A study followed 700 Swedish women between the ages of 70 and 92 years, who were all initially free from dementia. After five years, the researchers collected data on which women took calcium supplements (and dosage), as well as which women were clinically diagnosed with dementia. The odds among women who took supplemental calcium of developing dementia were twice that for women who did not take calcium. Further, among the women with a history of stroke, the odds of developing dementia among those who also supplemented calcium were six times the odds compared to women who did not take calcium. Although limited in sample size, the study results suggest that in elderly women, calcium supplementation may be potentially harmful, especially if they have a history of stroke or vascular problems.