Metabolic factors and the risk of colorectal cancer in 580,000 men and women in the metabolic syndrome and cancer project (Me-Can).

BACKGROUND

The metabolic syndrome (MetS) has been related to an increased risk of colorectal cancer, but the modest size of previous studies precluded detailed characterization of the role of individual MetS factors and their interaction on risk.

METHODS

In the Metabolic Syndrome and Cancer Project (Me-Can), data on body mass index (BMI), blood pressure, and blood levels of glucose, cholesterol, and triglycerides were available for 578,700 men and women. The mean age of participants at baseline was 44 years, and the mean follow-up was 12 years. Relative risks (RR) of colorectal cancer per 1 standard deviation increment in Z score of factors and for a combined MetS score, were calculated from Cox regression models, including adjustment for potential confounders.

RESULTS

During follow-up, 2834 men and 1861 women were diagnosed with colorectal cancer. The RR of colorectal cancer for the MetS score was 1.25 (95% confidence interval [CI], 1.18-1.32) in men, and 1.14 (95% CI, 1.06-1.22) in women. Significant associations also were observed in men for BMI (RR, 1.07; 95% CI, 1.02-1.13), blood pressure (RR, 1.10; 95% CI, 1.02-1.18), and triglycerides (RR, 1.17; 95% CI, 1.06-1.28) and, in women, for BMI (RR, 1.08; 95% CI, 1.01-1.15). There was no significant positive interaction between the metabolic factors on risk.

CONCLUSIONS

The combination of metabolic factors and some separate factors was related to an increased risk of colorectal cancer, but there was no interaction between metabolic factors.