Fit to fly: Britain's commercial airline pilots have fewer cardiovascular risk factors than the general population

One of the largest ever studies to examine the prevalence of cardiovascular risk factors among commercial aircrew has found significantly lower prevalence of smoking and obesity than in the general population, even when comparisons were made with comparably high income earners.

The study, reported today in the European Journal of Cardiovascular Prevention and Rehabilitation, was an analysis of data derived from the medical examinations of 14,379 pilots holding a commercial standard medical certificate issued in the UK.(1) Only 5.6 per cent were women, which, say the investigators, represents the proportion of the UK pilot workforce.

The risk factors evaluated (within stratified age bands) were body mass index, overweight and obesity, smoking, hypertension and diabetes. Prevalence rates were compared first with those of the UK general population as represented by the 2006 Health Survey for England, and then with those of the "highest income quintile" of the general population to control for the influence of socio-economic status.(2)
Results showed that the pilots had significantly lower prevalence of smoking and obesity compared to the general population.

• Body mass index. While overall mean BMI was significantly lower in almost all pilot age groups than in the general population, the prevalence of overweight (BMI 25-30kg/m2) among male pilots increased with age (as in the general population), and even tended to be higher in age groups under 25 and between 35 and 64. Conversely, female pilots tended to have a lower prevalence of overweight than the general population. However, both male and female pilots had significantly lower prevalence of obesity (BMI 30+kg/m2) than the general population (in many cases more than half the rate). For example, among the UK general population obesity rates among the 25-34 year age group were 21 per cent, but among the airline pilots 8.3 per cent.
• Smoking. The highest prevalence of current smoking among the pilots was in the 25-34 age band for men (10 per cent) and under 25 for women (8 per cent). However, overall smoking status among the pilots was generally much lower than in the general population. Indeed, smoking rates among the pilots were around three times lower than in the general population.Hypertension. Hypertension, defined as readings above 140/90 mmHg, increased with age (as in the general population), with some statistically significant differences according to age.
• Diabetes. Because diabetes sometimes precludes certification of commercial pilots, only 0.2 per cent of male pilots (and none female) were found to be diabetic.

When age-matched to the highest income quartile of the general population, prevalence differences were as follows:

The differences in prevalence rates for smoking and obesity were statistically significant.
Commenting on the results, principal investigator Dr Stephen Houston, Chief Medical Officer for the airline bmi, British Midland International, said: "Aviation authorities throughout the world have become increasingly interested in profiling the cardiovascular risk of commercial pilots. In Australia, for instance, further ECG stress testing is required for crew who have risk factors above a certain level.”

"What our study indicates is that the prevalence of two important cardiovascular risk factors among UK pilots - smoking and obesity - is much lower than in the general population. The higher rates of overweight may be because of the sedentary lifestyle, irregular shift work patterns and the poor diet associated with night-stopping away from home.”

"This is one the largest studies ever performed on cardiovascular risk factors among aircrew, and the results have strength because of the study's size. However, we can't rule out a 'healthy worker effect'. Since an individual must be relatively healthy to be employable and to remain in the workforce, it follows that cardiovascular morbidity and mortality may be lower than in the general population."

ENDS