Femoral neck and intertrochanteric fractures have different risk factors: a prospective study.

The aim of this study was to determine whether both types of hip fracture, femoral neck and intertrochanteric, have similar risk factors. A prospective cohort study was carried out on community-dwelling elderly women in four areas of the United States: Baltimore, MD; Pittsburgh, PA; Minneapolis, MN and Portland, OR. The participants were 9704 Caucasian women, 65 years and older, of whom 279 had fractured their femoral neck and 222 had fractured their trochanteric region of the proximal femur. The predictors used were the bone mass of the calcaneus and proximal femur, anthropometry, history of fracture (family and personal), medication use, functional status, physical activity and visual function. The main outcome measures were femoral neck and intertrochanteric fractures occurring during an average of 8 years of follow-up. In multivariate proportional hazards models, several risk factors increased the risk of both types of hip fracture; including femoral neck bone density and increased functional difficulty. In hazard regression models that directly compared risk factors for the two types of hip fracture, calcaneal bone mineral density (BMD) predicted femoral neck fractures more strongly than intertrochanteric fractures (OR = 1.16; 95% CI = 1.02-1.31). Steroid use and impaired functional status also predicted femoral neck fractures instead of intertrochanteric fractures. Poor health status (OR = 0.74; 95% CI = 0.55-1.00) predicted intertrochanteric fractures more strongly than femoral neck fractures. We conclude that femoral neck fractures are largely predicted by BMD and poor functional ability while aging and poor health status predispose to intertrochanteric fractures.