An investigation into a possible relationship between vitamin D, parathyroid hormone, calcium and magnesium in a normally pigmented and an albino rural black population in the Northern Province of South Africa

Vitamin D levels are important in the management of patients with various disorders of calcium metabolism associated with rickets, osteomalacia, osteodystrophy osteoporosis and hypoparathyroidism. 82 albinos and 58 normally pigmented children resident at the Siloe School for the Visually Impaired were sampled. Blood samples of fasting subjects were collected over a two-day period and analyzed for vitamin D, parathyroid hormone, plasma calcium and both plasma and red blood cell magnesium measurements. The height and weight of each subject was also recorded. The results are discussed in relation to the different skin pigmented groups, for specific age groups, sex and visual status. Statistical outliers were excluded from the results. It appears that the Albino group has significantly (p = 0.06) higher vitamin D levels against the background of a similar dietary intake and similar exposure to sunlight/day length. Thus black children/subjects require a significantly higher intake of vitamin D to attain the same level as their Albino counterparts. In spite of significantly higher vit D levels, the other homeostatic control mechanisms were not altered (i.e., PTH levels are similar in both groups). This study supports the postulate that a dark complexion predisposes to sub-optimal vit D status.