An insufficient intake of calcium seems to be associated with a higher risk of developing a common hormone condition in women, known as primary hyperparathyroidism, a new US study has proven.
In the observational study, the calcium intake of 58,354 US women (aged between 39 and 66 years) partici-pating in the “Nurses' Health Study I” was measured and cases of primary hyperparathyroidism (PHPT) were documented over a 22-year period (1). Calcium intake (from both dietary sources and supplements) was assessed every four years using food frequency questionnaires. The participants were divided into five groups, according to intake of dietary calcium. After adjusting for several factors including age, body mass index and ethnicity, the study results showed that women in the group with the highest calcium intake had a 44% reduced risk of developing PHPT compared with the group with the lowest intake. Even for women taking a modest 500 mg/day of calcium supplements, the risk of developing PHPT was 59% lower than those taking no calcium supplements.
The researchers concluded that these findings provide evidence to support physicians in encouraging female patients to increase calcium intake for PHPT prevention. Calcium supplements in modest doses would be like-ly to provide more benefits than risks. Over many years, even a moderate increase in calcium concentration could probably help reduce the incidence of parathyroid tumors.
PHPT, most common in post-menopausal women between 50-60 years of age, is caused by overactive para-thyroid glands secreting too much parathyroid hormone, which can result in weak bones, fractures and kidney stones. In recent years, several studies have also suggested a link between untreated PHPT and an increased risk of high blood pressure, heart attack and stroke. Calcium intake is known to influence parathy-roid hormone production and therefore may be important in the development of PHPT. However, no long-term study to date has explored this relation in detail.