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 I2 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; I2=34.8%). The increased risk regarding specific domains was 1.22 (95% CI: 1.09 to 1.37; I2=13.4%, n=10) for occupational domain, 1.34 (95% CI: 0.98 to 1.83; I2=53.7%, n=6) for leisure-time domain and 1.55 (95% CI: 1.27 to 1.89; I2=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.