BOSTON, Massachusetts —A new study showed that compared with normal-weight participants, obese people have an 81% greater risk for episodic migraine (EM), a condition characterized by up to 14 migraine episodes a month. The risk was highest among obese women or younger people who are obese and under 50 years of age.
It's another reason physicians should advise overweight patients with EM to exercise, eat a healthy diet, and try to maintain a healthy body weight, said lead study author B. Lee Peterlin, MD, associate professor, neurology, and director, Headache Research, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Dr. Peterlin will present her findings at the 2013 International Headache Congress.
Different Methods
Research shows that in general, women have a risk for EM that is up to 3-fold greater than that in men and that the risk is greatest between ages 20 and 49 years. Some previous studies have suggested that the association of obesity with migraine was only for chronic or high-frequency EM, where episodes occur 10 to 15 days per month or more.
"Our study shows that the risk is not just for chronic migraineurs, who represent a very small portion of all migraine patients," said Dr. Peterlin, adding that the prevalence of chronic migraine in the general population is only about 2% compared with 12% to 15% for EM. She and her colleagues hypothesized that previous research used different methods, evaluating younger and older participants together and/or substantial differences in racial sampling of study population, possibly diluting the findings.
The current cross-sectional study included 3862 white and black adult participants who were interviewed in the National Comorbidity Survey Replicated.(NCSR), a nationally representative face-to-face household survey of adult residents in the United States.
Researchers categorized EM according to diagnostic criteria from the International Classification of Health Disorders. They classfied weight as underweight (a body mass index [BMI] of under 18 kg/m2), normal weight (BMI of 18.5 to 24.9 kg/m2), overweight (BMI of 25 to 29.9 kg/m2), and obese (BMI of 30 kg/m2).
Overall, the study found that the odds ratio (OR) of EM was 81% greater in obese vs normal-weight people (OR, 1.81; 95% confidence interval, 1.27 - 2.57; P = .001).
The study also found a significant trend of increasing risk for EM with increasing obesity status, noted Dr. Peterlin. "As individuals went from normal weight, to overweight, to obese, the risk of episodic migraine significantly increased."
Subgroup Analysis
In addition, various analytical models of subgroups found that compared with normal-weight persons, the odds of EM were 86% greater in those who were obese and younger than 50 years (OR, 1.86; 95% CI, 1.20 - 2.89; P = .008), 106% greater in whites (OR, 2.06; 95% CI, 1.41 - 3.01; P < .001) and 95% greater in women (OR, 1.95; 95% CI, 1.38 - 2.76; P < .001).
The odds of EM were not increased in those 50 years and older or in men. The number of black particpants with EM was too small to permit conclusions about the odds of EM in in these participants alone. "Future studies will need to determine if the risk of episodic migraine in African Americans with obesity is less than in Caucasians," said Dr. Peterlin.
Further subgroup analysis also showed that the increased risk for EM among the obese was true even for very low-frequency EM, defined as 60 or fewer headaches per year or roughly 5 or fewer headaches per month.
How might an unhealthy body weight increase risk for EM? According to Dr. Peterlin, previous studies have shown an association between obesity and changes in brain and inflammatory pathways that are similar to those activated in EM.
"We don't know the direction of the episodic migraine-obesity association, but it's possible that both disorders share similar pathophysiological pathway activations. Specifically, the hypothalamus, the part of the brain that controls the drive to feed or not feed, is associated with obesity, and has been shown to be activated in migraine," she said. "States of being overweight and obese are also associated with activation of an inflammatory cascade and an increase in several inflammatory proteins that have also been shown to be linked to episodic migraine. Alternatively, it's also possible that having migraine leads to a more sedentary lifestyle which contributes to obesity."
Obesity rates rise across the nation, but it's unclear whether the prevalence of EM is also increasing. "This is controversial," said Dr. Peterlin. "Several studies suggest that the incidence and prevalence of migraine, including data from the Centers for Disease Control and Prevention, did increase in the 1980s and early 2000s, but other studies did not."
Important Caveat
Medscape Medical News invited Tobias Kurth, MD, director of research, neuroepidemiology, Institut national de la santé et de la recherché medicale (INSERM), Bordeaux, France, adjunct associate professor of epidemiology, Harvard School of Public Health, and associate epidemiologist, Division of Preventive Medicine, Brigham and Women's Hospital, Boston, Massachusetts, to comment on this research. He called this an important study, but with a significant caveat.
Despite the huge increase in obesity over the last 10 years, there has not been the same sort of increase in migraine, which there should have been if the two were linked. "Migraine prevalence has been stable," said Dr. Kurth.
He agreed, however, that it's possible that there is some sort of time delay between the development of obesity and that of migraine.
The authors have disclosed no relevant financial relationships.
International Headache Congress 2013. Abstract P170.
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Cite this: Obesity Increases Risk for Episodic Migraine - Medscape - Jun 26, 2013.
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