Body mass index, respiratory conditions, asthma, and chronic obstructive pulmonary disease

Background This study aims to assess the relationship of body mass index (BMI) status with respiratory conditions, asthma, and chronic obstructive pulmonary disease (COPD) in a state population. Methods Self-reported data from 11,868 adults aged ≥18 years in the 2012 South Carolina Behavioral Risk Factor Surveillance System telephone survey were analyzed using multivariable logistic regression that accounted for the complex sampling design and adjusted for sex, age, race/ethnicity, education, smoking status, physical inactivity, and cancer history. Results The distribution of BMI (kg/m²) was 1.5% for underweight (<18.5), 32.3% for normal weight (18.5-24.9), 34.6% for overweight (25.0-29.9), 26.5% for obese (30.0-39.9), and 5.1% for morbidly obese (≥40.0). Among respondents, 10.0% had frequent productive cough, 4.3% had frequent shortness of breath (SOB), 7.3% strongly agreed that SOB affected physical activity, 8.4% had current asthma, and 7.4% had COPD. Adults at extremes of body weight were more likely to report having asthma or COPD, and to report respiratory conditions. Age-adjusted U-shaped relationships of BMI categories with current asthma and strongly agreeing that SOB affected physical activity, but not U-shaped relationship with COPD, persisted after controlling for the covariates (p < 0.001). Morbidly obese but not underweight or obese respondents were significantly more likely to have frequent productive cough and frequent SOB than normal weight adults after adjustment. Conclusion Our data confirm that both underweight and obesity are associated with current asthma and obesity with COPD. Increased emphasis on exercise and nutrition may improve respiratory conditions.