Predictors of lung function in early adulthood: A population-based cohort study

Background and ObjectiveLung function reaches a peak/plateau in early adulthood before declining with age. Lower early adult lung function may increase the risk for chronic obstructive pulmonary disease (COPD) in mid-late adult life. Understanding the effects of multiple childhood/adolescent exposures and their potential interactions on plateau lung function would provide insights into the natural history of COPD.MethodsLongitudinal spirometry data from 688 participants with complete data from a population-based birth cohort (original n = 1037) were used to investigate associations between a wide range of childhood/adolescent exposures and repeated measures of FEV1, FVC and FEV1/FVC during the early-adult plateau phase. Generalized estimating equations were used to accommodate the multiple timepoints per participant.ResultsFEV1 reached a peak/plateau between ages 18 and 26 and FVC from 21 to 32 years, whereas FEV1/FVC declined throughout early adulthood. Childhood asthma and airway hyperresponsiveness were associated with lower early adult FEV1 and FEV1/FVC. Smoking by age 18 was associated with lower FEV1/FVC. Higher BMI during early adulthood was associated with lower FEV1 and FVC and lower FEV1/FVC. Physical activity during adolescence was positively associated with FEV1 and FEV1/FVC but this was only statistically significant in men. There was no convincing evidence of interactions between exposures.ConclusionChildhood asthma and airway hyperresponsiveness are associated with lower lung function in early adulthood. Interventions targeting these may reduce the risk of COPD in mid-late adult life. Promotion of physical activity during adolescence, prevention of cigarette smoking and maintenance of a healthy body weight in early adulthood are also priorities. Childhood asthma and airway hyperresponsiveness, and higher adult body mass index are associated with lower lung function in early adulthood and may enhance the risk for COPD in later life. Conversely, physical activity is associated with higher adult lung function, especially among boys, and may be protective.