Occult vitamin D deficiency in postmenopausal US women with acute hip fracture

Context Low vitamin D levels may contribute to hip fractures in women, alth ough limited data are available on vitamin D levels in US women admitted wi th acute hip fractures. Objective To determine whether postmenopausal women with hip fractures have low vitamin D and high parathyroid hormone levels compared with nonosteopo rotic and osteoporotic women admitted for elective joint replacement. Design Comparative case series conducted between January 1995 and June 1998 , Setting and Patients Ninety-eight postmenopausal community-dwelling women w ith no secondary causes of bone loss admitted for hip replacement, of whom 30 women had acute hip fractures and 68 women were admitted for elective jo int replacement. Of the women admitted for elective joint replacement, 17 h ad osteoporosis and 51 did not. Women with comorbid conditions or who were taking medications that affect bone density and turnover were excluded. Main Outcome Measures Primary measures were levels of vitamin D and parathy roid hormone; secondary measures were body composition and markers of bone turnover. Results Women with hip fractures had lower levels of 25-hydroxyvitamin D th an women without osteoporosis admitted for elective joint replacement (P=.0 2) and than women with osteoporosis admitted for elective joint replacement (P=.01) (medians, 32.4, 49.9, and 55.0 nmol/L, respectively; comparisons a djusted for age and estrogen intake). Parathyroid hormone levels were highe r in women with fractures than women in the nonosteoporotic control group ( P<.001) or than elective osteoporotic women (P=.001) (medians, 5.58, 3.26, and 3.79 pmol/L, respectively; comparisons adjusted for age and estrogen in take). Fifteen patients (50.0%) with hip fractures had deficient vitamin D levels (less than or equal to 30.0 nmol/L) and 11 (36.7%) had a parathyroid hormone level greater than 6.84 pmol/L, Levels of N-telopeptide, a marker of bone resorption, were greater in the women with hip fractures than in th e elective nonosteoporotic controls (P=.004). Conclusions Postmenopausal community-living women who presented with hip fr acture showed occult vitamin D deficiency. Repletion of vitamin D and suppr ession of parathyroid hormone at the time of fracture may reduce future fra cture risk and facilitate hip fracture repair. Because vitamin D deficiency is preventable, heightened awareness is necessary to ensure adequate vitam in D nutrition, particularly in northern latitudes.