Low-Carbohydrate Diet Score and the Risk of Colorectal Cancer: Findings from the Singapore Chinese Health Study.

BACKGROUND: Colorectal cancer (CRC) is common cancer with a high mortality rate. Low-carbohydrate diet (LCD) score holistically evaluates the LCD pattern from carbohydrate, protein, and fat intake. Epidemiologic data of LCD-CRC association are sparse.

METHODS: We evaluated the associations between LCD (i.e., total, animal- and plant-based) and CRC risk in the Singapore Chinese Health Study, a population-based prospective cohort study including 61,321 Chinese in Singapore who were 45-74 years old at baseline. Cox proportional hazard regression model was used to determine the hazard ratios (HRs) and respective 95% confidence intervals (CIs) for CRC associated with LCD after adjusting for potential confounders, including age, sex, BMI, physical activity, family history of CRC, etc. Results: After an average of 19.5 years of follow-up, 2,520 participants developed CRC (1,608 colon cancer and 912 rectal cancer). Overall, the association between total or plant-based LCD scores with the risk of colorectal, colon, or rectal cancer was null (all Ptrend ≥ 0.28). The animal-based LCD was modestly associated with colon cancer risk (P¬trend = 0.02), but not with rectal cancer. Compared with the lowest quartile, HRs (95% CIs) of colon cancer for quartiles 2, 3, and 4 of animal-based LCD were 1.12 (0.98, 1.29), 1.27 (1.10, 1.46), and 1.14 (0.99-1.31), respectively.

CONCLUSIONS: A low-level carbohydrate diet with a high level of animal protein and fat was associated with a moderate increase in the risk of colon cancer among Chinese Singaporeans.

IMPACT: High consumption of animal protein/fat and low consumption of carbohydrates may increase colon cancer risk.