was uncommon, vitamin D-deficient rickets was virtually eliminated. 9 Cognizant of the problem of labeling asymptomatic children as having vitamin D deficiency based on a laboratory measurement without other confirmatory evidence, Gordon et al obtained radiographs on study children with low levels. While signs of rickets were uncommon, one-third of these patients had radiographic evidence of demineralization. 7 To the authors, this relatively high frequency of signs of demineralization underscored the deleterious effects of vitamin D deficiency, as they have defined it. However, for 67% of the children classified as having deficiency there was no evidence of any bone abnormality.Perhaps more importantly, the clinical significance of mild to moderate bone demineralization on radiograph in a healthy infant or toddler is not well described. This is the other major issue to consider when interpreting the results of the study by Gordon et al. It is possible that some of the children with vitamin D levels of 20 ng/mL or lower and bone demineralization on radiograph will go on to develop rickets in the near future or have bone disease later in life. It is equally, or more, likely that for most of these asymptomatic children the changes seen on radiograph are transient and will go away when sunlight exposure and vitamin D intake increases.The results of this study suggest that a vitamin D level is not a good screening test for rickets in asymptomatic children; 92.5% of those with hypovitaminosis D, as defined by Gordon et al, had no evidence of rickets on radiograph. 7 Future research is needed to determine whether infants and toddlers with vitamin D levels of 20 ng/mL or lower are at significant short-or long-term risk for other bone disease or different conditions. Pending this research, the recommendations by Gordon et al that all young children should receive vitamin D supplementation and that children with risk factors should have periodic vitamin D levels obtained 7 may be premature. ). Financial Disclosure: None reported. REFERENCES 1. Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357(3):266-281. 2. Gartner LM, Greer FR. Prevention of rickets and vitamin D deficiency: new guidelines for vitamin D intake. Pediatrics. 2003;111(4, pt 1):908-910. 3. Ryan AS. The resurgence of breastfeeding in the United States.