Abstract P363: Association of Twenty-Four Hour Urine Calcium Excretion with Cardiovascular Events and Mortality: Data from the Heart and Soul Study
Background: Recent studies have raised concerns about the cardiovascular (CV) safety of calcium supplementation, particularly in regards to risk of myocardial infarction (MI). However, most prior studies have been limited by imprecise calcium ascertainment using food frequency questionnaires. In contrast, twenty-four hour urinary calcium excretion (UCE) provides an objective, quantitative measure of total daily calcium intake. Therefore, we sought to evaluate the association of UCE with CV events or death in persons with stable coronary heart disease (CHD).
Methods: Between 2000-02, 849 subjects with prevalent CHD provided twenty-four hour urine collections and UCE was measured. We used Cox proportional hazards models to evaluate the association of UCE with the composite endpoint of CV events (MI, heart failure, stroke) or all-cause mortality, which were determined by blinded review of medical records.
Results: During a mean follow-up of 7 ± 2 years, 374 subjects (44%) had a CV event or died. The mean UCE was 105.7 ± 111.4 mg/day. Following multivariate adjustment for demographics, traditional CV risk factors, and kidney function, there was no association between UCE and the composite of CV events or all-cause mortality (Table). Evaluation of individual CV outcomes revealed no association between UCE (entered per 20 mg/day greater urine calcium) and heart failure (HR 1.01, 95% CI 0.98-1.05, p=0.48) or stroke (HR 0.94, 95% CI 0.87-1.02, p=0.13), but a lower rate of MI (HR 0.94, 95% CI 0.89-1.00, p=0.04). The association was similar by sex, presence of chronic kidney disease, and use of calcium supplements (all p interactions > 0.10).
Conclusions: Greater UCE is not associated with higher overall CV event rates or mortality in outpatients with stable CHD, and may be associated with a modestly lower rate of MI. These findings suggest that greater daily calcium intake does not confer CV harm in outpatients with prevalent CHD.
- © 2012 by American Heart Association, Inc.