6/7/11 Getting adequate calcium is key for people with arthritis and related conditions, who may be at higher risk of fracture due to their disease, age or medications that can cause bone loss. However, getting higher amounts of daily calcium may not offer more protection for bones than moderate amounts, according to a recent study published online in the BMJ.
“[People] don't need to have an intake higher than about 700 milligrams per day. There is no additional benefit in fracture risk prevention above this level,” says study co-author Karl Michaëlsson, MD, PhD, a professor in medical epidemiology at Uppsala University in Sweden.
Swedish researchers wanted to see if higher calcium intake offered more protection against the bone loss that occurs naturally with aging. For the study, they reviewed data from a large, longitudinal study of more than 61,000 Swedish women born between 1914 and 1948. Participants were asked, in the period between 1987 and 1990 and again in 1997, to fill out questionnaires about their diet, intake of calcium, intake of supplements and vitamins, menopausal status, height, weight, smoking status and physical activity habits. Between 2003 and 2009, the researchers prospectively gave a subgroup of 5,022 women bone scans and asked them to fill out another questionnaire about diet and lifestyle factors.
Results showed that during the course of 19 years, nearly 15,000 women (24 percent of the study group) experienced a first fracture, of which almost 4,000 (6 percent) were hip fractures. In the subgroup, more than 1,000 women (20 percent) were diagnosed with osteoporosis.
When researchers compared how much calcium the women got, they found that a woman’s fracture risk was lowest when she consumed about 700 mg of calcium a day; getting more didn’t decrease her risk of osteoporosis or fracture, although getting less did increase the risk. In fact, women who got the most calcium had a slightly higher rate of hip fractures.
“The take-home message is that having a dietary intake of calcium in moderate amounts is enough to avoid fractures in this population, meaning that dietary calcium in adequate amounts – 700 to 800 mg – would be enough,” explains lead author Eva Warensjö, PhD, a researcher in the department of surgical sciences in the section of orthopaedics at Uppsala University. “We see that if you have a lower intake – less than 700 mg – then you are prone to fractures.”
U.S. experts say the study findings are in line with the recommendations in this country. Clifford J. Rosen, MD, is a senior scientist at the Maine Medical Center Research Institute in Scarborough, Maine, and a member of the U.S. committee that set new calcium-intake recommendations through the Institute of Medicine, or IOM, late last year. He says this study fits well with his group’s recommendations that most Americans, depending on their age, should be getting between 700 and 1,300 mg a day.
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