Vitamin D: a poor screening tool for biochemical and radiological rickets.
ABSTRACT This retrospective study aims to determine if a relationship exists between serum 25-hydroxyvitamin D level and the diagnosis of biochemical or radiological rickets in children with bone and joint pain, muscle fatigue or varus/valgus knees. A retrospective biochemistry database and case note study was undertaken on 115 new patients referred to the senior authors' elective Paediatric Orthopaedic Clinic in 2010. Their mean age was 10.95 years (95% CI 10.24-11.68). Mean serum vitamin D was 18.27 mcg/l (95% CI 16.13-20.41), while 30 mcg/l is the normal threshold. One hundred and three children (88%) had vitamin D levels below normal. Winter/springtime blood samples were more likely to be deficient and this was statistically significant. Three Asian females (2.61%) were diagnosed with radiological rickets. Vitamin D levels below normal are common in children presenting with vague limb or back pain, but this rarely presents with biochemical or radiological rickets. Serum vitamin D level is not a suitable screening tool for biochemical or radiological rickets. Vitamin D requirement in children is unclear and requires further study.