Lead and Psychiatric Symptoms in Aging People

Howard Hu, MD, Sc.D.
Brigham and Women's Hospital
R01ES05257, P42ES05947, and P30ES00002

Background: The effects of lead on cognitive function in children are well documented and have been common knowledge for decades; however, the effects of lead on older people are not well known. Lead is released from its major storage sight, the long bones, during periods of bone turnover such as gestation and lactation and as a result of osteoporosis. Therefore, there is cause to be concerned about the effects of lead in elderly persons as it may be relevant to neurologic diseases and dementia.

Advance: These NIEHS-supported researchers measured blood and bone lead concentrations in middle-aged to elderly men enrolled in the Normative Aging Study and used them to investigate lead's potential effects on psychiatric symptoms such as anxiety, depression, and phobic anxiety. Blood lead levels averaged 6.3 micrograms/dl while tibia and patellar lead levels were 21.9 and 32.5 micrograms/gram respectively. All of these lead levels are considered to be modest levels of exposure. Logistic regression models that adjusted for age, employment status, education, and alcohol consumption indicated that patellar bone lead was significantly associated with an increased risk for phobic anxiety. Similar associations were seen for tibia and blood lead.

Implication: These results led the researchers to conclude that cumulative lead exposure, even at these modest levels, could be a risk factor for the development of psychiatric symptoms in adults. If additional studies confirm these results, screening and treatment for lead exposure could be indicated for adults with similar psychiatric illnesses and symptoms.

Citation: Rhodes D, Spiro A 3rd, Aro A, Hu H. Relationship of bone and blood lead levels to psychiatric symptoms: the normative aging study. J Occup Environ Med. 2003 Nov;45(11):1144-51.