Childhood lead exposure linked to mental issues
oliver.lewis@stuff.co.nz
Childhood lead exposure could have longterm mental health consequences, according to new American research based on the Dunedin Study.
Duke University researchers, in a study published in found high childhood blood lead levels could be linked to higher rates of mental illness and difficult personality traits in adulthood.
However, experts say the results need to be treated with caution.
Previous studies have linked exposure to the heavy metal to a range of negative outcomes, including lower IQ, and greater rates of child behavioural problems, including hyperactivity and antisocial behaviour. Millions of people now entering middle age were exposed to high levels of lead as children, the study authors say, due to the use of leaded petrol, which was banned in New Zealand in 1996.
While they cautioned the link was modest, the authors suggested patients with a history of childhood lead exposure could benefit from increased screening and access to mental health services.
Of the 1037 original members of the Dunedin Study, a long-term study of people born in the city in 1972 and 1973, 579 had blood samples taken at age 11, which were tested for lead exposure.
The results showed 554, or 94 per cent, had blood lead levels in excess of five micrograms per deciliter – a value the study says would trigger further clinical assessment today.
Researchers found higher childhood blood lead levels were associated with more mental health problems throughout life and difficult adult personality traits, such as being more neurotic and less agreeable.
‘‘These results suggest that early life lead exposure in the era of leaded gasoline experienced by individuals who are currently adults may have contributed to subtle, lifelong differences in emotion and behaviour that are detectable at least up to 38 years of age.’’
The study was an observational one, and did not establish a cause-and-effect relationship.
‘‘These results suggest that early-life lead exposure in the era of leaded gasoline experienced by individuals who are currently adults may have contributed to subtle, lifelong differences in emotion and behaviour that are detectable at least up to 38 years of age.’’
University of Otago Professor Richie Poulton, director of the Dunedin Study, urged caution in interpreting the results of the new study.
‘‘There may be a very small risk to mental health in adulthood following high levels of exposure to lead during childhood, but at levels that no longer occur in New Zealand,’’ he said.
‘‘Independent replication is required before more concrete conclusions can be drawn.’’