Obesity was associated with greater migraine prevalence and attack frequency, according to new research published in The Journal of Headache and Pain.

Migraine, whether episodic or chronic, is comorbid with obesity. The risk of migraine increases with obesity status—from normal to overweight to obese. In addition, obesity increases the risk of someone with an episodic pattern of headaches transforming into a chronic pattern.

However, researchers point out that obesity defined by BMI cannot distinguish between fat and muscle mass or between abdominal and peripheral fat distribution. Abdominal visceral fat is metabolically different from other body fat and may be an independent risk factor for medical complications.

To better understand how obesity and body fat distribution are associated with migraines and tension-type headaches (TTH), investigators conducted a cross-sectional study based on data from 33,176 adult subjects.

Of the 18,191 women and 14,985 men included in the study (mean age of 54.4 years), 4290 (12.9%) had migraines, 4447(13.4%) had frequent TTH, and 24,439 acted as headache-free controls.

Analyses revealed:

• Obesity (BMI ≥ 30) was associated with increased odds of having migraines (OR 1.45; 95% CI, 1.32–1.59), both for women and for men, while the effect size was larger in participants < 50 years of age (OR 1.74; 95% CI, 1.54–1.98), and not seen for those ≥50 years.

• Obesity was associated with higher odds of having both migraines with aura (OR 1.51; 95% CI 1.33–1.71) and migraines without aura (OR 1.43; 95% CI, 1.26–1.62.)

• Being overweight (BMI 25–30) was associated with higher odds of having migraines with aura (OR 1.25; 95% CI, 1.12–1.39) and migraines without aura (OR 1.15; 95% CI, 1.04–1.29.)

• Abdominal obesity (waist circumference [WC] > 88 cm in women, > 102 cm in men) was associated with increased odds of having migraines (OR 1.29, 95% CI, 1.18–1.41) for women and men.

• Abdominal obesity effect size was larger when considering only participants < 50 years (OR 1.89; 95% CI, 1.69–2.11), but there was also an association for participants ≥50 years of age (OR 1.26; 95% CI, 1.10–1.45.)

Researchers also found weaker associations between obesity and TTH and a dose-response relationship between obesity categories and increased headache frequency in subjects with migraines.

The link between migraine and obesity has been studied for over 15 years, with more than a dozen studies conducted on patients of all ages and types. Taken as a whole, the evidence says that obesity raises the risk of having migraines by as much as 50% — about the same amount as having heart disease or bipolar disorder. But the risk grows as obesity increases, almost three-fold in patients with BMIs above 40.

The mechanisms linking obesity, weight loss, and migraine headaches remain unclear, but they may include alterations in chronic inflammation, adipocytokines, obesity comorbidities, and behavioral and psychological risk factors. 

The metabolic and hormonal activity of adipose tissue, increased release of pro-inflammatory substances, and neuroinflammation and neuropeptides involving hypothalamic function are among various mechanisms that may explain the association between migraines and obesity.

Researchers noted that using questionnaire-based headache diagnoses instead of clinical review limits the study. They also cautioned that the study's cross-sectional design prohibits conclusions about causality from being drawn and limits finding generalizations.

However, these findings may have clinical implications for the treatment of migraines and should be further investigated in population-based follow-up studies.