Gravlee et al: Race, Genetics, Social Inequality, and Health

Color SES SBP
Clarence Gravlee, Amy Non and Connie Mulligan have just published an outstanding article in PLoS ONE, Genetic Ancestry, Social Classification, and Racial Inequalities in Blood Pressure in Southeastern Puerto Rico. The abstract opens:

The role of race in human genetics and biomedical research is among the most contested issues in science. Much debate centers on the relative importance of genetic versus sociocultural factors in explaining racial inequalities in health. However, few studies integrate genetic and sociocultural data to test competing explanations directly.

Note how that fits so well into the points just made in Nature/Nurture: Slash to the Rescue. But Gravlee, Non and Mulligan don’t just say we need to overcome the nature vs. nurture dichotomy, they do research that bridges it and even better, test ideas on both sides: “We draw on ethnographic, epidemiologic, and genetic data collected in southeastern Puerto Rico to isolate two distinct variables for which race is often used as a proxy: genetic ancestry versus social classification.”

This type of collaborative research can be crucial to getting the data to answer complicated questions. Connie Mulligan and Lance Gravlee deserve credit for taking the time to discuss how to bring together their respective approaches before going out to do research. In this case, the data come down more on the nurture (or social) side. As they write:

Our preliminary results provide the most direct evidence to date that previously reported associations between genetic ancestry and health may be attributable to sociocultural factors related to race and racism, rather than to functional genetic differences between racially defined groups.

Before someone gets all hot and bothered, Lance has also shown how to bring nurture back to nature. In Gravlee’s recent paper, How Race Becomes Biology: Embodiment of Social Inequality (pdf), he gives us following: “Drawing on recent developments in neighboring disciplines, I present a model for explaining how racial inequality becomes embodied – literally – in the biological well-being of racialized groups and individuals. This model requires a shift in the way we articulate the critique of race as bad biology.”

In the PLoS paper, Lance, Amy and Connie are aiming squarely at the use of race in medicine, where it has become common in some circles to use racial classification as a proxy for genetics. Basically this research destroys the proxy notion, since social classification turns out to be a better predictor of blood pressure than genetic ancestry.

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Poverty and the Brain: Becoming Critical

poverty-race-opportunity
Poverty Poisons the Brain was one of our most popular posts last year. Recent research has brought that topic back into public light. It’s good research, but today I will get critical about what really matters in our emerging realization that social disadvantage results in neurological disadvantage.

Gary Evans and Michelle Shamberg recently published a PNAS paper, Childhood Poverty, Chronic Stress and Working Memory (pdf). Here’s the abstract:

The income–achievement gap is a formidable societal problem, but little is known about either neurocognitive or biological mechanisms that might account for income-related deficits in academic achievement. We show that childhood poverty is inversely related to working memory in young adults. Furthermore, this prospective relationship is mediated by elevated chronic stress during childhood. Chronic stress is measured by allostatic load, a biological marker of cumulative wear and tear on the body that is caused by the mobilization of multiple physiological systems in response to chronic environmental demands.

The Evans and Shamberg paper has gotten prominent media attention. Over at Wired, Poverty Goes Straight to the Brain got an enormous number of diggs. Brandon Keim’s opening lines are, “Growing up poor isn’t merely hard on kids. It might also be bad for their brains. A long-term study of cognitive development in lower- and middle-class students found strong links between childhood poverty, physiological stress and adult memory.”

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Measuring Process Not Belief: Shane Battier and Stress

The Wrong Box Score

The Wrong Box Score

Besides being a great read about Shane Battier and success in professional basketball, The No-Stats All-Star article by Michael Lewis in last Sunday’s New York Times Magazine carries a larger lesson about how our understanding of the world is shifting. One of its main points is that we are becoming increasingly statistics driven, with sports at the leading edge of this transformation. We can spend lots of money on stars, like the New York Yankees, or we look more closely at what actually leads to success and how we can achieve that with less money. Shane Battier epitomizes this change because his individual stats are rather mediocre, his physical skills rather normal for an NBA player. But he makes his team win.

The key question becomes, how does he do this? That is where Michael Lewis mixes qualitative research (interviews) and ethnographic insight (coming from Battier’s own experience) with an examination of new ways of measuring everything that might count about a basketball game. It’s a powerful mix.

For me it illustrates two important points about how we can develop better measures, ones that are closer to what actually determine outcomes and that don’t fall into so easily into measuring our own beliefs about the world. And yes, by “our own” I mean the researchers who come up with the measures. Here’s a relevant section describing Daryl Morey, the man behind the Houston Rockets new approach to figuring out what works:

What [Morey] will say, however, is that the big challenge on any basketball court is to measure the right things. The five players on any basketball team are far more than the sum of their parts; the Rockets devote a lot of energy to untangling subtle interactions among the team’s elements. To get at this they need something that basketball hasn’t historically supplied: meaningful statistics. For most of its history basketball has measured not so much what is important as what is easy to measure — points, rebounds, assists, steals, blocked shots — and these measurements have warped perceptions of the game. (“Someone created the box score,” Morey says, “and he should be shot.”) How many points a player scores, for example, is no true indication of how much he has helped his team.

Here is how it makes a difference. Battier doesn’t get great traditional stats – points scored, shots blocked, and so forth. But he does things that, on aggregate, make a bigger difference.

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Forever at War: Veterans’ Everyday Battles with Post-traumatic Stress Disorder

ptsd-iwo-jima“To this day, every time I smell firecrackers or fire arms being shot, I feel like I am right back there. All I have to do is close my eyes and I see the whole scenario over and over again. I can’t erase it.”

Hundreds of thousands of US veterans are not able to leave the horrors of war on the battlefield. They bring the combat home and re-experience it in their minds each and every day, no matter how much time has passed.

“I don’t like people. I just live my life.”

Many PTSD veterans live a life riddled with divorce, unemployment, and loneliness because they are unable to form lasting social networks within civilian life. It is not uncommon for a war veteran plagued with PTSD to desire a solitary life in the mountains. One informant described Montana as the ideal locale – far away and quiet.

“I should have buried him.”

This veteran is still tormented by the fact he did not give an honorable burial to a fellow soldier. He knows he would have met a similar fate if he tried to leave his foxhole; yet his inability to act haunts his memory. He asks himself everyday why he didn’t even try to honor his fallen comrade. He also has never been able to justify why he wasn’t the soldier left unburied on that remote Pacific island.

“I didn’t even have the motivation to kill myself.”

Many of these men and women believe their situation will never improve. Some contemplate suicide as their only relief from the symptoms of PTSD. A number of the veterans we spoke with had thought about or even tried to end their own lives. They also participate in risky activities, threatening their life in a deliberate yet indirect way.

“I always feel like there is someone behind me – following me.”

Being on edge is the only way to survive in combat. Unfortunately, many PTSD veterans are unable to readjust within the civilian world. Everyday life becomes a battlefield.

Something as mundane as walking through a crowded grocery store aisle can be a source of intense anxiety for a veteran suffering from PTSD. Overwhelmed by a feeling that the shoppers behind them are enemies, PTSD veterans always feel as if they are under attack. A trigger as simple as the clashing of shopping carts can make them jump in fear of an imminent explosion. They are forever at war.

OUTREACH

Over the course of 4 months, South Bend veterans with Posttraumatic Stress Disorder (PTSD) have revealed their daily realities to us, five undergraduates at the University of Notre Dame. In conjunction with a course taught by Dr. Daniel Lende entitled Researching Disease: Methods in Medical Anthropology, we have engaged in community-based research with members and supporters of PTSD, Vets, Inc. Here, with the approval and encouragement of these vets, we seek to give their experiences a well-deserved voice.

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Women on tests update: response to stress

A while ago, I posted an overly-long discussion of recent research on the ‘math gap’ between boys and girls on standardized testing (Girls closing math gap?: Troubles with intelligence #1). That posting discussed several studies published in Science that have shown the gap in average math scores between boys and girls is not set in stone. In one paper, an increase in the test pool brought on by the No Child Left Behind program, with mandatory universal tests instead of exams only for those wishing to go to college, caused the gap in average scores to disappear; in the other paper, a decrease in the ‘math gap’ was found to correlate with other measures of greater gender equality in European states.

As I pointed out in the previous post, however, many commentators suggest that it is not the gap in average test scores that really matters; rather, these critics argue that the different variance in boys’ and girls’ scores explains the disproportionate number of boys who produce exceptional scores (as well as exceptionally bad scores), and thus the marked gap of men and women in PhD math programs, in prestigious prizes for physics and related subjects, and in related fields like engineering. In the earlier post, I argued that even if this greater variance showed up reliably across all testing populations, what exactly was being illuminated was still not clear; that is, many other explanations–other than that men had better ‘math modules’ in their brains, or greater ‘innate’ mathematics ability, or something like that–could explain even very stable differences in math performance. At the time I suggested a number of other possibilities, such as sex differences in stress response during testing, as other possible explanations for even a universal ‘math gap’ (which still had to contend with studies like the two in Science which severely undermined the assertion of universality).

As if on cue, I stumbled upon a video and accompanying article in Science Daily on differences in stress responses among men and women: Neuroscientists Find That Men And Women Respond Differently To Stress (but don’t click on that link — keep reading!). Stress is a good candidate to explain a test-taking gap because the observable physiological processes offer abundant evidence that men and women don’t respond to stress in exactly the same way (although there are underlying commonalities). For example, stress causes different diseases in men and women, and some long-term psychological disorders that demonstrate sex-linked disparities seem to emerge from stress.

Unlike the ‘black box’ explanation that boys and simply better at math or evidence greater variability in innate ability, with no observable neural correlate or plausible explanatory mechanism, in variation in stress response we have a clear candidate for male-female difference that plausibly affects their performance and even physiology (for example, in different stress-related diseases).
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Relax your genes

Image from Good Karma Flags

Image from Good Karma Flags

Relax — it can affect your genes.

A recent article on PLoS One by a research team from the Benson-Henry Institute for Mind/Body Medicine at Massachusetts General Hospital (MGH) and the Genomics Center at Beth Israel Deaconess Medical Center (BIDMC) discusses the genetic effects of the relaxation response, a widespread bodily state induced by different mind-body techniques (such as meditation).

The original piece, Genomic Counter-Stress Changes Induced by the Relaxation Response, was published at PLoS One, and the findings are also discussed on ScienceDaily, Relaxation Response Can Influence Expression Of Stress-related Genes. It’s starting to be a bit of a refrain from genetics research, but it still bears repeating: the team is exploring a way that ‘changing the activity of the mind can alter the way basic genetic instructions are implemented,’ as Dr. Herbert Benson explained (in ScienceDaily).

The relaxation response is a bodily state, found in a variety of contexts, characterized by ‘decreased oxygen consumption, increased exhaled nitric oxide, and reduced psychological distress.’ Long-term effects of relaxation exercises include decreased oxygen intake and carbon dioxide elimination; reductions in blood pressure, heart and respiration rate; prominent low frequency heart rate oscillations; and some changes in cortical and subcortical brain regions, including increased thickness of the cortex (see NeuroReport and here also on the effect of meditation on aging).

For about three decades, dependable clinical studies have shown that relaxation response-producing exercises have a range of positive health benefits. What makes the current research distinctive (at least in my reading) is that the team traced this metabolic process to its genetic effects. As the authors write:

This study provides the first compelling evidence that the RR elicits specific gene expression changes in short-term and long-term practitioners. Our results suggest consistent and constitutive changes in gene expression resulting from RR may relate to long term physiological effects. Our study may stimulate new investigations into applying transcriptional profiling for accurately measuring RR and stress related responses in multiple disease settings.

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