Is vitamin D a risk factor in the development of Scheuermann’s kyphosis?

Evaluation of vitamin D (D vit) levels in Scheuermann's kyphosis is important for a better understanding of environmental and metabolic factors that may contribute to the etiopathogenesis of the disease and for revising screening approaches. We aimed to evaluate the relationship between serum D vit, calcium, phosphorus, and alkaline phosphatase (ALP) levels between individuals with Scheuermann's kyphosis and an age- and sex-matched healthy control group. A total of 400 individuals (200 Scheuermann's kyphosis and 200 control), aged between 10 and 18 years, were included. Participants were considered eligible if they: were aged 10-18, in the kyphosis group, had a thoracic Cobb angle ≥ 45°, had available laboratory data for D vit, calcium, phosphorus, and ALP, and had not received D vit supplementation before evaluation. The Scheuermann's kyphosis group was found to have low levels of D vit (P < 0.05). Both groups had the highest levels of D vit in the summer months and the lowest levels in the winter months, which was statistically significant (P < 0.05). When we compared the groups across seasons, serum D vit levels in the kyphosis group were found to be low in all seasons (all P < 0.05). In the Scheuermann's kyphosis group, a significant positive correlation was found between serum D vit and serum calcium levels (r = 0.18, P = 0.01) and a significant negative correlation was found between D vit and thoracic Cobb angle (r = -0.16, P = 0.02). We found that D vit levels in patients with Scheuermann's kyphosis were lower than in healthy individuals.