title: Calcium supplement intake and risk of cardiovascular disease in women.
abstract: Some recent reports suggest that calcium supplement use may increase risk of cardiovascular disease. In a prospective cohort study of 74,245 women in the Nurses' Health Study with 24 years of follow-up, we found no independent associations between supplemental calcium intake and risk of incident coronary heart disease (CHD) and stroke.
  
  
  BACKGROUND
  Some recent reports suggest that calcium supplements may increase cardiovascular disease (CVD) risk. The objective was to examine the independent associations between calcium supplement use and risk of CVD.
  
  
  METHODS
  We conducted a prospective cohort study of supplemental calcium use and incident CVD in 74,245 women in the Nurses' Health Study (1984-2008) free of CVD and cancer at baseline. Calcium supplement intake was assessed every 4 years. Outcomes were incident CHD (nonfatal or fatal MI) and stroke (ischemic or hemorrhagic), confirmed by medical record review.
  
  
  RESULTS
  During 24 years of follow-up, 4,565 cardiovascular events occurred (2,709 CHD and 1,856 strokes). At baseline, women who took calcium supplements had higher levels of physical activity, smoked less, and had lower trans fat intake compared with those who did not take calcium supplements. After multivariable adjustment for age, body mass index, dietary calcium, vitamin D intake, and other CVD risk factors, the relative risk of CVD for women taking >1,000 mg/day of calcium supplements compared with none was 0.82 (95% confidence interval [CI] 0.74 to 0.92; p for trend <0.001). For women taking >1,000 mg/day of calcium supplements compared with none, the multivariable-adjusted relative risk for CHD was 0.71 (0.61 to 0.83; p for trend < 0.001) and for stroke was 1.03 (0.87 to 1.21; p for trend = 0.61). The relative risks were similar in analyses limited to non-smokers, women without hypertension, and women who had regular physical exams.
  
  
  CONCLUSIONS
  Our findings do not support the hypothesis that calcium supplement intake increases CVD risk in women.
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA, jmpaik@partners.org.
authors.forename: J M
authors.initials: JM
authors.lastname: Paik
authors.forename: G C
authors.initials: GC
authors.lastname: Curhan
authors.forename: Q
authors.initials: Q
authors.lastname: Sun
authors.forename: K M
authors.initials: KM
authors.lastname: Rexrode
authors.forename: J E
authors.initials: JE
authors.lastname: Manson
authors.forename: E B
authors.initials: EB
authors.lastname: Rimm
authors.forename: E N
authors.initials: EN
authors.lastname: Taylor
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002118:Calcium / Q000008:administration & dosage / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000139:chemically induced* / Q000453:epidemiology; D003327:Coronary Disease / Q000139:chemically induced / Q000453:epidemiology; D004032:Diet / Q000706:statistics & numerical data; D019587:Dietary Supplements / Q000009:adverse effects* / Q000706:statistics & numerical data; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000139:chemically induced / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
chemical_list: D002118:Calcium