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Severe vitamin D deficient rickets in black Afro-Caribbean children
  1. S Hannam,
  2. S Lee,
  3. M Sellars
  1. Department of Child Health, 4th Floor, Golden Jubilee Wing, King’s College Hospital, Denmark Hill, London SE5 9RS, UK; simon.hannamkcl.ac.uk

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    Concern has been raised over the past few years, at the prevalence of rickets in British Asian children1 and recent immigrants to the UK.2 Here we describe five cases of severe rickets in children of second generation Black-African or Caribbean parents who presented to paediatric outpatients in a socially deprived area of inner London. Weaning had been unsuccessful in all of the cases. The affected children all had biochemical (table 1) and radiological evidence of severe rickets.

    Table 1

    Biochemical bone profiles and characteristics of infants at presentation

    Case 1

    This child was referred to clinic by his GP due to delay in walking. His mother was still breast feeding as he refused to drink cows’ milk. Solids had been introduced at 6 months of age but he was a “fussy” eater. His mother was also on a restricted diet for weight reduction. He looked well but had wrist swelling and his anterior fontanelle was still patent. His weight was on the 25th centile.

    Case 2

    This child was referred by her GP with an abnormal gait and bowing of her legs. She was breast fed till 1 year of age. From 3 months of age, her mother had excluded dairy products from her own diet due to concerns regarding milk allergies. From 1 year of age, the child had not received any dairy products. She had swelling of her wrist and ankle joints and a very wide shuffling gait with marked varus deformity and bowing of her legs (fig 1). Her anterior fontanelle was still patent. Height and weight were both on the 25th centile.

    Figure 1

    Radiograph of the legs from case 2 showing bilateral distal tibial varus procurvatum deformity.

    Case 3

    This child was referred to paediatric outpatients following several visits to the casualty department with recurrent fevers. She had been fully breast fed since birth. Her mother did not drink milk. She had tried to introduce solids into the child’s diet from 5 months of age without success. The child looked pale and had swollen wrists and knees. Her weight was just below the 2nd centile compared with the 9th centile at birth.

    Case 4

    This child was referred by his GP with possible rickets. His mother described him as a very poor eater and he was still exclusively breast fed. His mother was taking a full mixed diet. On examination he had marked genu varum and swelling of his wrists. His weight was on the 0.4th centile compared to the 9th centile at birth.

    Case 5

    This child was referred with failure to thrive and severe eczema. She had been gaining weight satisfactorily until 3 months of age, when she developed severe facial eczema. She had been exclusively breast fed until 6 months when she was put onto Neocate formula feeds which she did not seem to tolerate. She also refused to take solids. Her mother had been avoiding dairy products in her own diet in order to avoid passing on cows’ milk allergens. The infant’s weight was below the 0.4th centile compared to the 50th centile at birth. She had hypergammaglobulinaemia with an IgG of 44.4 g/l (normal range 4.1–10.9 g/l) and an iron deficient anaemia. A RAST test was positive for cows’ milk. She was HIV negative. Her hypergammaglobulinaemia resolved as the eczema improved. Of note, her mother had low levels of 25(OH)D (7.4 ng/l) and phosphate (0.65 mmol/l).

    Discussion

    Responses to a recent questionnaire sent to paediatricians in the West Midlands suggest that rickets is being seen in the Afro-Caribbean population.3 However, most attention has been given to the risk of rickets in the Asian population in the UK. Most vitamin D is obtained from the action of sunlight on the skin as 7-dehydrocholesterol is converted to cholecalciferol (vitamin D3). Undoubtedly increased skin pigmentation would have played a role in the decreased levels of vitamin D shown in the present cases.4 However, none of the mothers were following the Islamic custom of veil wearing which can further reduce vitamin D levels.5 Four of the five cases were exclusively breast fed. As there is relatively little vitamin D in breast milk, it has been recommended that lactating women should supplement their diets with vitamin D (10 μg daily).6 Weaning can be associated with a lowering in vitamin D levels. Although some commercially available weaning foods have added vitamin D, it is recommended that children under 2 years of age should receive additional supplementary vitamin D of 7 μg per day.6 None of the children or mothers in this series were receiving vitamin supplementation prior to referral. Four of the children have responded to treatment with vitamin D3 6000 units/day. In one case, there have been problems with parental compliance. In all the cases, the index of suspicion for rickets had been low, thus delaying referral and treatment. Awareness of rickets in the Black-African and Caribbean population needs to be raised in health visitors, GPs, and parents.

    References

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