A UCLA experiment suggests that “social stress and rejection are related to the release of certain inflammatory chemicals in the body; these chemicals have been linked to several medical conditions, including asthma, arthritis, and some kinds of cancer.“ Ars Technica has the low-down:

In the study, a group of researchers recruited a bunch of students at UCLA and subjected them to socially stressful situations. The students were asked write a speech and then read it to a pair of evaluators, who then acted as if the speech were abhorrently subpar. After that, they had to perform mental arithmetic for a proctor who would appear impatient with them and urge them to go faster. A subset of the participants were also made to play a game of “Cyberball” with two other people, who were asked to socially exclude them.

Throughout these socially stressful experiences, researchers took mouth swabs of the students and monitored their activity in the dorsal anterior cingulate cortex, a part of the brain known to process rejection-related distress. (It’s possible that the swabbing added to the stress.) The two measures showed that greater activity in this area of the brain correlated with a rise in two inflammatory chemicals that are known to play a role in the onset or progress of conditions like rheumatoid arthritis, cardiovascular disease, depression, and various types of cancer.

Correlation is not causation, of course… or, as Ars more bluntly puts it, it’s unclear whether “being a nerd begets asthma, or if asthma begets a nerd”.