WHR and adverse health outcomes: a prospective study on cancer incidence, all-cause and cancer-specific mortality

Obesity is a significant global public health issue, traditionally linked to adverse health outcomes. However, the “obesity paradox” suggests that in certain populations, obesity may be associated with better prognosis. This study investigates the relationship between waist-to-hip ratio (WHR), a marker of central obesity, and cancer incidence, all-cause mortality, and cancer-specific mortality in a large prospective cohort from Northern China. Data from the Kailuan Cohort, comprising 94,139 participants, were analyzed. WHR was categorized by sex (low, normal, high), and its associations with cancer incidence, all-cause mortality, and cancer-specific mortality were evaluated using multivariate Cox proportional hazards models. Higher WHR was significantly associated with increased risks of all-cause mortality (7% per SD increase, 95% CI: 1. 05–1. 09), and cancer-specific mortality (9% per SD increase, 95% CI: 1. 05–1. 13). Compared to low WHR, high WHR groups showed elevated risks for all outcomes (cancer incidence: HR = 1. 10, 95% CI: 1. 01–1. 21; all-cause mortality: HR = 1. 43, 95% CI: 1. 17–1. 75 in women; cancer-specific mortality: HR = 1. 23, 95% CI: 1. 08–1. 40). These associations were stronger in women, particularly for digestive system cancers (P for trend = 0. 008 overall, 0. 047 in women). Age-stratified analyses revealed significant interactions between WHR and mortality in older adults (P for interaction < 0. 001). Sensitivity analyses excluding early events confirmed the robustness of these findings. Higher WHR was independently associated with increased all-cause and cancer-specific mortality, while higher WHR categories were associated with a modest increase in cancer incidence. These findings underscore the importance of central obesity assessment in clinical practice and challenge aspects of the obesity paradox by highlighting the adverse effects of visceral fat accumulation.