Rickets, Vitamin D Deficiency and Tuberculosis in Children of St. Petersburg and Its Region

Introduction: Given the widespread prevalence of vitamin D insufficiency and its clinical manifestations (such as rickets and compromised immune status) in children, this study aimed to assess the likelihood of tuberculosis (TB) diagnosis in children with TB infection and positive ESAT-6/CFP-10 test results, alongside signs of vitamin D deficiency (clinical rickets and/or low serum vitamin D levels). Method: serum calcidiol (25(OH)D) measurement was performed. Result: Rickets-related changes were observed in 70.4±4.6% of cases. Vitamin D insufficiency was detected in 21.4±4.4%, moderate deficiency in 36.7±5.1%, and severe deficiency in 33.7±5.0%. A significantly higher probability of active TB diagnosis was found in children with: • Rickets signs: OR=4.009 (95% CI 1.609-9.987), RR=1.872 (1.148-3.054), φ=0.310. • Vitamin D deficiency: OR=10.411 (3.762-28.809), RR=3.182 (1.648-6.145), φ=0.493. • Either factor: OR=41.167 (10.699-158.404), RR=27.986 (2.720-23.443), φ=0.677 (strong association). Discussion: The low vitamin D levels in children require not only special attention from TB specialists to patients with tuberculosis infection who test positive in immunological tests for ESAT-6 and CFP-10 antigens and show signs of rickets and/or vitamin D deficiency, but also increased vigilance from pediatricians in the timely diagnosis and treatment of rickets. Rickets often manifests early, has a prolonged course, and can lead to impaired immune status, which is significant for the progression from latent tuberculosis infection to active disease. Conclusion: Vitamin D deficiency and rickets should prompt heightened TB monitoring in high-risk children, emphasizing early pediatric intervention to prevent immunodeficiency and TB progression.