Abstract

Background: Concerns have been raised around whether calcium supplements increase dementia risk. This post-hoc analysis of a five-year double-blind, placebo-controlled randomised trial of calcium supplements for primary fracture prevention evaluated the long-term risk for dementia in older women, randomised to either calcium supplements or placebo. Methods: 1460 community-dwelling dementia-free Australian women (≥70 years) were randomised to 1200 mg/day calcium carbonate (n = 730) or placebo (n = 730) for five years and were observed for an additional 9.5 years afterwards. Over 14.5 years, all-cause dementia events (comprising dementia-related hospitalisations and/or deaths) were identified from linked health records. The influence of calcium supplementation on dementia outcomes were examined using Kaplan–Meier survival curves and Cox regression under intention-to-treat (ITT) and per-protocol (PP, ≥80% tablet compliance, n = 830; 50.6% calcium supplements) criteria. Findings: Mean baseline age was 75.1 ± 2.7 years. Dementia events were recorded in 269 women (18.4%), comprising 243 hospitalisations (16.6%) or 114 deaths (7.8%). No differences in the cumulative dementia-free survival rates were observed between groups in ITT and PP analyses. Compared to placebo, calcium supplements did not increase risk of dementia-related events (unadjusted ITT hazard ratio [HR] 0.90, 95% confidence interval (CI) 0.71–1.15), hospitalisations (HR 0.89, 95% CI 0.69–1.15) or deaths (HR 0.78, 95% CI 0.54–1.13). Similar results were observed in PP analyses. Interpretation: Calcium supplementation for five years did not increase the risk of all-cause dementia events over 14.5 years in community-dwelling older women. Findings do not support concerns that calcium supplementation increases long-term risk of dementia. Funding: National Health and Medical Research Council of Australia.

Keywords

Calcium supplementation, Cognitive health, Dementia, Healthy aging, Women's health

Document Type

Journal Article

Date of Publication

10-1-2025

Article Number

101694

Volume

63

Publication Title

Lancet Regional Health Western Pacific

Publisher

Elsevier

School

Nutrition and Health Innovation Research Institute / School of Medical and Health Sciences / Centre for Precision Health

RAS ID

84240

Funding Information

The Perth Longitudinal Study of Aging Women (PLSAW) was funded by project grants 254627, 303169, and 572604 from the National Health and Medical Research Council of Australia (NHMRC). Professor Blossom Stephan holds a position as the Chair of Dementia at Curtin University. The salary for their position is partially supported by Dementia Australia. Dementia Australia had no role in the design, analyses, interpretation, or drafting of this manuscript. M.S.’s salary is funded through a Royal Perth Hospital Research Foundation Career Advancement Fellowship and an Emerging Leader Fellowship granted by the Western Australian Future Health Research and Innovation Fund (2021/6). J.R.L.’s salary is provided by a National Heart Foundation Future Leader Fellowship (102817).

Funding received from the National Health and Medical Research Council (NHMRC)

254627, 303169, 572604

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Recommended Citation

Ghasemifard, N., Lewis, J. R., Radavelli-Bagatini, S., Laws, S. M., Stephan, B. C., Hodgson, J. M., Zhu, K., Prince, R. L., & Sim, M. (2025). 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. The Lancet Regional Health Western Pacific, 63, Article 101694. https://doi.org/10.1016/j.lanwpc.2025.101694

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Link to publisher version (DOI)

10.1016/j.lanwpc.2025.101694