Abstract
OBJECTIVES: To examine whether adherence to a healthy lifestyle affects cancer incidence, cancer-related comorbidities, and survival among cancer patients. METHODS: We analyzed 400,714 participants in the UK Biobank who were free of cancer and major noncommunicable diseases (NCDs)-including atherosclerotic cardiovascular disease (ASCVD), type 2 diabetes (T2D), chronic obstructive pulmonary disease (COPD), and chronic kidney disease (CKD)-at baseline and remained cancer-free for at least 180 days post-enrollment. A Healthy Lifestyle Index (HLI) was constructed based on six lifestyle factors and categorized into low, intermediate, and high levels. Multivariable Cox regression was used to estimate associations between HLI levels and the risks of cancer and cancer-related comorbidities, defined as the co-occurrence of cancer and at least one NCD. Kaplan-Meier methods were used to assess survival outcomes among cancer patients, stratified by comorbidity status and HLI. RESULTS: Over a median follow-up of 13.8 years, 53,380 (13.3%) participants developed cancer, with 16,188 (4.0%) having cancer-related comorbidities. Compared to the low HLI group, participants with a high HLI had a significantly lower risk of cancer (HR = 0.92, 95% CI 0.90-0.94) and cancer-related comorbidities (HR = 0.51, 95% CI 0.49-0.53). Subgroup analyses showed marked reductions in comorbidity risk for multiple cancer types. Higher HLI was also associated with better survival, regardless of comorbidity status. CONCLUSIONS: Adherence to a healthy lifestyle is associated with reduced cancer risk, fewer comorbidities, and improved survival outcomes, underscoring the value of lifestyle interventions in cancer prevention and survivorship care.