Chicago kids who grow up with high levels of lead in their blood and in communities with high rates of violence and incarceration suffer as adults. That’s according to a new Harvard University study that examines data from Chicago children who grew up in the 1990s. The analysis was published this month in the Proceedings of the National Academy of Sciences. 

Co-authored by PhD student Robert Manduca and sociologist Robert Sampson, the study aimed to go beyond a more traditional focus on poverty and tease out possible correlations between specific environmental factors and adult outcomes. 

The researchers refer to the three factors of incarceration, violence and lead exposure as creating “toxic neighborhood environments.” And they found that these factors were associated with disparities between groups in areas of incarceration, more teen pregnancy and lower wages.

“According to our model, for example, if the poor black boys in our sample had been exposed to the toxicity levels experienced by their white peers, their predicted likelihood of incarceration after controlling for parent income would have been 5.8 percentage points lower, or almost 60 percent of the gap between blacks and whites in our sample,” the researchers concluded. 

Manduca said that the three factors often overlapped in communities, but to the extent that they could pull them apart, a couple of trends emerged. 

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“The incarceration rates were most predictive of negative outcomes in terms of income people grow up to earn while lead exposure was more predictive of whether people grow up to be incarcerated as adults,” Manduca said.

Anne Evens, CEO of Elevate Energy who has worked on lead issues in Chicago for several years, said the study bolsters existing data on the issue. 

“This study adds to the evidence that we are failing black children and their families by not addressing lead exposure, violence, and excessive incarceration,” Evens wrote in an email to WBEZ. “Elevate Energy works for equitable solutions where your neighborhood doesn’t predict your outcome. This isn’t a census tract problem. It’s a Chicago problem. It’s everyone’s problem.”

“If these complex and compound stressors — lead exposure, violence and excessive incarceration — aren’t addressed now, today’s children will have the same outcomes in the future,” Evens wrote.

When it comes to childhood blood lead levels, Illinois kids have long had some of the highest rates in the nation. City officials have also consistently resisted calls for a systematic removal of Chicago’s 360,000 lead water lines that connect homes to water mains and are the primary source of lead in Chicago water. 

Manduca said he knows that the study’s findings may seem like common sense, but that quantifying these kinds of trends is crucial. 

“It’s not perhaps surprising but I think it is important to recognize and document that this seems to explain a non-negligible chunk of the inequality in outcomes that these groups have experienced,” he said. “It’s a quantitative measure of how these might be driving these bad outcomes.” 

The data used for the study was constructed from records for more than 230,000 kids born in Chicago from 1978 to 1983. In follow-up research, Manduca said he hopes to expand the scope, and tease out more data on why one factor might influence the others.

Monica Eng is a WBEZ reporter. Follow her at @monicaeng or write to her at meng@wbez.org.

Correction: An earlier version of this story misattributed a quote related to trends gleaned from the study.