The link between headaches, particularly migraine, and obesity is a controversial one—studies have weighed in for and against it. Now the Centers for Disease Control and Prevention reports that being extremely overweight or underweight may be a risk factor for severe headaches or migraine.

Researchers based their findings on data collected from the National Health and Nutrition Examination Survey, which assessed health problems of 7,601 women and men, including problems associated with weight. The study categorized people based on their body mass index (BMI) and determined that those with a BMI under 18.5 or over 30 were more likely to have severe headaches or migraine compared with people of a normal weight.