title: Serum Lipids and Breast Cancer Risk: A Meta-Analysis of Prospective Cohort Studies.
abstract: OBJECTIVE
  Epidemiologic studies exploring causal associations between serum lipids and breast cancer risk have reported contradictory results. We conducted a meta-analysis of prospective cohort studies to evaluate these associations.
  
  
  METHODS
  Relevant studies were identified by searching PubMed and EMBASE through April 2015. We included prospective cohort studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of specific lipid components (i.e., total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and triglycerides [TG]) with breast cancer risk. Either a fixed- or a random-effects model was used to calculate pooled RRs.
  
  
  RESULTS
  Fifteen prospective cohort studies involving 1,189,635 participants and 23,369 breast cancer cases were included in the meta-analysis. The pooled RRs of breast cancer for the highest versus lowest categories were 0.96 (95% CI: 0.86-1.07) for TC, 0.92 (95% CI: 0.73-1.16) for HDL-C, 0.90 (95% CI: 0.77-1.06) for LDL-C, and 0.93 (95% CI: 0.86-1.00) for TG. Notably, for HDL-C, a significant reduction of breast cancer risk was observed among postmenopausal women (RR = 0.77, 95% CI: 0.64-0.93) but not among premenopausal women. Similar trends of the associations were observed in the dose-response analysis.
  
  
  CONCLUSIONS
  Our findings suggest that serum levels of TG but not TC and LDL-C may be inversely associated with breast cancer risk. Serum HDL-C may also protect against breast carcinogenesis among postmenopausal women.
authors.affiliation: Department of Neurosurgery, The First People's Hospital of Zhangjiagang City, Suzhou, Jiangsu, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Ni
authors.affiliation: Department of Neurosurgery, The First People's Hospital of Zhangjiagang City, Suzhou, Jiangsu, China.
authors.forename: Huixiang
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, The First People's Hospital of Zhangjiagang City, Suzhou, Jiangsu, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Gao
mesh_terms: D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D012306:Risk
chemical_list: D008055:Lipids