Hemodial Int. 2007;11:315-321
A study in Argentina found that vitamin D insufficiency and deficiency are highly prevalent in hemodialysis (HD) patients at the end of winter.
Elisa Del Valle, MD, of Fresenius Medical Care Quilmes Argentina and Instituto de Investigaciones Metabólicas in Buenos Aires, and her colleagues evaluated serum 25 (OH) vitamin D (calcidiol) levels in 84 stable patients (mean age 58.9 years) on chronic HD not receiving vitamin D supplements.
Levels of 25 (OH) vitamin D were measured at the end of September, which marks the end of winter in the southern hemisphere. The investigators also analyzed sunlight exposure. Vitamin D levels were considered adequate if they were above 30 ng/mL (as recommended by guidelines developed as part of the National Kidney Foundation’s Kidney Disease Outcome Quality Initiative). Vitamin D levels of 15-30 ng/mL were considered vitamin D insufficiency and levels below 15 ng/mL were considered vitamin D deficiency.
The investigators classified sunlight exposure of hands, face, and arms (about 15% of body surface) into three levels. Level 1 indicated less than one hour of exposure per week; level 2, one to three hours per week; and level 3, more than three hours per week.
Mean 25 (OH) vitamin D levels were 28.6 ng/mL in men and 18.9 ng/mL in women, a significant gender difference. Vitamin D insufficiency was found in 45 subjects (53.5%) and vitamin D deficiency was found in 19 (22.6%). After adjusting for confounders, only sunlight exposure and gender were associated with serum 25 (OH) vitamin D levels.
The authors noted that 84% of patients with calcidiol deficiency had level 1 sunlight exposure, where 85% of those with adequate calci-diol levels had level 2 or 3 exposure.
“This study highlights the importance of sunlight exposure in the HD population,” the authors wrote.