Lower income = more migraine?

Here’s a new study bound to stir up some discussion.  Today’s issue of Neurology reports on a study of adolescents with migraine.  As it turns out, children in families with incomes over US$90,000 had 50% fewer migraines than children in families with incomes under US$22,500.  Now, that didn’t include children in families that had a history of migraine.  In other words, if there was a known "hereditary factor", income didn’t seem to make a lot of difference.

I could talk about this for several pages; it really is an interesting study, and interesting to think about.  Why was there such a difference?  Are we making another discovery about different types of migraine (one more hereditary, one not)?

This study isn’t suggesting that there’s actually an environmental cause to migraine.  Likely there is something environmental that’s triggering attacks, but what is it?

A few things to notice:  First, we’re talking about a huge income difference here.  Second, similar studies have shown that lower-income adults have more migraine.  Third, these were all households in the USA – perhaps there are factors in low income families there that wouldn’t exist in other parts of the world.  Fourth, a lot of related diseases and obvious factors were not taken into consideration (such as clinical depression, or substance abuse).

One more interesting note.  This study does not support the "social selection" theory.  This theory says that people with migraine are going to make less money because they don’t tend to do as well at work.  Since the study dealt with kids, they were not generally contributing to the family income.  That’s why the researchers are focusing on environmental factors now.

Dr A. Hershey from the University of Cincinnati sums up the limitations and strengths of the study well:  expression of migraine clearly involves a complex interaction of genetics and environment. Bigal et al . . . have clearly demonstrated that the interplay between socioeconomic status and genetics contributes to this complexity. (quote from medpage article If No Genetic Link, Family Income Affects Migraine Risk)

In other words, no one’s saying that migraine is simply "environmental".  And, of course, lots of people with higher incomes had migraine too – just fewer.  However, environment does contribute, and studies like this help us narrow down exactly what parts of our environment are causing problems.