A recent study suggests that higher cumulative lead exposure stored in bones is strongly associated with an increased risk of Alzheimer’s disease and other dementias.
Individuals with the highest bone lead levels had nearly three times the risk of Alzheimer’s disease and more than double the risk of all-cause dementia compared with those with the lowest levels.
Current blood lead levels were not significantly associated with dementia risk, highlighting that lifetime exposure, not just recent exposure, may play a critical role in later cognitive decline.
Another recent study also indicates that lead exposure before birth may be associated with lower cognitive performance.
Michigan study overview and key findings
The study, led by researchers at the University of Michigan School of Public Health, highlights how historic environmental exposures, particularly from leaded gasoline, paint, and pipes before regulations dramatically reduced their use, may continue to affect cognitive health in people born before the 1980s.
The research team analyzed data from the National Health and Nutrition Examination Survey (NHANES)Trusted Source linked with Medicare claims and mortality records, following participants for up to 30 years.
Using machine learning models, the researchers estimated participants’ bone lead levels, which act as a biomarker of cumulative lifetime exposure.
The body stores lead in the teeth and bones, where it can accumulate over time. Thus, these reflect a better measure of cumulative exposure, as blood lead levels only reflect recent exposure and clears relatively quickly.
The study found that higher bone lead levels were strongly associated with increased dementia risk. Individuals in the highest quarterile of bone lead levels had nearly three times the risk of Alzheimer’s disease compared with those with the lowest level.
For all-cause dementia, the risk more than doubled among those with highest cumulative lead exposure.