Associations of asthma with body mass index and adult weight change among reproductive age women

Objective. To evaluate the cross-sectional relationship between asthma and pre-gravid body mass index (BMI), and to assess the risk of adult weight change among women with history of asthma diagnosed in childhood or adulthood, respectively. Study design. Study participants were 3737 pregnant women enrolled in a cohort study. Information on history of asthma, pre-gravid BMI, adult weight change (difference between BMI at age 18 and pre-gravid BMI), and other sociodemographic characteristics was collected using interviewer-administered questionnaires. Pre-gravid BMI was categorized into lean (BMI < 18.5 kg/m²), overweight (BMI = 2524.9 kg/m²), and obese (BMI ≥ 30 kg/m²). Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results. Approximately 13.1% of study participants reported history of asthma. Compared with the reference group (BMI = 18.524.9 kg/m²), the odds of asthma was higher among overweight (OR = 1.51; 95% CI = 1.181.93) and obese (OR = 1.47; 95% CI = 1.062.03) women while it was lower among lean women (OR = 0.42; 95% CI = 0.210.84) (trend p-value <.001). Women who gained ≥20 kg compared with those who maintained their weight (±2.5 kg) had a 2.7-fold increased odds of asthma (95% CI = 1.027.00). Conclusions. Overweight and obese women were more likely to have a history of asthma. Adult weight gain was positively associated with asthma diagnosis. Longitudinal studies designed to prospectively assess patterns of adult weight change in relation to asthma are warranted.