Abstract 4098: Does Calcium Supplementation Increase Cardiovascular Risk: the Women’s Health Initiative Randomized Trial
Background: Coronary and valvular calcification predict coronary heart disease (CHD) risk. Patients commonly ask if they should reduce their calcium consumption, but the literature on this topic is scant. We examined this link in the Women’s Health Initiative randomized trial of calcium/vitamin D supplementation.
Methods: 36,282 postmenopausal women were randomized to calcium 1000 mg with 400 IU of vitamin D daily or to placebo in a hip fracture prevention trial. Cardiovascular disease was a prespecfied secondary outcome. Myocardial infarction (MI), CHD death, stroke, hospitalized angina and coronary revascularization were ascertained semi-annually and adjudicated following medical record review. Treatment groups were compared in Cox proportional hazards models, stratified by age, enrollment in the hormone and dietary modification trials, and prevalent cardiovascular disease at baseline.
Results: Mean age was 62.4y in each treatment group. Although predominantly white, the cohort included 3317 black, 1507 Hispanic, 149 American Indian, 722 Asian women and 434 of unknown ethnicity. At baseline, cardiovascular disease was reported by 5%, diabetes by 6%, hypercholesterolemia by 12%, hypertension by 25%, smoking by 8%, aspirin use by 19% and statin use by 6%. Total dietary plus supplemental calcium intake at baseline was 1150 mg daily. Baseline characteristics were generally balanced between treatment groups, except that 7.7% and 25.6% of women in the active treatment group had untreated and treated hypertension, respectively, compared with 8.5% and 25.1% in the placebo group (p=.03). Clinical cardiovascular events during 7 year follow up are shown (Table⇓).
Conclusion: Calcium/vitamin D supplementation did not increase the risk of CHD or stroke. While conferring no cardiovascular protection, women taking calcium supplements for other reasons do not need to worry about increasing their CHD risk.