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. All were given a medical examination at the start of the study that included a blood test for lead, with readings ranging from less than 1mg per decilitre of blood to 56mg.
Researchers followed almost 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.
Of environmental lead exposure, he said: "If we took that seriously, without knowing anything more about genetics, without any more expensive drugs, we could much more strategically reduce deaths from heart disease, which is pretty hopeful, actually".
The condition is caused by muscle in the heart being starved of blood due to narrowed or blocked arteries.
People with the highest lead levels had a 37% greater risk than normal of a premature death and a 70% greater risk of death from cardiovascular disease.
The participants all had blood tests at the outset to measure past and current exposure to lead, as well as a urine test for the metal cadmium.
Safety regulations have significantly reduced the risk of lead exposure in recent decades, especially in developed countries, but the heavy metal can persist in the body for many years. About a fifth of Americans smoke, while 90 per cent of those who took part in the study were exposed to lead.
"Low levels of lead exposure are an important, but largely ignored, risk factor for death from cardiovascular disease", mainly heart attacks and strokes, said lead author Bruce Lanphear, a professor at Simon Fraser University in Canada.
For example, people with the highest lead levels were more likely to be men, smokers, and less educated, with poorer diets, high cholesterol, hypertension and diabetes, all of which are risk factors for cardiovascular disease.
Professor Kevin McConway, Emeritus Professor of Applied Statistics at the Open University, said: "The researchers make a very important point in their report - that it is more accurate to view this study as estimating how many deaths might have been prevented if historical exposures to lead had not occurred". The lead author does state, however, that action needs to continue to reduce exposure.
Researchers warned outside factors could lead to an "overestimation of the effect of concentrations of lead in blood, particularly from socioeconomic and occupational factors".
The risk of succumbing to coronary heart disease doubled in such cases, the study found.
"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 US, particularly from cardiovascular disease", Professor Lanphear said.