Bolstered by recent laboratory findings, researchers at the University of Rochester Medical Center are embarking on a National Institutes of Health-funded clinical study to better understand the deceptive role environmental lead exposure plays in bone maturation and loss.
The clinical trial is the latest in a growing body of research that is putting yet one more notch in the belt of diseases attributed to lead, and this time, researchers say, its target is older adults at risk for osteoporosis.
For decades, scientists have known that the human skeleton is a repository for lead in people who were exposed to high levels of this environmental toxin in their childhood, but thought this storage to be benign. Recently, a growing body of research is showing that the opposite is true, and that lead in bone actually sets off a bizarre chain reaction, first accelerating bone growth, and then eventually limiting it so that a high peak bone mass is not achieved. Preventing a high peak bone mass will predispose a young person to osteoporosis later in life.
Now, researchers in the Center for Musculoskeletal Research at the University of Rochester Medical Center are set to embark on the next phase of a four-year, $5 million research project funded by the National Institute of Environmental Health Sciences with a clinical study aimed at better understanding the deceptive role lead initially plays in bone development, growth and loss - and how this all might lead to earlier onset of osteoporosis in those exposed to high levels of lead as a child.
A metabolic bone disease that predominantly occurs in women, osteoporosis affects one in three American women over the age of 65. It is characterized by low bone mass that eventually leads to fractures, mostly of the hip and vertebrae. These fractures can be life-threatening; experts say that more women die each year from hip fracture complications than from cancer of the ovaries, cervix and uterus combined. Close to $20 billion dollars is spent each year treating osteoporosis and related fractures.
The pattern of growth in the skeleton determines the peak skeletal density of an individual, and this level is established by the time most people reach 20. Recent research completed at the University of Rochester Medical Center shows that lead adversely affects the normal maturation of the growth plate - but does so in an odd way.
"As a child, lead appears to accelerate bone development and maturation, so that lead-exposed children actually have a higher bone density than those not exposed to environmental lead," said James Campbell, M.D., M.P.H., associate professor of Pediatrics and a co-investigator of the study. "But, we believe this higher bone density effect is short-lived, and in fact, we believe it actually prevents these children from achieving an optimal peak bone mass later on in life."
J. Edward Puzas, Ph.D., professor of Orthopaedics and director of the overall project, added that limiting peak bone mass has dire consequences as a person begins to age.