Association of healthy plant-based diet-lifestyle score with obesity-related cancer incidence and mortality: a prospective cohort study in the UK Biobank

Abstract

Evidence regarding the combined influence of healthy plant-based dietary patterns and lifestyle behaviours on obesity-related cancer outcomes remains limited. We prospectively investigated the associations of the healthy plant-based diet-lifestyle (hPDI-Lifestyle) score with obesity-related cancer incidence and mortality in the UK Biobank. Among 104,713 eligible participants, 93,763 were included in the primary complete-case analyses. The hPDI-Lifestyle score integrated healthy plant-based dietary quality, physical activity, smoking status, and sleep duration. Restricted cubic spline analyses were used to examine dose–response relationships, and Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the three outcomes, including sex-stratified analyses. Several sensitivity analyses were conducted to assess the robustness of the findings. During median follow-up periods of 16.3, 15.0, and 15.1 years, respectively, 2,258 incident obesity-related cancers, 1,095 obesity-related cancer deaths, and 6,215 all-cause deaths were documented. Higher hPDI-Lifestyle scores were associated with lower risks of obesity-related cancer mortality and all-cause mortality. For obesity-related cancer incidence, an inverse association was observed overall, whereas sex-stratified analyses showed no statistically significant association among women. Compared with participants in the lowest tertile, those in the highest tertile had lower risks of obesity-related cancer incidence (HR: 0.82, 95% CI: 0.74–0.92), obesity-related cancer-specific mortality (HR: 0.66, 95% CI: 0.56–0.77), and all-cause mortality (HR: 0.64, 95% CI: 0.60–0.68). Each 1-SD increment in the hPDI-Lifestyle score was associated with 8, 18, and 22% lower risks of obesity-related cancer incidence, obesity-related cancer-specific mortality, and all-cause mortality, respectively. Higher hPDI-Lifestyle scores were associated with lower risks of obesity-related cancer incidence, cancer-specific mortality, and all-cause mortality. These findings require confirmation in more representative populations and intervention studies before preventive implications can be established.