A new research study, co-authored by Mary Lee, MD, chief of pediatric
endocrinology and diabetes, found a link between blood lead levels and the start
of puberty in boys. The study showed that boys with blood lead levels in the
high end of the current "acceptable" range, established by the Centers for
Disease Control and Prevention (CDC), start puberty later than boys with lower
About 480 8- to 9-year-old Russian boys from a largely industrial town were
followed for three years during which their lead levels and age they began
puberty were tracked. Researchers found that those with higher lead levels (but
still in the acceptable range) started puberty six to eight months later than
those with lower levels.
"When a small number of boys start slightly later, we don't get too
concerned," said Dr. Lee. "However, if this association causes a population
shift in the average age of the onset of puberty, more boys may end up having
'clinical delay,' which is when puberty hasn't started by age 13," said Dr. Lee.
Those with a clinical delay face higher risks of low self-esteem, and
reproductive, physical, social and psychological issues compared with their
The CDC considers high blood lead levels in children a concern. Children with
high levels can experience learning disabilities, lower IQs, behavioral problems
and other issues. The boys in this study had lead levels below the level of
concern, thus the results actually fell in the acceptable range.
"Our research team continues to gather data on the boys," Dr. Lee explained.
"In the long-term, we will look to see if what we found continues and if the
lead-associated delay in puberty affects how puberty progresses and adult
reproductive status." If this is the case, the team may urge that the CDC lower
the level of concern for blood levels.