Body mass and fracture risk. A study of 330 patients.

Low body mass is a major risk factor for low energy hip fractures among women. The purpose of this study was to ascertain whether normal body mass also protects against low energy wrist fractures. A retrospective analysis of body mass indices of 330 women who sustained hip or wrist fractures from falls was performed. Data were grouped by race and age. The mean body mass index for white patients with wrist fractures was 26.4, compared with a mean body mass index of 22.3 in white patients with hip fractures. For black patients, those with wrist fractures had a mean body mass index of 28.5, compared with a mean body mass index of 22.9 for those with hip fractures. Using data from The National Health and Nutrition Examination Surveys, the mean body mass index of patients with wrist fractures was seen to be equal to or greater than the national mean body mass index, whereas that of patients with hip fractures was substantially below average. Accordingly, normal body mass was protective against hip fractures but not against wrist fractures. Because adipose tissue more typically is distributed about the hip than the wrist, the protective mechanism of normal body mass against osteoporotic fractures may promote better preventative interventions against this disease.