[Effects of body mass index on bone mineral density in men]

A strong positive association between body mass index and bone mineral density is well defined in postmenopausal osteoporosis, but not in men.

The primary goal of the current research was to investigate this association in case of men.

According to WHO criteria (T-score below -1.0 at all measure site) seventy-two (mean age 55.7 +/- 0.99, range 38-78 yr normal density) healthy male with normal density were recruited. Exclusion criteria were the absence of any risk factors or signs of metabolic disease. Bone mineral measurements at the lumbar spine (L2-4) and femoral neck were performed by the dual-energy X-ray absorptiometry (DEXA, Lunar DPX-L, USA), bone mineral content of the non-dominant radius was measured with single photon absorptiometry (SPA, NK-364, Hungary). Participants were divided into three groups according to body mass index normal weight (18.5-24.9 kg/m2), moderate overweight (25-29.9 kg/m2) and obese subjects (> 30 kg/m2).

Femur neck density was significantly lower in the normal weight than in the overweight counterparts (0.969 +/- 0.03 vs 1.062 +/- 0.02 p = 0.01). There was a strong positive association between BMI and femur neck BMD (r = 0.412 p < 0.001). Body mass was an independent predictor of femur neck bone mineral density (regression coefficients 0.382, p = 0.001). There was not correlation at the lumbar spine and the radius sites.

Bone density at femur neck sites is lower in the normal weight men than in obese subjects, therefore the risk factors for proximal femur osteoporosis are higher in these cases. Prevention strategy is needed for men in the lowest quintile of body mass to prevent further decrease in BMD and reduce the risk of hip fracture.