Scientists just debunked the calcium and dementia myth

The investigation drew on data from an earlier project involving 1,460 older women who were randomly assigned to receive either calcium supplements or a placebo for five years. Researchers found that the supplements did not raise the likelihood of dementia in the long term.

"Calcium supplements are often recommended to prevent or manage osteoporosis," said ECU PhD student Ms. Negar Ghasemifard.

About 20 percent of women over 70 live with osteoporosis, and calcium is widely advised to help prevent bone fractures.

"Previous research has raised concerns around the impacts that calcium supplements could have on cognitive health, particularly dementia. Results from our study provides reassurance to patients and clinicians regarding the safety of calcium supplements in the context of dementia risk for older women," Ms. Ghasemifard said.

According to ECU Senior Research Fellow Dr. Marc Sim, even after adjusting for supplement use, diet, lifestyle factors, and genetic risk, the outcomes did not change.

"Previous research suggesting potential links between calcium supplement use and the risk for dementia was purely observational in nature. Our research, in comparison, consisted of a post-hoc analysis from a 5-year double-blind, placebo controlled randomized clinical trial on calcium supplements to prevent fracture. Whilst our study is still epidemiology, its design does reduce the likelihood of unmeasured confounding"

"Some 730 older women were given calcium supplements over five years, and a further 730 were given placebo. This study design offers more accurate data on dosage and duration, and we had a long follow-up period of 14.5 years, which strengthens our results," Dr. Sim said.

Although the findings suggest calcium does not increase the risk of dementia in older women, particularly those over 80, further studies are still needed, said Professor Simon Laws, Director of ECU's Centre for Precision Health.

"Whether this extrapolates to other demographics, such as men or even women commencing supplementation earlier in life, remains unknown. To confirm the current findings, particularly regarding brain health, and to address these population gaps, future clinical trials of calcium supplements, with or without vitamin D, would need to be undertaken. These should include specific and robust assessments of brain health as the primary outcome measures."

Professor Blossom Stephan, a Dementia Australia Honorary Medical Advisor said the research highlighted a very important finding that provides reassurance to clinicians and patients about the long-term safety of calcium supplementation.

"Given calcium's critical role in multiple physiological functions, including bone health, these results provide reassurance that long-term calcium supplementation did not increase dementia risk in older women," she said.