Number 42 n September 1, 2011

Health of Adults in Los Angeles County: Findings 

From the National Health and Nutrition Examination 

Survey, 1999–2004 

by Kathryn S. Porter, M.D., M.S.; Lester R. Curtin, Ph.D.; Margaret D. Carroll, M.S.P.H.; and Xianfen Li, M.S.,

National Center for Health Statistics; Leyla Mohadjer, Ph.D., Westat; and Margaret Shih, M.D., Ph.D.; Paul A.

Simon, M.D., M.P.H.; and Jonathan E. Fielding, M.D., M.P.H., Los Angeles County Department of Public Health

Abstract

Objective—Los Angeles County has the largest population of any county in

the nation. Population-based estimates of health conditions for Los Angeles

County are based primarily on telephone surveys, which are known to

underestimate conditions of public health importance. This report presents the

prevalence of selected health conditions for civilian noninstitutionalized adults

aged 20 and over living in Los Angeles County households and group quarters,

based on survey data using direct physical measurements.

Methods—Combined data from the 1999–2000, 2001–2002, and 2003–2004

National Health and Nutrition Examination Surveys (NHANES), conducted by

the Centers for Disease Control and Prevention’s National Center for Health

Statistics, were used for this report. Sample weights were recalculated for

participants examined in Los Angeles County using population totals provided by

the Los Angeles County Department of Public Health, excluding the

institutionalized population.

Results—Compared with the nation as a whole, adults in Los Angeles

County had similar rates of health conditions even after age and age-race

adjustment, with a few exceptions. A significantly smaller proportion of Los

Angeles County adults were obese (age-adjusted rate, 23.8%) compared with the

United States (31.0%); this difference held after age-race adjustment. The

age-adjusted rate of diagnosed diabetes for men was higher in Los Angeles

County (9.1%) than in the nation (7.3%); however, this difference did not hold

after age-race adjustment. The rates of total diabetes adjusted for age and

age-race were similar for men in Los Angeles County and the United States.

Conclusions—The rates of selected health conditions in this report were

similar for adults in Los Angeles County compared with adults in the United

States, with the exception of obesity. The rates of obesity adjusted for age and

age-race were lower among Los Angeles County adults compared with national

rates. Health estimates based on direct physical measurements can be useful for

local public health programs and prevention efforts.

Keywords: cross-sectional studies c epidemiologic methods c chronic disease

Introduction

National survey data based on direct

physical measurements are important to

benchmark the nation’s health and track

progress toward meeting the nation’s

health objectives (1). Comparable health

data are needed at the local level so that

public health agencies can monitor the

health status of their community and

track health improvement efforts (2).

Los Angeles County is the largest

county in the United States in

population size and comprises one of

the most diverse populations in the

world (3). Of the county’s population,

36% is foreign-born, with more than

one-third of these having moved to Los

Angeles after 1985 and one in two

households speaking a language other

than English at home. This tremendous

diversity makes it difficult to extrapolate

national data to the county level. Local

health data create more interest among

community policymakers, organizations,

and the public, and are necessary for

monitoring disease burden to identify

local health problems and disparities,

inform local policies and programs, and

allocate scarce public health resources.

The data sources currently available

at the county level include vital

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

National Center for Health Statistics 
Page 2 National Health Statistics Reports n Number 42 n September 1, 2011

statistics, hospital data, reportable

disease data, and data from state

(California Health Interview Survey)

and county (Los Angeles County Health

Survey) telephone surveys. The state

and county surveys in particular have

been very valuable in providing

information for surveillance and

program evaluation, but they provide

only self-reported data, which are

subject to recall bias and fail to capture

undiagnosed conditions. There currently

are no objective prevalence measures of

chronic diseases, such as diabetes and

hypertension. Chronic diseases account

for 80% of the Los Angeles County

disease burden as measured by

disability-adjusted life years (4). Using

national health examination data to

describe the health of adults in Los

Angeles County provides local health

officials with information that would

otherwise be unavailable.

Methods

Data from three cycles (1999–2000,

2001–2002, and 2003–2004) of the

National Health and Nutrition

Examination Survey (NHANES) were

combined and used for this report.

NHANES is a cross-sectional survey of

the civilian noninstitutionalized

household population of persons living

in the United States. NHANES is unique

in that it combines an in-person

interview with a health examination that

includes collection of biologic

specimens. A nationally representative

sample of individuals is selected

annually through a complex multistage,

stratified, clustered design. Additional

information on NHANES 1999–2004 is

available on the NHANES website

(5–7). NHANES protocol #98–12 was

approved by the National Center for

Health Statistics’ Research Ethics

Review Board, and all participants

provided documented consent. For this

report, the participants selected from

Los Angeles County were aggregated

and reweighted to match the known

population totals for Los Angeles

County.

Los Angeles County

weighting methodology

Selection of the primary sampling

units (PSUs) is the first stage of the

NHANES sample design process. Los

Angeles County is one of the largest

counties and a self-representing PSU

that is in the sample every year. A

self-representing PSU represents itself

and not a larger geographic area. During

1999–2004, six Los Angeles County

PSUs were selected for NHANES and

used for this analysis. The Los Angeles

County sample weights originated with

the base weights created for weighting

the national sample. The weights were

then adjusted for nonresponse to both

the interview and examination, and then

poststratified to the midpoint of

1999–2004 population totals for the

county.

The screener nonresponse-adjusted

base weights for sampled persons in Los

Angeles County were adjusted for

nonresponse to the interview. Of the

2,312 identified sampled persons in Los

Angeles County, 1,724, or 75%,

responded to the interview. The

Chi-squared Automatic Interaction

Detector (CHAID) was used to identify

variables related to response propensity.

The analysis performed at the interview

level showed that age category (under 1,

1–11, 12–19, 20–59, and 60 and over),

sex, and number of people living in the

household (1–2, 3–4, 5–6, and 7 or

more) were highly correlated to

response propensity. A crossclassification of these categories was

used to create initial interview

nonresponse adjustment cells. Cells were

combined in cases where the number of

respondents in a cell was small (less

than 25) or the nonresponse adjustment

factors were larger than 2.

The interview nonresponse-adjusted

weights for the respondents were

poststratified to population totals

provided by the Los Angeles County

Department of Public Health. The

interview weights were adjusted to

poststrata defined by race and ethnicity

(Hispanic, black, and other), age

category (0–5, 6–11, 12–19, 20–39,

40–59, and 60 and over), and sex. A

further adjustment was necessary to

remove the institutional population from

the counts. A single ratio adjustment

factor was applied to all interview

respondents in a given poststratification

cell. The numerator of the ratio was the

midpoint of the 1999–2004 population

total provided by Los Angeles County

with the aforementioned adjustments;

the denominator was the sum of the

weights for the interview respondents in

that cell.

A total of 1,628, or 94%, of the

1,724 interview respondents completed

the health examination. CHAID was

used to create examination nonresponse

adjustment cells using a process similar

to the interview nonresponse adjustment.

The results of a CHAID analysis

showed that age category (under 1, 1–5,

6–11, 12–19, 20–59, and 60 and over),

sex, number of people living in the

household (1–4, 5–6, and 7 or more),

and self-reported health status (excellent,

very good, and other) were highly

correlated to response propensity. These

nonresponse-adjusted examination

weights were then poststratified to the

same county totals as the interview

weights, using the same collapsed

poststrata.

Because health characteristics vary

by age, race and ethnicity, sex and

income status, NHANES is designed to

produce reliable health statistics for a

very large number of subdomains of the

general population. During 1999–2004,

African-American, Mexican-American,

and white persons; other persons with

low income (beginning in 2000);

pregnant women; adolescents aged

12–19; and persons aged 60 and over

were oversampled. As a result, the

weights are quite variable for samples

that include a number of the subdomains

mentioned. The Los Angeles County

weights were examined by broad

analytic domains defined by Hispanic or

non-Hispanic, categorized age, and sex,

and 21 examined persons had a final

exam weight five times larger than the

average weight of other persons in the

same group. In such cases, the weights

are commonly trimmed to reduce the

impact of the cases with extreme

weights on the outcome statistic.

However, the extreme weights were kept

in the data set because there was no
National Health Statistics Reports n Number 42 n September 1, 2011 Page 3

effect on the outcome when comparing

Los Angeles County with the United

States on selected health conditions.

Additional information on the Los

Angeles County Demographic File is

available on the NHANES website (8).

Data analyses

The analytic sample consisted of

adult participants aged 20 and over.

Data were analyzed using SAS for

Windows (release 9.1; SAS Institute

Inc., Cary, N.C.) and SUDAAN (release

9.0; RTI International, Research Triangle

Park, N.C.) statistical software

programs. Estimates of selected health

conditions were produced for both the

United States and Los Angeles County.

Interview weights were used in

calculating the prevalence of diagnosed

diabetes, since this was based on

self-reported information. Examination

weights were used in calculating the

prevalence of hypertension, high

cholesterol, overweight, and obesity.

Hypertension was defined as a high

measured blood pressure or taking

medication to lower blood pressure.

High cholesterol was defined as high

serum total cholesterol or taking

cholesterol-lowering medication. The

category of overweight and obese was

based on measured height and weight.

Fasting weights were used in addition to

interview weights to calculate the

estimates for total diabetes. Total

diabetes was defined as high fasting

plasma glucose or self-reported

diagnosed diabetes. Fasting weights

were calculated for participants

examined in the morning session who

had fasted for 9 hours or more; thus, the

sample sizes used for calculating total

diabetes are smaller than for the other

health conditions.

Weighted estimates are presented as

crude, age adjusted, and age-race

adjusted. The age-adjusted estimates

were computed using the direct method

of adjustment to the 2000 U.S. census

figures (9). The estimates adjusted for

age-race were computed using racial and

ethnic population totals from the Current

Population Survey (CPS) 2001–2002.

Fifteen race and age subgroups were

formed using three age groups (20–39,

40–59, and 60 and over) and five racial

and ethnic groups (Mexican American,

other Hispanic, non-Hispanic white,

non-Hispanic black, and other races).

Estimates adjusted for age-race were

computed by taking the sum of products

of these 15 age-race-specific estimates

times the proportion of the

corresponding age-race subgroup in the

population as measured by the CPS.

Sample weights were included in the

estimation process for all analyses to

account for the differential probabilities

of selection, nonresponse, and

noncoverage. Standard errors of the

percentages were estimated using the

Taylor series linearization method,

which incorporates the sample weights

and accounts for the sample design (10).

The relative standard error (RSE) is a

measure of an estimate’s reliability. The

RSE of an estimate is obtained by

dividing the standard error of the

estimate SE(r) by the estimate itself (r).

This quantity is expressed as a

percentage of the estimate and is

calculated as RSE = 100 × SE(r)/r.

Estimates with large RSEs are

considered unreliable. Estimates with an

RSE of 30% or more are considered

highly unreliable and are indicated by

an asterisk (*). Estimates with an RSE

of 40% or more are not shown.

Unreliable estimates should be

interpreted with caution (11).

A two-tailed t statistic at the

p < 0.05 level of significance was used

to detect differences in

sociodemographic and health

characteristics between adults of Los

Angeles County and the United States.

Terms such as ‘‘more likely,’’ ‘‘less

likely,’’ ‘‘was higher,’’ ‘‘was lower,’’ and

‘‘compared with’’ indicate a statistically

significant difference. Terms such as

‘‘similar’’ or ‘‘no difference’’ indicate

that the statistics being compared were

not statistically significant.

Results

Of all persons in Los Angeles

County eligible to participate in

NHANES during 1999–2004, 59% were

aged 20 or over (n = 1,054). Of these,

712 were interviewed (67.6%) and 667

were interviewed and examined

(63.3%). In the national sample, 20,228

adults aged 20 and over were identified

as eligible to participate. Of these,

15,332 were interviewed (75.8%) and

14,213 were interviewed and examined

(70.3%).

Sociodemographic characteristics of

the interviewed-and-examined sample

are presented separately (Tables 1 and

2). A significantly higher proportion of

Los Angeles County adults were

Mexican American (27.3%) compared

with the United States (7.3%), and a

higher proportion were aged 20–39

(46.1% compared with 39.5%).

Significantly fewer Los Angeles County

adults were non-Hispanic white persons

(36.4% compared with 71.3%), and

fewer were high school graduates

(13.7% compared with 26.0%). Adults

in Los Angeles County were more likely

to live below the poverty level (31.1%)

compared with adults in the United

States (19.7%).

Prevalence of hypertension, high

serum cholesterol, overweight and

obesity, and diabetes (diagnosed and

total) are presented in Tables 3–8.

Because Mexican-American persons

make up so much of the Los Angeles

County population, the sample sizes for

the ‘‘other Hispanic’’ and ‘‘other’’

population subgroups were too small to

obtain stable estimates of these health

conditions and are not shown.

The prevalence of hypertension

(Table 3) was similar in U.S. and Los

Angeles County adults, and no

differences emerged after age and

age-race adjustment of the estimates.

Hypertension increased with age among

U.S. and Los Angeles County adults.

The proportion of adults with high

cholesterol was similar in the United

States and Los Angeles County

(Table 4), and no differences were

detected after age and age-race

adjustment.

There were no differences in the

prevalence of overweight and obese

combined between U.S. and Los

Angeles County adults (Table 5).

However, the prevalence of obesity was

lower among adults in Los Angeles

County (23.6%) compared with the

United States (31.1%). The age-adjusted

obesity rate (23.8% compared with
Page 4 National Health Statistics Reports n Number 42 n September 1, 2011

31.0%) and the rate adjusted for

age-race (21.4% compared with 31.0%)

were also statistically lower (Table 6).

The prevalence of diagnosed

diabetes was similar between Los

Angeles County and U.S. adults;

although the age-adjusted rate of

diagnosed diabetes was higher among

Los Angeles County men (9.1%)

compared with U.S. men (7.3%), this

difference did not hold after adjusting

for both age and race (Table 7). The

prevalence of total diabetes was similar

for the United States and Los Angeles

County (Table 8). Estimates of

diagnosed and total diabetes could not

be made for all age and race subgroups

because of small cell sizes.

Discussion

Two characteristics of the NHANES

sample design allowed for the

production of county-based health

estimates. First, of all the PSUs selected

each year to represent the United States,

Los Angeles County was the only one

chosen with certainty (i.e., with a

probability of selection equal to 1). This

was due to its population density

(measure of size) and large MexicanAmerican population, which was a

target group for oversampling.

Therefore, the total sample size for Los

Angeles County is six times the average

PSU size in NHANES 1999–2004,

providing an adequate sample size for

the analysis presented in this report.

Second, the sample is representative of

the target population in Los Angeles

County because the county was chosen

as a self-representing PSU (meaning it

represented only itself and not a larger

geographic area). These elements

provided a unique opportunity for

estimating health conditions for Los

Angeles County, which cannot be done

for any other county sampled for

NHANES.

This is the first report to describe

the health characteristics of the Los

Angeles County adult population based

on direct physical measurements.

Because of the expense of populationbased health examination surveys, few

communities have invested in such an

effort except for New York City, which

in 2004 conducted the New York City

HANES (2), and the state of Wisconsin,

which fielded the Survey of the Health

of Wisconsin in 2008 (12). Most local

public health agencies use information

collected from telephone surveys to

monitor community health. Research has

shown that many population-based

studies using self-reported health

information underestimate the true

prevalence of conditions, particularly

among selected demographic subgroups.

Vargas et al. found a striking difference

in the prevalence of hypertension among

Mexican-American men in the United

States when comparing self-reported

questionnaire information with measured

systolic and diastolic brachial blood

pressures from NHANES III (13). The

self-reported hypertension prevalence,

19.0% (95% CI 16.7–21.3), was

significantly lower than the prevalence

based on measurements, 26.6% (95% CI

23.8–29.4). The latter estimate was

based on the definition of hypertension

recommended by the Third Report of

the Joint National Committee on

Detection, Evaluation, and Treatment of

High Blood Pressure, or JNC III: a

systolic blood pressure greater than or

equal to 140 mm Hg or diastolic blood

pressure greater than or equal to 90 mm

Hg or currently taking medication to

lower high blood pressure.

The Los Angeles County

Department of Public Health has been

monitoring the prevalence of

hypertension, as well as other health

conditions, using the Los Angeles

County Health Survey (LACHS). This

survey is a population-based telephone

survey that provides information

concerning the health of Los Angeles

County adults. The prevalence of

age-adjusted diagnosed hypertension for

adults aged 18 and over was 21.2%

during the 1999–2000 cycles and 21.6%

during the 2002–2003 cycles (14). The

present report found the age-adjusted

prevalence of hypertension among Los

Angeles County adults aged 20 and over

during a comparable time period to be

24.8%. Because coronary heart disease

was the leading cause of disabilityadjusted life years in Los Angeles

County (15), an accurate assessment of

hypertension prevalence in the county is

important for prevention efforts.

Data from LACHS also show the

prevalence of obesity to be lower than

the rates based on health examination

data. The prevalence of obesity for

adults aged 18 and over was 16.7%

during the 1999–2000 cycles and 19.3%

during the 2002–2003 cycles of LACHS

(16). The prevalence of obesity among

Los Angeles County adults based on

NHANES was 23.6%. Validation studies

have shown that when responding to

health surveys, men tend to overreport

their height and women tend to

underreport their weight (17). Thus,

estimates of obesity for a community

are best made using direct physical

measures from a population-based

sample.

The prevalence of obesity among

adults was found to be lower in Los

Angeles County compared with adults in

the United States. The lower prevalence

may be due to the much lower

prevalence among white persons in Los

Angeles County compared with the

subgroup nationally. The white

population in Los Angeles County is

more affluent and better educated than

the white population nationally.

The age-adjusted prevalence of

diagnosed diabetes in Los Angeles

County from NHANES (6.8%) is similar

to the estimates found in the 1999–2000

(7.5%) and 2002–2003 (7.6%) LACHS.

However, the true burden of diabetes in

Los Angeles County is reflected in the

total diabetes estimates from NHANES

that incorporate a fasting glucose

measurement to account for undiagnosed

diabetes. This report found the total

diabetes prevalence to be 9.9%. Trend

data from successive waves of LACHS

show diabetes to be an increasing

problem among adults in Los Angeles.

NHANES data shed light on the fact

that the burden of diabetes is actually

greater in the Los Angeles County

population than inferred from selfreported survey data.

This report is subject to several

limitations. NHANES was designed to

produce nationally representative health

estimates. Therefore, the weights created

for the national sample are not designed

to produce estimates for Los Angeles.
National Health Statistics Reports n Number 42 n September 1, 2011 Page 5

The effort to reweight the Los Angeles

County sample from NHANES was an

attempt to not only adjust for the

differential probability of selection and

response rates within Los Angeles, but

also poststratify the sample to match the

known population totals for Los

Angeles. In addition, despite aggregating

6 years of NHANES data, the Los

Angeles County sample size is small.

This limits the reliability of some of the

estimates produced. However, since

these are based on direct physical

measures and are not available

elsewhere, we have presented estimates

with RSEs greater than 30% but less

than 40% because they represent a

‘‘ballpark’’ of the estimate and can be

useful for sample size calculations for

statistical power for future studies.

The Los Angeles County sample is

predominately Mexican American, and

the sample sizes of other racial and

ethnic groups such as non-Hispanic

black is inadequate to produce stable

estimates, particularly for diabetes.

Lastly, comparisons of health estimates

were made between Los Angeles County

and the United States based on

statistical testing assuming independent

samples. Los Angeles County

participants are clearly part of the U.S.

sample, and a more correct comparison

would have been between Los Angeles

County and the United States excluding

Los Angeles County. It was not possible

to create such a U.S. sample minus Los

Angeles County because new weights

would have had to be calculated.

Given the cost of conducting a

community health examination survey,

creating local area estimates from

national health examination surveys

using known statistical techniques is a

viable, lower-cost alternative.

Partnerships among federal, state, and

local public health agencies are

important for the success in using

national survey systems to inform

county public health agencies in their

mission to improve the health of their

community.

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Page 6 National Health Statistics Reports n Number 42 n September 1, 2011

Table 1. Sociodemographic characteristics of interviewed adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Percent Standard Percent Standard

Characteristic n N distribution error n N distribution error

Total ........................... 15,332 200,708,000 100.0 . . . 712 6,718,000 100.0 . . .

Age

20–39 years1 .......... .......... 5,362 79,335,000 39.5 0.7 268 3,096,000 46.1 3.7

40–59 years ...................... 4,363 76,202,000 38.0 0.6 210 2,532,000 37.7 3.7

60 years and over1 ........ ........ 5,607 45,171,000 22.5 0.5 234 1,090,000 16.2 2.1

Race and ethnicity

Mexican American1 ........ ........ 3,380 14,647,000 7.3 0.9 434 1,831,000 27.3 3.7

Other Hispanic1

.......... .......... 699 11,512,000 5.7 1.2 53 912,000 13.6 2.9

Non-Hispanic white1 ........ ........ 7,761 143,176,000 71.3 1.7 96 2,442,000 36.4 5.9

Non-Hispanic black .................. 2,916 21,875,000 10.9 1.0 83 598,000 8.9 1.8

Other1 ............ ............ 576 9,497,000 4.7 0.4 46 935,000 13.9 2.5

Sex

Male ........................... 7,223 95,990.00 47.8 0.4 328 3,262,000 48.6 1.9

Female ......................... 8,109 104,718,000 52.2 0.4 384 3,456,000 51.4 1.9

Poverty income ratio (PIR)2

PIR less than 1.301 ........ ........ 5,397 39,568,000 19.7 1.0 249 2,089,000 31.1 4.7

1.30 less than or equal to PIR less than 3.5. . . 3,983 66,952,000 33.4 0.8 248 2,222,000 33.1 3.9

PIR greater than or equal to 3.51 ......... 4,452 77,276,000 38.5 1.2 127 1,714,000 25.5 6.3

Education

Less than high school1 ................ 5,050 41,750,000 20.8 0.7 347 2,060,000 30.7 3.5

High school diploma1 ................. 3,631 52,113,000 26.0 0.7 97 924,000 13.7 2.2

More than high school ................ 6,592 106,276,000 53.0 1.0 267 3,733,000 55.6 3.6

. . . Category not applicable. 1

t statistic p < 0.05. 2

Poverty status levels are based on PIR: the ratio of income to the family’s appropriate poverty threshold (U.S. Census Bureau). 

NOTES: ‘‘n’’ is the sample size in the NHANES data, and ‘‘N ’’ is the inflated population size. Numbers may not add to totals because of rounding. 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004. 
National Health Statistics Reports n Number 42 n September 1, 2011 Page 7

Table 2. Sociodemographic characteristics of interviewed-and-examined adults aged 20 and over: United States and Los Angeles

County, 1999–2004

United States Los Angeles County

Percent Standard Percent Standard

Characteristic n N distribution error n N distribution error

Total ........................... 14,213 200,708,000 100.0 . . . 667 6,718,000 100.0 . . .

Age

20–39 years1 ...................... 5,068 79,335,000 39.5 0.6 252 3,075,000 45.8 3.8

40–59 years ...................... 4,161 76,202,000 38.0 0.9 202 2,554,000 38.0 3.8

60 years and over1 .................. 4,984 45,171,000 22.5 0.6 213 1,090,000 16.2 2.3

Race and ethnicity

Mexican American1 .................. 3,207 14,647,000 7.3 0.9 407 1,831,000 27.3 3.7

Other Hispanic1 .................... 641 11,512,000 5.7 1.2 50 912,000 13.6 2.9

Non-Hispanic white1 ................. 7,101 143,176,000 71.3 1.7 90 2,442,000 36.4 5.9

Non-Hispanic black .................. 2,747 21,875,000 10.9 1.0 76 598,000 8.9 1.8

Other1 .......................... 517 9,497,000 4.7 0.4 44 935,000 13.9 2.5

Sex

Male ........................... 6,735 95,990,000 47.8 0.4 312 3,262,000 48.6 2.0

Female ......................... 7,478 104,718,000 52.2 0.4 355 3,456,000 51.4 2.0

Poverty income ratio (PIR)2

PIR less than 1.301 .................. 3,738 40,162,000 20.0 1.1 235 2,177,000 32.4 4.9

1.30 less than or equal to PIR less than 3.5. . . 5,055 67,686,000 33.7 0.8 236 2,244,000 33.4 4.1

PIR greater than or equal to 3.51 ......... 4,160 77,408,000 38.6 1.2 115 1,665,000 24.8 6.1

Education

Less than high school1 ................ 4,650 41,624,000 20.7 0.7 322 2,070,000 30.8 3.6

High school diploma1 ................. 3,371 52,352,000 26.1 0.7 91 972,000 14.5 2.4

More than high school ................ 6,160 106,409,000 53.0 1.0 253 3,676,000 54.7 3.6

. . . Category not applicable. 1

t statistic p < 0.05. 2

Poverty status levels are based on PIR: the ratio of income to the family’s appropriate poverty threshold (U.S. Census Bureau). 

NOTES: ‘‘n’’ is the sample size in the NHANES data and ‘‘N ’’ is the inflated population size. Numbers may not add to totals because of rounding. 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004. 
Page 8 National Health Statistics Reports n Number 42 n September 1, 2011

Table 3. Prevalence of hypertension among adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Prevalence Standard Prevalence Standard

Characteristic n (percent) error n (percent) error

Crude

Total ..................... 12,613 30.0 0.8 580 25.8 3.2

Sex

Men ..................... 6,386 28.2 1.0 289 26.0 3.6

Women ................... 6,227 31.7 0.9 291 25.6 4.3

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,817 17.7 1.5 345 19.2 2.4

Non-Hispanic white ............ 6,373 30.6 1.0 82 29.7 6.8

Non-Hispanic black ............ 2,432 37.7 1.2 70 34.2 5.7

Age

20–39 years ................ 4,059 7.5 0.6 201 *5.5 1.7

40–59 years ................ 3,939 30.9 1.2 184 32.9 6.6

60 years and over............. 4,615 66.7 1.0 195 66.1 4.9

Age adjusted

Total ..................... 12,613 25.2 0.6 580 24.8 2.8

Sex

Men ..................... 6,386 25.4 0.9 289 26.5 3.1

Women ................... 6,227 24.7 0.5 291 22.6 3.3

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,817 22.4 1.0 345 23.7 2.0

Non-Hispanic white ............ 6,373 24.0 0.7 82 20.9 4.4

Non-Hispanic black ............ 2,432 35.2 0.9 70 36.5 5.0

Age-race adjusted

Total ..................... 12,613 29.7 0.7 580 28.5 4.4

Sex

Men ..................... 6,386 29.3 1.0 289 27.9 4.1

Women ................... 6,227 29.6 0.7 291 27.2 5.6

* Figure does not meet standards of reliability or precision; relative standard error is greater than 30%. 

NOTES: ‘‘n’’ is the sample size in the NHANES data. Hypertension is defined as having a systolic blood pressure greater than or equal to 140 mm Hg, diastolic blood pressure greater than or 

equal to 90 mm Hg, or currently taking medication to lower high blood pressure. 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004. 
National Health Statistics Reports n Number 42 n September 1, 2011 Page 9

Table 4. Prevalence of high cholesterol among adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Prevalence Standard Prevalence Standard

Characteristic n (percent) error n (percent) error

Crude

Total ..................... 12,927 26.7 0.5 609 23.5 3.9

Sex

Men ..................... 6,150 26.9 0.6 287 22.6 3.3

Women ................... 6,777 26.5 0.8 322 24.3 5.4

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,932 17.0 0.7 372 19.4 2.3

Non-Hispanic white ............ 6,552 28.9 0.7 83 *29.2 9.7

Non-Hispanic black ............ 2,388 20.7 0.9 65 16.5 4.2

Age

20–39 years ................ 4,554 11.9 0.6 225 13.4 3.1

40–59 years ................ 3,848 30.7 0.9 188 28.6 6.5

60 years and over............. 4,525 45.4 0.7 196 38.2 5.5

Age adjusted

Total ..................... 12,927 26.5 0.4 609 22.5 3.6

Sex

Men ..................... 6,150 27.0 0.6 287 21.4 3.1

Women ................... 6,777 25.7 0.7 322 23.3 5.2

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,932 16.9 0.7 372 21.6 2.4

Non-Hispanic white ............ 6,552 28.7 0.5 83 *24.4 9.8

Non-Hispanic black ............ 2,388 20.7 0.9 65 16.8 4.1

Age-race adjusted

Total ..................... 12,927 26.5 0.4 609 25.7 7.1

Sex

Men ..................... 6150 27.0 0.6 287 21.0 4.6

Women ................... 6777 25.7 0.7 322 *28.9 9.2

* Figure does not meet standards of reliability or precision; relative standard error is greater than 30%. 

NOTES: ‘‘n’’ is the sample size in the NHANES data. High cholesterol is defined as having measured serum total cholesterol greater than or equal to 240 mg/dL or reporting taking cholesterollowering medications. 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004. 
Page 10 National Health Statistics Reports n Number 42 n September 1, 2011

Table 5. Prevalence of overweight and obese among adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Prevalence Standard Prevalence Standard

Characteristic n (percent) error n (percent) error

Crude

Total ..................... 12,961 65.7 0.7 611 62.6 3.0

Sex

Men ..................... 6,499 69.3 0.7 303 67.3 4.6

Women ................... 6,462 62.1 1.0 308 57.8 3.2

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,908 71.4 1.7 363 73.3 3.5

Non-Hispanic white ............ 6,491 64.4 0.9 86 58.7 7.8

Non-Hispanic black ............ 2,542 72.1 0.9 74 80.5 4.9

Age

20–39 years ................ 4,210 57.4 1.0 212 51.7 5.4

40–59 years ................ 4,053 70.9 1.1 194 75.8 3.9

60 years and over............. 4,698 70.9 0.9 205 61.9 5.9

Age adjusted

Total ..................... 12,961 65.4 0.7 611 63.0 2.6

Sex

Men ..................... 6,499 69.3 0.7 303 68.8 3.7

Women ................... 6,462 61.2 1.1 308 57.6 3.1

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,908 71.2 1.6 363 76.3 2.9

Non-Hispanic white ............ 6,491 64.3 0.9 86 55.2 7.4

Non-Hispanic black ............ 2,542 71.9 0.9 74 80.5 5.1

Age-race adjusted

Total ..................... 12,961 65.4 0.7 611 60.0 5.1

Sex

Men ..................... 6,499 69.3 0.7 303 65.8 4.4

Women ................... 6,462 61.2 1.1 308 53.3 7.7

NOTES: ‘‘n’’ is the sample size in the NHANES data. ‘‘Overweight and obese’’ is defined as having a body mass index greater than or equal to 25.

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004.
National Health Statistics Reports n Number 42 n September 1, 2011 Page 11

Table 6. Prevalence of obesity among adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Prevalence Standard Prevalence Standard

Characteristic n (percent) error n (percent) error

Crude

Total1

..................... 12,961 31.1 0.7 611 23.6 2.6

Sex

Men1 ..................... 6,499 28.7 0.7 303 20.4 2.7

Women ................... 6,462 33.4 1.0 308 26.8 3.6

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,908 32.9 1.5 363 36.3 3.3

Non-Hispanic white1 ........... 6,491 30.3 0.8 86 19.4 5.1

Non-Hispanic black ............ 2,542 41.2 1.1 74 34.4 7.2

Age

20–39 years ................ 4,210 26.8 0.8 212 20.3 4.0

40–59 years ................ 4,053 34.8 1.2 194 26.9 4.7

60 years and over............. 4,698 32.2 0.9 205 24.6 6.7

Age adjusted

Total1

..................... 12,961 31.0 0.7 611 23.8 2.7

Sex

Men1 ..................... 6,499 28.8 0.7 303 20.7 2.7

Women ................... 6,462 33.2 1.0 308 27.0 3.7

Race and ethnicity

Mexican American. . . . . . . . . . . . . 2,908 34.2 1.4 363 37.0 2.8

Non-Hispanic white1 ........... 6,491 29.8 0.8 86 18.4 4.6

Non-Hispanic black ............ 2,542 41.4 1.1 74 36.5 6.8

Age-race adjusted

Total1

..................... 12,961 31.0 0.7 611 21.4 3.5

Sex

Men ..................... 6,499 28.8 0.7 303 20.8 3.7

Women ................... 6,462 33.0 1.0 308 20.9 5.0

1

t statistic p < 0.05. 

NOTES: ‘‘n’’ is the sample size in the NHANES data. Obesity is defined as having a body mass index greater than or equal to 30. 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004. 
Page 12 National Health Statistics Reports n Number 42 n September 1, 2011

Table 7. Prevalence of diagnosed diabetes among adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Prevalence Standard Prevalence Standard

Characteristic n (percent) error n (percent) error

Crude

Total ..................... 15,321 6.9 0.3 711 6.9 1.0

Sex

Men ..................... 7,219 7.0 0.4 328 8.8 1.8

Women ................... 8,102 6.9 0.3 383 5.0 1.2

Race and ethnicity

Mexican American. . . . . . . . . . . . . 3,379 6.8 0.5 433 8.5 1.3

Non-Hispanic white ............ 7,758 6.2 0.3 96 *5.3 1.6

Non-Hispanic black ............ 2,915 10.3 0.6 83 † †

Age

20–39 years ................ 5,359 1.6 0.2 267 † †

40–59 years ................ 4,360 7.3 0.5 210 6.6 1.7

60 years and over............. 5,602 15.8 0.6 234 19.6 4.1

Age adjusted

Total ..................... 15,321 7.0 0.3 711 6.8 0.9

Sex

Men1 ..................... 7,219 7.3 0.4 328 9.1 1.6

Women ................... 8,102 6.7 0.3 383 4.7 1.1

Race and ethnicity

Mexican American. . . . . . . . . . . . . 3,379 11.1 0.4 433 10.1 1.4

Non-Hispanic white ............ 7,758 5.8 0.3 96 4.3 1.3

Non-Hispanic black ............ 2,915 11.6 0.6 83 † †

Age-race adjusted

Total ..................... 15,321 6.9 0.3 711 6.2 1.2

Sex

Men ..................... 7,219 7.3 0.4 328 9.8 2.1

Women ................... 8,102 6.6 0.3 383 † †

* Figure does not meet standards of reliability or precision; relative standard error is greater than 30% and less than or equal to 40%.

† Figure does not meet standards of reliability or precision; relative standard error is greater than 40%. 1

t statistic p < 0.05.

NOTES: ‘‘n’’ is the sample size in the NHANES data. Physician-diagnosed diabetes was obtained by self-report and excludes women who reported diabetes only during pregnancy.

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004.
National Health Statistics Reports n Number 42 n September 1, 2011 Page 13

Table 8. Prevalence of total diabetes among adults aged 20 and over: United States and Los Angeles County, 1999–2004

United States Los Angeles County

Prevalence Standard Prevalence Standard

Characteristic n (percent) error n (percent) error

Crude

Total ..................... 7,087 9.7 0.4 333 9.9 1.8

Sex

Men ..................... 3,377 10.6 0.5 171 12.5 2.4

Women ................... 3,710 8.8 0.4 162 *7.5 2.3

Race and ethnicity

Mexican American. . . . . . . . . . . . . 1,678 8.9 0.9 215 11.8 2.5

Non-Hispanic white ............ 3,522 8.9 0.4 39 *10.6 3.6

Non-Hispanic black ............ 1,337 13.2 0.8 38 † †

Age

20–39 years ................ 2,169 2.3 0.4 94 † †

40–59 years ................ 2,068 10.4 0.6 106 8.9 2.3

60 years and over............. 2,850 21.5 0.9 133 28.8 6.3

Age adjusted

Total ..................... 7,087 9.7 0.4 333 11.1 1.6

Sex

Men ..................... 3,377 11.0 0.5 171 14.6 2.4

Women ................... 3,710 8.6 0.4 162 8.0 2.2

Race and ethnicity

Mexican American. . . . . . . . . . . . . 1,678 14.1 0.7 215 15.4 2.2

Non-Hispanic white ............ 3,522 8.3 0.4 39 8.6 2.6

Non-Hispanic black ............ 1,337 14.7 0.8 38 † †

Age-race adjusted

Total ..................... 7,087 9.6 0.4 333 9.1 2.1

Sex

Men ..................... 3,377 11.0 0.5 171 14.0 3.3

Women ................... 3,710 8.5 0.4 162 *5.4 2.1

* Figure does not meet standards of reliability or precision; relative standard error is greater than 30% and less than or equal to 40%.

† Figure does not meet standards of reliability or precision; relative standard error is greater than 40%.

NOTES: ‘‘n’’ is the sample size in the NHANES data. Total diabetes prevalence is based on the adult having a fasting blood sugar of at least 126 mg/dL or self-reported, physician-diagnosed 

diabetes. 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, 1999–2004. 
Page 14 National Health Statistics Reports n Number 42 n September 1, 2011

Technical Notes

Definition of terms

Hypertension—Trained physicians

used a mercury sphygmomanometer to

measure systolic and diastolic brachial

blood pressures following a standard

protocol. Appropriate blood pressure

cuff sizes were used for participants

based on measurement of midarm

circumference. The average of up to

three readings was used for reported

systolic and diastolic blood pressure

values. All blood pressure readings were

obtained at a single examination visit.

Hypertension is defined as a systolic

blood pressure greater than or equal to

140 mm Hg or diastolic blood pressure

greater than or equal to 90 mm Hg or

currently taking medication to lower

high blood pressure.

Serum cholesterol—A venous blood

sample was collected in the mobile

examination center and shipped to the

Johns Hopkins University Lipid

Laboratory (Baltimore, Md.). This

laboratory was certified as having

documented traceability to the national

reference system for cholesterol. Serum

cholesterol was measured enzymatically

on a Hitachi 704 Analyzer (Roche

Diagnostics, Indianapolis, Ind.) using

commercial reagents. High cholesterol is

defined as measured serum total

cholesterol greater than or equal to

240 mg/dL or reporting taking

cholesterol-lowering medications.

Respondents were asked, ‘‘Are you now

following this advice [from a doctor or

health professional] to take prescribed

medicine [to lower your cholesterol]?’’

Overweight and obese—Trained

health technicians measured participants’

height and weight in a specially

equipped room in the mobile

examination center. Body mass index

(BMI) was calculated as weight in

kilograms divided by height in meters

squared, rounded to one decimal place.

For adults aged 20 years and over,

overweight is defined as a BMI equal to

or greater than 25.0 and less than 30.0.

Obesity is defined as a BMI of 30.0 or

higher (18).

Diabetes—Participants were asked

if, other than during pregnancy for

women, a doctor or a health care

professional had ever told them they had

diabetes. Those who said ‘‘yes’’ were

classified as having diagnosed diabetes.

Total diabetes was estimated by

combining the number of persons who

reported having diagnosed diabetes with

those who had undiagnosed diabetes

based on fasting blood glucose levels.

For the latter, participants who were

randomly assigned to a morning

examination session were asked to fast

for 9 hours prior to the exam. Plasma

glucose values were collected and

measured by using a hexokinase

enzymatic method with a coefficient of

variation of less than 2.5%. Diagnostic

criteria of the American Diabetes

Association were used to categorize

persons without previously diagnosed

diabetes if they had fasted 9 hours or

more and less than 24 hours, and had a

fasting plasma glucose level greater than

126 mg/dL (19).
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National Health Statistics Reports n Number 42 n September 1, 2011

Suggested citation

Porter KS, Curtin LR, Carroll MD, et al. Health

of adults in Los Angeles County: Findings from

the National Health and Nutrition Examination

Survey, 1999–2004. National health statistics

reports; no 42. Hyattsville, MD: National Center

for Health Statistics. 2011.

Copyright information

All material appearing in this report is in the

public domain and may be reproduced or

copied without permission; citation as to

source, however, is appreciated.

National Center for Health Statistics

Edward J. Sondik, Ph.D., Director 

Jennifer H. Madans, Ph.D., Associate Director 

for Science 

Division of Health and Nutrition 

Examination Surveys 

Clifford L. Johnson, M.S.P.H., Director

For e-mail updates on NCHS publication releases, subscribe online at: http://www.cdc.gov/nchs/govdelivery.htm 

For questions or general information about NCHS: Tel: 1–800–232–4636 • E-mail: cdcinfo@cdc.gov • Internet: http://www.cdc.gov/nchs 

DHHS Publication No. (PHS) 2011–1250 • CS224957