Nature

I haven’t fully formed my opinions on the matter yet, so I won’t comment. While many researchers advocate that idea of viewing race as a social construct, recent research has shown to find tests able to differentiate between various European populations. (Biologists like to avoid this entire debate by referring to “clusters” instead of “races.”)

In the end, and despite what the genticists want you to believe, genetics is very poorly understood. Classical (Mendelian) genetics came out in the early 1900s and DNA wasn’t discovered until 60 years ago. It wasn’t until the last couple of years we realized the importance of nonexpression in DNA (at least as equally important as expressed genes) or the ability for our current circumstances (such as social isolation) to alter genetic expression.

Both articles are a good read and worth a couple minutes.

The University of Glasgow studied over 40 million people living in England and the death records of over 350,000 people. Using some sort of measure for exposure to green space, they found an association with income, overall mortality, and cause-specific mortality. They also noticed that the gap between the lowest- and highest-income individuals was about half as large in areas with “ample” green space.

It makes sense. We can speculate that green space probably helps reduce health disparities by providing a place for residents to become physically active, reduce stress, feel more empowered, etc. Or it could be something completely different… perhaps green spaces have more markets with healthy (and cheap) foods? Perhaps low income individuals in areas with park space are there because they have more active lifestyles and prefer living closer to a park. Who knows? I haven’t actually read the article yet, but it looks promising.

[Photo: mine.]

Interesting Public Health Fact #1.

(My parents and friends ask me what I learn in school and I tell them about all the interesting things, but I never convey it in its absolute fullness and often end up getting polite “ohh… right… ok…” responses. I’ve decided to start a new category called “Interesting Public Health Facts” so I can put up the interesting things I read and learn so I can just point people in this direction instead of boring them with my inadequate attempts to articulate the awesomeness of public health.)

It’s been long established that loneliness (or “social isolation” in hip, public health speak) has really bad effects on your health.

You can use social isolation to predict mortality and morbidity in the general population, and it is especially good at predicting coronary heart disease. And the thing is, it is just a deficiency of social relationships that really matters — that’s to say that after a certain threshold of relationships, an increase in relationships does not lead to an increase in health. Or put more simply, being alone is bad for your health, but being popular is not necessarily better for your health than just having an average number of social contacts.

There are a lot of hypotheses on why this is the case. Some are pretty common sense (but inadequate)–such as having more friends will likely lead you to engaging in less self-destructive activities and support you in sleeping right, diet, exercise, alcohol consumption, etc etc. But none of the current theories really explain this in great detail and a lot of it has to do with just the difficulty of finding data. Imagine trying to find people and interview them and test them and talk to them and engage them when they really to be left alone or have been left alone for so long.

Before we go further, I should probably note that social isolation is not the same as solitude. A person who is socially isolated and a person who is seeking solitude may both be alone, but only the socially isolated person perceives loneliness.

Ok. So what?

Maybe I haven’t piqued your interest yet, but how about this: Did you know that feelings of loneliness may literally make you feel cold? Two psychologists from the University of Toronoto conducted a psychology study where they divided a group into two and asked them to recall either a time they were rejected or a time they were accepted into a group and then asked them to estimate the temperature of the room. They found people who recalled rejection often perceived a colder temperature. They then conducted an experiment with a computer game where some of the volunteers were purposely left out of the game and then asked each for a preference for snack and found the unpopular volunteers preferred “cold day” snacks such as hot coffee or soup.

Or did you know a group of UCLA researchers found that social isolation leads to effects on the immune system on a genetic level? They found that “feelings of social isolation are linked to alterations in the activity of genes that drive inflammation, the first response of the immune system” while at the same time “key gene sets were under-expressed”. In normal people speak, feeling lonely not only has psychological or medical implications but it has a genetic factor as well. Feeling lonely fundamentally alters our immune system.

Think about the impact this has on our approach to heart disease or mental disorders like depression. This changes the framework for a lot of policy–maybe we should focus more on helping older populations maintain social networks (Facebook for the elderly?). Maybe one day we’ll see really thin sweaters with happy thoughts on them and that’ll be enough to keep you warm–ok, maybe not. Still, it is profound how much of our health is dependent on our relationships with other people and our mental state.

[Photo by Grandhi via Flickr.]

What I want to focus on here is society’s effect on health. Specifically, I’m going to talk about how racism affects infant mortality rates and the evidence against race.

Sir Michael Marmot is also mentioned in the incredibly interesting PBS series, Unnatural Causes: Is inequality making us sick?. In hour two of this series, they discuss infant mortality. There are many causes for infant mortality — SIDS, congenital abnormalities, and being born too early and underdeveloped are the three main reasons.

The United States ranks as one of the lowest in the industrialized world in terms of infant mortality — with a whopping rate of 6.3/1000. To put that into perspective, Sweden has 2.75/1000 and Cuba is on par with us at 5.9/1000.

That’s pretty bad considering we are also the nation that spends the most per capita on health care… But that’s not what is really interesting here. The most interesting thing is the breakdown by race.

It turns out, African Americans have two and a half times the infant mortality rate of white women. Unimpressed? You’re an intelligent person and you say that this must be attributed to racial differences–African American women are, generally, in a lower socioeconomic status (SES) than white women and that is the deciding factor. Due to their lower SES, less African American women are able to afford prenatal care or continue to work while pregnant longer or something of that sort. However, it turns out that when you adjust for education, the infant mortality gap actually widens. College educated African American women have a rate of 10.2/1000 vs the 3.7/1000 of white college educated women. That’s on the same scale as a white woman with no high school education (9.9/1000). Obviously, income and education is not the deciding factor here.

If that is the case, it is easy to assume that the cause must be genetic in nature. Perhaps being of African descent is in and of itself what is causing the higher infant mortality rate. How would you test that? Well, one research team did it by weighing African American babies to recently immigrated African babies and white babies. We know this is a reasonable comparison because genetic variations within a population take generations upon generations (thousands of years for humans) to cause any sort of significant difference. Therefore, women of African descent should have the same baby weight as African American women. What they found was that the African babies (immigrant) were the same weight as the white babies and both were significantly heavier than the African American babies.

The finding is profound. It means that the act of growing up black in America is enough to negatively affect the weight of your child. Why? Racism. Researchers found that women who felt racially prejudiced were twice as likely to give birth to underweight babies. The public health implactions here are significant. For so long, health care in America has been focused around the hospital and doctor. Through social epidemiology, public health, and other forms of social research, we’re discovering that the external factors to your health are much more dramatic than previously imagined.

[Image by lulazzo via Flickr.]

28 August 2008 | GENEVA — A child born in a Glasgow, Scotland suburb can expect a life 28 years shorter than another living only 13 kilometres [8 miles] away. A girl in Lesotho is likely to live 42 years less than another in Japan. In Sweden, the risk of a woman dying during pregnancy and childbirth is 1 in 17 400; in Afghanistan, the odds are 1 in 8. Biology does not explain any of this. Instead, the differences between – and within – countries result from the social environment where people are born, live, grow, work and age.

That is a quote from a recent press release by the World Health Organization.

It’s been stated in the public health profession that posing social issues such as these — povert, war, etc — in a public health perspective has serious perils but I don’t think these facts can or should be ignored.

How is it that within 8 miles of the same country there can be a 28 year disparity in life expectancy? How is it that the disparity between countries can be so high? These are obviously not biological factors as the disparities within countries — even within cities — can be even greater than the disparity between countries.

These are questions that must be more thoroughly investigated and answered not just for the sake of the world’s poorest but also for the benefit of the world’s richest countries. The investigation this press releases was based on was a three year long investigation by academics, heads of states, ministers of health, etc and largely focuses on the social determinants of health.

After reading mounds of academic journals, I’m relieved to have gone through this report. It’s for the layman and the focus on SDOH instead of epidemiological sources is evidence of a new trend in public health research geared not only towards individuals and institutions but the entire social context of populations and how they affect health.

The study refers to status gradients that are universal — poor people die sooner than medium income people who die sooner than rich people regardless of the wealth of the nation as a whole. This may make sense economically but the universality of status gradients is further extended in other facets of life — education, working conditions, social status, occupational prestige, etc. Ultimately, issues that are most often funded are issues that affect rich countries. Thankfully, this is an issue that affects rich countries but resulting research findings and paradigms may be applied to poor countries as well.

The report is a good read but if I’d recommend at least reading the press release. Just the facts alone are interesting enough to make you want to read the whole thing.

[Image is mine and under CC License. Some rights reserved.]