Recent research coming out of Simon Fraser University’s Faculty of Health Science suggests that the connection between low-level exposure to lead and cardiovascular disease has strengthened.
While municipalities have recently pushed to eliminate older lead piping from municipal systems and at residential connections, the new study suggests that there is an elevated risk delaying the replacement of the older systems and escalating the risk of exposure.
The research, led by professor Bruce Lanphear of SFU, found that exposure occurs from lead that remains in the environment from historic use in plumbing, fuel, and paint, as well as ongoing exposures from foods, emissions from industrial sources, and contamination from lead smelting sites and lead batteries.
“Our study estimates the impact of historical lead exposure on adults currently aged 44 years old or over in the USA, whose exposure to lead occurred in the years before the study began,” says lead author professor Lanphear. “Today, lead exposure is much lower because of regulations banning the use of lead in petrol, paints, and other consumer products, so the number of deaths from lead exposure will be lower in younger generations. Still, lead represents a leading cause of disease and death, and it is important to continue our efforts to reduce environmental lead exposure.”
Although the study was conducted on the U.S. population, exposure rates in Canada are expected to have a similar proportional impact. Previous estimates, which assumed that low-level lead exposure did not increase the risk of premature death, produced substantially fewer deaths. However, this new study finds that low-level lead exposure (between 1 to 5 micrograms of lead per decilitre of blood) increases the risk of premature death, especially from cardiovascular disease.
“Our study calls into question the assumption that specific toxicants, like lead, have safe levels, and suggests that low-level environmental lead exposure is a leading risk factor for premature death in the USA, particularly from cardiovascular disease,” says professor Lanphear. “Estimating the contribution of low-level lead exposure is essential to understanding trends in cardiovascular disease mortality and developing comprehensive strategies to prevent cardiovascular disease.”
The study estimated that approximately 256,000 premature deaths from cardiovascular disease—including 185,000 deaths from ischemic (coronary) heart disease—in the USA could be linked to historical lead exposure in middle-aged and older adults. The observational study followed 14,300 people for almost 20 years and was published in The Lancet Public Health journal.