UC Irvine

Background

Studies in healthy pediatric populations and adults treated with dialysis demonstrate higher parathyroid hormone (PTH) and lower 25-hydroxyvitamin D levels in African-Americans. Despite these findings, African-Americans on dialysis demonstrate greater bone strength and a decreased risk of fracture compared to the Caucasian dialysis population. The presence of such differences in children and young adult dialysis patients is unknown.

Methods

Differences in the markers of mineral and bone metabolism (MBM) were assessed in 661 incident dialysis patients (aged 1 month to < 21 years). Racial-ethnic differences in PTH, calcium, phosphate, and total alkaline phosphatase (AP) activity were analyzed over the first year of dialysis using multivariate linear mixed models.

Results

African-American race predicted 23% higher serum PTH (95% CI, 4.7-41.3%) when compared to Caucasian patients, while Hispanic ethnicity predicted 17.5% higher PTH (95% CI, 2.3-38%). Upon gender stratification, the differences in PTH were magnified in African-American and Hispanic females: 38% (95% CI, 14.8-69.8%) and 28.8% (95% CI, 4.7-54.9%) higher PTH compared to Caucasian females. Despite higher PTH values, African-American females persistently demonstrated up to 10.9% lower serum AP activity (95% CI, - 20.6-- 0.7%).

Conclusions

There are racial-ethnic differences in the markers of MBM. Higher PTH is seen in African-American and Hispanic children and young adults on dialysis with a magnification of this difference amongst the female population. There is a need to consider how factors like race, ethnicity, and gender impact the goal-targeted treatment of MBM disorders.