The researchers found that after 1972, when much of the truth behind Tuskegee was revealed, mistrust among African-Americans toward the medical profession spiked. They found that use of the health care system fell, and that mortality increased years later. They hypothesized that each factor led to the next: The news caused African-Americans to doubt the health care profession was interested in their well-being, they stopped going to the doctor, and this led to earlier deaths. They even showed that the closer you lived to Macon County, Ala., where the study took place, the greater the effect.

This is an impressive paper. Although establishing causality in a study like this is nearly impossible, the authors anticipated many potential critiques. They did tests to account for migration. They looked at other measures of mortality. They even performed the geographic analysis from all 50 states to show that centering it on Macon County yielded different results than in most other places.

Still, I think there are limitations that argue against making a causal leap. The biggest is that this effect was seen in black men, but not in black women. The authors posit that this might be because women are forced to engage in the health care system (during childbirth) in ways that men are not, and that this led to a greater level of trust. But this dynamic isn’t assured. You can have a baby and still mistrust the health care system enough to avoid screening later in life. I find it hard to believe that black men and women didn’t share their fears and mistrust of the system with each other.

A second concern involves geography. The analysis looked at the distance from Macon County to show that those closer had fewer doctor and hospital visits and greater mortality than those outside the circle. If you look at the map they provide, a circle around that point almost perfectly encapsulates the Deep South. Disparities in care might have arisen in that region for any number of reasons, and blame can’t be assigned entirely to the Tuskegee study.

A third concern involves the arrow of causality. The authors argue that their evidence supports a theory explaining that mistrust causes less use of doctors, which causes higher mortality. Given what we know of disparities in care in the United States, it still seems possible that the medical system itself could have been throwing up barriers. It’s easy to believe that black men had a harder time getting care than white men, or they might have been subtly turned away or dismissed, which also would lead to less use and perhaps higher mortality.