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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.