A variation of vitamin D deficiency in children

The clinical characteristics of vitamin D deficiency in childhood: a systematic literature review of Japanese patients

To describe the characteristics of children with vitamin D deficiency, we reviewed the reports of vitamin D deficiency among Japanese children that were published between 1989 and 2008. We identified 25 patients with vitamin D deficiency in 9 published studies and evaluated their clinical characteristics together with those of 3 patients we recently treated. The patients were distributed in two distinct age groups at diagnosis: < 1 year old and > or = 1 year old. The main symptom of the < 1 year old age group was hypocalcemic convulsions and that of the > or = 1 year old age group was bowed legs. Serum calcium, intact PTH, and 1,25(OH)2D levels were significantly lower in the < 1 year age group than in the > or = 1 year age group. It would be useful to find and make early interventions in cases of children at a high-risk of vitamin D deficiency.

Presentation of vitamin D deficiency

AIMS

To describe the various ways in which vitamin D deficiency presents in children in selected districts of London and to identify which factors, if any, determine the mode of presentation.

METHODS

Retrospective review of patients presenting to Newham General, Royal London, Great Ormond Street, and King's College Hospitals between 1996 and 2001 with either hypocalcaemia or rickets caused by vitamin D deficiency. Children with plasma 25-hydroxyvitamin D levels <25 nmol/l (10 ng/ml) were considered to have vitamin D deficiency.

RESULTS

Sixty five children, mostly from Black or Asian ethnic minority groups, were identified, 29 of whom had hypocalcaemic symptoms. Seventeen of these had no radiological evidence of rickets. The remainder (48 children) had radiological evidence of rickets with or without clinical signs. Symptoms and signs reverted to normal in all cases with vitamin D supplementation. All children who presented with symptomatic hypocalcaemia were aged either <3 or >10 years. There was a strong correlation between age at presentation and population growth velocity reference data.

CONCLUSIONS

Rickets remains a problem in the UK especially in "at risk" ethnic minority groups. Symptomatic hypocalcaemia is an important, but under-recognised presenting feature. Growth rate is likely to be an important factor in determining the mode of presentation. Unexplained hypocalcaemia should be attributed to vitamin D deficiency in "at risk" ethnic minority groups until proved otherwise.