Changes in volumetric bone mineral density after gastrectomy as assessed by dual energy X-ray absorptiometry

We used dual energy X-ray absorptiometry (DXA) to study changes in estimated volumetric bone mineral density (EstVBMD) of the lumbar spine after gastrectomy. The study group comprised 41 men and 32 women. When EstVBMD was compared according to sex among patients younger than 60 years of age, patients 60 to 69 years of age, and patients these three groups in men (0.185 g/cm3, 0.187 g/cm3, 0.187 g/cm3, respectively). In contrast, EstVBMD was significantly lower in women 60 to 69 years of age (0.157 g/cm3) and those 70 years of age or older (0.159 g/cm3) than in women younger than 60 years (0.200 g/cm3) (P < 0.01). When the relation between EstVBMD and the number of months after gastrectomy was studied according to sex in patients younger than 70 years, EstVBMD negatively correlated with the interval after operation in men (r = -0.365, P < 0.05), whereas there was no correlation between these variables in women. These results suggest that after gastrectomy bone mineral density decreases gradually in men younger than 70 years, but not in women. The lack of a consistent change in bone mineral density after gastrectomy in women is apparently caused by the marked effect on bone metabolism of decreased female hormone levels after menopause.