The association between serum triglycerides and colorectal cancer incidence in community-dwelling middle-aged and older adults in Korea: a secondary analysis of a community-based prospective cohort

Purpose: This study examined the association between serum triglyceride levels and the incidence of colorectal cancer (CRC) among community-dwelling middle-aged and older adults.Methods: The study included 8,371 adults aged 40~69 years without CRC at baseline who were enrolled in the Korean Genome and Epidemiology Study and followed biennially for 20 years to ascertain incident CRC cases. Participants were classified into four groups according to baseline triglyceride quartiles (Q1 = 32~99 mg/dL, Q2 = 100~134 mg/dL, Q3 = 135~187 mg/dL, and Q4 = 188~498 mg/dL). Kaplan–Meier survival analysis with the log-rank test and Cox proportional hazards regression models were used to evaluate CRC incidence across quartiles. Results: During the follow-up period, 104 participants (1.24%) developed CRC. The overall incidence rate of CRC was 0.78 per 1,000 person-years, with rates of 0.95, 0.48, 0.70, and 1.01 per 1,000 person-years in Q1, Q2, Q3, and Q4, respectively. CRC-free survival did not differ significantly among the quartile groups (log-rank χ² = 7.55, p = .056). However, after adjustment for major confounding factors, participants in both Q1 and Q4 exhibited a significantly higher risk of CRC compared with those in Q2 (Q1: hazard ratio [HR] = 2.13, 95% confidence interval [CI] = 1.15~3.95, p = .016; Q4: HR = 1.95, 95% CI = 1.02~3.73, p = .043).Conclusion: Serum triglyceride levels were associated with CRC risk in this population. Compared with Q2, CRC risk was elevated among those in both Q1 and Q4, indicating a non-linear relationship between triglyceride levels and CRC incidence. These findings highlight the potential value of preventive strategies tailored to serum triglyceride profiles, including identifying risk groups and improving CRC screening adherence.