‘Astonishing’ Rates of CVD Linked to Lead Exposure

The harms posed by exposure to lead resulted in more than 5 million adult lives lost to cardiovascular disease in 2019 around the globe, according to a new report from the World Bank. The toxin also impaired mental and intellectual development in children.

Together, these health and economic impacts—which cost economies US $6 trillion in 2019—are on par with those caused by PM_2.5 air pollution, the study’s authors say. Three-quarters of that cost stemmed from CVD mortality and a quarter from IQ loss.

This is far from the first evidence that lead has ill effects on the heart, and earlier this summer, the American Heart Association (AHA) released a scientific statement addressing contaminant metals. Lead’s harms arise from inflammation, oxidative stress, epigenetic modifications, and endothelial injury, as well as changes in lipid metabolism and heart rhythm, according to the AHA. The metal has been “linked to subclinical atherosclerosis, coronary artery stenosis, and calcification as well as to increased risk of ischemic heart disease and stroke, left ventricular hypertrophy and heart failure, and peripheral artery disease.”

For CVD death, this analysis goes beyond earlier reports that quantified only mortality mediated by hypertension, Bjorn Larsen, MBA, Ernesto Sánchez-Triana, PhD (both World Bank, Washington, DC), note in their paper, which was published this week in the Lancet Planetary Health.

Larsen, to TCTMD, said the scale of their findings was striking.

“We were very surprised by the number of CVD deaths we estimated from lead exposure,” Larsen wrote in an email. In fact, the death rate was six times higher than had been estimated by the Global Burden of Disease (GBD) 2019 study, he added.

Jamal Rana, MD, PhD (The Permanente Medical Group, Oakland, CA), past president of the California chapter of the American College of Cardiology, agreed with this assessment. “The fact that this paper showed that cardiovascular death was six times higher due to this exposure than previously estimated is astonishing, and it’s very disheartening to hear that,” he told TCTMD.

Also noteworthy, added Rana, are the “ongoing disparities at a global level,” wherein fully 90% of these deaths occurred in low- and middle-income countries. These countries “are already grappling with so much socioeconomic strain, so with them it doesn’t [rise to] the top of their priorities,” he noted. And for clinicians practicing in regions where resources are hard to come by, it can be complicated to ask their patients to get a blood test, Rana continued.

Studies like this one are valuable in that they raise awareness on a societal level, he said. “I think the onus is also on high-income countries, and in fact the whole global community, to support the interventions that can help bring this environmental change of lesser lead exposure.”

These numbers suggest lead exposure may be the third leading risk factor for CVD after high blood pressure and dietary risks, and ahead of tobacco smoking and cholesterol. Bjorn Larsen

Larsen and Sánchez-Triana used data from the GBD to obtain country-level estimates of lead in the blood for 2019. The researchers then developed models to calculate that exposure’s health impact.

They estimated that 5.55 million adults age 25 and older died from cardiovascular disease in 2019 due to lead exposure. By comparison, PM_2.5 air pollution (both ambient and household), caused around 6.45 million deaths—not just due to CVD but from all causes.

“These numbers suggest lead exposure may be the third leading risk factor for CVD after high blood pressure and dietary risks, and ahead of tobacco smoking and cholesterol,” Larsen said.

The number of deaths attributable to CVD varies across countries for two reasons, he pointed out. One factor is high blood levels, mainly seen in South Asia, and the other is an aging population that’s susceptible to CVD, as is found in Europe and Central Asia. Per 100,000 people in 2019, lead exposure caused 36.1 deaths in sub-Saharan Africa, 53.3 in Latin America and the Caribbean, 75.9 in South Asia, 86.9 in the Middle East and North Africa, 95.8 in East Asia and the Pacific, and 136.9 in Europe and Central Asia.

For IQ score, lead resulted in 765 million IQ points lost among children younger than 5 years in 2019, 95.3% of that in low- and middle-income countries.

The US $6 trillion for CVD mortality and lost IQ represents nearly 7% of the global gross domestic product (GDP) in 2019. By comparison PM_2.5 air pollution cost 6.1% of the global GDP that year.

It's time to take action on this issue, Larsen stressed. “The first and foremost priority is institutionalizing routine nationwide blood lead level (BLL) measurements in both children and adults,” not only in low- and middle-income countries but also in any high-income countries that still lack routine testing, said Larsen. “This must be accompanied by comprehensive identification of sources of lead exposure, especially in locations and regions with elevated BLLs.”

How people come into contact with lead varies across low- and middle-income countries, where exposure tends to be highest. Sources include “lead acid battery recycling, metal mining, food, soil and dust, water, leaded paint, cookware from recycled materials, lead-glazed pottery and ceramics, spices, toys, cosmetics, electronic waste, fertilizers, and cultured fish feed,” Larsen noted. Better understanding the contribution of each source will enable more effective mitigation, he added.

For Rana, these data are yet another reminder that environmental exposures can directly affect cardiovascular health.

Rana pointed out that given lead’s effects, interventions to address it would likely be cost-effective. “There’s such a big financial burden,” he said. The potential to save money “could be used to start a conversation or start legislative changes.”