Association between domain-specific sedentary behaviour and endometrial cancer: a systematic review and meta-analysis

OBJECTIVE: Sedentary behaviour is associated with increased cancer risk. We aim to assess the associations of domain-specific and total sedentary behaviour with risk of endometrial cancer, with additional attention paid to potential differences in adjustment strategy for obesity and physical activity. DESIGN: A systematic review and meta-analysis was conducted in accordance with the guidelines of Preferred Reporting Items for Systematic Reviews (PRISMA) and Meta-Analyses and the Meta-analysis of Observational Studies in Epidemiology (MOOSE). DATA SOURCES: PubMed, Embase and MEDLINE databases were searched up to 28 February 2023, supplemented by grey literature searches. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Observational human studies evaluating the association between sedentary behaviour and endometrial cancer. DATA EXTRACTION AND SYNTHESIS: Two reviewers extracted data and conducted the quality assessment based on Newcastle-Ottawa Scale (NOS) independently. We used a random-effects model with inverse variance approach to pool the estimates. The extent of heterogeneity was quantified with the I(2) statistics. RESULTS: Sixteen studies were included in the systematic review. Fourteen studies involving 882 686 participants were included in the meta-analysis. The pooled relative risks (RRs) for high versus low level of overall sedentary behaviour was 1.28 (95% CI: 1.14 to 1.43; I(2)=34.8%). The increased risk regarding specific domains was 1.22 (95% CI: 1.09 to 1.37; I(2)=13.4%, n=10) for occupational domain, 1.34 (95% CI: 0.98 to 1.83; I(2)=53.7%, n=6) for leisure-time domain and 1.55 (95% CI: 1.27 to 1.89; I(2)=0.0%, n=2) for total sedentary behaviour. Larger pooled RRs were observed among studies with adjustment for physical activity and studies without adjustment for body mass index. CONCLUSIONS: Higher levels of sedentary behaviour, total and occupational sedentary behaviour in particular, increase the risk of endometrial cancer. Future studies are needed to verify domain-specific associations based on objective quantification of sedentary behaviour, as well as the interaction of physical activity, adiposity and sedentary time on endometrial cancer.