Princeton Study: Being Black Doesn't Cause Asthma; the Neighborhood Does

The numbers didn’t lie, but they were hard to explain: black children are twice as likely as others to develop asthma.

There was evidence that low birth weight was a culprit, but could “being black” be a risk factor in asthma, as some believed?

Two scholars from Princeton University have concluded that it’s not race, but living conditions, that accounts for the disparity. The data are compelling, alright: they show the effects of ongoing segregation, which trap African American children in poor neighborhoods, surrounded by pollution.

Janet M. Currie, PhD, professor of economics and public affairs at Princeton, and Diane Alexander, PhD, of the Federal Reserve Bank of Chicago, made this finding after examining New Jersey health data for low birth weight children of all races living in zip codes where more than half the population was African American.

Within these neighborhoods, the racial disparities vanished: all low birthweight children had a higher risk of asthma.

Children with a low birth weight may be premature, which increases the risk for lung problems. The trigger for asthma comes from things found in aging neighborhoods with older housing: mold, rodent infestation, or air pollution. Being around people who smoke also causes asthma, even if a baby’s mother does not smoke. According to CDC, black men have much higher smoking rates (20%) than the overall population (15%), and the authors find that black women are more likely to smoke during pregnancy than white women.

New Jersey’s industrial history means many black residents live near pollution sources or close to highways that produce harmful soot. Housing in these areas is, on average, 7 years older than housing elsewhere. Currie said these conditions can cause women to have low birth weight babies in the first place.

“The United States continues to be highly racially segregated,” Currie said in a statement, “with African-American neighborhoods suffering higher poverty, lower average educational attainments, higher unemployment, higher exposure to pollution, and other ills.”

The authors state, “Our results suggest that the racial gap in asthma rates arises for three reasons: because African-American children are more likely to be low birth weight, because they are more likely to come from families with other characteristics that are associated with poorer health (such as maternal smoking and poverty), and because of where they live.”

African Americans of all ages tend to have poorer health than whites, and neighborhood divides may play a part. New Jersey, in fact, has spent decades trying to comply with a series of 1980s court rulings that called for creating more affordable housing in the suburbs, but those battles are still being fought.

The findings have widespread policy implications, if it means that investments in better housing could cut Medicaid costs over a child’s lifetime. A 2016 report from Express Scripts finds that Medicaid is the largest payer for asthma-related hospitalizations among children and adults, and asthma medications are in the top 3 spending classes, per member per month, at $62.73.

There has been some progress to improve the health of poor children in urban housing. In 2014, a study by CDC found that ending smoking in public housing would save $497 million a year, including $310 million in medical costs. In response, in November 2016, the Obama administration imposed a rule to ban smoking in all public housing.

The study covered New Jersey health data for children born from 2006 to 2010 and records from emergency department visits from 2006 to 2012, which let the researchers see which children were treated for asthma. The zip codes that included areas that were more than 50% African American covered 63% of all African American children born in New Jersey, as well as 16% children of other races.

Currie’s and Alexander’s article appears as a working paper in the National Bureau of Economic Research and will be published in the Journal of Health Economics.