Birth Weight and Lung Function in Adulthood: A Systematic Review and Meta-analysis

Rationale There is evidence suggesting that birth weight may influence lung function in adulthood, but it is unclear whether it might differentially affect restrictive (FVC) and obstructive (FEV1/FVC) patterns. Objectives To summarize evidence available on the association of birth weight, weight at 1 year, and weight gain in the first year of life with FVC and FEV1/FVC in adulthood. Methods We performed a systematic review of the literature by searching MEDLINE, EMBASE, and Web of Science through January 2015. Data were combined using inverse-variance weighted meta-analysis with random effects models and between-study heterogeneity evaluated. We conducted a priori subgroup or sensitivity analyses by age, country wealth, ethnicity, sex, and smoking. We evaluated risk of bias using the Newcastle Ottawa Scale and reporting bias using funnel plots. Results Eighteen articles were included in the review and 13 in the meta-analyses. Most studies were from high-income countries, and all had a low risk of bias. We found strong evidence of an association of birth weight with adult FVC, a 59.4 ml higher FVC in adulthood per kilogram increase in birth weight (95% confidence interval, 43.3–75.5), with no evidence of heterogeneity. Evidence of an association of birth weight with FEV1/FVC was weaker and showed some inconsistency across studies. Only one study investigated weight at 1 year, and another one reported weight gain in the first year. Conclusions Our meta-analyses show strong and consistent evidence of an association of birth weight with adult FVC, a measure of restrictive impairment, with much weaker evidence for airflow obstruction.