For decades, many fine journalists and academics have looked at the overlap between crime in Chicago and other health outcomes, by way of looking at crime as a social health problem instead of merely a problem of criminology. Sometimes it's illness as metaphor; other times, the overlap of physical health outcomes and crime in the city.

A recent study out of the Chicago Fed, by senior economist Susan Longworth, takes it a bit farther, running statistical correlations between health and crime (and lots of other things) in the city's community areas.

Perhaps it shouldn't be surprising, but the degree to which crime rates correlates with health outcomes still has the power to astonish.

For the health outcomes Longworth looked at, every one but tuberculosis was statistically significant at the five percent level. It's not, obviously, causation, but the correlation is dramatic. (Longworth also finds strong positive correlations between all of the above categories and unemployment, and the percent of vacant units in a community area as well.)

Among those correlations, researchers have been busy trying to build a promising causative bridge to one health outcome: lead poisoning. I've written about this before, as have Megan Cottrell and Kevin Drum, both of whom are well worth reading.

In terms of community outcomes, Longworth focuses on North and South Lawndale. Both are heavily minority neighborhoods, the former black and the latter Hispanic; both have very low socioeconomic status on the whole. But health outcomes (and crime) are better in South Lawndale.

I'm familiar with some of the research on this, which Longworth dips her toe into. What surprised me, though, was this: the percent black population in a neighborhood is strongly correlated with childhood lead poisoning. The percent Hispanic population is negatively correlated, though not to a statistically significant level.

Which seems odd, especially if you focus on North and South Lawndale. They are, as their names suggest, neighbors. And according to city data, the percent of elevated blood levels in children has been consistently higher in North Lawndale than South Lawndale for years, two or three times as high.

It's something of a mystery. They're right next to each other; they share many of the same environmental concerns, like a history of industry and proximity to dense transportation lines. But I can't help but wonder if it's related to something that's been discussed a lot recently: real estate, redlining, and white flight.

North Lawndale is the subject of Beryl Satter's epic Family Properties. It's where Ta-Nehisi Coates set his immense Atlantic cover story on reparations, with its focus on housing, disinvestment, discrimination, and capital flight.

Their works are exceptional, but it's not a new story. In 1971, the National Urban league produced The National Survey of Housing Abandonment, which inevitably touches on North Lawndale, along with Woodlawn and neighborhoods in other cities. And it might give a clue as to why lead poisoning is much worse in North Lawndale.

There has been virtually no new capital flowing into Lawndale for the past ten years or into Woodlawn for the past fifteen. In Lawndale, the racial transition which occurred in the end of the 1950s was aided by at least some of the financial institutions which provided mortgage money for investor-speculators in accompanying the racial change. These investor-speculators would panic white owners, purchase the property at depressed prices, take out a mortgage based upon either the actual or inflated market value, then sell a purchase contract to a Negro buyer…. The seller would then resell his property to another would-be home owner and repeat this process as long as the property would sustain it. This process continues to go on although many properties have been forced off the market due to over-exploitation.

After this initial wave in the late 1950s, banks began to appreciate what was transpiring and decline to make any further investment in North Lawndale. Subsequently, there has been very little real estate activity in this neighborhood except for resale of purchase money mortgages, and the simple abandonment of properties by their owners when they became unmanageable or when cash-flow becomes negative.

In short, absentee investor-speculators rode the properties until they broke, then left them for dead.

In part from the experiences in these crises [sic] ghetto neighborhoods, and in part due to the general shortage of investment capital or the competition for monies from alternative investments, little capital is available either for transfer or refinancing of properties, or for purposes of major improvements in any of the black neighborhoods in Chicago.

This is how you destroy housing stock. And the process was intense in North Lawndale. Fed by restrictive covenants, the black population swelled as the community area's population increased by almost a quarter from 1950-1960; the population then fell by almost a quarter from 1960-1970; by 35 percent from 1970-1980; and another 23 percent from 1980-1990. Then 12 percent, then 14 percent.

In South Lawndale, that just never happened. From 1950-1960, the neighborhood lost nine percent of its population, then gained three percent, then gained 20 percent.

Longworth isn't the first writer to contrast North and South Lawndale. Eric Klinenberg, in his famous book Heat Wave: A Social Autopsy of Disaster in Chicago, notes how much more slowly white flight occurred in South Lawndale—98 percent white to 27 percent white over four decades, instead of a near-total change over a decade or two—and why that happened:

There are at least two reasons that Little Village was spared the fate of North Lawndale and other predominantly African-American communities in Chicago. The first has to do with processes of exclusion and oppression that we conventionally call racism…. Douglas Massey and Nancy Denton capture part of the process in their argument that North Lawndale "became a wasteland" while Little Village evolved into "a beehive of commercial activity" because of "the degree of segregation" in North Lawndale. Yet the differences between the two areas—both of which are dominated by so-called minority populations and had few whites—clearly extend beyond segregation. Unlike African Americans in North Lawndale and several other Chicago community areas, Latinos in Little Village did not experience the particular constraints of ghettoization, the rapid and continuous abandonment of institutions and residents, or the arson and violence that contribute to the destruction of the local social ecology. The second crucial reason that Little Village developed into a commercial and residential hub is that since the 1960s the area has become a magnet for Mexican and Central American migrants and immigrants…. The continuous migration of Mexican Americans to this community area has replenished its human resources and regenerated the commercial economy of retailers and small local businesses….

Klinenberg's work describes the larger differences between North and South Lawndale and their grounding in history. But it makes the lead poisoning differences no less strange. It is true that lead poisoning can be mitigated by behavioral effects such as diet, like calcium intake, but my impression is that isn't terribly well-known, and there's research (conducted here in Chicago) that suggests parents are much more knowledgable about lead exposure than prevention and diet.

In that study, an impressive 95 percent of respondents knew that lead paint chips are poisonous, and 91 percent knew that "high lead in the body can affect a child's ability to learn." Which is genuinely impressive penetration of public-health knowledge. But only 12 and nine percent knew that iron-containing foods and calcium help prevent lead poisoning (I didn't, and I actually read a fair amount of this stuff).

So there's still good reason to think that, broadly speaking, the built environment and not behavioral differences is still incredibly significant when it comes to lead poisoning. And mitigation of lead poisoning in that context requires capital, which requires investment and access. What North Lawndale got was capital flight and a declining housing stock, raising the question of whether the elements of discrimination and decline can be traced literally into the city's veins.