Histological osteomalacia due to dietary calcium deficiency in children.

We performed a histomorphometric study of trabecular-bone formation and resorption in undecalcified sections of iliac crest from three children presenting with clinical, radiologic, and biochemical evidence of rickets associated with dietary calcium deficiency. All three children had severe osteomalacia documented by hyperosteoidosis and reduced static and dynamic indicators of bone mineralization. There was a reduction of the calcified bone volume associated with a decreased bone formation rate and features of increased bone resorption. Correction of dietary calcium intake in two of the patients led to normal serum and urinary calcium levels and reduced alkaline phosphatase levels. After calcium therapy, the calcified bone volume was normal and indicators of bone mineralization returned to normal. We conclude that low calcium intake in children may be associated with a histologic picture of severe osteomalacia. Our finding that adequate amounts of calcium rapidly improved bone mineralization demonstrates that calcium deficiency can cause osteomalacia in children.