Lifestyle factors and hand eczema: A systematic review and meta-analysis of observational studies.

Evidence regarding the association between lifestyle factors and hand eczema is limited.To extensively investigate the association between lifestyle factors (smoking, alcohol consumption, stress, physical activity, body mass index, diet, and sleep) and the prevalence, incidence, subtype, severity, and prognosis of hand eczema, a systematic review and meta-analysis were conducted in accordance with the Meta-analysis Of Observational Studies in Epidemiology consensus statement. MEDLINE, Embase, and Web of Science were searched up to October 2021. The (modified) Newcastle-Ottawa Scale was used to judge risk of bias. Quality of the evidence was rated using the Grades of Recommendation, Assessment, Development and Evaluation approach. Eligibility and quality were blindly assessed by two independent investigators; disagreements were resolved by a third investigator. Data were pooled using a random-effects model, and when insufficient for a meta-analysis, evidence was narratively summarized. Fifty-five studies were included. The meta-analysis (17 studies) found very low quality evidence that smoking is associated with a higher prevalence of hand eczema (odds ratio 1.18, 95% confidence interval 1.09-1.26). No convincing evidence of associations for the other lifestyle factors with hand eczema were found, mostly due to heterogeneity, conflicting results, and/or the limited number of studies per outcome.