How social status determines your health

You wouldn’t think how people perceive you could directly affect your health, would you?  Luckily, science is here to save the day and to tell you, you’re wrong.  A pair of papers published in PNAS in the last month have investigated the interaction between social status and health, and the findings compliment each other rather nicely.

The authors of the first paper tracked baboons over thirty years and made a compelling figure (show at right) showing that low-ranking males are sick more often, and for longer, than high-ranking males.  It has been theorized that the biological effects of high social status – testosterone, high glucocorticoids, high reproductive effort – would reduce health.  After all, if these high-ranking male baboons have to spend all their time and energy making sweet monkey love, there wouldn’t be much energy left over for healing, would there?  However, they found no evidence for this.  In fact, alpha males seemed to heal faster than anyone else.

The authors of the other paper examined the different genes that are regulated in low- and high-status female rhesus monkeys.  The previous paper tracked male animals in the wild, and this one kept female animals in the laboratory.  The authors took blood samples from the monkeys to profile gene expression – though only after dominance order had been established.  It would have been great had they done so before hand to see if there were genes predictive of social status, or if expression changed in any appreciable way.  But no matter.  By using a PCA analysis – basically, finding the combinations of genes that most explained the variance in the behavior – they found that the first principle component was predictive of social status.  This tells us that gene expression is intertwined with your social status.

Almost 1000 genes were found to be associated with rank, 535 of which were more enriched in high-ranking individuals and 452 of which were more enriched in low-ranking individuals.  So a lot is going on in there and getting changed!  Consistent with the previous paper, there was the largest cluster of enriched genes were immune-related.  This included interleukin signaling, T-cell activation, and chemokine/cytokine inflammation.  Perhaps, then, the reason high-ranking males heal faster is because the right immune-related genes were enriched.  But that leaves the question, why should that be so?

The paper included an excel spreadsheet of the enriched genes which can be a bit fun to scroll through; following on something I touched on in the previous post, I expected to find dopamine receptor genes enriched in one of the conditions but I didn’t.  Something to keep in mind.

I guess the moral of story here is: socializing is dangerous.  Or maybe not socializing is dangerous.  Either way, watch out!

References

Archie, E., Altmann, J., & Alberts, S. (2012). Social status predicts wound healing in wild baboons Proceedings of the National Academy of Sciences, 109 (23), 9017-9022 DOI: 10.1073/pnas.1206391109

Tung J, Barreiro LB, Johnson ZP, Hansen KD, Michopoulos V, Toufexis D, Michelini K, Wilson ME, & Gilad Y (2012). Social environment is associated with gene regulatory variation in the rhesus macaque immune system. Proceedings of the National Academy of Sciences of the United States of America, 109 (17), 6490-5 PMID: 22493251

Advertisements

4 thoughts on “How social status determines your health

  1. “It would have been great had they done [the sampling] before hand to see if there were genes predictive of social status, or if expression changed in any appreciable way.”

    I think it would have added a lot to this study. That way it could have been possible to show that having a good social status affects expression of genes which make you more or less susceptible to disease and tell whether social status is the cause or result of health effects.

  2. When I read it, I wondered if they had originally intended to do a different study, but got this genetic data and realized it would be interesting to analyze. Otherwise I really can’t understand why they didn’t take initial blood sample. In fairness, there was an additional analysis they performed that I didn’t mention in my post.

    They used a machine-learning technique called a support vector machine (SVM) to see if genetic expression levels were sufficient to predict social status (ie, can you look at genetic expression and determine what the social status of the animal is). I think they got ~80% success rate. Then they looked at five individuals who had switched rank during the experiment and who they happened to have blood samples for pre- and post-. They report that their SVM was able to look at the expression data and correctly predict rank for these animals, too.

    That suggests that the genetic data is plastic in some way to social status, but the low number of individuals makes me a bit suspicious (I really wish they would have expanded on this analysis because it is one of the more interesting parts!)

  3. Pingback: Why the new paper by Christakis and Fowler on friendship makes me queasy | neuroecology

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s