London, May 13 (IANS): Taking calcium and vitamin D supplements may prevent bone fractures in elderly women but the net benefits may be outweighed by an increased risk of heart attack and stroke, researchers have warned.

The findings showed that if 100,000 65-year-old women take 1,000 mg calcium every day, 5,890 hip fractures and 3,820 other fractures would be prevented. 

On the other hand, as many as 5,917 heart attacks and 4,373 strokes could be caused. So for women above age 60, the risks outweigh the benefits. 

"The moderate effect of calcium and vitamin D supplements on the risk of fractures is not large enough to outweigh the potential increased risk of cardiovascular disease, specifically in women who are at a low risk of bone fracture," said lead study author Gunhild Hagen from Norwegian University of Science and Technology.

Previous studies have also shown that taking supplemental calcium may also increase the risk of heart attack and stroke.

The team used an advanced analytical model to investigate the total health effect of taking a combined calcium and vitamin D supplement, compared to taking no supplements based on a group of healthy women aged 65. 

The findings, published in the journal Osteoporosis International, showed that more than 10,000 heart attacks and strokes would be caused by supplemental calcium and vitamin D in a group of 100,000 65-year-old women, whereas the medium-risk model predicted about 5,000.

The number of years of high-quality life lost by taking calcium was higher than the number of years of high-quality life saved by preventing broken bones.

They also investigated the cost-effectiveness of offering 65-year-old women supplemental calcium and vitamin D, assuming that the women were at a low risk of cardiovascular problems. 

Providing supplements in this situation is cost-effective and good for public health, given that the benefits outweigh the risks, the authors stated.