Taste 2.—NS, S, and ES are defined in Table 1.
%=percent of 27 questions (BMRC question-
naire) answer “yes.” m=mean, SE=standard
error, and N=number of subjects.

BMRC AGE

(eyes) __30-39_40°49_50°59 _=60__All
ml] 52 87 74 30 | 68

NS se} ua 25 a7 is 12
nN] 22 22 20 5 69
nm i27 1 | 230 - 159

Sse] 31 34 42 - 22
n} ig 18 8 - 55
nf 25 a8 93 1e5 | 103

ES sel 40 19 18 149 \7
n| oe 24 20 5 87
m 93 oT 129 10.7 10.7

All se] 16 1s 19 75 lo
N 49 64 58 10 181

numbers of >60-year-old smoking pilots reside in
proximity to the location of this study, all who
were actively solicited for the study refused to
participate.

For all five spirometric parameters, the data
within each smoking category reveal a general
pattern of decreasing values with age. Despite
the absence of data in this study for the>60-
year-old smokers, this group’s age-related decre-
ments in spirometric parameters would conserv-
atively be expected to equal or exceed those
manifested by the>60-year-old ex-smoker group
(Tables 3~7).2*

Taste 3.—Summary of FEV, data. A=number
of individuals with minor spirometrie impair-
ment, defined as a % of predicted normal value
of <80%. []=number of individuals with mod-
erate spirometric impairment, defined as a %
of predicted normal value of <70%. All other
symbols are defined in Table 1.

FEV) AGE
coped) 30°39 40-49 50:59 =60 All
mf i073 |] Wa 15.6 woos | m2
NS SE} 29 24 32 54 16
Sr) ° ° ° °
Oo] o ° ° ° °
mf 152 | 1009 | 1000 ~ 1020
Ss se] 43 30 27 ~ 20
Ay 2 ° ° - 2
of: ° ° = 1
ml] 1056 | 1036 | 1062 843 | 1031
ES se] 32 25 34 14) 24
Alo ° 1 1 2
of oo ° ' 1 2
mf) wee2 | 1055 | 1075 | 970 | 1059
Al SEP 2! 16 20 83 i
AL 2 ° Hl 1 4
o] - ° ' \ 3

Taste 4.—Summary of FVC data. All symbols
are defined in Table 3.

FVC AGE
(Ped) 30-39 40-49 5059 _=60__All
mf] i048 | 1066 | 1099 1019 | 1067
NS Sef 28 25 30 49 18
A} 0 ° 0 0 °
oO} oo ° ° ° °
ml] i046 | 982 98.1 = 1004
S se] 35 29 23 - 17
Alo ° I = 1
a} o ° ° - °
mi 1044 103.5 103.9 31.0 102.7
ES SE 35 20 25 8.0 15
A} 0 1 ° 1 2
QO} o ° ° 1 1
mit 104.7 103.1 104.2 96.4 103.5,
al Sey 1S 15 16 48 09
A] oO v H V 3
oj} o ° ° i 1
Taste Summary of FEV,% data. A=number
y

of individuals with minor spirometric impair-
ment, defined as a % of measured FVC of
<75%. [)=number of individuals with mod-
erate spirometric impairment, defined as a %
of measured FVC of <65%. All other symbols
are defined in Table 2.

FEV) % AGE.

(%) 30-39_ 40-49 5059 =60 All
m] 833 eat | 813 eos | 824

NS SE] 07 or 12 ul 05
A} oO 1 3 ° 4
a} oo ° ° ° °
mt er 83 783 = 604

Ss se] 20 10 15 - 09
Al 2 f 5 - 8
Bl] ° ° - 1
mi 628 792 72 | 668 | 786
seu ul 18 80 Ml

ES “Alo 6 4 3 13
a] o ° 2 1 3
m) 626 | ei 736 | 737 | 806

Al SEL 08 06 0g 44 08
At 2 8 12 3 25
of ° 2 1 4

As reflected in Tables 3-7, most of the age
bracket/smoking category mean values for this
sample of the male general aviation population
exceeded the commensurate normal values for
the male United States population.? * Although
these data indicate a higher average-state-ot-
pulmonary-health in airmen, some individuals
within this sample did manifest spirometric
values that quantitatively indicated minor or
moderate spirometrie impairment. In Tables
3-7, the A symbol designates the number of indi-
viduals manifesting minor spirometric impair-
ment and the [] symbol, the number manifesting
moderate impairment. Minor spirometric im-
pairment was indicated by the data values of 25





Tasty 1—-NS=nonsmoker=never smoked, or
smoked for<1 pack year and had quit for>5
years, S=smoker=current smoker with a
total smoking amount of >5 pack years. ES=
ex-smoker=total smoking amount of >5 pack
years and had currently quit for>6 months.
Pack year=an average of 20 cigarettes smoked
per day per year. Age calculated to the near-
est completed year. Ht=height in cm meas-
ured in stocking feet. Wt=weight in ke
measured shirtless and shoeless and corrected
for residual clothing weight.2. FRW= Fram-
ingham relative weight=[actual weight in
pounds/136 pounds+4 (Ht in inches—60) ] x

100.°
Smoking Categories
NS s ES
m 45.5 445 48.1
‘ge sey out 12 ul
Ht m 175.5 77.5 1745
(cm) SE 08 0.8 0.8
83.1 84.1 820
wo
(kg) SE 15. \7 ik)
FRW m 1062 105.4 105.6
%) SE] 16 19 18
Amount mi} ou 296 325
Pimoked SE|| 0.007 2.4 35
N 69 55 57

using the directly measured parameters. A 12-
sec portion of the best 20-see MVV recording
was measured and proportionalized to represent
the MVV per minute. All gas volumes were
corrected to BTPS. As a correlate of FVC,
circumferential chest expansion (maximum in-
spiration minus maxinrum expiration) was meas-
ured in centimeters horizontally at the nipple
level with a steel tape according to a standard
anthropometric procedure.’

Ill. Results.

BMRC Questionnaire. This questionnaire
covers seven subjective respiratory symptom
areas and has a total of 27 yes/no questions.
Table 2 summarizes the percent of “yes” answers

for all subjects in each age bracket and smoking
category. In the “all ages” category, nonsmok-
ers manifested the fewest subjective respiratory
symptoms followed in ascending order by the
ex-smokers and smokers. This general sympto-
matic separation of the three smoking categories
was even more accentuated in each of the
“cough,” “phlegm,” “breathlessness,” “wheezing,”
and “weather” categories of the questionnaire.
The smaller percentage of respiratory symptoms
in the ex-smokers compared with the smokers
may reflect a real benefit of quitting the habit.
Within each smoking category, the relationship
of increasing subjective symptoms with age was
not as clear cut as might be expected. The un-
expected lowest percentage of symptoms occurred
in the nonsmokers who were 60 yr of age or older.
This probably reflects unique health maintenance
by these five older pilots, because most of their
spirometry parameters exceeded 100 percent of
their predicted normal values,

Spirometry. In this study, all FEV,, FVC,
and MVV values are expressed as percentages
of the predicted normal values based on the
Veterans Administration-Army  study.° All
FEF.;-;;% values are expressed in the same
manner but are based on the study of Morris
et a@l4* For these four parameters, 80 percent,
is the generally accepted threshold value for
minor spirometric impairment* and 70 percent,
for moderate impairment.’ AJl values greater
than 80 percent indicate normality, and those
between 70 and 80 percent indicate minor im-
pairment. For FEV,%, the commensurate
threshold values for minor and moderate spiro-
metric impairment are 75 percent and 65 percent
respectively.

The FEV,, FVC, FEV,%, MVV, and
FEF.,-;:% data are summarized in Tables 3-7;
age brackets and smoking categories are identical
to those in Table 2. Subject numbers in each
age bracket/smoking category are omitted from
these five tables because the identical data are
compiled in Table 2. For all five parameters,
the data within each age bracket reveal a general
pattern of greatest separation between the non-
smokers and the other two smoking categories.
Tn the “all ages” category of each table, an ex-
pected stronger data separation between the
smokers and ex-smokers was most probably
diluted by the complete absence of data for
the>60-year-old smokers, Although sufficient


Taste 6.—Summary of MVV data. All symbols
are defined in Table 3.

Mvv AGE

(%Pred) 30°39 _ 40-49 50°59 260 _All
nf use | 239 | 114 93 | 1251

NS SE} 58 37 48 i64 | 28
Al o ° ° ° °
ay oo ° ° ° °
mf izit igs 1138 = N83

S se] 60 57 40 _ 30
Ai 0 ° _ f
QO ! ° ° _ 1
ml] woo | a4 | ure e565 | 1125

ES sey 34 38 60 127 32
Ajo i 0 2 3
Oo} o ° ° 2 2
mf nes 192 1213 toz4 | ig

Al Sef 35 25 3.1 135 18
Ay 1 0 2 4
ie) ° ° 2 3

Taste 7—Summary of FEF, 5.75% data. All
symbols are defined in Table 3.

FEFos-75% AGE
(%Pred) 30°39 40-49 50-59 260 All
ml 1075 1.0 224 | 20 | 133
NS se] 49 47 74 78 3
A 4 ' 1 oO 6
oy o ° ° ° °
m 98.7 99.9 90.9 _ 965
S se] 66 65 55 _ 36
Ay 3 5 5 _ 13
ay 1 2 5 _ 8
mi 104.5 945 105.0 59.0 965
ES Se 7.4 6.) iad 144 43
ye) 8 4 4 16
Qy oo 7 3 3 13
m] 1036 | 117 | 66 | 655 | 1029
Al SEY 36 34 43 7 22
Al 7 14 10 4 35
Qa | 9 8 3 2

individuals (13.8%) for FEV,% (Table 5) and
by 35 individuals (19.3%) for FEF»,-:5% (Table
7). At most, only 2.2 percent of the individuals
manifested minor spirometric impairment in
FEV,, FVC, and MVV (Tables 3, 4, and 6).
Although only 4 (2.2%) subjects manifested
data values indicating moderate impairment for
FEV,%, 21 (11.6%) did so for FEF,;-;,%. The
greater prevalence of moderate impairment for
this latter parameter is not surprising in view
of the general knowledge that FEF,;-7,% is a
more sensitive detector of peripheral airway im-
pairment, which is usually manifested earlier in
COPD than spirometric impairment of the more
proximal larger airways.®

Because analysis of the circumferential chest
expansion data revealed no useful distinctions,
further consideration of this parameter was
deemed unnecessary.

IV. Discussion.

Although the general value of a BMRC-type
of questionnaire is well recognized, its use as a
quantitative reflection of COPD is somewhat
limited.* The cigarette-smoking history is a bit
more rewarding in its use, because it has been
established that both the number of cigarettes
smoked per day and the number of years of such
inhaled smoking are directly related to the se-
verity of COPD." The pack-year unit continues
to be useful in this regard.*

As reflected in Tables 3-7, substantial amounts
of minor and moderate spirometric impairment
were manifested in this sample of male general
aviation pilots. Table 8 summarizes the pereent-
ages of prevalence of minor and moderate spiro-
metric impairment for all five spirometric
parameters combined. The %A symbol desig-
nates the percentage of individuals manifesting
minor impairment in at least one spirometric
parameter; the %[] designates the percentage of
individuals manifesting moderate impairment in
at least one parameter. In the “all ages” cate-
gory of Table 8, (i) the smokers and ex-smokers
clearly manifest much greater prevalences for
minor and moderate impairment compared to
the nonsmokers and (ii) the greater prevalences
for the ex-smokers compared with the smokers
is most probably due to the absence of data for
the>60-year-old smokers, because the average
number of pack-years of smoking for this latter
group probably equals or exceeds the 85.4 pack-
year average for the>60-year-old ex-smokers
who had already ceased smoking for 12.4 yr.
In all three smoking categories combined in
Table 8, (i) a trend of increasing prevalence for
minor and moderate spirometric impairment with
age is manifested; (ii) the expected largest age-
related prevalence of spirometric impairment
manifested by the>60-year-old group are prob-
ably underestimates because of the absence of
data for the>60-year-old smokers; and (iii) the
first sharp increase in prevalence of moderate
spirometric impairment occurs in the fourth age
decade and is due mainly to the smokers and
ex-smokers. The prevalence values appearing in
Table 8 are due almost entirely to impairment
of FEV,% and FEF),;-;3%. This general find-
ing is completely consonant with the accepted
theory that the earliest manifestation of COPD
is usually peripheral airway impairment.” These
data suggest that a reasonable quantitative


Technical Report Documentation Page

Ty Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM~77-3
4, Title and Subtitle 5. Report Date
SPIROMETRIC ASSESSMENT OF POTENTIAL RESPIRATORY
IMPAIRMENT IN GENERAL AVIATION AIRMEN 6. Performing Organization Code

[8. Performing Organization Report No.

7, Author's) Michael T. Lategola, Marinus Flux, and
Peggy J. Lyne

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

Oklahoma City, Oklahoma 73125

T3. Type of Report and Period Covered

12, Sponsoring Agency Name ond 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 Task AM-A-76-PHY-92.
16, Abstract

Chronic obstructive pulmonary disease continues to manifest an increasing prevalence
in male Americans. A recent study of commercial airline pilots revealed a 12-percent
prevalence of minor-to-moderate spirometric impairment, Because commensurate data
were not available for general aviation pilots, in whom such impairment could also
compromise flight safety, a parallel study was made,

The British Medical Research Council and smoking questionnaires, chest expansion,
and spirometric measurements of FEV), FVC, FEV, MV, and -FEF95_7 y, were assessed
in 181 male general aviation pilots. All data showed a general cat eeionship to
increasing age and amount of smoking. Based on FEV]% and FEF95..757, combined,
minor degrees of spirometric impairment were exceeded by 25.4 percent of the pilots
and moderate degrees, by 12.7 percent. Negligible impairment was reflected in the
remaining spirometric parameters. Subsequent testing of such spirometrically
impaired pilots for altitude, fatigue, and orthostatic tolerances related to
general aviation is planned.

17, Key Words 18, Distribution Statement

General Aviation Airmen, Spirometric Document is available to the public

Impairment, Chronic Obstructive through the National Technical Information

Pulmonary Disease, Flight Safety Service, Springfield, Virginia 22151

19. Security Claseif, (of this report) 20, Security Classif. (of this page) 21. No. of Pages | 22. Price
Unclassified Unclassified

Form DOT F 1700.7 (8-72) Reproduction of completed poge authorized



Taste 8—Summary of % prevalence of minor
and moderate spirometric impairment. %A=
percentage of individuals having at least one
spirometric value <75% for FEV,% or <80%
for the remaining four spirometric parameters.
%C)= percentage of individuals having at least
one spirometric value <65% for FEV,% or
<70% for the remaining spirometric param-
eters. All other symbols are defined in Table 2.

screening for spirometric impairment in airmen
can be achieved by using only the expired FVC
maneuver from which both FEV,% and
FEF 575% are measured.

On the basis of objective quantitative data,
substantial amounts of minor and moderate
spirometric impairment were manifested in this
sample of male general aviation pilots. How-
ever, for any such airman, the appearance of a

Prevalence of AGE. measured value that: is quantitatively equivalent

ioc 30-3940-49 50-59 __=60 All to minor or moderate spirometric impairment

%A) 227 @1 200 0 159 implies only the possibility of an existing medi-

NS gol o ° 50 ° 14 cal pulmonary condition that could adversely

Nf 22 22 20 5 69 affect safe flight. Spirometry is merely a way

eal 263 278 389 _ 309 of quantitating the various mechanical aspects

S ~o} 105 ml 278 — 164 of ventilatory impairment. Whether the quan-

nN} 19 ig Ig = 55 titated minor-to-moderate spirometric impair-

wal o 375 250 800 | 316 ment observed in this study constitutes an

ES aol oo 292 15.0 600 | 228 incursion on safe flight to any degree can be

nj o8 24 20 5 87 ascertained only by testing such spirometrically

%AL 204 25.0 276 400 254 impaired pilots in critical aspects of flight safety

All xo} 4 141 155 300 | 127 such as altitude, fatigue, and orthostatic toler-

Np 49 84 58 to 81 ances. Such studies have already been planned.
References

1, American College of Chest Physicians, Committee 9. Gelb, A. F., and B. J, MacAnally: Early Detection

on Pulmonary Disease: Clinical Spirometry, DIS.

CHEST, 43:214-219, 1963.
. American Lung Association and American Thoracic
Society: Report of the Task Force on Comprehen-
sive and Continuing Care for Patients with Chronic
Obstructive Pulmonary Disease, American Lung As-
sociation, 1975, p. 3.
Bates, D. V., and R. V. Christie: Respiratory Func-
tion in Discase, Philadelphia and London, Saunders,
1964, p. 91.
. Catlett, G. F., and G. J. Kidera: Detection of Res-
piratory Impairment in Pilots, AEROSP. MED.,
40 31252-1257, 1969.

Dawber, T. R., F. E. Moore, and G. V. Mann: Coro-
nary Heart Disease in the Framingham Study, AM.
J. PUB, HEALTH, 47:(suppl.) 4-24, 1957.
6, FAA Office of Aviation Medicine: Guide for Aviation
Medical Examiners, Washington, D.C., U.S. Govern-
ment Printing Office, 1970, p. 40,
Ferris, B. G. Jr, and H. W. Stoudt: Correlation of
Anthropometry and Simple Tests of Pulmonary
Function, ARCH, ENVIRON. HEALTH, 22 :672-676,
1971.
Ferris, B. G. Jv, IT. 'T. Higgins, M. W. Higgins,
and J. M. Peters: Chronic Nonspecific Respiratory
Disease in Berlin, New Hampshire, 1961-1967, A
Follow-up Study, AM. REV. RESP, DIS., 107:110-
122, 1978.

i

2

s

o

a

w%

of Obstructive Lung Disease by Analysis of Maximal
Expiratory Flow-Volume Curves, CHEST, 64:749-
753, 1973.

10. Kory, R. CG. R. Callahan, H. G. Boren, and J. C.
Syner: The Veteran’s Administration-Army Coop-
erative Study of Pulmonary Function: I. Clinical
Spirometry in Normal Men, AM. J. MED., 80:243-
258, 1961.

11. Medical Research Council's Committee on the
Aetiology of Chronic Bronchitis: Standardized
Questionnaires on Respiratory Symptoms, BR. MED.
J., 2 21665-1670, 1960.

12. Morris, J. F., A. Koski, and L. C. Johnson: Spiro-
metric Standards for Healthy Nonsmoking Adults,
AM, REY. RESP. DIS., 108 :57-67, 1971.

13. Roberts, J.: The Mortality fram Emphysema and
Bronchitis Still Goes Up, PUBLIC HEALTH RE-
PORTS, 90 :382-383, 1975.

14, Rose, G. A., and H. Blackburn: Cardiovascular Sur-
yey Methods, WHO Monograph Series, 56 :1-188,
1968.

. Wilhelmsen, L., and G, Tibblin: Tobacco Smoking
in Fifty-Year-Old Men: I. Respiratory Symptoms
and Ventilatory Function Tests, SCAND, J. RESP.
DIS., 47 :121-130, 1966.



Acknowledgment

The authors sincerely acknowledge the contributions of Drs. Samuel F.
Flynn and Lyle B. Cartwright in the areas of recruitment and medical
screening of subjects.


SPIROMETRIC ASSESSMENT OF POTENTIAL RESPIRATORY IMPAIRMENT
IN GENERAL AVIATION AIRMEN

I. Introduction.

Chronic obstructive pulmonary disease
(COPD) mainly encompasses emphysema,
chronic bronchitis, and asthma. Recent statistics
indicate an increasing prevalence of COPD in
the American population. *® The risk of in-
curring COPD is estimated at 5 to 10 times
greater in men than in women.‘ In° general,
COPD is positively correlated with age, inhaled
cigarette smoking, and contamination of the
gaseous environment.®

Several variations of COPD of “sufficient de-
gree to be symptomatic” and/or “to interfere
with pulmonary function” are among the condi-
tions for which medical certification of airmen
is denied or deferred.’ Quantitative spirometric
standards for healthy, normal American males
have been established by previous  studies.*? ”
Quantitative spirometry in a recent study of 257
commercial airline pilots (40-59 yr of age)
showed that minor-to-moderate spirometric im-
pairment existed in 12 percent of this population
and was highly correlated with age and ciga-
rette smoking.* Unless clinically indicated,
quantitative spirometric evaluation is not a man-
datory part of the aeromedical examination.
Minor-to-moderate spirometric impairment could
adversely affect safe flight by the general avia-
tion pilot breathing only ambient air at cabin
altitudes approaching 12,500 ft.

Currently, published prevalence data on minor-
to-moderate degrees of spirometric impairment
in general aviation pilots do not appear to exist.
Based on quantitative spirometry, the main ob-
jectives of this study are to ascertain if minor
spirometric impairment is present or exceeded in
the male general aviation population and, if
present, at what age threshold such impairment
appears in the nonsmokers (NS), smokers (S),
and ex-smokers (ES) of this population, If
spirometric impairment is present to substantial
degrees, additional research can be initiated to

test. the effect of such degrees of impairment on
critical aspects of safe flight. Any adverse effect
revealed by such testing could be countered by
an educational Advisory Circular and/or the
formulation of a relevant screening aeromedical
standard based on quantitative spirometric
values.

II. Materials and Methods.

Selection of Subjects. Volunteer males, 30 yr
of age or older, were recruited from personnel
of the FAA Aeronautical Center and residents
of communities surrounding Oklahoma City.
Each volunteer was a general aviation pilot and
possessed a current airman medical certificate at
the time of spirometric assessment. Prior to.
spirometry, each subject was examined medically
for any thoracie condition that would preclude
testing of this type. A questionnaire on smoking
historyTM and one by the British Medical Re-
search Council (BMRC) on respiratory symp-
toms" were completed by all subjects. Age,
height, weight, Framingham relative weight, and
total number of pack years of inhaled cigarette
smoking for all subjects in each smoking cate-
gory are summarized in Table 1.

Spirometry Protocol. All spirometry was
conducted in a temperature-controlled room with
each subject seated in a comfortable padded
chair, A Collins 13.5-liter spirometer was used
to obtain timed paper recordings of the expira-
tory forced vital capacity (FVC) and maximum
ventilatory volume (MVV) maneuvers. Both
maneuvers were conducted in accordance with
standardized clinical spirometry procedures.*
For each of these two maneuvers, the best re-
cording from three maximum efforts was selected
for subsequent analysis? From the FVC re-
cording, the 1-see forced expired volune (FEV,),
the FVC, and the forced midexpiratory flow
(FEF,;-;;%) were measured directly. The
FEV,/FVC x 100 (FEV,%) was calculated by