title: Calcium intake and breast cancer risk: meta-analysis of prospective cohort studies.
abstract: Findings from observational studies have suggested a possible relation between Ca and breast cancer risk. However, the results of these studies are inconclusive, and the dose-response relationship between Ca intake and risk of breast cancer remains to be determined. A meta-analysis of prospective studies was conducted to address these issues. PubMed and Embase databases were searched for relevant studies concerning the association between Ca intake and breast cancer up to March 2016. The summary relative risks (RR) with 95 % CI were calculated with a random-effects model. The final analysis included eleven prospective cohort studies involving 26 606 cases and 872 895 participants. The overall RR of breast cancer for high v. low intake of Ca was 0·92 (95 % CI 0·85, 0·99), with moderate heterogeneity (P=0·026, I 2=44·2 %). In the subgroup analysis, the inverse association appeared stronger for premenopausal breast cancer (RR 0·75; 95 % CI 0·59, 0·96) than for postmenopausal breast cancer (RR 0·94; 95 % CI 0·87, 1·01). Dose-response analysis revealed that each 300 mg/d increase in Ca intake was associated with 2 % (RR 0·98; 95 % CI 0·96, 0·99), 8 % (RR 0·92; 95 % CI 0·87, 0·98) and 2 % (RR 0·98; 95 % CI 0·97, 0·99) reduction in the risk of total, premenopausal and postmenopausal breast cancer, respectively. Our findings suggest an inverse dose-response association between Ca intake and risk of breast cancer.
authors.affiliation: 1Department of Nutrition and Food Hygiene,School of Public Health,Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Khemayanto
authors.initials: K
authors.lastname: Hidayat
authors.affiliation: 1Department of Nutrition and Food Hygiene,School of Public Health,Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Guo-Chong
authors.initials: GC
authors.lastname: Chen
authors.affiliation: 1Department of Nutrition and Food Hygiene,School of Public Health,Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Ru
authors.initials: R
authors.lastname: Zhang
authors.affiliation: 2Department of Endocrinology and Metabolism,the First Affiliated Hospital of Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Du
authors.affiliation: 2Department of Endocrinology and Metabolism,the First Affiliated Hospital of Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Sheng-Yi
authors.initials: SY
authors.lastname: Zou
authors.affiliation: 2Department of Endocrinology and Metabolism,the First Affiliated Hospital of Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Bi-Min
authors.initials: BM
authors.lastname: Shi
authors.affiliation: 1Department of Nutrition and Food Hygiene,School of Public Health,Soochow University,Suzhou 215123,People's Republic of China.
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Qin
mesh_terms: D001943:Breast Neoplasms / Q000209:etiology*; D002136:Calcium, Dietary; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D012307:Risk Factors
chemical_list: D002136:Calcium, Dietary
keywords: Breast cancer; Calcium; Dose–response associations; ER oestrogen receptor; Meta-analyses; PR progesterone receptor; RR relative risk