Researchers at Uppsala University in Sweden analysed data on a national mammography cohort including over 61,000 women aged between 40 and 73 at the time of the cohort's establishment. In a 19-year follow-up period, there were nearly 4,000 cases of death from cardiovascular disease, some 1,900 died from heart disease and 1,100 from stroke.
The study found that women consuming over 1,400 milligrams of calcium a day had the highest rate of death from cardiovascular disease and heart disease as well as from all causes. Women in this group were over two times as likely to die as women whose daily calcium intake was between 600 and 1,000 milligrams. However, the risk of death was also higher for women whose diet included less than 600 milligrams of calcium daily.
The findings also showed that the death risk of all causes was even higher for women whose daily calcium consumption of over 1,400 milligrams also included a calcium supplement.
According to the authors of the study, women consuming too much or too little calcium can see their body's normal control being overridden which could lead to changes in blood levels of calcium. They suggested that more attention should be paid to people with low-calcium diets instead of worrying about boosting the calcium consumption of people who get enough through their diet.