New research from Australian universities shows that calcium supplements do not increase dementia risk in older women. The findings, based on a long-term study of over 1,400 participants, counter earlier concerns about cognitive effects. Experts say the results reassure users taking calcium for osteoporosis prevention.
A collaborative study by Edith Cowan University, Curtin University, and the University of Western Australia has found no evidence that calcium supplements raise the risk of dementia in older women. Published in The Lancet Regional Health - Western Pacific in 2025, the research analyzed data from the Perth Longitudinal Study of Aging Women.
The investigation stemmed from a five-year double-blind, placebo-controlled randomized clinical trial aimed at preventing fractures. In that trial, 1,460 women were randomly assigned to receive either calcium supplements or a placebo, with 730 in each group. Researchers then followed participants for an additional 14.5 years, tracking cognitive health outcomes.
"Calcium supplements are often recommended to prevent or manage osteoporosis," said ECU PhD student Negar Ghasemifard. About 20 percent of women over 70 live with osteoporosis, making calcium a common recommendation to avoid bone fractures.
Previous observational studies had suggested potential links between calcium use and dementia, but this post-hoc analysis adjusted for factors like diet, lifestyle, genetics, and supplement dosage, finding no association. "Our research... consisted of a post-hoc analysis from a 5-year double-blind, placebo controlled randomized clinical trial," explained ECU Senior Research Fellow Dr. Marc Sim, noting the design's strength in reducing confounding variables.
The results particularly apply to women over 80, providing reassurance for this group. However, Professor Simon Laws, Director of ECU's Centre for Precision Health, emphasized limitations: "Whether this extrapolates to other demographics, such as men or even women commencing supplementation earlier in life, remains unknown." He called for future trials with brain health as primary outcomes, possibly including vitamin D.
Professor Blossom Stephan, a Dementia Australia Honorary Medical Advisor, welcomed the findings: "These results provide reassurance that long-term calcium supplementation did not increase dementia risk in older women."
Overall, the study eases fears for osteoporosis patients but highlights the need for broader research to confirm safety across populations.