Fitness, obesity and risk of asthma among Army trainees.

BACKGROUND Epidemiological data suggest an association between overweight/obesity and asthma. However, less is known about the relationship between physical fitness and asthma. AIMS To enumerate new-onset asthma diagnoses in Army recruits during the first 2 years of service and determine associations with fitness and excess body fat (EBF) at military entrance. METHODS New asthma diagnoses over 2 years in Army recruits at six entrance stations were obtained from military health and personnel records. Poisson regression models were used to determine associations of asthma diagnosis with pre-accession fitness testing, EBF and other potential factors. RESULTS In 9979 weight-qualified and 1117 EBF entrants with no prior history of asthma, 256 new cases of asthma were diagnosed within 2 years of military entry. Low level of fitness, defined by a step test and EBF, was significantly associated with new asthma diagnosis [adjusted incidence rate ratio (IRR), 1.47; 95% confidence interval (CI) 1.11-1.96 and adjusted IRR, 1.53; 95% CI 1.06-2.20, respectively]. CONCLUSIONS Individuals with low fitness levels, EBF or both are at higher risk of asthma diagnosis in the first 2 years of military service.