International Journal of Preventive Medicine (Int J Prev Med)2008-780213112023020127352735ENIsfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, IsfahanApplied Physiology Research center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, IsfahanDepartment of Community Medicine, Isfahan University of Medical Sciences, IsfahanIsfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan20230125<p><strong>Background</strong>: This meta-analysis was performed to investigate the effect of serum lipids on the risk of breast cancer incidence. Methods: PubMed, Web of Science, Scopus, and EMBASE were searched systematically from January 1998 to April 2019. Inclusion criteria were English observational studies (cohort or case-control) and the concentration of at least one of the lipid profile components (total cholesterol/triglycerides/low‑density lipoprotein cholesterol/high‑density lipoprotein cholesterol) measured before a diagnosis of breast cancer (BC). The studies were included in which the relative risk (RR) had been reported with 95% confidence intervals (CIs). A random-effects model was used.</p><p><strong>Results</strong>: A total of 25 studies were found, including 2,882,789 participants in cohort studies with 45,481 cases with BC, and 1983 BC cases and 2963 case-control studies. Combined RR of cohort studies for the highest versus lowest for the BC was LDL-C: 0.95 (95% CI: 0.89–1.01), triglycerides (TG): 0.95 (95% CI: 0.91–0.99; P = 0.02), total cholesterol (TC): 0.98 (95% CI: 0.91–1.05), and HDL-C: 0.86 (95% CI: 0.63–1.18). Combined RR of case-control studies for the highest versus lowest was LDL-C: 1.08 (95% CI: 0.78–1.48), TG: 1.73 (95% CI: 0.94–3.18), TC: 1.02 (95% CI: 0.80–1.29), and HDL-C: 0.79 (95% CI: 0.65–0.97).</p><p><strong>Conclusions</strong>: Based on the results, it can be concluded that only TG but not TC and/or LDL‑C had a significant inverse association with the risk of BC incidence. HDL‑C showed a significant protective effect against breast cancer in postmenopausal women and case-control studies.</p>http://ijpm.mui.ac.ir/index.php/ijpm/article/view/2735http://ijpm.mui.ac.ir/index.php/ijpm/article/download/2735/717718576