Requirement for vitamin D supplementation in patients using photoprotection: variations in vitamin D levels and bone formation markers.

BACKGROUND

Avoiding sun exposure is obligatory in photodermatoses; however, the need for oral supplementation with vitamin D appears unrecognized. The aim of the study was to investigate the seasonal variation of vitamin D level and bone formation markers in healthy individuals and to compare it with vitamin D status in patients using photoprotection.

METHODS

Thirty-four healthy inhabitants of the Lodz region, Poland, a country in central Europe (51° and 52° north latitudes), were examined at the baseline visit within 2 weeks of peak sun exposure during recreational activity on vacation, after 8, and after 16 weeks. The group of patients using photoprotection comprised 104 patients with systemic lupus erythematosus. Serum 25(OH) vitamin D, procollagen type I N-terminal propeptide (PINP), and osteocalcin levels were measured.

RESULTS

The serum 25-hydroxyvitamin D concentration was lower and vitamin D deficiency more common in patients using photoprotection than in healthy individuals during the warm and the cold season (P < 0.05). In healthy individuals, vitamin D deficiency was more prevalent after 8 and 16 weeks than at baseline assessment (P < 0.001). PINP level was 39.56 (30.51-53.22) ng/ml, and elevated in 50% of individuals, whereas osteocalcin was 18.88 (13.52-21.33) ng/ml, and within reference range.

CONCLUSIONS

Diagnoses of vitamin D deficiency and oral supplementation in patients using photoprotection need to be included in practice. Peak 25-hydroxyvitamin D levels are probably achieved from vitamin D skin synthesis during the summertime and fall over time, starting from August. Elevated levels of PINP appear in line with the process of bone remodeling related to age.