Vitamin D status in dark-skinned patients undergoing hemodialysis in a continually sunny country

Abstract

Vitamin D (vitD) insufficiency is common in end-stage renal disease. Seasonal and ethnic differences in vitD status have been reported previously. We hypothesized that vitD status in Afro-Caribbean patients on hemodialysis (HD) living in a country with a constant sunny climate would be better than that in African-American HD patients living in countries with a winter season. A cross-sectional study was conducted in 152 Afro-Caribbean HD patients in a dialysis center located in Guadeloupe. We evaluated the prevalence of vitD insufficiency, defined as serum 25-hydroxyvitamin D (25(OH)D) levels below 30 ng/mL, compared with those results previously reported in African-American HD patients (88%). Prevalence of vitD insufficiency was 60% and thus lower than that in the African-American patients considered as the reference population (p<0.001). In our diabetic patients, this prevalence was 72.4%. Globally, 9.2% of patients had 25(OH)D below 15 ng/mL. Alfacalcidol therapy was prescribed in 29%. Mean 25(OH)D levels were higher in treated than in untreated patients (32 vs. 27 ng/mL; p=0.009). Patients with vitD insufficiency had dyslipidemia and diabetes more frequently. No significant differences were found between patients with and without vitD insufficiency for serum calcium, phosphorus and parathyroid hormone (PTH). In untreated patients, no significant correlation was found between 25(OH)D and PTH levels. Prevalence of vitD insufficiency in Afro-Caribbean HD patients was lower than that previously reported in African Americans undergoing HD in the United States. This finding may be due to the constantly sunny weather with a high intensity of UVB radiation in Guadeloupe.