Exposure to lead in early childhood may delay puberty in girls.
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. To look if exposure to lead causes any pubertal problems in girls, researchers analysed the findings of blood samples taken from more than 705 American girls aged between 6 and 11 years.
It was found that those with elevated levels of lead (5 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. It was also found that lead-related delay of puberty was more common in girls with iron deficiency.
The researchers noted that 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. Current guidelines advise treatment for blood lead levels higher than 10 micrograms per deciliter but the study findings warn that damage can occur at even lower levels.
The findings suggest childhood exposure to lead has worrisome effects as children age and reach adolescence and the issue is of concern in countries where children are exposed to leaded gasoline, paint or industrial pollutants.