February 27, 2013
Risk of Dying Doubles for Women With Highest
Calcium Intake

Uppsala, Sweden—Another new study is warning about cardiovascular risks associated with high intake of calcium—this time suggesting that women with the greatest levels of calcium intake have twice the risk of dying as those with more moderate levels.

The Swedish study published recently by BMJ, The British Medical Journal, suggests that too much calcium in women is associated with a higher risk of death from all causes, and cardiovascular disease in particular, compared with women with lower calcium intake.

In fact, women with a high dietary calcium intake of more than 1,400 mg/day were more than twice as likely to die compared with women with a 600–999 mg/day calcium intake. Somewhat higher death rates also were observed among women with the lowest calcium intakes—below 600 mg/day.

To test the association between cardiovascular risks and calcium intake, researchers from Uppsala University in Sweden studied 61,443 older Swedish women, born between 1914 and 1948, for an average of 19 years. Data came from the Swedish Cause of Death Registry and Swedish Mammography Cohort, which includes information on diet.

For the study, total calcium intake included both dietary sources and supplemental calcium. The mean intake ranged from 572 mg/day in the lowest quartile to 2,137 mg/day in the highest.

Study subjects also provided information on menopausal status, postmenopausal estrogen therapy, parity information, weight and height, smoking habits, leisure-time physical activity, and educational level.

During the 19 years of follow-up, 11,944 women, 17%, died—3,862 (32%) from cardiovascular disease; 1,932 (16%) from heart disease; and 1,100 (8%) from stroke, according to the study.

Researchers determined that the highest rates of all-cause, cardiovascular and heart disease were observed among those with a dietary calcium intake higher than 1,400 mg/day. Women who had a higher dietary intake of calcium exceeding 1,400 mg/day and also used supplements had a higher death rate compared to those not taking supplements.

Study authors suggested that diets very low or very high in calcium can override normal homeostatic control, causing changes in blood levels of calcium.

“In this study of women in the Swedish mammography cohort, a high calcium intake (>1400 mg/day) was associated with an increased rate of mortality, including death from cardiovascular disease,” the authors write. “The increase was moderate with a high dietary calcium intake without supplement use, but the combination of a high dietary calcium intake and calcium tablet use resulted in a more pronounced increase in mortality. For most women with lower intakes we observed only modest differences in risk.”

They recommended that medical professionals focus on patients with a low intake of calcium when recommending supplementation to prevent bone fractures.

“Our present data together with previous observations suggest that for the prevention of fractures in elderly people and simultaneous avoidance of possible serious adverse events related to a high calcium intake (such as higher risk of hip fracture, cardiovascular disease, renal stones, and, as observed in the current study, mortality) emphasis should be placed on people with a low intake of calcium rather than increasing the intake of those already consuming satisfactory amounts,” according to the study.

U.S. Pharmacist Social Connect