Cancer risk according to lifestyle risk score trajectories: a population-based cohort study.

Background: While individual lifestyle behaviors have been associated with cancer risk, combined impact of these factors remains understudied. This research explores relationships between lifestyle risk score trajectories and cancer risk within the Korean population.

Methods: A cohort of 3,451,189 cancer-free men and women who participated in a health examination between 2002 and 2003, provided by the National Health Insurance, was studied. Lifestyle risk score trajectories were determined using group-based trajectory modeling based on total score of four modifiable unhealthy behaviors: current smoking, heavy alcohol drinking, excess body weight, and physical inactivity repeatedly observed three times between 2002 and 2007. Scores ranged between 0 (low risk) and 8 (high risk). The Cox proportional hazards model was applied to examine the association between these trajectories and cancer incidence.

Results: During the follow-up time (2008-2019), 312,075 cancer cases were identified. Among men, seven trajectories were identified, and trajectories of high lifestyle risk scores increased cancer risk of all cancer combined, cancer subgroupings, upper aero-digestive, stomach, colorectal, liver, gallbladder, pancreatic, lung, and bladder cancer, but inverse relation was observed for prostate cancer. Among women, four trajectory groups showed similar trends.

Conclusions: Maintaining a healthy lifestyle and avoiding unhealthy behaviors are essential for cancer prevention.