Influence of age and sex on bone mineral density in dialysis patients

In the present study, we evaluated bone mineral density (BMD) in relation to the age and sex of dialysis patients. The study was performed in 30 patients divided into two groups according to age (older group: 12 patients older than 65 years; younger group: 18 patients 65 years of age or younger) and according to sex (18 women, 12 men). We used dual-energy X-ray absorptiometry to examine BMD in the femoral neck (N) and lumbar spine (L2-L4). We simultaneously evaluated parathyroid hormone, calcium-phosphate balance, blood pH, markers of inflammation and nutrition status, and measurements of body composition by bioimpedance analysis. We found significant differences for BMD measured in N (older group: 0. 709 +/- 0.111 g/cm2; younger group: 0.884 +/- 0.130 g/cm2), T-score [older group: -2.64 (range: -4.06 to -0.17); younger group: -0.88 (range: -3.25 to 2.37)], and BMD as a percentage of peak bone density [older group: 68.0% (54.2%-97.0%); younger group: 89.5% (range; 61.4%-135.0%)]. The older patients also had lower serum albumin and higher serum ferritin. After adjustment of the results by sex, the older group also showed lower serum Ca and lean body mass and higher serum glucose. Grouping of the patients by sex revealed significant differences in BMD when results were adjusted for age: men had a higher BMD in N (0.85 +/- 0.16 g/cm2) than women did (0. 79 +/- 0.14 g/cm2). We conclude that older age, which is more frequently associated with protein malnutrition, inflammation, and glucose abnormalities than is younger age, is also the important factor influencing BMD loss in dialysis patients.