Review Article The association between serum lipids and colorectal neoplasm: a systemic review and meta-analysis

Objective: There have been inconsistent results published regarding the relationship between dyslipidaemia and an increased risk of colorectal neoplasia (CRN), including colorectal adenoma (CRA) and colorectal cancer (CRC). We conducted a meta-analysis to explore the relationship between dyslipidaemia and CRN. Design: We identified studies by performing a literature search using PubMed, EMBASE and the Science Citation Index through October 2013. Setting: We analysed thirty-three independent studies reporting the association between CRN and at least one of the selected lipid components, including total cholesterol (TC), TAG, HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C). Subjects: CRN cases (n 21 809) were identified. Results: Overall, people with high levels of serum TAG (risk ratio (RR)= 1·08; 95 % CI 1·05, 1·12, P< 0·00001) and LDL-C (RR= 1·07; 95 % CI 1·00, 1·14, P= 0·04) presented an increased prevalence of CRN. Subgroup analyses revealed that high levels of serum TC (RR= 1·04; 95 % CI 1·01, 1·09, P= 0·02), TAG (RR= 1·06; 95 % CI 1·03, 1·10, P= 0·0009) and LDL-C (RR= 1·11; 95 % CI 1·04, 1·19, P= 0·003) increased the risk of CRA but not of CRC. No association between serum HDL-C and risk for CRN (including CRA and CRC) was observed. Conclusions: Both TAG and LDL-C were significantly associated with an increasing prevalence of CRN. High levels of serum TC, TAG and LDL-C were positively associated with CRA but not with CRC. No significant association was observed between levels of serum HDL-C and CRN.