NEW YORK (Reuters Health) - Headaches associated with air travel appear to be a "huge and painful problem," Israeli researchers report.

In a study of 906 men and women who had traveled more than once by plane, nearly 6 percent reported that they experienced headaches associated with flying.

Based on 3.3 billion seats available each year on commercial flights, with 70 percent occupancy, Dr. Israel Potasman and colleagues from Bnai Zion Medical Center in Haifa estimate that more than 100 million people suffer from flight-associated headaches annually.

"This finding has enormous impact both in terms of suffering and economics," they write in the medical journal Cephalalgia.

There are a number of mechanisms that could contribute to headaches during air travel, including stress, poor air quality, engine noise and changes in barometric pressure, the investigators note. To investigate the prevalence of flight-associated headaches, they surveyed visitors to the travel clinic at their medical center.

More than one in five of the study participants had headaches at least once a month that weren't related to flying, the researchers found. But just over half of the 5.7 percent who reported flight-associated headaches suffered headaches this frequently. They were also slightly more likely to have migraines. Two-thirds of those who suffered flight-associated headaches were women, and one-third had a family history of headache.

Among the flight-associated headache sufferers, 19.2 percent said they had headaches every time they flew. Nearly a quarter said their headaches got worse as the plane climbed, while a fifth said the pain became worse as the plane descended to the Dead Sea, which is about 400 meters below sea level, suggesting that barometric pressure may be a factor.

The average age of the study participants, who had gone to the clinic to be vaccinated before traveling to the tropics, was 33, the researchers note, so "we may have missed many older business travelers flying to Europe or the USA." The vast majority of those surveyed (97 percent) said they flew economy class.

This study, the researchers conclude, suggests that flight-associated headache "seems to affect a significant number of the travel population."

SOURCE: Cephalalgia, August 2008.

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