Effect of serum lipid profile on the risk of breast cancer: systematic review and meta-analysis of 1,717,054 women

Abstract Background Dyslipidemia has been linked to breast cancer incidence. However, conflicting results exist regarding the associations between lipid components and breast cancer development. Purpose The aim of the present meta-analysis was to further investigate the relationships between serum lipid profile and the risk of breast cancer. Methods The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed to conduct the present systematic review and meta-analysis. Databases such as the PubMed, EMBASE, and Web of Sciences, were searched up to the end of January 2021, using certain MeSH and non-MeSH keywords and their combination to extract related published articles. Results Twenty-six prospective studies met the inclusion criteria involving 1,717,054 women, of whom 36,590 were diagnosed with breast cancer during the follow-up. A negative and significant association was found between HDL-C levels and the risk of breast cancer [relative risk (RR): 0.85, 95% CI: 0.72–0.99, I2: 67.6%, p=0.04) (Figure). In contrast, TG (RR: 1.02, 95% CI: 0.91–1.13, I2: 54.2%, p=0.79), total cholesterol (TC) (RR: 0.98, 95% CI: 0.90–1.06, I2: 67.2%, p=0.57), apolipoprotein A (ApoA) (RR: 0.96, 95% CI: 0.70–1.30, I2: 83.5%, p=0.78) and LDL-C (RR: 0.93, 95% CI: 0.79–1.09, I2: 0%, p=0.386) were not associated with breast cancer development. In studies adjusting for hormone use and physical activity, TC was positively correlated to breast cancer risk (RR: 1.05, 95% CI: 1.01–1.10 and 1.05, 95% CI: 1.01–1.10, respectively), as was TG in studies adjusting for baseline lipids (RR: 0.92, 95% CI: 0.85–0.99) and race (RR: 1.80, 95% CI: 1.22–2.65). Conclusions In the present meta-analysis, HDL-C was inversely related to breast cancer risk. In contrast, no significant associations were found for TC (except after adjusting for hormone use and physical activity), TG (except after adjusting for baseline lipids and race), LDL-C and ApoA. Overall, data on the links between lipids and breast cancer are conflicting. However, there is increasing evidence supporting that low HDL-C is related to an increased risk for this malignancy. Further research is needed to establish the associations between different lipid components and breast cancer risk in certain populations. Funding Acknowledgement Type of funding sources: None.