Body composition from 18 to 22 years and pulmonary function at 22 years—1993 Pelotas Birth Cohort

The objective was to verify the association between body composition from 18 to 22 years and pulmonary function at 22 years of age. This longitudinal analysis was conducted with a Brazilian birth cohort data. The outcomes were the forced expiratory volume in the first second and forced vital capacity (FVC), measured at 22 years follow-up. Main exposures: obesity (body mass index ≥ 30kg/m2), and highest tertiles of fat mass (FM) and fat mass index (air displacement plethysmography) measured at 18 and 22 years-old follow-ups. The reference category (not exposed) was defined by those individuals who were not classified in the highest adiposity categories mentioned, in both ages. Multivariable linear regressions stratified by sex were used. The sample comprised 3,511 participants. Those who belonged to the highest adiposity categories in 18 and 22 years follow-ups showed lower pulmonary function at 22 years when compared to those who were not classified in the higher adiposity categories in both ages (reference category); those in the highest tertile of FM showed a mean FVC -313mL (95%CI -421; -206) and -259mL (95%CI -336; -182) in men and women, compared to the reference category, respectively. Those who changed from the higher to the lower adiposity categories (from 18 to 22 years) showed pulmonary function similar to the reference, and those who presented the opposite body composition trajectory, showed decreased pulmonary function results at 22 years, mainly among women. We concluded that high body adiposity in two follow-ups and especially contemporary adiposity was associated with lower pulmonary function at 22 years.