These findings, while not conclusive, add to mounting research that has suggested that weight — particularly obesity — may be risk factor for migraines, at least among some people.
“The recognition of this risk is important given that obesity is a potentially modifiable disease risk factor for migraine,” write the authors of the study.
Migraine headaches are attacks of moderate to severe throbbing or pulsing pain that can last from four to 72 hours, according to the National Institute of Neurological Disorders and Stroke. They also often involve sensitivity to light and noise, and may cause nausea or vomiting.
Experts estimate that 12 percent of Americans have migraines. There is currently no cure for these debilitating headaches, but treatments include self-care (such as stress reduction, diet modification and improved sleep), as well as various medications.
For the new study, researchers from several universities, including Harvard University and Johns Hopkins University in the United States, used data from 12 previously published studies on migraine and weight involving almost 290,000 individuals, aged 18 to 98. They then pooled the data from those studies into a meta-analysis to see if they could find statistically significant correlations between migraine risk and different categories of weight.
The weight categories — underweight, normal weight, overweight and obese — were based on body-mass index (BMI) calculations.
After crunching all the data, the researchers found that people who were obese or underweight — but not those who were overweight — were more likely to have migraines than normal-weight people.
Specifically, people who were obese were 27 percent more likely to experience the headaches, and underweight people were 13 percent more likely.
The researchers also found that, when it came to obesity and migraines, age and gender were important variables, with the correlation strongest among women and younger adults.
A ‘moderate’ link
The authors of the study describe the increased risk between obesity and migraines as “moderate” — about the same as the link between migraines and ischemic heart disease and between migraines and bipolar disorder.
Why would weight affect migraines? It’s not clear, but several possibilities are being studied.
“Adipose tissue, or fatty tissue, secretes a wide range of molecules that could play a role in developing or triggering migraine,” said Dr. B. Lee Peterlin, director of headache research at Johns Hopkins University, in a released statement. “It’s also possible that other factors such as changes in physical activity, medications, or other conditions such as depression play a role in the relationship between migraine and body composition.”
Limitations and implications
This study comes with several important caveats. To begin with, all the data used in the meta-analysis were from observational studies, which are not designed to show a direct causal relationship between two things. The results of this meta-analysis do not definitely demonstrate, therefore, that weight causes migraines. Other, not-yet-identified factors may explain the observed correlations.
Also, half of the studies in the meta-analysis used the participants’ self-reports — not official medical diagnoses — of their migraines. Those self-reports may not have been accurate. Several of the studies also had people self-report their height and weight to determine their BMIs — another possible source of error.
So, although maintaining a healthy weight is something all of us should strive for, this current study can’t tell us if losing weight (for people who are obese) or gaining weight (for people who are underweight) helps reduce either the frequency or severity of migraines.
Still, as background information in the meta-analysis points out, other — albeit limited — research has found that when morbidly obese people with a history of migraines lost significant weight after bariatric surgery, the severity of their headaches decreased within six months. And other studies have suggested that aerobic exercise can reduce the frequency and intensity of migraine headaches.
Scientists aren’t sure how exercise helps, but it may be as much due to the weight loss as to the exercise itself.
For more information: You’ll find an abstract of the meta-analysis on Neurology’s website, but the full study is behind a paywall. The journal is published by the Minneapolis-headquartered American Academy of Neurology.