Calcium supplements associated with dementia in older women with existing cerebrovascular disease

By Liz Meszaros, MDLinx
Published August 19, 2016

Key Takeaways

In older women who have had a stroke or exhibit other signs of cerebrovascular disease, calcium supplements may be linked to a higher risk of dementia, according to results from a recent study published online in the August 17, 2015 issue of  the journal Neurology.

“Osteoporosis is a common problem in the elderly. Because calcium deficiency contributes to osteoporosis, daily calcium intake of 1000 to 1200 mg is recommended. Getting this recommended amount through diet alone can be difficult, so calcium supplements are widely used,” said study author Silke Kern, MD, PhD, University of Gothenburg in Sweden. “Recently, however, the use of supplements and their effect on health has been questioned.”

For this longitudinal, population-based study, Dr. Kern and colleagues included 700 dementia-free women aged 70 to 92 years from the Prospective Population Study of Women and the H70 Birth Cohort Study in Gothenburg, Sweden, and followed them for 5 years. Subjects underwent baseline and follow-up comprehensive neuropsychiatric and somatic assessments. Testing included memory and thinking skills assessments, among others, and a CT brain scan, done in 447 subjects at study initiation. Calcium supplementation and dementia diagnoses, as per DSM-III-R criteria, were also assessed.

At study initiation, 98 women were taking calcium supplements, and 54 women had had a stroke. During the study, 54 additional subjects had strokes, and 59 developed dementia. Of the 447 women who underwent CT scanning, 71% had white matter lesions, a classic marker for cerebrovascular disease.

Dr. Kern and fellow researchers found that only women treated with calcium supplements were twice as likely to develop dementia compared with women who did not take supplements (OR: 2.10; 95% CI: 1.01-4.37; P=0.046) and at a higher risk of developing subtype stroke-related dementia including vascular and mixed dementias (OR: 4.40; 95% CI: 1.54-12.61; P=0.006). 

In women with a history of stroke who were also taking calcium supplements, they found an almost 7-times increased risk of dementia compared with women with a history of stroke who did not take calcium supplements (OR: 6.77; 95% CI: 1.36-33.75; P=0.20). Furthermore, women with the presence of white matter lesions who took calcium supplements were three times more likely to develop dementia compared with those with white matter lesions who did not take supplements (OR: 2.99; 95% CI: 1.28-6.96; P=0.011). Those with no history of stroke and without white matter lesions who took calcium supplements had no increased risk.

“It is important to note that our study is observational, so we cannot assume that calcium supplements cause dementia,” said Dr. Kern, who added that limitations included the small size of the study, which precludes generalization of these results to the overall population.

Dr. Kern also added the caveat that calcium from food affects the body differently than calcium from supplements and may be safe or even offer protective effects against vascular problems.

This study was supported by grants from the American Alzheimer's Association, Swedish Research Council, Swedish Research Council for Health, Working Life and Welfare.

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