Childhood body size and risk of chronic obstructive pulmonary disease in adulthood: a prospective cohort study.

Introduction: Although previous studies have suggested links between childhood body size and lung function and asthma in adolescence and adulthood, the association with COPD is unclear. Therefore, we investigated whether trajectories of body mass index (BMI) in childhood were associated with COPD in adulthood.

Methods: In this prospective cohort study, we included 276,747 children born from 1930-1982, with weight and height measurements available at ages 6-15 years from the Copenhagen School Health Records Register. We followed individuals from 1977 to 2022 in national health registers and identified those with a COPD diagnosis from age 40 years onwards. Hazard ratios (HR) and 95% confidence intervals (CI) for the associations between five childhood BMI trajectories and COPD were estimated separately for females and males using Cox proportional hazard regression analyses.

Results: During follow-up, 18,227 females and 15,789 males had a COPD diagnosis. Compared to females with an average childhood BMI trajectory, a higher hazard of COPD was observed for females who had an above-average (HR=1.10; 95%CI: 1.06-1.15), overweight (HR=1.26; 95%CI: 1.20-1.33) or obesity BMI trajectory (HR=1.65; 95%CI: 1.50-1.83). Results were largely similar for males. Among females, a below average childhood BMI trajectory was associated with a lower hazard of COPD (HR=0.91; 95%CI: 0.87-0.95).

Conclusion: We found that a BMI trajectory above average throughout childhood was positively associated with COPD in adulthood. Thus, our results suggest that having overweight or obesity during this early period of life is an indicator of risk for the later development of COPD.