Background: Low serum estrogen levels are associated with increased risk for hip fractures in healthy postmenopausal women. Although the rate of hip fractures is 4- to 24-fold greater in postmenopausal hemodialysis-dependent women (PHDW) compared with the general population, no published study has examined the prevalence of low serum estrogen levels or factors associated with low serum estrogen levels in this population.
Methods: We measured serum estrone (E1) and total estradiol (E2) levels in PHDW and investigated the independent association between serum estrogen levels and demographic and dialysis-related factors.
Results: Of 186 PHDW not administered postmenopausal hormones, 44% and 30% had low serum E1 (<15 pg/mL [55.50 pmol/L]) and total E2 levels (<5 pg/mL [18.35 pmol/L]), respectively. Serum E1 and total E2 levels were significantly lower in Caucasian women compared with non-Caucasian women and in women with a body mass index (BMI) less than 25 kg/m2 versus 25 kg/m2 or greater. After adjusting for age, BMI, dialysis vintage, dialysis dose, and history of bilateral oophorectomy, Caucasian race was associated with an increased risk for low serum E1 (odds ratio [OR], 3.42; 95% confidence interval [CI], 1.63 to 7.19) and total E2 levels (OR, 2.47; 95% CI, 1.11 to 5.49) compared with non-Caucasians. In addition, we noted a significant and independent association between BMI and serum estrogen levels. For every 1-kg/m2 increase in BMI, risk for low serum E1 and total E2 levels decreased by 12% (OR, 0.88; 95% CI, 0.83 to 0.94) and 15% (OR, 0.85; 95% CI, 0.80 to 0.91), respectively. No significant association was noted between age, dialysis vintage, or dialysis dose and low serum E1 or total E2 levels.
Conclusion: A substantial number of PHDW have low serum estrogen levels. Caucasian race and low BMI are independently associated with low serum estrogen levels in PHDW, whereas dialysis-related factors are not.