Lead Exposure May Have Lowered The IQ of Half of Americans Since 1940

According to a new study, childhood lead exposure in the United States is much more concerning than previous estimates have suggested.

More than 54 percent of Americans alive in 2015 had been exposed to dangerous levels of lead as children, when researchers analyzed leaded gas use from 1940 and combined it with data on blood-lead levels from the mid 1970s.

More than 170 million adults are now at greater risk of developing brain and cardiovascular diseases because of the lead they absorbed as kids.

Lead exposure is not safe at any point in a person's life, but it can be particularly harmful for children as it can affect brain development and lead to permanent learning difficulties.

Researchers estimate leaded gas has reduced the nation's IQ score by over 800 million points.

The average is just that. When leaded gas use peaked, those born in the 1960s and 1970s could have lost an average of six to seven IQ points. The cohort's lead exposure was eight times higher than the health limits.

For some people who have lower than average cognitive ability, the effects can lead to a diagnosis of intellectual disability.

Michael McFarland is a sociologist from Florida State University.

Childhood lead exposure has fallen since the US government banned leaded gasoline in 1996. Many Americans are still dealing with the consequences of their upbringing.

Compared to generations before the preindustrial era, children born after 1996 have lower blood-lead levels.

There are thousands of communities in the US that still suffer from the legacy of unlimited lead use, and the racial disparity is stark.

Black adults over the age of 45 had higher levels of blood-lead than their White counterparts, and that was true even for those born after 1996.

The long-term consequences of that exposure are being examined by the authors of the study to see if it can account for racial differences in health outcomes.

Millions of people are walking around with a history of lead exposure, according to a clinical psychologist.

It is not like you got into a car accident and had a rotator cuff tear that heals and you are fine. It appears to be an insult carried in the body in different ways that we are still trying to understand but that can have implications for life.

Lead poisoning can be found by nature. Even though restrictions are better than they used to be in the US, enormous quantities of lead have already seeped into our drinking water, our airways, and our homes.

Lead gas from car exhaust is no longer a threat to humans, but other sources of lead pollution, like hunting ammunition, plumbing and industrial waste, still pose a threat to humans and the environment.

A study of over a million American children found lead in the blood of half the group. Children who live in zip codes with predominantly Black populations are more likely to fall into this group.

IQ points lost from lead exposure are used as a proxy for the health effects of lead pollution.

Last year, researchers found that lead exposure was linked to high IQ and alarming losses.

The new estimates found higher blood-lead levels among older adults.

By providing more complete estimates of the number of people exposed to lead in early life, this study makes a considerable step toward understanding the full extent of the damage done to the US population in one specific domain.

The study was published in a journal.