On the other hand, calcium intakes did not show any benefits for men, while vitamin D was not associated with any benefits in either sex, according to results published in the Journal of Clinical Endocrinology & Metabolism.
“Our analysis showed that total calcium intake among women was more likely to be beneficial than harmful and that the same was true of calcium intake from dairy sources, nondairy sources, and supplements,” wrote the researchers from the Canadian Multicenter Osteoporosis Study (CaMos) Research Group.
“In fact, we observed that supplemental calcium intake up to 1000 mg/d among women was associated with statistically significant decreased mortality, although the results were inconclusive for supplement intake exceeding 1000 mg/d.
“Consequently, we cannot at this time advocate intakes in excess of this amount.”
Several reports in the literature have questioned the safety of calcium supplements taken to reduce the risk of osteoporosis in terms of a possible increase in the risk of cardiovascular problems. Most recently, a report in JAMA Internal Medicine concluded that high intakes of calcium from supplements may increase the risk of cardiovascular disease for men, but not women.
On the other hand, a recent report from the Institute of Medicine concluded that “evidence from clinical trials currently does not support an effect of calcium intake on risk of cardiovascular disease”.
The new study appears to show benefits of calcium supplements for women, but not men. Commenting on the potential mechanism behind the apparent benefits the CaMos Research Group noted that the mineral may lower improve lipid profiles, and reduce the risk of elevated blood pressure.
“Supplemental calcium will also protect against the potential adverse effects of low calcium intake, such as secondary hyperparathyroidism and high serum PTH levels, which may accelerate bone turnover and mobilize bone calcium, resulting in bone loss, cause cardiovascular effects due to calcification of blood vessels, and be associated with increased mortality risk,” they added.
The mineral may also exert benefits in the colon, while supplements could also be a marker of improved lifestyle patterns, they added.
The CaMos Research Group analyzed data from 9,033 men and women in their population-based longitudinal study. During the 10 years of study, a total of 1,160 deaths were documented.
After crunching the numbers, the researchers found that only women had a benefit from increased total calcium intake, with every 500 mg increase in daily calcium intake linked to a 5% reduction in the risk of so-called all-cause mortality.
Calcium supplements were also associated with a 22% reduction in mortality for users versus non-users, said the researchers. No benefits were observed for men, they added.
“We did not find any significant independent association between vitamin D intake and mortality nor did vitamin D intake affect the association noted between calcium and mortality,” they added.
“Thus, our recommendation is to assess dietary intake to meet calcium and vitamin D requirements for bone health and to consider supplementation necessary to meet the requirements.”
Source: Journal of Clinical Endocrinology & Metabolism
Published online ahead of print, doi: 10.1210/jc.2013-1516
“Calcium and Vitamin D Intake and Mortality: Results from the Canadian Multicentre Osteoporosis Study (CaMos)”
Authors: Langsetmo L, Berger C, Kreiger N, Kovacs CS, et al.