Image for article titled Half of Americans Exposed to IQ-Lowering Levels of Lead Growing Up, Study Finds

The decision to add lead to our gasoline a century ago has implications for our health according to new research. According to a study, half of Americans alive in 2015 were exposed to damaging levels of lead in their childhood from leaded gasoline. The researchers say that this exposure could have had a long-term effect on people's brain health.

In an effort to reduce wear and tear on car engines, car manufacturers added lead to gasoline in the 1920s. It was the latest example of lead'sVersatility, with the metal having been used in construction, cosmetics, and paint for a long time. During the 1960s and 1970s, lead use in gasoline peaked.

The harmful effects of lead poisoning were well-established before leaded gasoline was introduced. Heavy exposure can cause organ damage and even death. Even though there is no safe level of lead exposure, even low levels of lead can still be dangerous to the developing brains of children. There is some evidence that lead can affect people's behavior and that it may have increased crime rates in the past.

It would take until the mid 1990s for leaded gasoline to be completely banned in the US and other countries, but it took until last year for it to be completely banned worldwide. According to the authors of the new study, a lot of American kids were being poisoned by lead.

The study attempts to quantify the amount of brain harm caused by childhood lead exposure in America.

Historical data on how much lead Americans were exposed to as children, as well as data on levels of leaded gasoline use throughout the country, were analyzed to find out how much lead Americans were exposed to. Lead in gasoline becomes aerosolized and is breathed in through car exhaust, and it can also affect the environment.

Roughly half of the American population is thought to have worrying levels of lead exposure growing up. They used IQ as a proxy to calculate the effect that lead exposure had on people. They estimated that lead exposure in the U.S. resulted in a drop in IQ points of almost three points per person. The authors estimated that people in the mid-to-late 1960s may have lost up to six IQ points. They estimated that those with the highest lead levels lost up to seven points.

The sociologist at Duke University said in a statement that he was shocked.

Lead exposure is still a pressing public health issue even though much has been done to reduce the presence of lead in our environment. There are many drinking water supplies in the U.S. that still have lead in them. It is estimated that lead poisoning contributed to as many as 900,000 deaths in the world in 2019.

The ramifications of lead poisoning are likely to follow people decades down the road, the researchers say. They plan to study how lead exposure in childhood may affect people's brains in their older years. Black children are more likely to be exposed to higher lead levels than other children, so they hope to study the disproportionate effect that lead has had on different groups of Americans.

Millions of people are walking around with a history of lead exposure. 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.