Calcium supplements, long recommended for bone health, especially among older women, do not increase the risk of dementia, a large-scale study suggests, providing reassurance to millions of people who take calcium supplements to prevent osteoporosis.
It is well known that calcium plays an important role in maintaining bone strength, especially in postmenopausal women. However, some early observational studies have suggested that calcium supplements may lead to blood vessel damage or calcium buildup in the brain, potential pathways to dementia.
A new study jointly conducted by Edith Cowan University (ECU), Curtin University and the University of Western Australia in Australia aims to further clarify whether calcium is associated with dementia through a large-scale, long-term randomized controlled trial.
"Calcium supplements are often recommended to prevent or treat osteoporosis," said Negar Ghasemifard, first author of the study and a doctoral student at ECU. "Previous research has raised concerns about the impact of calcium supplements on cognitive health, especially dementia. The results of this study provide patients and clinicians with safety assurance regarding the risk of dementia."
This study used the gold standard randomized controlled trial (RCT) to fill the shortcomings of previous observational studies. The study population was 1,460 community-dwelling women aged 70 and over who were initially asymptomatic of dementia and included in the Perth Longitudinal Study of Older Women (PLSAW). They were randomly divided into two groups. One group received a daily supplement of 1,200 mg of calcium carbonate for five years; the other group received a placebo. After the trial ended, the researchers followed the women through their health records for 9.5 years, for a cumulative follow-up period of 14.5 years. Dementia cases were collected from hospitalization and death records and included all major dementia subtypes, including Alzheimer's disease and vascular dementia.
During the study period, a total of 269 people (18.4%) were diagnosed with dementia, but there was no difference between the calcium supplement group and the placebo group. The risk ratio of dementia among those who took calcium supplements was 0.90, indicating that the risk was basically the same as that among those who did not take calcium supplements. The results remained unchanged even after adjusting for other dementia risk factors such as age, smoking, physical activity, cardiovascular health, socioeconomic status and the APOE ε4 gene.
"Given the important role of calcium in multiple life processes, including bones, these results show that long-term calcium supplementation does not increase the risk of dementia in older women." Professor Blossom Stephan, Director of the Dementia Center of Excellence at Curtin University, said.
The study also pointed out limitations: the participants were only older white Australian women, and the results may not be applicable to men, younger groups or other ethnic groups; participants' continued calcium supplementation was not tracked in the later stages of the trial; dementia diagnoses were based on hospitalization and death records, which may underestimate the actual number of cases. In addition, the original trial was not focused on cognitive status, the results were not evaluated in depth, and the average dietary calcium intake of participants was slightly below recommended levels, so the results may not necessarily apply to people with very low calcium intakes.
"It is uncertain whether these findings can be generalized to men or younger women, or those who start calcium supplementation earlier." Professor Simon Laws, director of the ECU Precision Health Center, reminded, "To further confirm the current conclusions and fill the gap in the population, future clinical trials should pay more attention to brain health as the main outcome indicator."
尽管存在上述限制，该研究为老年女性继续服用钙补充剂维护骨骼健康、预防骨折提供了有力支持。
The research has been published in the journal The Lancet Regional Health: Western Pacific.