Observational and instrumental variable estimates of the effect of BMI on current asthma at ages 11 to 14-diagnosed asthma at ages 7½ to 15 y in boys and girls and stratified by atopy at 7½ y.

†Adjusted for gender, birth weight, pre- and postnatal maternal exposure to smoking, and maternal education.*Derived using ever doctor-diagnosed asthma (available at 7½, 11, 14, and 15 y) and parent-reported current asthma or wheezing or treatment in last 12 mo.DDA, doctor-diagnosed asthma; NA, not available.