Femur bone mineral density, age and fracture type in 300 hip-fractured women

Background and aims: Several studies showed that cervical and trochanteric hip fractures were associated with different levels of bone mineral density (BMD). Our aim was to investigate the association between femur BMD and hip fracture type at different ages. Methods: We studied 300 postmenopausal women affected by their first hip fracture. 17 women could not undergo BMD measurement and were excluded. The fractures of the remaining 283 women were classified as either cervical (N=129) or trochanteric (N=154). The BMD of the unfractured femur was assessed by DXA. Results: The women with trochanteric fracture had significantly lower BMD than those with cervical fracture at four sites: total proximal femur (p<0.001), trochanter (p<0.001), intertrochanteric area (p<0.01), and Ward's triangle (p<0.05). Logistic multiple regression showed that the association between hip fracture type and BMD was independent of age, weight, height, time between fracture occurrence and DXA assessment, number of concomitant diseases and number of drugs administered when BMD was evaluated at total proximal femur (p<0.001), trochanter (p<0.001), and intertrochanteric area (p<0.01). Age stratification showed that BMD was actually lower in the group with trochanteric fracture in the women aged 69 years and younger, and in those aged 80 years and older, but not in the intermediate age group (70-79 years). Conclusions: Data confirm previous reports showing that the two types of hip fractures are associated with different levels of BMD. Moreover, we show that the role played by BMD as a determinant of the hip fracture type varies with age.