Researchers have discovered that risk of depression, anxiety and panic disorders in young adults may be increased by higher blood levels of lead.
In a recent study, those in their 20s and 30s with the highest levels of lead in their blood were more than twice as likely to develop major depression as those in the same age group with the lowest blood lead levels. The results also showed that the risk of panic disorders was five times greater.
"This is true for the average American. We are not talking about excessively high exposures, it's just average exposures," said Dr. Maryse Bouchard of the University of Montreal, Canada, and the Harvard School of Public Health, Boston.
This is despite environmental and blood levels of lead having fallen steadily over recent decades with the widespread discontinued use of lead in petrol/gas and paint. A recent survey by the US Centers for Disease Control and Prevention (CDC) found that blood lead levels have been declining steadily since the 1970s and that levels between 1999-2004, the latest data available, were the lowest yet.
However, lead is still found in many common consumer products. The CDC reports that old lead paint, and contaminated food and water are still significant sources of exposure while the Environmental Working Group (EWG) reports significant levels in a number of lipstick brands.
It is well established that lead is toxic to the nervous system so the findings of this latest research should not come as too much of a surprise. Previous research has linked higher cumulative lead exposure to more rapid cognitive decline.
The latest study published in the December issue of the Archives of General Psychiatry looked at the blood lead levels of a total of 2,000 men and women between 20 and 40 years of age.
The results of the study suggest that the risk of depression or panic disorder is directly proportional to the level of lead in the blood.
The researchers discounted the results from 628 smokers originally screened for the study, since tobacco consumption can increase blood lead levels.
Source: Archives of General Psychiatry