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, . Report No. 2. Government Accession No. 3. Rec.p.ent's Catalog No.

4 FAA-AM-81-9 ,4 J) ~4. Title and Subt,tle a . * n

, PREVALENCE OF SELECTED PATHOLOGY AMONG CURRENTLY April 1981

CERTIFIED ACTIVE AIRMEN 6. Performing Orgonization Code

8. Performing Organization Report No,

7. Author, s)

Charles F.Booze. Jrl9. PeYfmttyrg'gTgq ironfe and Address 10. Work Unt No. ITRAISJ

FAA Civil Aeromedical InstituteP.O. Box 25082 11. Contract ,, .... No.

Oklahoma City, Oklahoma 7312513. Type of Report and Period Coered

12. Sponsoring Agency Name and Address _

Office of Aviation MedicineFederal Aviation Administration •800 Independence Avenue, S.W. "-° / 14. Sponsorng Agency Code

Washington, D.C. 20591 -- ,_ _ _ __"

15. Supplementary Notes . t

16. Abstract

,-t has been the policy of the Federal Aviation Administration to medically certifyindividuals, for a variety of flying privileges, who also have medical deficiencyor disease, provided it can be determined that such action does not compromiseair safety. During recent years, for example, standards have been relaxed withrespect to contact lens use and medication allowed for control of hypertension.

This descriptive epidemiologic study presents the point prevalence of pathologyamong active airmen as of January 1, 1980, by major body system and for otherselected pathologies of interest within the major body systems. Data wereobtained from active computer files maintained by the Aeromedical CertificationBranch of the Civil Aeromedical Institute in connection with the certificationprogram. Some 350,701 (42%) active airmen require correction for some visualdeficiency. Of this total, 20,058 are contact lens wearers. After eye pathology,cardiovascular and abdominal pathology represent the most prevalent medicalconditions among active airmen (3.7% and 2.6% respectively).

Overall, disease prevalence is greater among currently certified airmen thanamong previous groups studied. This increase in prevalence is probably areflection of more liberal standards more than any other single factor.

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17. Key Words 18. Distribution Statement

Airman Certification (Medical) Document is available to the publicDisease, Prevalence and Incidence through the National Technical

Information Service, Springfield,Virginia 22161

19. Security Classif. (of this report) 20. Security Clossif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 10

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

I. -. .. .

PREVALENCE OF SELECTED PATHOLOGYAMONG CURRENTLY CERTIFIED ACTIVE AIRMEN

INTRODUCTION

The Federal Aviation Administration (FAA) and its predecessors havebeen charged with the responsibility for medical certification of allUnited States and some international civil airmen since 1927. Each airmanmust hold a current medical certificate of the appropriate class tovalidate any pilot certificates he or she may possess. As of January 1, 1980,an unprecedented 827,592 active airmen were medically certified. FederalAviation Regulations require that physical examinations must be performedat 6-month intervals for air transport pilots, annually for other commercialpilots, and at 2-year intervals for private pilots.

The Aeromedical Certification Branch of the Civil Aeromedical Institute(CAMI), located in Oklahoma City, Oklahoma, is the central screening facilityand repository within the FAA for collection, processing, adjudication,investigation, and analyses of medical data generated by the aeromedicalcertification and related regulatory programs.

Medical certification criteria have changed dramatically in favor ofthe airman during recent years as a result of the evolution of aviationmedicine and increased efforts in the area of aeromedical research. Aprimary function of CAMI is to identify and provide substantive data insupport of current medical criteria in the furtherance of aviation safetyas well as provide a better service to the airman. It has been the policyof the FAA to medically certify individuals, for a variety of flyingprivileges, who also have medical deficiency or disease, provided it canbe determined that such action does not compromise air safety. Duringrecent years, for example, standards have been relaxed with respect tocontact lens use and medication allowed for control of hypertension.

This descriptive epidemiologic study presents the point prevalence ofpathology among active airmen as of January 1, 1980, by age, class of medicalcertificate, major body system, and other selected pathologies of interestwithin the major body systems.

METHODS

Physical examinations to detect medical conditions which could incapaci-tate or otherwise adversely affect pilot performance are given by some 7,716designated aviation medical examiners (AMEs), most of whom are physiciansin private practice. Military applicants receive their examinations at 489designated military facilities. Reports of these examinations from through-out the world are forwarded to the Aeromedical Certi - n n h inOklahoma City.

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Federal Aviation Regulations, Part 67, specify that a medical certificatewill be denied if an applicant has an established medical history or clinicaldiagnosis of any of the following conditions.

1. A personality disorder that is severe enough to have repeatedlymanifested itself by overt acts.

2. A psychosis.3. Alcoholism.4. Drug dependence.5. Epilepsy.6. Disturbance of consciousness without satisfactory medical explanation

of the cause.7. Myocardial infarction.8. Angina pectoris or other eiidence of coronary disease.9. Diabetes mellitus, requiring insulin or other hypoglycemic drug

for control.

However, certification is possible despite the existence of one of theab~ve disqualifying medical conditions if exemption from the regulations isgzanted after extensive medical review by FAA and consultant specialists.The primary considerations in such exemption cases are history, prognosis,and potential risk of sudden incapacitation. It is appropriate to note,however, that airmen with disqualifying conditions are issued medicalcertificates with special medical and operational restrictions that allowfor control of risk.

Automated medical record files maintained by the Aeromedical Certifi-cation Branch provided the source data for the study. The files utilizedcontain only the most recent application for medical certification from anairman within the past 3 years. Pathology detected by previous medicalexaminations is brought forward to the current automated medical file inorder to maintain as complete a history as possible. While this filecontains records for a total of 3 years, a medically certified airman isconsidered "tv" for a maximum of 24 calendar months following his orher most recent FAA medical examination; i.e., regardless of the class ofmedical certificate originally issued, it is valid for third class airmanpurposes for a period of time up to 24 calendar months unless otherwiselimited or recalled by the FAA.

Prevalence data were automatically produced from the automated filesdescribed above. Prevalence data in this population are expected to besomewhat conservative since problems have been experienced in the acqui-sition of complete and accurate histories from pilots with a job, hobby,or aircraft investment to protect.

Prevalence data are obviously a function of incidence and duration ofdiseases; therefore, one would not expect the more immediately lethaldiseases to be represented to the same extent as less serious diseases oflonger duration. Additionally, airmen with more serious health problems

24

are likely to be denied medical certification and would not become eligiblefor study. These data do, however, indicate the relative importance ofvarious diseases among airmen, even though conservative in some instances,and provide insight concerning potential health problem interaction viththe aviation environment. Since general literature prevalence data arelimited with respect to some of the diseases reported on in this study,some further benefit is expected in that regard.

RESULTS AND DISCUSSION

Reference to Tables I and II indicates that eye diseases are the most Iprevalent medical problems among active airmen. While representing a seriousthreat to air safety if not recognized and treated by adequate correction,most eye pathology is relatively innocuous. Of the 827,592 active airmen asof January 1, 1980, some 42 percent (350,701) required lens correction forsome visual deficiency. Of this total,' 20,058 are contact lens wearers.Additionally, 5,156 airmen are certified to fly with blindness or absenceof an eye (which includes visual acuity worse than 20/200 uncorrected ineither eye). Serious incapacitation during flight is possible shouldcorrective lenses become dislocated and temporarily unavailable during acritical phase of flight. Considerable research effort has been and willcontinue to be devoted to this important area of potentially health-relatedpilot dysfunction.

Diseases of the cardiovascular system are the next most frequentlyobserved diseases among active airmen. As expected, hypertension is thegreatest contributor to the total prevalence rate. However, as may be seenin Table II, the prevalence of hypertension is only a fraction of that whichwould be expected in an unscreened population. The low prevalence of hyper-tension in this population is due to higher than usual upper limit cutoffsfor assignment of a hypertensive diagnosis among airmen (170/100 for appli-cants for second- and third-class certification, and only slightly morestringent for class one applicants). more severe hypertensive airman appli-cants are also excluded from this population due to the type or dosage ofmedication required for control. Mild diuretics without other derivativesand some beta-blockers in low dosage are currently allowed for hypertensioncontrol. Clearly this excludes many hypertensive applicants requiringlarger doses or combination of drugs for effective control.

Heart murmurs, including functional or physiologic murmurs, accountfor over 20 percent of all heart diseases observed to exist among activeairmen.

Prevalence of abdominal diseases is third in total body system impor-tance. Specific disesases making major contributions include currenthernias, history of kidney stones, and uncomplicated ulcers.

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Major body system prevalence rates for neuropsychiatric and bone andjoint diseases are approximately equal at 11.5 per 1,000 airmen. Withinthese systems no single disease entity makes a contribution significantenough to deserve separate mention. Both major body systems contain 30 to40 distinct disease categories, with each making minor contributions totalingthe approximate 11.5 per 1,000 rate for the major body system.

The "miscellaneous" category of disease includes endocrinopathies, skindiseases, drug usage by type, allergies, tropical diseases, and generalsystemic conditions. Nearly half of all disease observed in this categorywas "hay fever." Other major contributors to this category included anti-histamine drug usage, asthma, and diabetes controlled by diet.

The most prevalent diseases observed among active airmen are presentedin Table II. Diseases found to increase with age include hypertension,hernia, blindness or absence of an eye, defective hearing, history of neo-plasm, limitation of motion, peripheral vascular disease, arthritis, anddiabetes controlled by diet. Diseases demonstrating a trend of decreasewith age included contact lens use, hay fever, asthma, and disturbance ofconsciousness. Heart murmurs were most coummon among young and older ageswith lower prevalence among the middle ages. History of kidney stones andprevalence of uncomplicated ulcers appear to increase with age through themiddle ages and decrease among older ages.

These age/disease findings are consistent with expectation except forthe decreasing prevalence of hay fever with age, which may be due tounderreporting.

Disease is most prevalent among third class (general aviation) airmenand least prevalent among class one airmen (professional pilots). Sincethe professional pilot undergoes a more thorough and rigid examination andis subjected to stricter standards by the FAA as well as employers, onemust assume that these results reflect the effects of more thorough earlyscreening out of problem medical cases which results in less subsequentdisease among the remaining group, or that medical history (which wouldlead to disease detection) is being masked to a greater extent among theprofessional category pilots. Certainly the incentive is great, bothmonetary and otherwise, for the latter hypothesis.

The prevalence findings of this study and previous research effortsinvolving the airman population or segments thereof are generally similarwith respect to major body systems presenting the highest prevalence rates;i.e., eye, cardiovascular, and abdominal (1,2). However, as seen inFigure 2, prevalence rates are higher than those in previous studies formost major body systems partially due to the fact that prevalence, bydefinition, is an accumulation of disease at a point in time and would begreater in a given population at successive measurements for nonlethaldiseases. The second consideration with regard to increased prevalence ratessurely has to do with the fact that medical requirements have been relaxedover recent years to allow airmen to continue flying with various medicalproblems not previously acceptable.

6

Rates per 1.000 Airmen

Eye 46.6

ENT 2 . 3

F2.0Respiratory 2.4

2.2

Cardiovascular t 39.1(////////,-/ 36.7

Abdominal 27.1(G. I., G.U., etc.)

Neuropsychiatric 1.812.67.5 ,, , class

Bones and Joints 12.0 L 2nd Class0.8 1 3rd Class

Muscles 1.41.9

Miscellaneous 23.6 .7Endocrinopathles, 47.Drugs, etc.)

Fig. 1. Disease prevalence among active airmen by body system

and class of medical certificate.

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Rates per 1,000 Airmen

Eye 1.448.9

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Respiratory 2.3

Cardiovascular 3.

Abdominal - 57.0(G. I., G.U., etc.) 26.5

9.8Neuropsychlatric 11.9

Bones and Joints 11.

Muscles

Miscellaneous 1.(Endocrinopathles, 4 0.8Drugs, etc.)

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Fig. 2. Comparison of disease prevalence among airmen by

by body system, 1965 versus 1980.

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The substantial decrease in abdominal pathology between the 1965 and1980 prevalence studies is largely due to the fact that only current herniaconditions were included in the present study, and less importantly due toa decrease in the prevalence of uncomplicated ulcers from 1965 to 1980.

SUMMARY

Health findings in the active airman population are generally consistentwith those that might be expected in the general U.S. population, exceptscaled to reflect lower prevalence due to prescreening and other problemsassociated with accurate reporting of symptoms and history by pilots.

Eye disease is the most common problem among pilots with some 42 percentof all airmen requiring lens correction for some visual deficiency.

Cardiovascular diseases are next in frequency of occurrence amongactive airmen. As expected, hypertension is the greatest contributor tocardiovascular disease prevalence.

Abdominal disease prevalence is third in total body system importance.Major contributors to the category include current hernia conditions,history of kidney stones, and uncomplicated ulcers.

Overall, disease prevalence is greater among currently certifiedairmen than among previous groups studied. This increase in prevalence isprobably a reflection of more liberal standards more than any other singlefactor. Through the years the trend has been toward relaxation of medicalstandards where possible when not resulting in a compromise of air safety.

The greater prevalence of disease observed among general aviationpilots compared to professional pilots likely reflects the impact ofstricter standards and examination for professional pilots with somegreater masking of disease and history among the professional pilotssuspected.

Further civil aviation research priorities should consider conmmonmedical problems of airmen in an effort to elucidate possible health andflight environment interactions which could result in safety hazards.

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REFERENCES

1. Booze, C., 1973. Prevalence and incidence of disease among airmenmedically certified during 1965. FAA Office of Aviation MedicineReport No. AM-73-8.

2. Booze, C., 1979. Morbidity experience of air traffic control personnel -

1967-77. Aviation, Space, and Environmental Medicine, 50(1):1-8.

10*U. S. GOVIZm4MNNT PRDETUC 07FICK: 1991 341-428 1201