Abstract
BACKGROUND: The effect of planetary health diet (PHD) may differ by sex, and the associations with cancer risk remain unclear. This study aimed to investigate sex differences in the associations between PHD and overall cancer risk, as well as the joint effects of PHD and genetic risk.
METHODS: This study included 177 441 participants from the UK Biobank. The PHD score was calculated by summing the scores of 14 dietary components, each assessed on an adjustable 0-10 scoring system. To evaluate genetic risk, an overall cancer polygenic risk score (CPRS) was constructed using 1025 single-nucleotide polymorphisms. The outcome was overall cancer, defined by 20 site-specific cancers.
RESULTS: During a median follow-up of 12.98 years, 15 476 cancer cases were identified, comprising 82 146 men and 95 295 women. In the multivariable-adjusted model, participants in the highest quintile of PHD adherence showed a borderline significant reduction in overall cancer risk (hazard ratio [HR]: 0.95, 95% confidence intervals [CI]: 0.90-1.00) relative to the lowest quintile. Additionally, each standard deviation increase in PHD score was associated with a 4% reduction in overall cancer risk (HR: 0.96, 95% CI: 0.95-0.98). When stratified by sex, individuals with the highest PHD score were associated with lower cancer risk in men (HR: 0.92, 95% CI: 0.86-0.99), but not in women (HR: 0.96, 95% CI: 0.89-1.03). In the joint analysis, individuals with high PHD scores and low CPRS had the relatively lowest risk of overall cancer compared to those with low PHD scores and high CPRS, in both men (HR: 0.39, 95% CI: 0.33-0.46) and women (HR: 0.55, 95% CI: 0.47-0.65).
CONCLUSION: The PHD was associated with a reduced overall cancer risk among men. Individuals with high PHD scores and low CPRS had the relatively lowest cancer risk. These findings highlight that the PHD may be particularly beneficial in men for cancer prevention.