Low Vitamin D Levels Highly Prevalent in Dialysis Patients
Hemodial Int. 2007;11:315-321
A study in
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.