Lead toxicity in older adults.

Recent studies have shown that lead, even at relatively low levels of exposure, has the potential to harm not only the young and the occupationally-exposed, but also older people. Because they have been alive for a longer period of time, older adults have had more potential exposures to lead. They may have been exposed to lead while working in unregulated occupations, or they may have encountered more lead in the environment on a daily basis. Several large epidemiological studies have found that older people have higher blood and bone lead levels than younger adults. Additionally, sporadic clusters of acute lead exposure among older adults as a result of activities such as ceramic glaze hobby work and consumption of moonshine whiskey continue to be reported. After lead enters the body, it circulates in the blood reaching the soft tissues and bone. Researchers have learned that lead can hibernate within bone for decades. Although lead within bone is of uncertain toxicity to bone tissue, conditions of bone resorption, such as osteoporosis, can cause bone lead to reenter the bloodstream where it can then re-expose the soft tissue, and, potentially, exert delayed deleterious effects. Evidence is emerging that blood and bone lead levels, reflecting relatively modest exposures, are associated with hypertension, renal insufficiency, and cognitive impairment. Medical treatments that now exist to slow the rate of bone resorption may maintain lead within bones. On-going studies evaluating the relationship between body lead stores and both cognitive and renal impairment, as well as the potential modifying effect of bone resorption, will help determine whether bone resorption should be retarded specifically to preserve organ function. Physicians should be aware of potential past and present lead exposures among their older patients. Ongoing lead exposure should be prevented. In the future, treatment of osteoporosis may be undertaken not only to improve bone health but also to prevent mobilization of bone lead stores and subsequent toxicity.