LOS ANGELES, Sept. 4 (Xinhua) -- Girls exposed to lead in early childhood may be more likely to experience delay in puberty, a new study available here on Saturday suggests.
The delay occurs even at blood levels below those recommended for treatment, the U.S. National Institute of Child Health and Human Development (NICHHD) said in the study published in the Sept. issue of the journal Environmental Health Perspectives.
By analyzing blood samples taken from more than 700 girls aged 6 to 11, NICHHD researchers found that those with elevated levels of lead (five or more micrograms of lead per deciliter of blood) were 75 percent less likely than those with low levels of lead to have adolescence-related hormones at levels associated with the start of puberty.
This difference in hormone levels was even greater in girls with elevated levels of both lead and cadmium, which can damage the kidneys, lungs and bones and increase the risk of cancer, the study noted.
Children are usually exposed to lead through old, deteriorating lead-based paint and lead-contaminated dust and soil, while breathing in cigarette smoke is a leading source of cadmium exposure, according to the study.
Lead, alone or together with cadmium, may suppress the ovaries' production of hormones that prepare a young girl's body to release an egg (ovulate) for the first time, said the study.
The U.S. Centers for Disease Control and Prevention advises treatment for blood lead levels higher than 10 micrograms per deciliter, the researchers said, but warned that the findings indicate damage can occur at even lower levels.
"Our findings suggest childhood exposure to lead has worrisome effects as children age and reach adolescence. These issues are of concern in some parts of the United States as well as in countries where children are exposed to leaded gasoline, paint or industrial pollutants," study author Audra L. Gollenberg said in an institute news release published by HealthDay News this week.
The researchers also found that lead-related delay of puberty was more common in girls with iron deficiency.
"Iron deficiency appears to be a critical factor in the context of lead exposure. Health-care providers may wish to pay particular attention to the importance of screening for iron deficiency among girls at high risk for exposure to lead," Gollenberg said.
