The Effect of CKD on Associations between Lifestyle Factors and All-cause, Cancer, and Cardiovascular Mortality: A Population-based Cohort Study

OBJECTIVE: Results from previous studies on the dose-dependent effect of adhering to multiple lifestyle factors on all-cause mortality in patients with chronic kidney disease (CKD) are inconsistent, despite the reported dose-dependent effect in the general population. This study aimed to examine whether CKD modifies the dose-dependent effect of adhering to multiple lifestyle factors on mortality. METHODS: This population-based prospective cohort study targeted 262,011 men and women aged 40-74 years at baseline. Of these, 18.5% had CKD, which was defined as GFR <60 mL/min/1.73 m(2), ≥1+ proteinuria on urinalysis, or both. The following lifestyle behaviors were considered healthy: no smoking, body mass index <25 kg/m(2), moderate or lower alcohol consumption, regular exercise, and healthy eating habits. Healthy lifestyle scores were calculated by adding the total number of lifestyle factors for which each participant was at low risk. Cox proportional hazards models were used to examine associations between healthy lifestyle scores and all-cause, cancer, and cardiovascular mortality, and whether CKD modified these associations. RESULTS: During a median follow-up of 4.7 years, 3,471 participants died. The risks of all-cause and cancer mortality decreased as the number of five healthy lifestyle factors that were adhered to increased, irrespective of the CKD status. The risk of cardiovascular mortality, however, was modified by CKD (interaction p=0.07), and an unhealthy lifestyle and CKD synergistically increased cardiovascular mortality. CONCLUSION: A healthy lifestyle can reduce the risk of all-cause and cancer death in patients with or without CKD, while the prevention of CKD is essential for reducing the risk of cardiovascular death.