Gender-specific determinants of asthma among U.S. adults.

Background: Asthma, a chronic respiratory disease affecting over 18.7 million American adults, has marked disparities by gender, race/ethnicity and socioeconomic status. Our goal was to identify gender-specific demographic and socioeconomic determinants of asthma prevalence among U.S. adults using data from the Behavioral Risk Factors Surveillance System (BRFSS) and the National Health and Nutrition Examination Survey (NHANES).

Methods: Gender-specific regression analyses were performed to model the relationship between asthma prevalence with age, race/ethnicity, income, education level, smoking status, and body mass index (BMI), while taking into account the study designs.

Results: Based on BRFSS data from 1,003,894 respondents, weighted asthma prevalence was 6.2% in males and 10.6% in females. Asthma prevalence among grade 2 obese and grade 3 obese vs. not overweight or obese women was 2.5 and 3.5 times higher, respectively, while that in men was 1.7 and 2.4 times higher; asthma prevalence among current vs. never smoker women was 1.4 times higher, while that in men was 1.1 times higher. Similar results were obtained with NHANES data from 13,364 respondents: asthma prevalence among grade 2 obese and grade 3 obese vs. not overweight or obese respondents was 2.0 and 3.3 times higher for women, though there was no significant difference for men; asthma prevalence among current vs. never smokers was 1.8 times higher for women and not significantly different in men. Asthma prevalence by race/ethnicity and income levels did not differ considerably between men and women.

Conclusions: Our results underscore the importance of obesity and smoking as modifiable asthma risk factors that most strongly affect women.