Association of lipid profile levels in premenopausal and postmenopausal women with breast cancer: a meta-analysis

Background: Published epidemiological evidence of the association between circulating lipids and lipoproteins and breast cancer (BC) in premenopausal and/or postmenopausal women remains controversial. A metaanalysis was therefore designed to estimate a more accurate association. Methods: Systematic literature retrieval was performed on the databases of Web of Science, PubMed and Cochrane library up to December 1th, 2015. Only studies reporting the data on the association of lipid components with premenopausal and/or postmenopausal BC patients were included. The pooled estimates of standardized mean difference (SMD) with 95% confidence intervals (CIs) were calculated by fixed-effect model or random-effect model. Results: A total of 12 studies which documented 9 investigations in premenopausal and postmenopausal women and 3 investigations in postmenopausal women containing 1042 BC patients and 1283 normal controls were included in the systematic review. In premenopausal group, the pooled SMD of triglyceride (TG) was 0.33 (95% CI: 0.07 to 0.59). In postmenopausal group, the pooled SMDs of triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) were 0.94 (95% CI 0.33 to 1.55), and -0.62 (95% CI: -1.11 to -0.13), respectively. No significant differences were noted for total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA1), and apolipoprotein B (ApoB) between premenopausal and postmenopausal cases and controls. Conclusions: The study showed that TG levels were higher in both premenopausal and postmenopausal BC compared with controls. An inverse association between levels of HDL-C and BC was detected among postmenopausal women. The results should be interpreted with caution on account of methodological flaws.