CHAPEL HILL -- North Carolina researchers have discovered new evidence that nutritional rickets, a bone-weakening condition in infants and children caused by too little vitamin D, is making a comeback, especially among breastfed black children. Other dark-skinned children may be at risk for what appears to be a growing, potentially crippling problem, physicians say.
Surprisingly, causes may include more women breastfeeding, fewer infants receiving vitamin D supplements, and mothers and children being exposed to less sunlight than in the past. Breastfeeding still needs to be encouraged, the researchers say, but all dark-skinned, breastfed infants ought to receive vitamin D supplements.
Doctors at the University of North Carolina at Chapel Hill School of Medicine identified and treated 17 cases of nutritional rickets between 1990 and 1999, while colleagues at Wake Forest University School of Medicine found and treated another 13. More than half the cases occurred in 1998 and the first half of 1999. They also received reports of other cases across North Carolina and the nation.
Working together, the researchers described their findings in a paper appearing in the August issue of the Journal of Pediatrics.
"Nutritional rickets, once a major problem in industrialized nations, largely disappeared in this country beginning in the 1930s when it became law that vitamin D had to be added to milk," said Dr. Henry N. Kirkman Jr., Kenan professor emeritus of pediatrics at UNC-CH and an expert on the illness. "The only cases of rickets I treated between 1965 and about 1990 were inherited ones. Then, to my surprise, nutritional rickets began showing up in our clinic in the early 1990s."
Kirkman checked with his counterpart at Wake Forest University, Dr. Robert P. Schwartz, a pediatrics professor who said he also was beginning to see cases of nutritional rickets. All occurred in black children whose mothers had breastfed them.