Summary: A long-term follow-up of more than 1,400 older women found no evidence that calcium supplements increase the risk of dementia. Over 14.5 years of observation, researchers who compared women assigned calcium monotherapy with women given a placebo saw no difference in cognitive outcomes, providing reassurance about the cognitive safety of calcium supplementation in older women.
This analysis accounted for genetic risk, diet, lifestyle factors and supplement adherence, and the lack of association between calcium use and dementia remained consistent. For clinicians and patients concerned about the brain health implications of calcium given for fracture prevention and osteoporosis, these results add important clarity.
Key Facts:
- No dementia link: Calcium supplements did not raise dementia risk over 14.5 years of follow-up.
- Randomized evidence: Results are derived from a randomized, double-blind, placebo-controlled trial involving 1,460 women.
- Clinical reassurance: Findings support the continued use of calcium for bone health in older women when clinically indicated.
Source: Edith Cowan University
Overview
Researchers from Edith Cowan University, Curtin University and the University of Western Australia conducted a post-hoc analysis of a large randomized clinical trial to investigate whether calcium monotherapy increases long-term dementia risk in older women. The original trial randomized 1,460 community-dwelling women aged 70 or older to receive either calcium carbonate or placebo for five years; participants were then observed for an additional 9.5 years, giving a total follow-up of 14.5 years.
“Calcium supplements are commonly recommended to prevent or manage osteoporosis,” said ECU PhD candidate Negar Ghasemifard. Osteoporosis affects a substantial proportion of older women and calcium supplementation is a widely used strategy to reduce fracture risk.
Earlier observational studies suggested possible links between calcium supplement use and cognitive decline. By contrast, this analysis used randomized trial data that provide more reliable measures of dose and duration and reduce many forms of bias common in observational research.
ECU Senior Research Fellow Dr Marc Sim emphasized that the results were robust. After adjusting for supplement adherence, dietary calcium intake, lifestyle factors and genetic risk, the absence of an association between calcium supplementation and dementia outcomes persisted.
In the original trial, roughly half of participants (730 women) received 1,200 mg/day calcium carbonate for five years while the other 730 received placebo. The investigators identified dementia-related hospitalizations and deaths from linked health records during the 14.5-year observation period. The randomized design and lengthy follow-up strengthen confidence in the null finding for dementia risk.
Professor Simon Laws, Director of ECU’s Centre for Precision Health, cautioned that while these results are reassuring for older women, questions remain about other populations. It is not yet known whether the findings apply to men or to people who begin supplementation earlier in life. He recommended future randomized trials that include specific, robust measures of brain health as primary outcomes, and that examine calcium with and without vitamin D.
Professor Blossom Stephan, Dementia Australia Honorary Medical Advisor, highlighted the study’s practical importance: given calcium’s essential role in bone and other physiological functions, evidence that long-term supplementation did not increase dementia risk in this large, well-characterized cohort provides reassurance for clinicians and patients making treatment decisions.
Key Questions Answered:
A: The analysis found no evidence that calcium supplements increased long-term dementia risk in older women over 14.5 years.
A: Unlike prior observational studies, this work draws on a five-year double-blind, placebo-controlled randomized trial with nearly 15 years of follow-up, reducing bias related to confounding and improving the accuracy of dosage and duration data.
A: The findings support continued use of calcium supplements for bone health in older women when clinically indicated. Additional research is needed to confirm effects in men and in younger populations.
About this supplements and brain health research news
Author: Esmarie Iannucci
Source: Edith Cowan University
Contact: Esmarie Iannucci – Edith Cowan University
Image: Image credit: Neuroscience News
Original research: Open access. Title: “Calcium supplementation and the risk of dementia in the Perth Longitudinal Study of Aging Women: a post-hoc analysis of a randomised clinical trial for fracture prevention” by Negar Ghasemifard et al., published in The Lancet regional journal.
Abstract
Calcium supplementation and the risk of dementia in the Perth Longitudinal Study of Aging Women: a post-hoc analysis of a randomised clinical trial for fracture prevention
Background
Questions have been raised about whether calcium supplements could increase dementia risk. This post-hoc analysis examined long-term dementia outcomes in older women who had been randomized to calcium supplements or placebo in a five-year double-blind trial originally designed to test fracture prevention.
Methods
A total of 1,460 community-dwelling, dementia-free Australian women aged 70 years and older were randomized to receive 1,200 mg/day of calcium carbonate (n = 730) or placebo (n = 730) for five years. Participants were subsequently monitored for an additional 9.5 years, resulting in 14.5 years of total follow-up. Dementia-related events were identified through linked hospitalization and death records. Analyses included Kaplan–Meier survival curves and Cox proportional hazards models under both intention-to-treat (ITT) and per-protocol (PP) frameworks, with the per-protocol group defined as ≥80% tablet compliance.
Findings
The mean baseline age was 75.1 years. Over the follow-up period, 269 women (18.4%) experienced dementia-related events, which included hospitalizations and deaths attributed to dementia. There were no statistically significant differences in dementia-free survival between the calcium and placebo groups in either ITT or PP analyses. Unadjusted ITT hazard ratios comparing calcium to placebo were 0.90 (95% CI 0.71–1.15) for all-cause dementia events, 0.89 (95% CI 0.69–1.15) for dementia-related hospitalizations, and 0.78 (95% CI 0.54–1.13) for dementia-related deaths. Per-protocol analyses produced similar results.
Interpretation
Five years of calcium supplementation did not increase the long-term risk of all-cause dementia events over 14.5 years in community-dwelling older women. These findings do not support earlier concerns that calcium supplementation elevates dementia risk in this population.
Funding
Funded by the National Health and Medical Research Council of Australia.