Association between leptin and asthma in adults.

BACKGROUND Leptin, a pro-inflammatory cytokine produced by adipose tissue, has previously been shown to be associated with asthma in children. We hypothesised that high serum leptin concentrations would also be associated with asthma in adults. METHODS The Third National Health and Nutrition Examination Survey is a cross sectional study that included fasting serum leptin concentrations and self-report of doctor diagnosed asthma. Data were analysed using multivariable logistic regression analysis. RESULTS Of 5876 participants, those with current asthma had a higher mean unadjusted leptin concentration than those who had never had asthma (geometric mean (SE) 9.2 (0.6) microg/l v 7.6 (0.2) microg/l; p = 0.02). After adjustment for triceps skinfold thickness and other covariates, the association between leptin and asthma appeared stronger in women than in men, and in premenopausal women than in postmenopausal women. Body mass index (BMI) was also associated with current asthma in women, but this association was not significantly affected by adjustment for leptin concentrations. CONCLUSIONS The results of this large population based study support the hypothesis that leptin is associated with asthma in women. In addition, while BMI also is related to asthma in women, this study does not support the suggestion that leptin contributes significantly to this association.