[Aspects of juvenile rickets/osteopenia in black children].

Juvenile rickets or osteopenia in rural black children is thought to be due to low calcium intake. Characteristic findings include mild calcium deficiency, normal serum phosphate levels, increased alkaline phosphatase concentrations and normal plasma vitamin D levels. The present series consisted of 62 black children (average age 6.82 years), 41 males and 21 females. Low levels of serum calcium and phosphate were present in 34 (54%) and 18 (29%) of the patients respectively. Alkaline phosphatase concentrations were raised (greater than 350 IU/l) in 38 (61%). Serum sodium, potassium, chloride, total bicarbonate, magnesium, ceruloplasmin and albumin levels were generally within normal limits. Urinary acidification was normal and barium studies were reported as normal in all but 4 children. Malabsorption was not an important feature. Serum vitamin D levels were not determined. All 18 patients with hypophosphataemia improved. Eleven children showed no clear response after at least 8 weeks in hospital--8 remained hypocalcaemic and 2 of the 3 patients with normal biochemical values showed no radiological improvement of osteopenia after 2 and 4 months in hospital, while the 3rd showed only very slight improvement after 7 months in hospital. It is not clear why these patients did not respond and whether even longer hospitalisation would have been effective.