Calcium supplementation, cardiovascular disease and mortality in older women

To investigate the long-term cumulative effect of calcium and vitamin D supplementation on cardiovascular outcomes and death in older women.

We undertook an observational cohort study using UK electronic primary care records in the Doctor's Independent Network (DIN-LINK) database; 9910 women aged 60-89 who started calcium and vitamin D supplementation between 2000 and 2005, with no heart disease or stroke history and who survived disease free for 2 years after supplement initiation were studied. The main outcome was first occurrence of myocardial infarction (MI), stroke or death more than 2 years after initiation.

In the period from 2 years after supplement initiation, women who had received >600 days supplementation in these first 2 years were no more at risk of MI, stroke or death (hazard ratio 0.82 (0.67-1.01)) compared to women who received < or = 90 days supplementation in the first 2 years. Outcomes in the first 2 years were analysed separately and showed similar baseline risks in our comparison groups.

Two years after initiation, women who have consistently received supplementation with calcium and vitamin D do not experience more cardiovascular events or deaths than women who received minimal supplementation.