Previous studies have reported that oral calcium supplementation is associated with elevated risk for adverse cardiovascular (CV) events such as myocardial infarction  Moreover, in a recent study  high-dose calcium supplementation was associated with excess CV-related mortality in men. In this prospective cohort study, Swedish investigators assessed the associations between long-term calcium intake and all-cause and CV-related death in 61,000 women born between 1914 and 1948. Researchers estimated dietary, supplemental, and total calcium intake from food-frequency questionnaires that were completed at baseline (1987–1990) and in 1997. Median follow-up was 19 years. Compared with dietary calcium intakes of 600 to 999 mg daily, daily intakes of 1400 mg were associated with significantly higher rates of death from all causes (multivariate adjusted hazard ratio, 1.4), CV disease (AHR, 1.5), and ischemic heart disease (AHR, 2.1), but not from stroke. Similar results were obtained for total calcium intake. Vitamin D intake did not modify the associations.

Published in Journal Watch General Medicine

Comment: This is a case of too much of a good thing; the study suggests that people avoid excessive calcium intake (i.e., 1400 mg daily) and that high calcium intake should be reserved for situations in which benefits clearly outweigh risks. For more information about Calcium and Vitamin D please see the post titled: “Vitamin D and Calcium Supplementation in Women: Making Sense of Conflicting Data” on this blog. _BA

CITATION Michaëlsson K et al. Long term calcium intake and rates of all cause and cardiovascular mortality: Community based prospective longitudinal cohort study. BMJ 2013 Feb 13; 346:f228. (http://dx.doi.org/10.1136/bmj.f228)