Fruit and Vegetable Intake and the Risk of Chronic Obstructive Pulmonary Disease: A Dose-Response Meta-Analysis of Observational Studies

Object. Results on the associations of fruit and vegetable intake with risk of chronic obstructive pulmonary disease (COPD) are still in conflict. Hence, we conducted a meta-analysis to quantitatively evaluate the association between fruit and vegetable intake and the risk of COPD. Methods. PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI) were searched for relevant studies published up to September 2019. Combined relative risks (RRs) and 95% confidence intervals (CIs) were calculated with the random effects model (REM). Dose-response relationship was assessed by the restricted cubic spline model. Results. There are 8 studies involving 5,787 COPD cases among 244,154 participants included in this meta-analysis. For the highest versus the lowest level, the pooled RR of COPD was 0.75 (95% CI, 0.68–0.84; I2 = 46.7%) for fruits plus vegetables, 0.72 (95% CI, 0.66–0.79; I2 = 1.3%) for fruits, and 0.76 (95% CI, 0.63–0.92; I2 = 62.7%) for vegetables. In subgroup analysis of fruit plus vegetable intake and COPD risk, the inverse association exists in all three study designs. A nonlinear dose-response relationship was found for COPD risk with fruit ( ). Conclusions. This meta-analysis indicates that fruit and vegetable intake might be related to a lower risk of COPD.