Abstract
Aim
Assess the incidence of Vitamin D deficiency from a cohort of new referrals to a general Paediatric Orthopaedic outpatient clinic and evaluate the relationship between Vitamin D deficiency and the diagnosis of radiological or biochemical nutritional rickets.
Methods
We performed a retrospective case note and biochemistry database review of all new patients seen in an elective Paediatric Orthopaedic clinic in the year 2010, who had Vitamin D levels measured. Radiographs were reviewed by the senior author to determine the presence or absence of radiological rickets. Biochemical rickets was diagnosed if there was deficient Vitamin D (< 20 mcg/ml) and raised PTH.
Results
We identified 115 children with a mean age of 10.95 years (95% CI 10.24 to 11.68). There were 63 females, 52 males and 51 were of Asian ethnicity. The mean vitamin D level was 18.27mcg/ml (95% CI 16.13 to 20.41). One hundred and three patients (88%) were found to have sub-optimum vitamin D levels. Although, males and those of Asian origin were more likely to be deficient, this was not statistically significant. Winter/Springtime blood sampling was statistically more likely to show Vitamin D deficiency than in Summer/Autumn. Three Asian female children (2.61%) had radiological rickets. The association between low Vitamin D levels (< 20) and radiological or biochemical rickets had poor positive predictive values PPV.
Conclusion
Suboptimal Vitamin D levels are common in children presenting with vague limb or back pain, suggesting ‘growing pains’ might reflect deficiency. Vitamin D levels cannot be used as a screening test for the diagnosis of radiological or biochemical ‘rickets’ due to its poor Positive Predictive Value. Further research into Vitamin D requirement is necessary, particularly in relation to growth and age, as growth is not linear and Vitamin D requirement is likely to vary accordingly.
