps 0.5 years should therefore beadded to each

ofthe means shown. On the other hand, it maybe

that women reporting m,enarche at age xmeant

that it occurred aroundtheirxth birthday,inwhich

case 0..5 years should not be added. Girls aged

15-17 years in Cycle III whoseperiods had begun

had a mean menarcheal ageof 12.5 years ifitis

assumed that they were reporting their nearest

birthday or 13.0 if it is assumed that they were

reporting their age at last birthday. These figures, compared with the 12.8 estimated from the

girls aged 10-15 years, and assuming that little

secular change couldhave occurred overaperiod

as short as 5 years, imply that some women reported age at menarche one way and some the

other. The means for women in Cycle I are

therefore presented without addition of the half

year. It should be recognized, however, that, because of the difference in method of eliciting information, the means estimated from Cycle I

cannot be compared with data from Cycles H and

111. As already mentioned, it seems reasonable

to regard the estimate based on current observations (Cycles H andIII) as the best estimate of

the present median ageatmenarche andtouse the

data from adult women (Cycle I) only for internal

comparisons.

Among women in Cycle I—for all of whom

the method of ascertainment of information was

similar—thereis seen intable B for white wornen a decline in mean age at menarche ofalmost 1 year in the40 years between the central

points of the two extreme age groups. The decline for black women is much smaIler. It is

also seen that for white women the standard

deviation of reported age atmenarcheis greater

in the older than in the younger women. It cannot

be determined from these data whether there

was in fact abroader rangeofdistributionof ages

at menarche 40 years agoor whether the larger

standard deviation results fromincreasingly random (as distinct from factual) responses asinterval since the event increases.

Table 5 shows the distribution of Cycle I

women in the three broad age groups by age at

which they reported their menstrual periods had

begun. Neither the distributions in table 5 nor

the means shown in table B are consistent with

the earlier onset of menarche observed for black

girls in Cycles II and III. For women in Cycle I

the mean reported age at menarche is slightly

lower for black than for white. However, the difference occurs almost exclusively among women

55-79 years of age—an age group when the interval

since the event would seem to make the information

least reliable. Indeed, among women 18-34 years

old the percentage reporting menarche prior to

age 12 is higher among white than among black

women (table 5) and the mean age at menarche is

4
lower for white than for black women. These

discrepancies accent the differences possibly introduced by the different methods of ascertaining

age at menarche and reinforce suspicions regarding the accuracy of reporting of age at menarche by women several years past the event. This

accuracy is certainly influenced by random misreporting, but it may also be affected bys ystematic

differences in misreporting indifferent subsets of

the population.

Table 6 gives mean reported menarcheal

age by geographic region of current residence.

Among the white population there are no notable

differences. In the black population differences

show no consistent trends.

Mean age at menarche by population size of

place of current residence is examined in table

7, Again there are no notable differences among

white women. For black women the only remarkable feature is the low menarcheal age reported

by young residents of giant Standard Metropolitan Statistical Areas. A similar finding is observed in the data for Cycles II and III (table 3).

Variation in mean menarcheal age by years of

education completed and by annual family income

is shown in tables 8 and 9. For both races, the

youngest age group shows a trend towards earlier

menarche with increasing duration of education.

A comparable trend of earlier menarche with increasing family income is seen for black women

but not for white.

No notable variation in mean age at menarche

is seen by current height (table 10), but among

the young white women a very marked decline in

mean menarcheal age with increase in current

weight is observed (table 11). Table 12 shows for

both white and black women a sharp decline in

menarcheal age with increase in skinfold thickness.

DISCUSSION

In a recent review of genetic and environmental factors associated with variation in age at

menarche, Zacharias and Wurtman categorize

three methods of measuring age at menarche in

a population as follows: 8

The prospective method. Girls who have not

yet started to menstruate are questioned at

suitable intervals over a period of years and

the age at which their first menstrual period

occurs is recorded.

The stutus quo method. A cross section of

girls over the range of ages during which

menarche may occur is questioned as to

whether or not their menstrual periods have

begun. The percentages of girls at each age

who are menstruating are fitted to a probit

or logistic model which describes the median

and variation in age at menarche.

The ~et~ospective method. Women who are

past menarcheal age are asked at what age

they experienced their first menstrual period. The population must be past the range

of menarcheal ages or the mean menarcheal

age will be biased downwards by the exclusion of older girls whose menarche has

not yet occurred. Such a bias has been shown

in retrospective reporting of age at menopause.7

Little information is available that permits

comparison of the parameters of menarcheal age

derived from these three different methods. Four

prospective studies of small groups of girls in the

United States since 19486 give mean menarcheal

ages between 12.6 and 12.9—values quite similar

to that of 12.8 derived by the stutus quo method

used here on the data from HES Cycles II and III.

On theoretical grounds, also, there seems no reason to think that these two methods would give different results (on the same population) unless very

rapid changes —i.e., changes measurable within 3

or 4 years—in menarcheal age are occurring in

the populations under study.

Similarity of the mean menarcheal age reported by the young adult women in Cycle I of the

Health Examination Survey and that computed from

the data for the girls in Cycles II and III suggests

that the stitu.s quo and retrospective methods also

give similar results (at least when the women for

whom the retrospective histories are being’ obtained are young) —provided it is recognized that

women being interviewed retrospectively seem to

report their age to the closest birthday rather

than their age at last birthday. The same conclusion is suggested by a comparison of the two

methods in a group of Singapore girls. s However,

the 0.5 years average difference introduced by

5
reporting age at nearest, rather than last, birthday is asubstantial onein the context of thedifferences observed between populations in mean

menarcheal age and must be kept in mind when

comparisons are made thatinvolve analyses using

the different methods.

Furthermore, one cannot be confident that

retrospective questions are responded to in comparable fashion in different populations or in different subgroups of a single population. The fact

that the cross-sectional (status quo) study of

Cycles II and HI indicates a difference between

white and black girls in median age at menarche,

while no such difference is reported retrospectively by the young women of Cycle 1, suggests

that the questions are being responded to differently by the two racial groups. Intuitively, it seems

likely that the stutus quo method is less susceptible to such biases than the retrospective method

and that the racial difference noted in Cycles II

and 111is real.

Both of the other major differences in mean

age at- menarche noted within this sample are

compatible with previous observations on selected

populations. The increase in reported age at menarche with increase in current age—suggesting

a decline in age at rnenarche over time—has been

reported in many studies. For example, in a group

of mothers and their daughters a difference in

mean menarcheal age of 1.52 years was noted. ~

This suggests a somewhat sharper decline than

that seen in the women of Cycle I in this survey.

However, in the mother-daughter study age at

menarche was ascertained by the retrospective

method for the mothers but by the prospective

method for the daughters, and the investigators

assumed that the mothers were reporting their

age at last birthday—that is to say, 0.5 years was

added to the reported ages: If in facithe tendency

was to report age at nearest birthday—as the

present data indicate might be so, at least for

some women—the decline would be approximately

1 year over a generation. Such a decline is more

similar to that noted in the HES sample and by

other investigators.

The strong decline in menarcheal age with

increase in body weight and skinf old thickness

confirms previous

ships with weight

reports of similar relationand ponderal index.1”

o o—

6
REFERENCES

1National Center for Health Statistics: Plan and initial

program of the Health Examination Survey. Vital mzd Health

St~tistics. PHS Pub, No, 1000-Series l-No, 4. Public Health

.%rvicc. Washington. U.S. Government Printing Office, July

1965.

~National Center for Health Statistics: Cycle I of the

Health Examination Survey, sample and response. Vital and

Ifwkh .St~tistics. PHS pub. No, 1000-Series 1 l-No, 1. public

Hcahh Scrvicc. Washington. U.S. Government Printing Office,

tlpr. 1964,

3National Center for Health Statistics: plan, operation,

and re.sponsc results of a.program of children’s examinations.

l’it~~wdHe,dth ,$ttrtistics. PHS Pub. No. 1000-Series l-No.5.

Public Health Scrvicc, Washington. U.S. Government Printing

Office, Oct. 1967.

~National Center for Health Statistics: Sample design and

estimation procedures for a national Health Examination Survey of Children. Vital and Health Statistics. Series 2-No. 43.

DHEW pub, No, (HSM) 72-1005, Health Services and Mental

Health Administration, Washington. U.S. Government Printing

Office, Aug. 1971,

5 Nationa] Center for Health Statistics: Plan and operation

of a Hcakh Examination Survey of U.S. youths 12-17 years of

age. [‘it,d ,zncf Ifeuhh SWistics. PHS pub. No. 1000-Series

l-No. & public Health Service, Washington. U.S. Government

Printing Office, Sept. 1969.

6Zacharias, L., and Wurtman, R. J.: Age at menarche,

gene tic and environmental influences. N. Eng. ]. Med.

280:868-875,1969.

7National Center for Health Statistics: Age at menopause,

United States, 1960-62. Vital and Health Statistics. PHS pub.

No. 1000-Series 1 l-No. 19. Public Health Service, Washington.

U.S. Government Printing Office, Oct. 1966.

8 Aw, E., and Tye, C. Y.: Age of menarche of a group of

Singapore girls. Hum. Biol. 42:329-336, 1970.

9Damon, A., Damon, S. TO, Reed, R. B., and Valadian, 10:

Age at menarche of mothers and daughters, with a note on

accuracy of recall. Hum. Biol. 41:161-175, 1969.

1 OHillman, R. w., S]ater, p., and Ne150n, M. J.: season of

birth, parental age, menarcheal age and body form some interrelationships in young women. Hum. Bio~. 42:570-580, 1970.

11 National Center for Health Statistics: Replication, an

approach to the analysis of data from complex surveYs. Vital

and Heakh Statistics. PHS Pub. No. 1000-Series 2-No. 14.

public Health Service, Washington. U.S. Government Printing

Office, Apr. 1966.

12 National Center for Health Statistics: Pseudoreplication, further evaluation and application of the balanced halfsample technique. l~ituf and Health Statistics. PHS Pub. No.

1000-Series 2-No. 31. Public Health Service. Washington. U.S.

Government Prinring Office, Jan. 1969.

7
LIST OF DETAILED TABLES

Page

Table 1.

2.

3.

4.

5*

6.

7.

8.

9*

10.

11.

12*

Sample frequenciesand populationestimatesof females in Cycles I, II, end III

of the Health ExaminationSurvey, by race and age: Health ExaminationSurveys,

1960-70-------------------------------------------------------------------------

Percentageof girls in Cycles II and III of the Health ExaminationSurvey whose

menst~al periods had started, by age and race, with standard errors of the estimates:United States----------------------------------------------------------

Constants of logistic curves fitted to the percentageof girls 11 through 14

years of age whose menstruationhad started, by race and selected characteristics: United States-------------------------------------------------------------

Mean’age at menarche reported by women in Cycle I of the Health ExaminationSurvey, by race and age, with standard errors of the estimates:United States------q

Percent distributionof women in Cycle I of the Health ExaminationSurvey, by

reported age at menarche, race, and age, with standard errors of the estimates:

United States------------------------------------- ----------------------------

Mean age at menarche reported by women in Cycle I of the Health ExaminationSurvey by geographicregion, race, and age, with standard errors of the estimates:

United States-------------------------------------------------------------------

Mean age at menarche reported by women in Cycle I of the Health ExaminationSurvey by population size of place of residence, race, and age, with standard errors of the estimates:United States--------------------------------------------

.

Mean age at menarche reported by women in Cycle I of the Health ExaminationSurvey, by educationallevel, race, and age, with standard errors of the estimates:

United States-------------------------------------------------------------------

Mean age at menarche reportedby women in Cycle I of the Health ExaminationSurvey, by annual family income, race, and age, with standard errors,of the estimates: United States------------------------------------------------------------

Mean age at menarche reported by women in Cycle I of the Health ExaminationSurvey, by height, race, and age, with standard errors of the estimates:United

States--------------------------------------------------------------------------

Mean age at menarche reported by women in Cycle I of the Health ExaminationSurvey, by weight, race, and age, with standard errors of the estimates:United

States------------------------------------------------------------------------

Mean age at menarche reported by women in Cycle I of the Health ExaminationSurvey, by sum of skinfolds,race, and age, with standard errors of the estimates:

United States-------------------------------------------------------------------

.10

11

12

13

14

15

16

17

18

20

21

22

9
Table 1. Sample frequencies and population estimates of females in Cycles I, II, and

T--oo;othe Health Examination Survey, by race and age: Health Examination Surveys,

Cycles II and 111

6-17 years-----------

6-9 years------------------

10 years-------------------

U years-------------------

12 years-------------------’

13 years-------------------

14 years-------------------

15 years-------------------

16-17

18-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

years ----------------

Cycle I

18-79 years----------

years----------------

years----------------

years----------------

years----------------

years----------------

years ----------------

years----------------

years----------------

years----------------

years----------------

years----------------

years----------------

years----------------

All

races zWhite Black

Sample fr

6,710

2,339

584

564

540

604

581

500

998

3,581

1

149

385

383

363

419

365

396

309

245

198

173

126

70

5,635

1,965

505

477

448

509

480

423

828

3,050

117

322

318

304

348

322

342

259

221

171

157

110

59

uencies

1,043

362

77

84

88

94

100

72

166

469

28

51

53

52

65

36

51

47

23

24

15

15

9

Other

races

32

12

2

3

4

1

1

5

4

62

4

12

12

7

6

7

3

3

1

3

1

1

2

ZJEE3ii

Estimates of population

in thousands

!2,905

7,931

1,904

1,868

1,940

2,031

1,885

1,834

3,511

58,343

2,370

6,059

5,755

5,536

6,583

5,741

5,849

4,692

4,494

3,626

3,557

2,635

1,443

19,634

6,775

1,632

1,605

1,654

1,743

1,619

1,581

3,023

51,184

1,977

5,253

4,860

4,796

5,584

5,138

5,179

4,107

4,072

3,260

3,300

2,384

1,271

3,156

1,110

265

252

271

284

263

231

475

6,219

337

629

719

652

908

482

622

540

407

325

236

231

131

113

45

6

10

13

3

2

21

11

940

56

177

176

89

91

121

48

45

15

41

20

20

41

10
Table 2. PerCeIItage of girls in Cycles 11 and 111 of the Health Examination Survey

whose menstrual periods had started, by age and race, with standard errors of the

estimates: United States

I

. ,..,. . . . . . . , . .

Race

All racesl ------

White -----------------

Black-----------------

All racesl ------

White -----------------

Black-----------------

6-17

years

I

Age

6-9 10 11 12 13 14 15 16-17

years years years years years years years years

Percentage of girls

42.9 0.2

45.2 0.2

J- 0.75 0.09

2.15 0.22

1.2 12.8 43.3 73.2 91.7 98.3 99.7

0.8 11.6 41.7 72.9 91.4 98.2 99.6

4.0 21.3 51.2 74.1 93.5 98.7 100.0

Standard error

0.44 1.86 2.36 2.27 1.76 0.49 0.18

0.44 1.73 2.60 2.28 1.99 0.55 0.21

2.30 5.89 7.41 6.65 2.00 0.86

~Includes data for “other races” , which are not shown separately.

.

11
Table 3. Constants of logistic curves fitted to the percentage of girls 11 through 14

years of age whose menstruation had started, by race and selected characteristics:

United States

Characteristic

Total----------------------------

Geographic region

Northeast------------------------------

Midwest--------------------------------

South----------------------------------

West-----------------------------------

Population size of place of residence

Giant SMSA-----------------------------

Other large SMSA-----------------------

Other SMSA------------------------------

other areas----------------------------

Annual family income

Median age at

menarche

All

races1

12.76

12.71

12.88

12.68

12.72

12.57

12.96

12.70

12.80

12.61

12.81

12.81

12.87

12.68

12.79

White

12.80

12.79

12.90

12.69

12.75

12.65

13.01

12.69

12.83

12.65

12.91

12.86

12.88

12.69

12.81

Black

Less than $3,000-----------------------

$3,000-$4,999--------------------------

$5,000-$6,999--------------------------

$7,000-$9,999--------------------------

$10,000-$14,999------------------------

$15,000 or more------------------------

lIncludes data for “other races,” which are not shown separately.

NOTE: Constantsof the logistic, i.e.,median age and :lopqwere computed on weighted

data for girls aged 11 through 14 years. See appendix II.

12.52

12.21

12.66

12.67

12.43

12.23

12.76

*

*

12.49

12.43

12.39

12.72

*

*

Slope

All

races

White

1.41 1.44

1.21 1.25

1.54 1.57

1.50 1.56

1.38 1.40

1.40 1.63

1.44 1.39

1.52 1.49

1.37 1.38

1.38 1.52

1.27 1.35

1.42 1.44

1.35 1.30

1.66 1.64

1.46 1.41

Black

1.25

1.08

1.36

1.34

1.13

0.90

1.64

*

*

1.15

1.04

1.29

2.82

*

*

12
Table 4. Mean age at menarche reported by women in Cycle I of the Health Examination

Survey, by race and age, with standard errors of the estimates: United States

Age at time of survey

18-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

18-79 years----------------------

years----------------------------

years----------------------------

years----------------------------

years----------------------------

years----------------------------

years----------------------------

years----------------------------

years------.---------------------

years----------------------------

years----------------------------

years----------------------------

years----------------------------

years----------------------------

Mean age at menarche

13.08

12.75

12.77

12.73

12.80

12.96

13.20

13.02

13.09

13.47

13.32

13.54

13.88

13.61

13.09

12.60

12.75

12.69

12.78

12.95

13.19

‘13.06

13.09

13.47

13.36

13.53

13.98

13.61

12.94

13.39

12.78

12.80

12.71

12.93

13.14

12.60

13.12

13.35

12.90

13.36

12.69

13.13

All

racesl White Black

Standard error

0.02

0.12

0.06

0.07

0.08

0.06

0.07

0.08

0.06

0.10

0.16

0.14

0.32

0.36

0.02

0.15

0.07

0.08

0.08

0.08

0.08

0.10

0.08

0.12

0.19

0.17

0.32

“0.37

0.08

0.35

0.20

0.21

0.38

0.17

0.20

0.26

0.16

0.32

0.26

0.58

0.72

0.52

lIncludes data for !Iotherraces,t!which are not shown separately.

13
distribution of women in Cycle I

at menarche, race, and age, with

of the Health Examination Survey,

standard errors of the estimates:

Table 5. Percent

by reported age

United States

II

Age at menarche

=FJJ=

All

ages

Race and age Less

than 11

11 years

years

17

years

or

more

16

years

Percent distribution

All racesl

18-79 years--- 10.8 I 23.6

I

27.8 [ 18.7 I 8.4] 5.4 I 2.4

30.1 15.0 6.7 3.2 0.8

27.9 19.6 4.6 1.9

24.8 22.1 ;:; 9.4 5.3

13.1 27.3

11.2 23.6

7.3 18.9

18-34 years----------

35-54 years----------

55-79 years----------

100.O

100.0

100.0

3.8

2.2

2.5

White 18-79

years----------- 100.OII 2.7 10.9I 23.3 28.3 18.8 8.4 5.3 I 2.2

31.1 14.2

28.6 19.8 ::;

24.4 23.0 10.1

0.7

::; 1.8

9.4 5.2

13.8

11.2

6.9

27.1

23.4

18.6

18-34 years----------

35-54 years----------

55-79 years----------

100.0

100.0

100.0

3.8

1.9

2.5

Black 18-79

years-----------

t

100.0 4.3

100.0

100.0 :::

100.0 2.8 7

11.8 25.8

10.8 28.8

12.1 24.5

12.8 22.5

26.41 15.9 I 8.6 5.3 I 2.0

18-34

35-54

55-79

18-34

35-54

55-79

25.0 17.2 7.8 $: ;.;

25.3 16.3 10.3

31.1 12.6 6.5 7:3 4:4

years----------

years----------

years----------

Standard error

All racesl

18-79 years--- 0.52 0.84 0.74 0.65

0.78 1.26 1.30 0.95

1.01 1.40 0.95 1.08

1.04 1.60 1.78 1.30

0,42 0.49 0.43 0.26

0.55

0.38

0.77

0.47

0.82

0.68

1.35

0.29

0.35

0.97

years-------=--

years----------

years----------

0.58

0.77

0.74

White 18-79

years-----------

18-34 years----------

35-54 years----------

55-79 years----------

Black 18-79

years-----------

18-34 years----------

35-54 years----------

55-79 years----------

0.56 0.77 0.65 0.83 0.59 0.46 0.27

0.75 1.33 1.30 1.24

1.01 1.57 1.05 1.37

1.01 1.58 1.91 1.52

0.67

0.38

0.81

0.99

0.86

0.85

1.52

0.62

0.83

0.74

0.33

0.38

1.03

1.371 2.99 ] 2.631 1.29 1.34 1.50

1.75

2.12

3.82

0.63

1.74

1.48

1.68

2.49 3.29

2.27 4.51

3.17 4.51

3.43 2.45

3.10 2.00

5.10 2.92

1.86

2.53

2.76

0.38

0.84

2.69

1

Includes data for “other races,” which are not shown separately.

14
Table 6.

Survey

United

Mean age at menarche

by geographic region,

States

Race and age

18-34

35-54

55-79

All racesl 18-79

years-----------

years------------

years------------

years------------

White 18-79 years--

18-34 years------------

35-54 years------------

55-79 years------------

Black 18-79 years--

18-34 years------------

35-54 years------------

55-79 years------------

reported by women in Cycle I of the Health Examination

race, and age, with standard errors of the estimates:

Region Region

United United

States North- States

South West Northeast east South West

Mean age at menarche Standard error

13.08 13.06 13.09 13.11 0.02 0.04 0.04

12.76 12.74 12.78 12.78 0.03 0.06 0.03

13.06 12.99 13.11 13.10 0.04 0.09 0.07

13.53 13.56 13.54 13.49 0.06 0.13 0.12

13.09 13.07 13.12 13.08 0.02 0.05 0.06

12.72 12.72 12.74 12.72 0.03 0.04 0.05

13.06 13.03 13.12 13.07 0.05 0.10 0.11

13.55 13.55 13.70 13.46 0.06 0.13 0.12

12.94 12.85 12.99 12.90 0.08 0.21 0.11

12.85 12.89 12.94 12.58 0.17 0.62 0.15

12.92 12.50 13.11 13.12 0.12 0.26 0.17

13.10 13.75 12.85 13.20 0.17 0.39 0.25

0.07

0.08

0.09

0.17

0.05

0.09

0.07

0.17

0.22

0.24

0.43

0.46

lIncludesdata for “other races,” which are not shown separately.

15
Table 7. Mean age at menarche reported by women in Cycle I of the Health Examination

survey, by population size of place of residence, race, and age,with standard errors

of the estimates: United States

Population size

~

All

population

sizes

Race and age

Mean age at menarche

All racesl 18-79 years------------ 13.08

12.76

13.06

13.53

13.09

13.15

12.76

13.09

13.67

13.19

12.99

12.67

13.01

13.39

12.99

13.03

12.59

13.03

13.63

13.07

13.03 13.19

12.88

13.04

13.30

13.01

12.94

13.14

13.54

13.13

18-34 years------------------------------

35-54 years-----------------------------

55-79 years-----------------------------

White 18-79 years-------------------

18-34 years-----------------------------

35-54 years-----------------------------

55-79 years-----------------------------

12.72

13.06

13.55

12.94

12.83

13.10

13.67

12.79

12.35

12.88

13.66

12.63

13.05

13.37

13.00

13.01

12.73

13.53

12.58

13.09

13.68

12.60

12.64

12.32

12.88

12.82

12.99

13.38

13.16

13.23

13.32

12.72

0.07

0.09

0.07

0.15

0.09

12.80

13.08

13.53

13.06

13.04

13.12

13.01

0.10

Black 18-79 years-------------------

18-34

35-54

55-79

12.85

12.92

13.10

0.02

0.03

0.04

0.06

0.02

0.03

0.05

0.06

0.08

0.17

0.12

0.17

years-----------------------------

years-----------------------------

years------------------------------

Standard error

All racesl 18-79 years------------

18-34

35-54

55-79

0.10

0.08

0.27

0.09

0.09

0.20

0.13

0.16

0.17

0.10

0.13

0.11

0.06

years-----------------------------

years-----------------------------

years-----------------------------

White 18-79 years------------------- O.1OI 0.061 0.08

0.12 0.04 0.13

0.12 0.08 0.15

0.29 0.16 0.15

0.12

0.13

0.22

0.08

0.08

0.12

0.08

0.15

18-34 years-----------------------------

35-54 years-----------------------------

55-79 years----------,-------------------

Black 18-79 years------------------- 0,13 0.46 0.43

18-34 years-----------------------------

35-54 years-----------------------------

55-79 years-----------------------------

0.19

0.23

0.44

0.97

0.28

0.90

0.69

0.95

0.93

0.18

0.25

0.34

0.14

0.19

0.17

lI~cludes data for Ilotherraces,!!which are not shown separately.

16
Table 8. Mean age at menarche reported by women in Cycle I Of the Health ExaminationSurvev. bv

educational‘level

Race and age

18-34

35-54

55-79

All racesl

18-79 years----

years-----------

years-----------

years-----------

White 18-79

years------------

18-34 years-----------

35-54 years-----------

55-79 years-----------

Black 18-79

years------------

18-34 years-----------

35-54 years-----------

55-79 years-----------

race, and-age,with standard errors of the estimates:United States-- -

Educationallevel

All

zducational Less 13

levels than 5-8 9-12 years

5 years years or

years more

Mean age at menarche

13.08

12.76

13.06

13.53

I

13.09

12.72

13.06

13.55

12.94

12.85

12.92

13.10

13.65

13.27

13.05

14.09

13.92

13.06

12.94

14.55

12.64

13.05

12.93

12.31

T

13.33 12.96 12.87

12.97 12.78 12.51

13.17 13.03 12.95

13.63 13.23 13.43

IT13.38 12.95 12.88

12.93 12.75 12.51

13.27 13.01 12.99

13.63 13.24 13.38

m

13.00 13.00 12.75

12.85 12.91 12.40

12.70 13.20 12.54

13.62 12.73 *

II Educationallevel

Standard error

===41 0.02 0.25 I 0.07 I 0.031 0.06

I I 1

0.03

0.04

0.06

0.02

0.03

0.05

0.06

0.08 I

0.17

0.12

0.17

I’Includesdata for “other races,” which are not shown separately.

‘0.33 0.11 0.04 0.09

0.10 0.09 0.06 0.11

0.36 0.09 0.11 0.14

0.32 0.08 0.04 0.06

0.20 0.15 0.04 0.09

0.31 0.11 0.06 0.12

0.37 0.10 0.12 0.13

0.21 0.07 0.13 0.31

, 1 I

0.87 0.17 0.16 0.42

0.32 0.14 0.23 0.43

0.34 0.22 0.99 *

NOTE: Educationwas not recorded for 57 women whose weighted mean menarcheal age was 13.52

years, with a standarderror of 0.40.

17.
Table 9. Mean age at menarche reported by women in Cycle I of the Health Examination

Survey, by annual family income,race,and age, with standard errors of the estimates:

United States

Race and sex

18-34

35-54

55-79

All racesl 18-79

years--------------

years---------------

years---------------

years---------------

White 18-79 years-----

18-34 years---------------

35-54 years---------------

55-79 years---------------

Black 18-79 years-----

18-34 years---------------

35-54 years---------------

55-79 years---------------

All

incomes

13.08

12.76

13.06

13.53

13.09

12.72

13.06

13.55

12.94

12;85

12.92

13.10

Annual family income

i I I I I

Less

than

$2,000

I 13.37

13.03

13.11

13.72

13.46

12.79

13.21

13.86

12.96

13.20

12.80

12.91

$2,000- $4,000- $7,000-

$3,999 $6,999 $9,999

Mean age at menarche

13.05 I 12.96! 13.07

I I

12.69 12.64 12.74

13.17 13.11 12.98

13.34 13.42 14.00

12.67 12.63 12.76

12.16 12.14 12.99

13.33 13.45 14.00

13.00 12.68 12.84

I I

12.65 12.60 12.41

13.22 12.69 12.85

13.50 12.89

$10,000

or more

12.95

12.77

13.00

13.05

12.96

12.78

13.00

13.05

12.61

12.61

unknown

13.20

13.06

12.92

13.59

13.16

13.05

12.83

13.54

13.22

13.10

13.12

13,49

lIncludes data for “other races,IIwhich are not shown Separately.

18
Table 9. Mean age at menarche reported by women in Cycle I of the Health Examination

Survey, by annual family income,racq and age

United States-Con.

, with standard errors of the estimates:

Race and age

18-34

35-54

55-79

All racesl 18-79

years --------------

years ---------------

years ---------------

years ---------------

White 18-79 years -----

18-34 years ---------------

35-54 years ---------------

55-79 years ---------------

Black 18-79 years -----

18-34 years ---------------

35-54 years ---------------

5!5-79years ---------------

Annual family income

All

incomes ga; $2,000- p:;- $7,000- $10,000 “Un-

$2,000 $3,999 $9,999 or more known

Standard error

0.02 0.12 0.05 0.04 0.10 0.07 0.10

0.03 0.14 0.07 0.06 0.09 0.09 0.13

0.04 0.13 0.08 0.05 0.15 0.06 0.11

0.06 0.20 0.14 0.13 0.21 0.23 0.16

0.02 0.13 ,, 0.07 0.04 0.10 0.07 0.10

0.03 0.15 0.09 0.06 0.08 0.11 0.16

0.05 0.20 0.11 0.08 0.15 0.06 0.13

0.06 0.20 0.13 0.13 0.22 0.23 0.15

0.08 0.17 0.09 0.13 0.32 0.54 0.28

0.17 0.18 0.30 0.24 0.45 0.54 0.27

0.12 0.22 0.24 0.33 0.30 0.49

0.17 0.28 0.65 0.80 0.73

19
Table 10. Mean age at menarche reported by women in Cycle I of the Health Examination

Survey,by height,race, and age, with standard errors of the estimates: United States

Race and age

18-34

35-54

55-79

All races1 18-79 years ------------

years-----------------------------

years-----------------------------

years-----------------------------

White 18-79 years------------------

18-34 years-----------------------------

35-54 years-----------------------------

55-79 years-----------------------------

Black 18-79 years-------------------

18-34

35-54

55-79

18-34

35-54

55-79

years-----------------------------

years-----------------------------

years------------------------------

All racesl 18-79 years------------

years -----------------------------

years-----------------------------

years----------------------------

White 18-79 years-------------------

18-34 years-----------------------------

35-54 years-----------------------------

55-79 years----------.------------------

Black 18-79 years--------------------

18-34 years-----------------------------

35-54 years............................-

55-79 years -------- . . -------------- .-.--

Height in centimeters at time

of survey

All

heights

Less

than 155- 159- 163- 167

155 158 162 166 or

more

Mean age at menarche

=x=

12.76 12.70

13.06 12.90

13.53 15.52

13.09 II13.13

12.72 12.58

13.06 12.88

13.55 13.56

12.94

12.85

12.92

13.10

12.91

12.91

13.03

12.73

13.11

12.67

13.04

13.56

13.11

12.59

13.05

13.61

12.86

12.89

12.76

13.01

Standard

+W

0.03 0.10 0.11

0.04 0.08 0.06

0.06 0.17 0.09

0.02 0.10 0.07

0.03 0.13 0.13

0.05 0.10 0.08

0.06 0.18 0.10

0.08 0.14 0.20

0.17 0.39 0.23

0.12 0.20 0.30

0.17 0.29 0.40

13.06

12.88

12.98

13.41

13.06

12.84

12.98

13.44

12.86

13.20

12.65

12.72

rror

13.04

12.65

13.13

13.83

13.06

12.64

13.16

13.82

12.89

12.63

12.86

13.92

13.11

12.87

13.29

13.41

13.10

12.88

13.28

13.33

13.23

12.82

13.40

14.62

0.08 0.08 0.07

0.10 0.09 0.09

0.09 0.14 0.29

0.04 0.05 0.06

I

0.08 0.09

0.11 0.08

0.08 0.19

0.08

0.11

0.36

0.22 0.25 0.19

I

0.37 0.25 0.42

0.22 0.38 0.27

0.48 0.59 1.39

1

Includes data for “other races,” which are not shown separately.

20
Table 11. Mean age at menarche reported by women in Cycle I of the Health Examination

Survey, by weight, race, and age, with standard errors of the estimates: United

States

Weight in pounds at time of survey

All

weights Less 115- 130- 145- 200

than 165- or

115 129 144 164 199

more

Race and age

Mean age at menarche

All racesl 18-79 years-----

1~

13.08 13.14 13.07 13.05 13.23 12.98 12.94

12.76 13.01 12.78 12.66 12.80 12.37 12.32

13.06 13.22 13.06 13.08 13.10 12.89 13.04

13.53 13.40 13.78 13.45 13.73 13.37 13.17

18-34 years----------------------

35-54 years ----------------------

55-79 years----------------------

White 18-79 years------------ -2=-II 13.08 13.07 13.06 13.22 13.06 12.88

12.95 12.75

13.19 13.07

13.32 13.81

18-34 years----------------------

35-54 years----------------------

55-79 years----------------------

12.64

13.08

13.47

12.72

13.06

13.55

12.76

13.06

13.73

12.36

12.97

13.43

11.94

13.02

13.21

Black 18-79 years------------

--i

12.94 12.28 12.93 12.85 13.17 12.57 13.05

18-34

35-54

55-79

18-34

35-54

55-79

12.85 II II 13.27 12.92 12.62 12.78 12.36 13.41

12.92 13.37 12.99 13.10 13.21 12.49 12.90

13.10 13.19 12.76 12.89 13.78 12.90 13.03

years ----------------------

years----------------------

years----------------------

Standard error

All racesl 18-79 years----- 0.02

0.03

0.04

0.06

0.02

0.04

0.06

0.11

0.24

0.05

0.05

0.06

0.11

0.21

0.05

0.06

0.11

0.08

0.14

0.06

0.08 0.10

0.15

0.10

0.15

0.11

0.10

0.28

0.16

0.19

0.09

0.10

0.10

0.17

0.08

years----------------------

years----------------------

years----------------------

White 18-79 years------------

18-34 years----------------------

35-54 years----------------------

55-79 years----------------------

0.03

0.05

0.06

0.08

0,07

0.12

0.26

0.27

0.06

0.12

0.23

0.18

0.11

0.09

0.15

0.19

0.12

0.11

0.16

0.21

0.20

0.12

0.16

0.19

0.10

0.14

0.24

Black 18-79 years------------ 0.29

18-34 years----------------------

35-54 years----------------------

55-79 years----------------------

0.17

0.12

0.17

0.35

0.51

0.70

0.27

0.33

0.17

0.33

0.30

0.28

0.22

0.36

0.70

0.28

0.26

0.41

1.02

0.40

0.68

lIncludesdata for “other races,” which are not shown separately.

21
Table 12. Mean age

Survey, by sum of

United States

at menarche reported by women in

skinfolds, race, and age, with

Race and age

—..

All racesl 18-79 years -----------

18-34 years .------ ---------------- -----

35-54 years ----------------------------

55-79 years -------- ---------------- ----

White 18-79 years ------------------

18-34 years ------------------------ ----

35-54 years ---------------- ------------

55-79 years ----------------------------

Black 18-79 years ------------------

18-34

35-54

55-79

18-34

35-54

55-79

years ----------------------------

years -------- ---------------- ----

years ---------------- ------------

All racesl 18-79 years -----------

years ------------------------ ----

years ---------------- -------- ----

years ----------------------------

White 18-79 years ------------------

18-34 years -------- -------- -------- ----

35-54 years -------- -------- -------- ----

55-79 years ------------------------ ----

Black 18-79 years ------------------

18-34 years -------- -------- ------------

35-54 years ----------------------------

55-79 years ----------------------------

Cycle I of the Health Examination

standard errors of the estimates:

Sum of skinfolds in centimeters

at time of survey

otal IILess I9K-1=’.5- $.:- :;0 than ;“;- ,

2.5 “

;:4 4.Y

more

Mean age at menarche

13.08

12.76

13.06

13.53

13.09

12.72

13.06

13.55

12.94

12.85

12.92

13.10

0.02

0.03

0.04

0.06

0.02

0.03

0,05

0.06

0.08

0.17

0.12

().17

13.03 12.70 12.69

13.17 13.14 13.07

13.60 13.78 13.53

T

13.11 13.04

13.00 12.66

13.15 13.13

13.49 13.76

13.10

12.64

13.03

13.58

13.17 13.20 13.06

1 I

13.11 13.04 12.43

13.21 13.25 13.47

13.34 13,79 13.08

Standard error

0.08 0.06

0.09 0.07

0.21 0.15

T

0.05 0.04

0.08 0.06

0.12 0.07

0.18 0.15

0.20 0.22

0.23 0.44

0.49 0.30

0.40 0.58

0.06

0.10

0.11

0.18

0,07

0.12

0.12

0.21

0.18

0.18

0.27

0.41

13.13

12.82

12.90

13.62

13.18

12.81

12.90

13.71

12.51

12.75

12.53

12.11

0.08

0.14

0.15

0.21

0.09

0.34

0,16

0.22

0.32

0.34

0.46

0.79

13.03

12*40

13.00

13.37

13.09

12.38

13.07

13.40

12.66

12.48

12.55

13.05

0.06

0.12

0.06

0.11

0.06

0.14

0.06

0.12

0.15

0,44

0.20

0.34

1

Includes data for “other races, “ which are not shown separately.

22
cycle I

WOMEN ONLY

a.

b.

&

h.

j.

k,

1,

Source:

APPENDIX I

QUESTIONNAIRE ITEMS ON MENARCHE

Age when periods started

Have periods stopped? (Not counting pregnancy)

w

c. Age when periods steppe+

d, Was this due to an operation?

IF NO:

e. Have they begun to stop?

f. Date of last period

How many babies have you ever

EIEI

Elm

IEIIISI

had who were born alive?

Have you ever had any pregnancies

that did not result in a live birth? BE

IF YES, how many?

Are you pregnant now? Elliml

IF YES, how many months?—

Self-Administered Medical Historv.- Questionnaire (HES-204)

cycle II

FOR GIRLS ONLY

Have her monthly periods started?

ClYES❑ NO❑ DOIIttkIIOW

—J IF YES how old was she when they

started?— Year ~Months

Source: Child’s Medical History Form (HES-256) completed by parent

Cycle Ill

FOR GIRLS ONLY*

Have her monthly

ation) started?

periods (menstru -

❑b n ,,Low) NO (IF NO, OMIT QUESTIONS

IF YES

a. Had she been told about them befo~e

hers began?

❑ ‘Es ❑ INO ❑ ‘onft ‘now

b. How old was she when they

started?— Years —Months

c. Does she have pain or discomfort?

OMIT REST OF QUESTIONS)

If there is pain or discomfort,

is it:

❑Very often •1 Occasionally

u:

child❑ No-ten‘evere

At that time, does she frequently: (Check

all tkatapply)

e.

•1Take medicine •1 Stay home from

school

a For the teenage girls of Cycle 111, information on menstrual status was also obtained from the girls themselves on a questionnaire

administered by a nurse in the mobile examination center. Overall

agreement between the two sources of information on menstrual statue wae high-96 percent. For this reason, and to maintain consistency with information on menarche for the girls 6-11 yeara old of

Cycle II, which was provided only hy a parent, it was decided to use

in this report only the information on menstrual etatus of teenage girle

provided by the parent,

23
D Go to the sick room ❑None of these

or nurse

❑ Stay in bed

Source: Medical History of Youth completed ‘by parent

f. Has she talked to a doctor about painful

menstruation?

❑ YES •1 NO ❑ Don’t know

ooo—

24
APPENDIX II

TECHNICAL NOTES

Survey Design

The sample designs for the first three programs,

or Cycles I-III, of the Health Examination Survey have

been essentially similar in that each has been a

multistage, stratified probability sample of clusters of

households in land-based segments. The successive

elements of selection for these designs were primary

sampling unit, census enumeration district, segment

(a cluster of households), household, eligible person,

and finally the sample person. In each cycle the target

population was defined as the civilian noninstitutional

population of the United States in the age range of

concern.

In the first stage of this design the nearly 2,000

primary sampling units, geographic units into which

the United States was divided, were grouped into 357

strata for the use of the Health Interview Survey and

of the Current Population Survey of the U.S. Bureau

of the Census and were then further grouped into 42

strata (40 for Cycles II and HI). In Cycle I the stratification variables were geographic location and population density. The strata were formed so that each had

approximately 3.5 million persons aged 18-79 years in

1%0. In Cycles 11 and 111the strata boundaries were

formed so as to obtain a high degree of homogeneity

within strata with respect to geographic location,

population density, population size, and rate of population change.

Using a controlled selection technique, one primary

sampling unit was selected from each stratum with a

probability proportional to population. Generally, within

each primary sampling unit, 20 census enumeration

districts were selected with the probability of selection

of a particular enumeration district proportional to its

popu~ation in the age group being sampled. A similar

method was used for selecting one segment in each

enumeration district. Sample persons in the appropriate

age range were systematically- selected from the

designated sample households in each segment.

The 40 sample areas and the segments utilized in

the design of Cycle 111 were the same as those in

Cycle H. This feature of the design along with the age

groups sampled in the two cycles made it possible

to gather longitudinal data on about 30 percent of the

Cycle III sample, More complete accounts of the

sample designs may be found in references’1 through 5.

Standard Errors

The probability design of the survey makes possible

the estimation of standard errors corresponding to

the weighted estimates presented. However, in complex

studies such as the Health Examination Survey this task

is complicated by at least three factors: (1) Measurement

process error and “pure” sampling error are confounded

in the data—it is not easy to find a procedure which will

either completely include both or treat one or the other

separately. (2) The survey design and estimation

procedure are complex and accordingly require computationally involved techniques for the estimation of

standard errors. (3) Thousands of statistics come from

the survey, many for subclasses of the population for

which there are small numbers of sample cases.

Estimated standard errors of the estimates presented

are derived by a technique which yields overall variability through observation of variation among subsamples of the total sample.11,1~ The method reflects

“pure” sampling variance and a part of measurement

variance. The estimates of standard errors presented

are themselves subject to sampling error, which maybe

large when the number of cases in a cell is small or

occasionally even when the number of cases is substantial.

When the estimated standard error of a statistic is

large in relation to the size of the estimate, the

usefulness of the statistic is frequently compromised

to some extent. This situation usually indicates that the

sample size in the cell is small and/or the occurrence

of measurements from the general population falling

into this category is infrequent.

In accordance with usual practice, a 68-percent

confidence interval may be considered that range within

one standard error of the estimate and a 95-percent

confidence interval that range within two standard

errors. An approximate standard error of a difference,

d = x - y, of two statistics, x and y is given by the

formula:

{

,*d = =X2 + SV2

}

1/2

where sX and Sy are the standard errors of x and y

respectively.

25
Logistic Curves

Age at menarche in the girls of HES Cycles II

and 111 has been described in terms of constants of

logistic curves fitted to the percentage of the population

whose menstrual periods had begun at each year of age

between 10 and 15, or, as noted below, be(ween 11 and

14. The curves were fitted by maximum likelihood. The

curves were of the form:

~b(x, -u)

Pi=— I+eb(xi -a)

where P, is the percentage whose menstrual periods had

begun by age Xi, the constant b is a measure of the

slope of the curve, and the constant a is the age at which

P is 0,5. The latter may be considered the median age

at occurrence of menarche, and since the distribution

is essentially normal, is also an estimate of the mean.

The constants a and b are descriptive and should not be

interpreted fin terms of theory underlying the logistic.

The method of computation has been described in

detail in an earlier report on age at menopause in the

United States population. 7

The constants used in figure 1 and table 3 are

derived from curves computed using percentages of

postmenarcheal girls at each age estimated for the

population as a whole. That is to say, the sample has

been weighted to derive population estimates as described under “Methods of Analysis” in the body of this

report. However, for such estimates obtained from the

present sample design, it was not considered feasible to

evaluate the goodness of fit of the data to the logistic

model other than by the visual inspection possible

from, for example, figure 1. For a more formal

evaluation it has been assumed that the sample of girls

aged 10 through 15 years is a random sample of the

target population, and the percentages have been computed directly from the sample values without weighting.

The data are given in table I. The constants of the

logistic fitted to the unweighed percentages (u= 12.79,b =

1.48) are very similar to those fitted to the weighted

data (a= 12.77,b = 1.53). The X2test for goodness of

fit for the curve based on unweighed percentages

gives X2= 13.!5,4 degrees of freedom and p <0.01. However, more than half the total X2 is contributed by the

youngest age grou~ the fit in the central and older

ages appears good.

Virtually identical constants (u= 12.76,b = 1.40) are

obtained if curves are fitted to the data for the 4 years

11 through 14. In this case, X2 for goodness of fit is

3.36, degrees of freedom 2, and p > o.I. It would

appear, therefore, that the logistic gives a good fit

over the range of ages when menarche most frequently

occurs,. but extrapolation to ages under 11 (when the

Table 1. Percentage of girls aged 10-15 years

in the unweighed sample whose raenarche had

occurred

1 I I

Age

10 years -----

11 years -----

12 years -----

13 years -----

14 years -----

15 years -----

Number

in

sample

569

507

579

575

581

500

Percentage

with menarche

T

Ob- Comserved putedl

d::

43.7

73.4

91.4

98.0

Contri -

bution

to X2

7.31

0.00

4.42

0.18

1.42

0.17

1Computed from the f itted logistic curve with

constants a = 12.79, b = 1.48.

observed number of post menarcheal girls is very

small) leads to significant deviation from the model.

Specifically, among 569 girls aged 10 years, seven

reported that menses had begun, whereas, from the

logistic fitted to the entire age range 10-15 years,

18 would have been expected. While such discrepancies

close to the zero or 100 percent points make large

contributions to the X2for goodness of fit, they are of

little consequence in estimating the median age at

menarche in the population as a whole. Nevertheless,

it seems most appropriate to compute the parameters

of the logistic from the age range over which the model

gives a good fit. The constants given for subdivisions

of the population in table 3 are therefore estimated from

the data for girls in the age range 11 through 14 years.

While estimates of standard errora can be made by

the pseudoreplication technique outlined above for the

percentages of the population postmenarcheal at each

age, it was not felt practical in this instance to obtain

estimatea of the standard errors of the constants of

the fitted logistic functions by the pseudoreplication

method. As already noted, however, for the total population these constanta are similar whether computed from

the population estimates or from the unweighed sample.

Table II ‘therefore provides estimates of the median

ages at menarche and their stand’ard errors for the same

demographic subdivisions aa given in table 3 but computed on the assumption that the sample aged 11 through

14 years was a simple random sample of the target

population. The median values are almost identical to

those of table 3, and the standard errors can be used

to provide approximate confidence limits of the estimates.

26
Table II. Median and standard error of age at menarche, derived from the logistic fitted to the

unweighed percentage of the females in the samplewhose menstruationhad begun, accordingto

race, region and populationsize of residence, and income: United States

Demographicvariable

Total-------------..-------------------

Region

Northeast-----------------------------------

Midwest---.---------------------------------

South---------------------------------------

Weat----------------------------------------

Populationsize of place of residence

Giant SMSA----------------------------------

Other large SMSA----------------------------

Other SMSA--------------------------=--------

Other areas---------------------------------

Annual family income

Less than $3,000----------------------------

/!

3,000- 4,999-------------------------------

5,000- 6,999-------------------------------

7,000- 9,999---------------------------- ----

10,000-$14,999-----------------------------

15,000 or more---------------------------- -

Median

+

12.76 12.80

12.72

12.88

12.70

12.72

12.58

12.90

12.74

i2.82

12.61

12.79

12.80

12.85

12.67

12.83

12.81

12.91

12.70

12.75

12.67

12.95

12.73

12.85

12.66

12.93

12.86

12.86

12.68

12.85

Black

12.52

12.19

12.57

12.69

12.36

12.23

12.76

*

*

12.49

12.35

12.42

12.73

*

*

llncludesdata for “other racea,” which are not shown separately.

Standard error

All

:acesl

.038

.087

.069

.073

.077

.079

.074

.073

.078

.106

.103

.089

.083

.081

.136

White

.041

.093

.072

.084

.079

.081

.086

.078

.079

.124

.114

.096

.088

.083

.143

Black

.111

.276

.240

.152

.362

.235

.148

*

*

.203

.265

.246

.188

*

*

NOTE : Based on data for the sample aged 11 through 14 years only.

-000

27
APPENDIX

DEMOGRAPHIC

Age.—The age recorded for each person was the age

at last birthday. Age was recorded in, single years.

Race .—Race was recorded by observation in the

survey as “white,” “Negro, “ or “other races. ” The

last category included American Indians, Chinese, Japanese, and all races other than white or Negro. In this

report, the term “black” replaces the term “Negro.”

Geographic refl”on.-For the purpose of classifying

the population by geographic area in Cycle I, the United

States was dividdd into three major regione. This division was made specifically for the design of the HES

sample. The regions and the States included were as

follows:

Region

Northeast -------

South -----------

West -----------

States Included

Maine, Vermont, New Hampshire,

Massachusetts, Connecticut, Rhode

Island, New York, New Jersey,

Pennsylvania, Ohio, and Michigan

Delawar,e, Maryland, District of

Columbia, West Virginia, Virginia,

North Carolina, South Carolina,

Georgia, Florida, Kentucky,

Tennessee, Alabama, Mississippi,

Arkansas, Louisiana, Oklahoma,

and Texas

Washington, Oregon, California,

Idaho, Nevada, Montana, Utah,

Arizona, Wyoming, Colorado, New

Mexico, North Dakota, South Dakota,

Nebraska, Kansaq, Minnesota, Iowa,

Missouri, “Wisconsin, Illinois, and

Indiana

For Cycles 11 and III, region was defined in terms of

four broad geographic groups of approximately equal

population. These

with those used by

as follows:

Rep”on

Northeast -------

South -----------

regions, which correspond closely

the U.S. Bureau of the Census, were

States Included

Maine, Vermont, New Hampshire,

Massachusetts, Connecticut, Rhode

Island, New York, New Jersey, and

Pennsylvania

Delaware, Maryland, District of

Columbia, West Virginia, Virginia,

Ill

TERMS

Midwest --------

West -----------

Kentucky, Tennessee, North

Carolina, South Carolina, Georgia,

Florida, Alabama, Mississippi,

Louisiana, and Arkansas

Ohio, Illinois, Indiana, Michigan,

Wisconsin, Minnesota, Iowa, and

Missouri

Washington, Oregon, California,

Nevada, New Mexico, Arizona,

Texas, Oklahoma, Kansas,

Nebraska, North Dakota, South

Dakota, Idaho, Utah, Colorado,

Montana, Wyoming, Alaska, and

Hawaii

Poptdhtionsize of place of residence. —In Cycle 1,

the five population size classes were derived from the

design of the sample, which accomplished a stratification of the primary sampling units by population size in

each of three broad geographic locations. Because the

survey was started in 1960, the primary sampling units

within each of the five population-size classes were

necessarily based on populations and definitions of the

1950 census. The name of each selected primary sampling unit within each population-size class and geographic location, along with other selected sample data,

is presented in an earlier report.2

The definition for each of the five population-size

classes is as follows:

Giant SMSi4ts include primary sampling units defined as standard metropolitan statistical areas

(SMSA’S) with a population of 3,000,000 persons or

more as ,determined in the 1950 census.

Othev Urge SMf24ts include primary sampling

units defined as SMSA’S with a population of

500,000 to 3,000,000 as determined in the 1950

census.

OtlZeYSM~’S include primary sampling units defined as SMSA’S with a population of less than

500,000 as determined in the 1950 census.

Otkzr wban areas include primary sampling units

which are highly urban in composition but are not

defiqed as SMSA’s.

28
RUKJl areas include primary sampling units which

are primarily rural in composition according to

census definitions.

In Cycles II and HI, four population density groups

were used to divide the U.S. population into four approximately equal parts. These groups were defined

differently for each of the four geographic regions to

obtain a division of each region into the following four

ckises:

1. The largest metropolitan areas are referred to

in this report as Gzbnt SMSA?S.

2. Standard metropolitan statistical areas of specified size are referred to in this report as Other

large SMSA ‘s.

3. Other SMSA’S or specified highly urban areas

are referred to in this report as Other SMSA ~s.

4, Other urban areas and rural areas are referred

to as Other areas.

Additional information on this classification is presented

in an earlier report.4

Income of family or urweiizted individuals. —Each

member of a family was classified according to the

total income of the family of which she was a member.

Within the household all persons related to each other

by blood, marriage, or adoption were considered to constitute a family. Unrelated individuals were classified

according to their own income.

The income recorded was the total of all income

received by members of the family in the 12-month

period preceding the week of interview. Income from

all sources was included, e.g., wages, salaries, rents

from properties, pensions, and help from relatives.

Education .—Each person was classified by education in terms of the highest grade of school completed. Only grades completed in regular schools,

where persons are given a formal education, are included. A “regular” school is one which advances a

person toward an elementary or high school diploma

or a college, university, or professional school degree.

Thus education in vocational, trade, or business

schools outside the regular school system was not

counted in determining the highest grade of school completed.

000

* U. S.GOVEI?NMENT PSINTI.NGOFFICE :1974S43-8S1/41

29
Series 1.

Series 2.

VITAL AND HEALTH STATISTICS PUBLICATION SERIES

Originally hblic Health Service Publication No. 1000

programs and collection procedures. — Reports which describe the general programs of the National

Center for Health Statistics and its offices and divisions, data collection methods used, definitions,

and other material necessary for understanding the data.

Data evacuation and methods research. — Studies of new statistical methodology including: experi -

mental tests of new survey methods, studies of vital statistics collection methods, new analytical

techniques, objective evaluations of reliability of collected data, contributions to statistical theory.

Series 3. Analytical studies. —Reports presenting analytical or interpretive studies based on vital and health

Series 4.

Series 10.

Series 11.

Series 12.

Series 13.

Sevies 14.

Se7ies 20.

Sew”es 22.

?

statistics, carrying the analysis further than the expository types of reports in the other series.

Documents and committee vepovts. — Final reports of major committees concerned with vital and

health statistics, and documents such as recommended model vital registration laws and revised

birth and death certificates.

Data from the Health Interview Survev. —Statistics on illness, accidental injuries, disability, use

of hospital, medical, dental, and other services, and other health-related topics, based on data

collected in a continuing national household interview survey.

Data from the Heulth Examination Survey. —Data from direct examination, testing, and measurement of national samples of the civilian, noninstitutional population provide the basis for two types

of reports: (1) estimates of the medically defined prevalence of specific diseases in the United

States and the distributions of the population with respect to physical, physiological, and psychological characteristics; and (2) analysis of relationships among the various measurements without

reference to an explicit finite universe of persons.

Data from the Institutional Po~tion Surveys — Statistics relating to the health characteristics of

persons in institutions, and their medical, nursing, and personal care received, based on national

samples of establishments providing these services and samples of the residents or patients.

Data from the Hospitil Discharge Survey. —Statistics relating to discharged patients in short-stay

hospitals, based on a sample of patient records in a national sample of hospitals.

Data on health resources: rnanpowtw and facilities. —Statistics on the numbers, geographic tiistribution, and characteristics of health resources including physicians, dentists, nurses, other health

occupations, hospitals, nursing homes, and outpatient facilities.

Data on mortality. —Various statistics on mortality other than as included in regular annual or

monthly reports-special analyses by cause of death, age, and other demographic variables, also

geographic and time series analyses.

Data on na.tality, marriage, and divo-rce. —Various statistics on natality, marriage, and divorce

other than as included in regular annual or monthly reports +pecial analyses by demographic

variables, also geographic and time series analyses, studies of fertility.

Dati from the National Natalit y and Mortality Surveys. — Statistics on characteristics of births

and deaths not available from the vital records, based on sample surveys stemming from these

records, including such topics as mortality by socioeconomic class, hospital experience in the

last year of life, medical care during pregnancy, health insurance coverage, etc.

For a list of titles of reports published in these series, write to: Office of Information

Nat ional Center for Health Statistics

Public Health Service, HRA

Rockville, Md. 20852

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U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

PUBLIC HEALTH SERVICE

Health Resources Administration

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