THE USE OF SIMPLE INDICATORS FOR DETECTING POTENTIAL
CORONARY HEART DISEASE SUSCEPTIBILITY IN THE
THIRD-CLASS AIRMAN POPULATION

I. Introduction.

According to recent epidemiological statistics,
arteriosclerotic heart disease, which includes
coronary heart disease (CHD), caused 31.0% of
all deaths in the United States... A recent survey
on silent CHD estimates its magnitude at a
minimum of 5.0% in United States males over
35 years of age.* Other studies concerning the
magnitude and age distribution of silent CHD
jn the general population have been reviewed in
a previous report. The Framingham Heart
Study (FHS) has uncovered strong correlations
between silent CHD and both sudden incapacita-
tion and/or sudden death.t In view of the un-
expectedness of most CHD deaths and the
absence of a definite prior diagnosis of this dis-
ease, the FHS concludes that “the only road to
a substantial reduction in premature CHD mor-
tality is the prevention of this disease entity.”
In the category of sudden, unexpected death
without a prior definite diagnosis of CHD, 80.0%
of the victims had manifested risk clearly in at
least one of the Framingham susceptibility indi-
cators.*

In 1970, the FAA conducted the aeromedical
certification examination of 444,000 airmen.°
The repetitively examined airman population
should contain less prevalent silent CHD than
the 5.0% manifested by the general population.
One way of detecting this maximum 5.0% aliquot
is the comprehensive cardiological examination
of approximately 444,000 airmen each year.
Assuming one-hundred dollars per examination
of this type, this solution for detecting the maxi-
mum 5.0% aliquot, at a cost of 44.4 million dollars
per year, would be economically inefficient. ‘This
report presents and explores an alternative and
more economical possible solution in the specific
context of the third-class airman segment of the
airman population. A similar report focused on

the entire air traffic controller (ATC) population
has been prepared.*

In a previous report, an analysis was made of
an eight-year interval change in several Fram-
ingham indicators of CHD susceptibility as
measured on 475 male ATC personnel.’ The
distribution of each of the Framingham param-
eters used was compiled in an age versus Fram-
ingham relative weight index (FRWI) table.
The distributions of the initial 1960-1963 data
revealed a general trend of increasing relative
susceptibility with age and FRWI. This is con-
sistent with the FHS findings of greater CHD
susceptibility with advanced age and obesity.’
The distributions of the eight-year interval data
revealed the same general trend with age and
FRWI, as well as an increased concentration of
greater relative susceptibility in the older/obese
combined categories. To test these earlier find-
ings, an analysis of similar data from 424,333
male third-class airmen was accomplished. A
similar analysis on 23,826 male ATC personnel
has also been accomplished.*

II. Methods.

All data were obtained from the active aero-
medical certification records in January 1971.
The complete rationale of the age versus FRWI
table format has been presented in a previous
report? Each table contains one total and four
segmental age categories versus one total, one
subtotal and three segmental FRWI categories.
The FRWI was caleulated from the Framingham
formula using height in inches and weight in
pounds. The parameters analyzed in the present
study are resting systolic and diastolic blood
pressures (SBP and DBP), resting heart rate
(HR) and % prevalence of the 400 pathology
code. The FAA codes all cardiovascular pa-
thologies under the 400 series. The measure-





AGE (yrs.)

FRWI
(%)

<30 30-39 40-49 >50 All Ages
73.1 76.0 77.7 79.4 753
<l00.0 £0.02 £0.03 +£0.04 +£0.06 £0.02
(124,337) | (52,612) | (45,658) | (22,249) | (244,856)
76.4 78.6 80.2 81.9 78.9
00.0 +£0.03 £0.03 +0.04 £0.05 +0.02
119.9 |) (44,287) | (45,114) | (46,677) | (21,835) | (157,913)
742 772 79.0 806 767
<l20.0 +0.01 £0.02 +£0.02 +0.04 +0.01
(168,624) | (97,726) | (92,335) | (44,084) | (402,769)
80.0 81.9 82.9 83.9 81.9
2120.0 +£0.11 +£0.10 +£0.10 +£0.17 +0.06
(6,228) | (6,402) | (6,284) | (2,650) | (21,564)
Al 74.4 775 79.2 809 77.0
FRWIs || £0.01 +£0.02 +0.02 +£0.03 +0.01
(174,852) | (104,128) | (98,619) | (46,734) | (424,333)

‘Tasre 2. Tabulation of Mean DBP Versus Age and FRWI Categories. Each table cell contains the mean DBP (in
mm Hg), the standard error of the mean (+ mm Hg) and in parentheses the number of data used in their

calculation.

the concentration of the higher blood pressure
values in the combined older/obese categories.

Table 3 presents the age versus FRWI tabula-
tion of mean resting HR values. Per se, none of
the HR values in this table are considered to be
medically abnormal.? In the All Ages and All
FRWI’s columns, an increase in HR with in-
creasing age and obesity is present, although the
increments of HR increase in the latter column
are appreciably small. With few exceptions, a
pattern of HR increase within each segmental
age and FRWI category is present, again sug-
gesting the possibility that age and obesity may
be acting independently on the vesting HR.

Table 4 presents the age versus FRWI tabula-
tion of the 400 pathology code % prevalence.
The parenthesized value in each table cell repre-
sents the % prevalence of the 400 pathology code.

In the All Ages and All FRWI’s columns of this
table an increase in 400 pathology code % prev-
alence with increasing age and obesity is clearly
manifested. That obesity and age may be acting
independently on the 400 pathology code %
prevalence is suggested strongly by the same
pattern of increase within each age and FRWI
segment. The increased concentration of this
parameter in the combined older/obese categories
is of paramount interest.

Iv.

In general corroboration of the findings pre-
sented in a previous report,’ the trends of the
parameters presented here in similar age versus
FRWI tables support the presence of a rela-
tively increasing CHD susceptibility with age
and obesity in the third-class airman population.

Discussion.



ment methods for these four parameters have
been presented in detail in a previous report.*
The distribution of each of these four parameters
was compiled in the age versus FRWI table.

Til. Results.

Tables 1 and 2 present the age versus FRWI
tabulations of mean SBP and mean DBP re-
spectively. In the All FRWI’s and All Ages
columns of both tables, an increase in both SBP
and DBP with increasing age and obesity are
quite apparent. That age and obesity may be
acting independently on the SBP and DBP is
suggested strongly by the same pattern of in-
crease within each of the age and FRWI seg-
ments. The summary tables of nine major
population samplings of age versus blood pres-
sure were examined in relevance to the All
FRWI’s data columns of Tables 1 and 2. Com-

pared across age groups alone, the SBP and
DBP values in Tables 1 and 2 were greater than
those in four of these studies* and less than those
in the remaining five? In one of these popu-
lation samplings® based on data from 235,000
males, a single table summary of age versus
height and weight categories for resting SBP
and DBP was compiled. Mathematical conver-
sion of these height and weight data to FRWI
equivalents for a subsequent comparison with
equivalent age and FRWI categories in Tables 1
and 2 was accomplished. Compared on this
basis, all the SBP and DBP values in Tables 1
and 2 were greater than those of the compared
population study. Per se, none of the SBP and
DBP values in Tables 1 and 2 are considered to
be medically abnormal.®*? The points of salient
interest in Tables 1 and 2 are the increase in
SBP and DBP with both age and obesity, and

AGE (yrs.)

FRWI
(%)

<30 30-39 40-49 >50 All Ages
120.4 122.8 125.2 130.7 122.7
<i00.0 £0.02 +0.05 +£0.05 +£0.09 £0.02
(124,337) | (52,612) | (45,658) | (22,249) | (244,856)
125.1 126.5 128.9 134.0 127.9
100.0-]) +£0.05 +£0.05 +0.05 +£0.08 +£0.03
119.9 |] (44,287) | (45,114) | (46,677) | (21,835) | (157,913)
121.6 1245 127.1 132.3 124.7
<120.0 +0.02 +£0.03 +0.04 +0.06 +£0.02
(168,624) | (97,726) | (92,335) | (44,084) | (402,769)
1309 131.8 133.6 138.1 132.8
2120.0 +0.16 £0.15 +£0.15 +£0.26 +0.08
(6,228) | (6,402) | (6,284) (2,650) (21,564)
All 121.9 125.0 1275 132.6 125.2
FRWIs +0.03 +£0.03 +0.04 +£0.06 40.02
(174,852) | (104,128) | (98,619) | (46,734) | (424,333)
Tasre 1. Tabulation of Mean SBP Versus Age and FRWI Categories. Each table cell contains the mean SBP value

(in mm Hg), the standard error of the mean (:-+ mm Hg) and in parentheses, the number of data used in

their calculation.


RWI
(%)

AGE (yrs)

=30 30-39 40-49 >50 All Ages
<1000 ||885/124337 |5i2/s2,612 | 710/48,658 | 722/22,249 | 2,829/244,856
(0.71) (0.97) (156) (3.25) (1.16)
100.0-|| 489/44.287 | 493745,114 | 891/46,677 | 716/21,835 | 2,559/157,913
119.9 (1.04) (1.09) (1.91) (3.28) (1.62)
1,344/168,624 |1,005/97,726 | |,601/92,335 | |,438/44,084 |5,388/402,769

<120.0

(0.80)

(1.03)

(1.73)

(3.26)

(1.34)

>1200 124/6,228 | 102/6,402 | 140/6,284 | 110/2,650 | 476/21,564

es (1.99) (1.59) (2.23) (4.15) (2.21)
All 1,468/174,852 |1,107/104,128 | 1,741/98,619 | |,548/46,734 |5,864/424,333

FRWIs || (oga) | (106) | (77) | (3.31) (1.38)

Taste 4, Tabulation of the 400 Pathology Code % Prevalence Versus Age and FRWI Categories.

Each table cell

contains the ratio of the 400 code prevalence number to the total number of cell individuals and in paren-
theses, the equivalent of the ratio in terms of % prevalence.

cardiological examination would most probably
reveal a greater % prevalence of the CHD in the
older/obese combined categories with the higher
blood pressures than in the younger/thinner
combined categories with the lower blood pres-
sures.

A detailed rationale for the relationship be-
tween increased resting HR and CHD suscepti-
bility has been presented in a previous report.*
Although none of the HR values in Table 3 are
considered to be medically abnormal,’ a general
pattern of increase with age and obesity is pres-
ent. The increase in HR with age within each
FRWI segment appears to be much smaller than
the more consistent increase in HR with FRWI
within each age segment. Exceptions to the pat-
tern of HR increase with age occur in the 100-
119.9% FRWI segment, in which it flattens out
in the last two age groups and in the >120.0%

FRWI segment, in which directional reversal
occurs. No firm interpretation of these two ex-
ceptions is possible at this time. It is possible
that the more consistent increase in HR. with
FRWI within each age segment could signify
that the HR/obesity relationship may be more
directly involved in CHD susceptibility than the
HR/age relationship. The overall trend in Table
8 still supports an increasing relative CHD sus-
ceptibility with age and obesity with a concen-
tration of the higher HR values in the combined
older/obese categories.

Because of the unequivocal documented nature
of 400 pathology code incidents, the data in Table
4 constitute the strongest evidence in support of
the presence of an increasing relative CHD sus-
ceptibility with age and obesity and the concen-
tration of the highest relative susceptibility in
the older/obese combined categories. The gen-



TECHNICAL REPORT STANDARD TITLE PAGE

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA~AM-72-26

4, Title and Subtitle 5. Report Date

THE USE OF SIMPLE INDICATORS FOR DETECTING POTENTIAL July 1972

CORONARY HEART DISEASE SUSCEPTIBILITY IN THE THIRD- 5. Parfoming Orgontvonon Cole

CLASS AIRMAN POPULATION

7. Author(s) 8. Performing Organization Report No.

Michael T. Lategola, Ph.D.

9. Performing Organization Name and Address 10. Work Unit No.
FAA Civil Aeromedical Institute
P. 0. Box 25082 TT. Contract or Grant No.

Oklahoma City, Oklahoma 73125

13. Type of Report and Period Covered

12. Sponsoring Agency Name and Address

Office of Aviation Medicine OAM Report
Federal Aviation Administration
800 Independence Avenue, S.W. 14. Sponsoring Agency Code

Washington, D. C. 20591

15. Supplementary Notes

Work was performed under Tasks AM-D-67-PHY-1 and AM-B-71-PHY-2.

16, Abstract
In report number FAA-AM-71-19, an analysis was made of an eight-year interval change

in several Framingham Heart Study (FHS) indicators of coronary heart disease (CHD)
susceptibility as measured on 475 male air traffic control (ATC) personnel. The
initial measurements were obtained from these personnel as ATC students in 1960-1963
and the subsequent data were obtained eight years later from their current aeromedi-
cal certification records. This analysis revealed a general trend of advancing
relative susceptibility to CHD with age and obesity.’ Sample sizes (in age by obesit:
cells) were frequently too small to warrant any statement of significance for this
general trend.

As a logical followup, analyses of similar data from 23,826 male ATC personnel and
424,333 male third-class airmen were accomplished. This report covers only the
latter population segment. The data were obtained from current aeromedical certifi-
cation records in January 1971. The distributions of resting blood pressure (BP),
resting heart rate (HR) and the 400 pathology code prevalence were compiled in age
versus Framingham relative weight index (FRWI) tables. In accordance with the FHS,
obesity was defined as a minimum FRWI of 120.0%. Substantiating earlier findings
all parameters generally increased with age and obesity. These findings are direct1
relevant to the mass aeromedical screening, early detection, susceptibility reversal
and preventive aspects of CHD.

17. Key Words Third-class airmen, Cardio-~ 18, Distribution Statement .
vascular health, Coronary heart disease, Availability is unlimited. Document may be

Aeromedical screening, Early detection released to the National Technical Informa-
Susceptibility reversal, Preventive main tion Service, Springfield, Virginia 22151,

tenance, Age, Obesity, Blood pressure, for sale to the public.

Heart rate, Cardiovascular pathology
19. Security Classi, (of this report) 2. Security Classif. (of this page) TI. No. of Pages | 22, Price

Unclassified Unclassified 7 $3.00
Form DOT F 1700.7 (e-69)



AGE (yrs)

FRW
(%)

<30 30-39 40-49 >50 All Ages
73.2 74.0 74.2 74.3 73.7
<l00.0 0.02 £0.03 £0.03 £0.04 £0.01
(124,337) | (52,612) | (45,658) | (22,249) | (244,856)
73.8 745 74.7 74.7 74.4
100.0-]] +0.03 £0.03 +£0.03 +£0.05 +0.02
9.9 |} (44,287) | (45,114) | (46,677) | (21,835) | (157,913)
73.4 74.2 74.4 745 739
<|20.0 |} +001 +£0.02 +0.02 +0.02 +£0.01
(168,624) | (97,726) | (92,335) | (44,084) | (402,769)
75.9 76.2 75.9 75.8 76.0
2120.0 +0.10 +0.09 +£0.09 +£0.14 +0.05
(6,228) | (6,402) | (6,284) | (2,650) | (21,564)
All 735 743 745 74.6 74.0
FRWIs || +£0.04 +0.02 +0.02 +0.02 +0.01
(174,852) | (104,128) | (98,619) | (46,734) | (424,333)

Tare 3. Tabulation of Mean Resting HR Versus Age and FRWI Categories.

Each table cell contains the mean

resting HR (in beats per minute), the standard error of the mean (+ beats per minute) and in parentheses,

the number of data used in their calculation.

Further, a general concentration of the elevated
parametric values reflecting the highest relative
susceptibility to CHD occurs in the combined
older/obese categories.

Although all the SBP and DBP values in
Tables 1 and 2 appear to be somewhat below the
threshold values for marked CHD susceptibility,”
a general increase with age and obesity is ap-
parent with a concentration of the higher values
in the combined older/obese categories. Al-
though the highest SBP and DBP values in the
combined older/obese categories do not exceed
the threshold values for marked CHD suscepti-
bility," it appears quite reasonable to assume
that a greater relative CHD susceptibility exists
in these categories than in the younger/thinner
counterpart categories manifesting the lower
SBP and DBP values. Over its 20 years of
experience, the FHS has definitely established the

prospective relationship of initial hypertensive
levels of blood pressure (>160 mm Hg SBP and/
or >95 mm Hg DBP) to the subsequent devel-
opment of overt CHD.*%*** This relationship
is a continuum which includes non-hypertensive
levels of blood pressure.* As specifically stated
in this particular FHS report** based on the first
14 of its 20 years of data: “Risk of every mani-
festation of CHD including angina, coronary
insufficiency, myocardial infarction and sudden
death was distinctly and impressively related to
the antecedent level of both systolic and diastolic
blood pressure. Risk was related not solely to
‘hypertension’ but was proportional to the level
of blood pressure—even at non-hypertensive
pressures—from the lowest to the highest re-
corded.” Therefore, if covert CHD is present at
all in the third-class airman population, it ap-
pears reasonable to assume that comprehensive




ACKNOWLEDGMENT

The author sincerely acknowledges the significant efforts of Mrs. Peggy
Lyne and Mrs. Paula Grape in several data processing areas. Mr. Charles
Booze and Dr. Earl Folk are gratefully acknowledged for their facilitation
of access to pertinent medical certification data and adjunct consultation
concerning data analysis.