Longitudinal association between sex hormone levels, @entity604 , and bone turnover in elderly XXXX .

@entity1 @entity172 @entity3930 @entity251 @entity604 @entity53 @entity134 @entity2331 @entity342 @entity10819 @entity443
@entity3930 is an increasingly important health problem. It is known that sex @entity134 hormones play an important role in regulating bone turnover and bone mass in males as well as in females. However, the exact mechanism of @entity604 in @entity1 remains unknown. In the present study, 200 elderly @entity1 (age range, 55-85 yr) were followed for 4 yr to evaluate the relationships between hormone levels, bone turnover markers, bone mineral density, and rates of @entity604 . Femoral and lumbar bone mineral density, bone ultrasound parameters at the os calcis, serum @entity251 (T), serum @entity53 ( @entity10819 ), @entity443 levels, and bone turnover markers (urinary crosslaps and bone alkaline phosphatase) were evaluated for each @entity1 at enrollment and 4 yr afterward. The free @entity342 index (FAI) and free @entity172 index (FEI) as well as measures of the bioavailable sex hormones [calculated bioavailable @entity10819 (c-bioE(2)) and T (c-bioT)] were calculated from total hormone levels and @entity443 . In the total population, T, c-bioT, c-bioE(2), FAI, and FEI, but not @entity10819 , decreased significantly with age, whereas @entity443 increased significantly. Subjects with FEI, c-bioE(2), and @entity10819 levels below the median showed higher rates of @entity604 at the lumbar spine and the femoral neck as well as higher speed-of-sounds decrease at the calcaneus with respect to @entity1 with FEI, c-bioE(2), and @entity10819 levels above the median. Serum bone alkaline phosphatase and urinary crosslaps were significantly higher in @entity1 with FEI, c-bioE(2), and @entity10819 in the lower quartile than in @entity1 with FEI, c-bioE(2), and @entity10819 levels in the higher quartile. No statistically significant differences were observed in relation to T, c-bioT, or FAI levels. Finally, the ratio between @entity10819 and T, an indirect measure for aromatase activity, increased significantly with age and was higher in normal than in osteoporotic subjects. In conclusion, results from the present study indicate an important role of @entity172 , and particularly of the ability to aromatize T to @entity10819 , in the regulation of @entity2331 in elderly @entity1 .
