An international study has found that low-level lead exposure could be responsible for 30 per cent of premature deaths from cardiovascular disease in the United States.
Research published in the Lancet Public Health Journal by a team from the Simon Fraser University in Canada found that 256,000 premature deaths in America each year may be the result of historical lead exposure.
Researchers followed nearly 14,300 participants for two decades and discovered that despite previous studies suggesting that low-level lead exposure did not increase the risk of premature death, this might not be the case. The results from the study said that low-levels of lead exposure, between one and five micrograms per decilitre of blood, can increase the risk of premature death. The risk factor is even higher for people with cardiovascular disease, given that lead exposure is linked to high blood pressure, the hardening of the arteries and ischemic (coronary) heart disease.
The study found that lead is common in a variety of common items including fuel, paint and plumbing and can even be found in certain foods, emissions from industrial sources, and contamination from lead smelting sites and lead batteries.
Lead author Professor Bruce Lanphear said that many people in the study were actually exposed to lead before they were being analysed.
“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,” he explained. “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.”
Using data from the Third National Health and Nutrition Examination Survey, 4,422 of the 14,289 participants died after an average of 19.3 years. Of those, 1,801 died from cardiovascular disease and 988 passed away from heart disease.
The research found that people with high lead levels were at 37 per cent greater risk of premature death from any cause, 70 per cent times greater risk of cardiovascular death, and double the risk of death from ischemic heart disease, compared to those with lower levels.
This led researchers to conclude that 28.7 per cent of premature cardiovascular disease deaths were linked to lead exposure.
“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,” Professor Lanphear said.
“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. Currently, low levels of lead exposure are an important, but largely ignored risk factor for deaths from cardiovascular disease.”
He suggested that public health measures such as abating older housing, phasing out lead-containing jet fuels and replacing lead-plumbing lines could prevent future lead exposure. The findings comes after an Australian study found up to 21 per cent of Melbourne’s vegetable gardens contain dangerous levels of lead.