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African-American children in urban areas are more likely to be deficient in vitamin D and have higher blood lead levels when compared with their Hispanic counterparts, according to a study by NJMS researchers Francis Kemp and Dr. John Bogden. The study also found that increases in blood lead during the summer were associated with increases in blood vitamin D levels in the 4- to 8-year-old children studied.
The study was the subject of a recent Environmental Health Perspectives article entitled "Elevated Blood Lead Concentrations and Vitamin D Deficiency in Winter and Summer in Young Urban Children." It confirms prior research that shows blood lead concentrations are higher in the summer than in winter.
Environmental factors such as more exposure of children to lead in dust in the summer are one reason for this seasonal effect. However the relationships of blood lead to sunlight-induced vitamin D synthesis had not been adequately investigated in the past. The authors studied vitamin D status because it is influenced by diet, sunlight exposure, age, skin pigmentation, other factors, and based on studies in animals may increase gastrointestinal lead absorption or release of lead stored in bones into the bloodstream.
The cohort, 91 African American and 51 Hispanic children, were participants enrolled in the Women, Infants, and Children (WIC) program at UMDNJ. The researchers found that in the summer more than 20 percent of the African American children who were between ages one and three had elevated blood lead concentrations compared to about 10 percent with high levels during the winter. In contrast, only one Hispanic child had an elevated lead level. African American children who were between ages four and eight were more likely to have vitamin D deficiency in the winter than African American children ages one to three. Season and age had a much smaller impact on blood lead levels and Vitamin D concentrations in Hispanic children in those age groups.