[Proximal femoral fractures: risk factors, bone mineral density, body composition and biochemical changes in and age-matched patients and controls].

During one year (6/93-5/94) we performed a prospective study in patients with hip fracture, treated at the Hospital de Clínicas. A total of 102 women 52 to 94 years of age (Mean +/- 1SD: 79.5 +/- 9.1 years) and 17 men 61 to 98 years of age (79.7 +/- 9.9 years) who had sustained a hip fracture due to mild or moderate trauma were included. The ratio women: men was 6:1. We also studied 55 age-matched control women without diseases that could affect the skeleton or previous hip fracture (77.1 +/- 5.8 years of age). We did not study a control group in men. Women with hip fractures had lower weight (p < 0.01), lower age of onset of the menopause (p < 0.01) and a tendency to have with a greater frequency a mother with hip fracture (p < 0.08) compared with age-matched controls. When vertebral fractures were excluded, 44% of the hip fracture women had sustained previous skeletal fractures, while only 16% of the age-matched controls had suffered previous skeletal fractures (p < 0.001) (Table 2). The most frequent previous skeletal fractures were wrist and humerus. Forty eight percent of hip fracture women had had at least one vertebral fracture. About 17% of the hip fractured men had sustained previous skeletal fractures, while 5/12 men had suffered at least one vertebral fracture. Hip fractured women and men sustained greater history of diseases which provoke postural instability (Table 3). Biochemical determinations showed significantly diminished levels of serum albumin (p < 0.001) and calcium (p < 0.01), and increased serum PTH (p < 0.05) compared to age-matched controls (Table 4). Bone mineral density (determined by dual energy X-ray absorptiometry) was significantly diminished over proximal femur, total skeleton, legs and pelvis (p < 0.001), head and spine (p < 0.05) (Table 5). Body composition measurements showed that hip fracture women had a significantly lower lean mass compared with controls (p < 0.05). Fat mass also was lower in fracture patients compared with controls, but the difference was not statistically significant (Table 5). We conclude that hip fracture in our population is related to several previous factors: earlier onset of menopause, lower nutrition and body weight, previous diseases that increase the likelihood of falling, increased levels of PTH and reduced bone mass. Prevention of hip fractures should take into account all these factors, specially those that could be modified.