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OBESITY IS A RISK FACTOR FOR CHRONIC DAILY HEADACHE

MIAMI BEACH—A telephone survey of more than 140,000 people found that obesity nearly doubles the risk that an episodic headache will develop into chronic daily headache (CDH).

The study, led by Marcelo E. Bigal, MD, PhD, Associate Professor of Neurology at the Albert Einstein College of Medicine, also found that headache severity and disability is higher in obese and morbidly obese subjects.

A second study of 150 patients enrolled in headache prevention clinical trials found that obese patients were at least as likely to benefit from prevention as non-obese patients. Both reports were presented here in April at the AAN Annual Meeting.

The population-based telephone interview study, called The Master Health Survey, gathered information on headache features, height, and weight. Researchers interviewed 143,433 individuals – in New York, New Jersey, Pennsylvania, and Maryland – and identified 30,850 subjects with at least one headache attack in the prior year and gathered the BMI (body mass index) information for each person. Sixty-four percent of the subjects were women and the mean age was 43.1.

RISK FACTORS, CHRONIC DAILY HEADACHE

“We were interested in understanding the risk factors for chronic daily headache, why some people will progress to chronic daily headache, and others will not,” Dr. Bigal said.

Among key findings: the prevalence of CDH – more than 15 headaches per month, each lasting more than four hours per day – was 4 percent. In normal weighted patients, the prevalence of CDH was 3.9 percent; in obese participants, it was 5.2 percent. The prevalence in the morbidly obese group was 7.1 percent.

While the percentage differences don't seem large, Dr. Bigal noted they are statistically significant, with p values of 0.001 or less.

Women progressed to chronic daily headache twice as much as men. “So, a person at a higher risk for progression is a woman, middle-aged, and overweight. That's the worst,” Dr. Bigal said. But he noted, that even with all these risk factors, still only 7 percent develop CDH, and the overall progression rate of people who have episodic headache per year is 3 percent.

The disability for obese subjects was also more severe than for those with normal weight. They had more nausea, phonophobia, and photophobia. They also were more likely to miss work or school and to report more severe pain due to their headaches compared to non-obese participants.

For example, 33 percent of obese subjects missed work for more than four days due to headaches, while 27.2 percent of overweight and normal weight participants missed that much work because of headaches, numbers that are statistically significant. Nearly 36 percent of obese subjects reported severe pain compared to 31.7 percent of overweight subjects and 29.5 percent of normal weight subjects.

TREATING OBESE PATIENTS

The investigators enrolled about 150 subjects, including obese and non-obese headache sufferers in a prevention trial to see if it would be more difficult to treat obese subjects versus non-obese subjects. The patients received standard therapies for migraine: beta-blockers, antiepileptic drugs, and anti-depressant drugs. Medications that could cause weight loss, topiramate, for example, were excluded.

“We found that it's not more difficult to treat obese headache sufferers,” Dr. Bigal said. “They responded even better than those at normal weight. So, I think this is an interesting message: Obesity is a risk factor for developing chronic daily headache, but if you develop chronic daily headache, you can come back.”

The researchers are also determining if loss of weight due to bariatric surgery will reduce headaches in morbidly obese headache sufferers. So far, there is no data on that study, Dr. Bigal said.

Dr. Bigal noted that a previous Johns Hopkins study (Pain 2003;106(1–2):81–89), led by Ann I. Scher, PhD, now at the Division of Epidemiology and Biostatistics at Uniformed Services University of the Health Sciences in Bethesda, MD, found that migraine sufferers who were obese were six times more likely to develop chronic daily headache than non-obese migraine sufferers.

“Her data were the first to say obesity is a risk factor. My data confirms that,” Dr. Bigal said.

CONFOUNDING VARIABLES

Thomas N. Ward, MD, Director of the Headache Clinic at Dartmouth-Hitchcock Medical Center in Lebanon, NH, said the study was “interesting and a tribute to the hard work of Dr. Bigal and colleagues.”

He noted that snoring does correlate with CDH as well, “which is not surprising given the body habitus of many of these patients.”

He said a confounding variable in the obese patients could be increased intracranial pressure with or without papilledema, which is more common in the overweight patients. Notably, the thinner patients (in Dr. Bigal's study) had features more typical of migraine – for example, nausea. “Whether weight loss would improve the headache pattern or merely change it is at present unknown,” he said.

ARTICLE IN BRIEF

  • ✓ Investigators reported that headache severity and disability is higher in obese and morbidly obese subjects, but that obese patients were at least as likely to benefit from prevention as non-obese patients.