Active commuting and the risk of obesity, hypertension and diabetes: A systematic review and meta-analysis of observational studies

Active commuting may hold a potential for preventing adverse health outcomes. However, evidence of the association of active commuting and the risk of health outcomes remains debatable. The current study systematically and quantitatively summarised research findings on the association between active commuting and the risk of the mentioned health outcomes. We comprehensively searched four databases (PubMed, EMBASE, Web of Science and Open Grey) from inception to 2 August 2020 for observational studies investigating the associations among adult population. Summary relative risks (RRs) and 95% CIs were estimated for the association. Heterogeneity was investigated using Cochran's Q test and the I 2 statistic. Restricted cubic splines were used to evaluate linear and nonlinear relations. The search yielded 7581 initial references. We included 28 articles in the meta-analysis. Compared with inactive commuting, active commuting reduced the risk of obesity (RR=0.88, 95% CI 0.83 to 0.94, I 2 =69.1%), hypertension (RR=0.95, 95% CI 0.87 to 1.04, I 2 =82.2%) and diabetes (RR=0.82, 95% CI 0.76 to 0.90, I 2 =44.5%). Restricted cubic splines showed linear associations between active commuting and obesity, hypertension and diabetes (P nonlinearity =0.640; P nonlinearity =0.886; P nonlinearity =0.099). As compared with the lowest active commuting group, the risk of obesity, hypertension and diabetes in the highest active commuting group were reduced by 13% (95% CI 0.82 to 0.93, I 2 =65.2%); 6% (95% CI 0.86 to 1.02, I 2 =75.2%) and 19% (95% CI 0.73 to 0.91, I 2 =49.8%) respectively. Active commuting seemed to be associated with lower risk of obesity, hypertension and diabetes. However, the results should be interpreted cautiously because this meta-analysis was based solely on observational studies. PROSPERO registration number CRD42020202723.