I think people aren't surprised that very wealthy people are a lot healthier than very poor people. But what is striking about your research is that at each rung of the income or educational-attainment ladder, people get better outcomes than those who are one rung lower. What are the implications of that?
If you just see a difference between the poor and everybody else, I think it's easier to say, "You know, the poor are poor because they were lazy, they weren't smart, they don't take care of themselves." That doesn't fit. Don't tell me that people with income levels three to four times the federal poverty level are lazier and not as smart as people with incomes four to five times the poverty level.
Your papers also show that at the same income level, African-Americans will often have worse health outcomes than whites. Why is that?
One [reason] is unmeasured socioeconomic differences, and the other is stress. Within the same income quintile, blacks have far less wealth than whites. At the same income or education level, blacks are more likely to live in socioeconomically deprived neighborhoods, and there is a growing literature that strongly suggests the characteristics of neighborhoods can affect health as well. Also, socioeconomic hardship is stressful, but [for African-Americans] at all levels of the ladder, there is also the stress of living in a society in which, historically, the group that you belong to has been assumed to be inferior.
How does class affect health, in terms of biology?
If I experience stress, one region of my brain, the hypothalamus, signals another region of my brain, the anterior pituitary, that I'm stressed. And then the anterior pituitary sends a signal to my adrenal glands, which then pump out cortisol and other stress hormones. If I'm just stressed acutely, it doesn't look like that's usually damaging. But if I face chronic stress, my adrenals are constantly pumping out the cortisol, which can cause disregulation of immune systems [and] inflammation. Inflammation and immune phenomena are thought to be behind a lot of chronic disease.
Many unhealthy behaviors are more prevalent in lower-income families than more-affluent ones. What is the role of personal choice?
I think it's silly to say there's no role for personal responsibility. Even those of us who are pretty privileged know that it's hard eating right, exercising. But the mistake is neglecting to ask, what is it that shapes personal behaviors? We have a huge body of literature that documents how behavior is shaped by the contexts in which people live and work. And then how those contexts are shaped by their opportunities. Do we think it's an accident that [good] behaviors are arrayed socioeconomically? Where does this all begin? Is it the choice of a child to be born into a poor family?
Stephanie Czekalinski contributed to this article