Migraine and Socioeconomic Status - What's the Link?
Studies have shown that Migraine is more common among people with lower income. What those studies haven't addressed is which comes first. A new study in the journal Neurology examined the chicken-or-the-egg issue of whether developing Migraine disease limits people's educational and career choices and leads to a lower income status, or whether issues related to low income increase the odds of developing Migraines.
"To determine whether the known higher prevalence of migraine in lower household (HH) income groups is explained by a higher incidence rate or a lower remission rate"1
- Researchers used data from the American Migraine Prevalence and Prevention Study (AMPP).
Incidence and remission rates were estimated within three gender-specific household income groups:
- less than $22,500,
- $22,500 - $59,999, and
- more than $60,000
- Migraine prevalence increased as household income decreased for women and men.
- The differences were not explained by race and other known factors such as race, age and gender.
- Variation in prevalence was largely explained, by a higher incidence rate in the lower household income groups for both women and men.
- Migraine remission rates did not differ by household income.
- Those in the group with income less than $22,500 were more likely than those in higher income groups to have extremely severe pain from their Migraines and severe disability with missed work or school due to Migraine.
- People in the low-income group were more likely than those with higher incomes to have extremely severe pain from their Migraines and severe disability with missed work or school due to Migraine.
"In general, these findings strongly support social causation as a mediator of variation in prevalence by household income, but they do not exclude social selection as a possible explanation of some of the HH income variance. Measures of pain and disability are more severe in lower household income groups, a finding that is also consistent with the social causation hypothesis."1
One theory has been that social stressors increase the rate of Migraine in people with low incomes. However, the researchers found that "remission rate," Migraines lessening or stopping, was the same, regardless of income. Study author Walter F. Stewart, PhD, commented:
"If the stresses of low income were the sole determinant, we would expect low-income people to be less likely to stop having migraines. It’s possible that the start of the disease may have a different cause than the stopping of the disease."3
"New evidence from this study shows that a higher percentage of people have migraine in low income groups because more people get migraine, not because people in lower income groups have migraine for a longer period of time. Because the remission rate does not differ by income, it means that the duration of time that people have migraine is not different by income level. These results strongly support the theory that stressors associated with lower income play an important role in the relationship between migraine and income. Identifying these factors may be a crucial step toward developing prevention strategies."3
An accompanying editorial:
In their accompanying editorial, Peterlin and Scher begin by reviewing question of social selection vs social causation, whether disease leads to low socioeconomic status (SES) or the other way around, and simply state the end result of each theory:
Social selection: Disease → Low SES.
Social causation: Low SES → Disease.2
Peterlin and Scher suggest caution in interpreting the findings of Stewart et. al, making excellent points:
- Income is only one component of SES, and it is the only one used in the study.
- The study excluded participants with chronic Migraine.
- It's possible that other factors associated with SES, such as race and marital status, added to the association between Migraine and SES.
Summary and comments:
The question of whether Migraine leads to low socioeconomic status or low socioeconomic status leads to Migraine is analogous to the age-old question of nature vs. nurture. There have been studies that support both social selection and social causation.
The reality is that both can be correct; neither needs to preclude the other. The findings of this study do not preclude genetics and other endogenous factors playing a significant role. This is not a black-and-white issue, and the answer to the question lies in a combination of both.
Peterlin and Scher frame the question differently, in a manner that is more likely to accurately and fully address the issue:
"Do migraine environmental and genetic factors affect one another reciprocally or even dynamically across the lifespan (i.e., indirect selection)?"2
Attempting to make Migraine disease, it's causation, and the results fit into either social selection or social causation could lead to narrowed focus and a loss of overall perspective.
1 Stewart, Walter F., PhD; Roy, Jason, PhD; Lipton, Richard B., MD. "Migraine prevalence, socioeconomic status, and social causation." Neurology 2013;81:948–955.
2 Peterlin, Lee B., DO; Scher, Ann I., PhD. "Migraine and the social selection vs causation hypotheses." Neurology® 2013;81:942–943.
3 Press Release. "Does Migraine Affect Income or Income Affect Migraine?" American Academy of Neurology. August 28, 2013.
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© Teri Robert, 2013
Last updated September 16, 2013.