Patients with chronic kidney disease (CKD) are at increased fracture risk. Low bone mineral density (BMD) is a risk factor for fracture in these patients. Hypogonadism predisposes to low BMD and fracture in the general population and oestradiol is the predominate sex hormone regulating bone health in normal men. Gonadal dysfunction is a frequent finding in men with CKD receiving dialysis, however the contribution of gonadal steroids to bone health in these patients has been under-investigated and remains unknown.

Aim: To examine the effect of gonadal steroids on BMD in men with CKD receiving dialysis pre-transplant.

Methods: Cross sectional study of male dialysis patients wait-listed for renal transplantation. Biochemistry, gonadal steroids and BMD were routinely performed on all patients prior to transplantation. Multivariable linear regression models were applied to study associations between gonadal steroids and BMD . 

Results: 546 males, mean age 45.5 years (range 17-75 years) were identified. Pre-existing diabetes was present in 29% and mean dialysis time was 42 months. Using linear regression modelling adjusting for age, BMI, dialysis time and pre-existing diabetes, total oestradiol, but not free or total testosterone levels, was significantly associated with LS BMD in the complete cohort (p= 0.001). Given the expansive age range, the population was also dichotomized into men aged <50 or >50 years. Oestradiol remained significantly associated with LS BMD when adjusted for SHBG in men aged >50 years (p= 0.004) and there was a trend towards significance in men aged <50 years (p= 0.052). PTH was not significantly associated with LS BMD.

Conclusion: In this largest study to examine the effects of gonadal steroids on BMD in men receiving dialysis, oestradiol levels were strongly associated with LS BMD. These findings may have important therapeutic implications for preservation of bone health given the high fracture risk in this patient cohort.