Dyslipidemia and colorectal cancer risk: a meta-analysis of prospective studies

The findings from epidemiologic studies of dyslipidemia and colorectal cancer risk have been conflicting. We performed a dose-response meta-analysis of published prospective studies to assess the aforementioned association.

Relevant studies that reported the association between the components of dyslipidemia (serum triglyceride, total cholesterol, and high-/low-density lipoprotein cholesterol) and colorectal cancer risk were identified by searching PubMed until the end of May 2014. We pooled the relative risks (RRs) from individual studies using a random- and fixed-effects models and performed dose-response, heterogeneity, and publication bias analyses.

Seventeen prospective studies, including 1,987,753 individuals with 10,876 colorectal cancer events, were included in the meta-analysis. The overall pooled RR for high versus low concentrations for triglyceride (n = 9 studies) was 1.18 (95 % CI 1.04-1.34; I (2) = 47.8 %), for total cholesterol (n = 10 studies) was 1.11 (95 % CI 1.01-1.21; I (2) = 46.7 %), for high-density lipoprotein cholesterol (n = 6 studies) was 0.84 (95 % CI 0.69-1.02; I (2) = 42.5 %), and for low-density lipoprotein cholesterol (n = 3 studies) was 1.04 (95 % CI 0.60-1.81; I (2) = 82.7 %). In the dose-response analysis, the overall pooled RR was 1.01 (95 % CI 1.00-1.03; I (2) = 0 %) per 50 mg/dL of triglyceride and 1.01 (95 % CI 0.97-1.05; I (2) = 64.3 %) per 100 mg/dL of total cholesterol.

This meta-analysis of prospective studies suggests that dyslipidemia, especially high levels of serum triglyceride and total cholesterol, is associated with an increased risk of colorectal cancer, whereas high-density lipoprotein cholesterol might associate with a decreased risk of colorectal cancer. Further studies are warranted to determine whether altering the concentrations of these metabolic variables may reduce colorectal cancer risk.