Lower level of Vitamin D strongly increases hip fracture risk in older women

August 21, 2008

     University of Pennsylvania School of Medicine researchers conclude that if you are a postmenopausal woman and you have a lower blood concentration of vitamin D you have a 70% increased likelihood suffering with a dangerous hip fracture. The researchers studied eight hundred 50 to 79 year-old women for an average of seven years who were selected from candidates who were not using estrogens or other bone-saving drugs. The mean age of the participants was 70 years. Of the 800 selected from 40 clinical centres across the US, 400 patients of the same sex and race had suffered hip fractures while 400 had not. Those women who had hip fractures had lower blood levels of vitamin D.
     They measured serum 25-hydroxyvitamin D 25(OH) levels – the form in which vitamin D is stored in the body. “In our prospective, nested case–control study, we found that women with the lowest 25(OH) vitamin D concentrations (47.6 nmol/L) at study entry had a significantly greater increased risk for subsequent hip fracture during the next seven years than did women with the highest concentrations (70.7 nmol/L),” the researchers wrote. They added that the correlation between vitamin D concentration and hip fracture was linear (there was an absolute match between lower or higher levels of the Vitamin and hip fracture risk) and the risk was unaffected by age. The number of physical falls did not differ between the control and active groups.
     The results are consistent with the Third National Health and Nutrition Examination Survey as well as a 2005 cohort study conducted among Swedish women which found those with 25(OH) levels below 52.5 nmol/L had twice the risk of hip fracture. Previous studies with younger populations (average age of 53 years) had not produced a strong correlation causing the researchers to reason: “Vitamin D concentration may be more strongly linked to frailty-related fractures, such as hip fractures, which tend to occur in much older women.” The study is published in the August 19 issue of the journal Annals of Internal Medicine.