Obese Men at higher risk for asthma
   
   Men who are obese are more likely to have asthma, with the heaviest men having almost a four times higher risk of developing asthma than the thinnest men, according to study results presented at the annual meeting of the American Academy of Allergy, Asthma and Immunology.

"Recently, there's been interest in the possibility that increasing obesity is part of what's going on with the increase in asthma," explained Kathryn Held, a doctoral candidate in medical anthropology at the University of Oklahoma in Norman. The prevalence of asthma in men increased nearly 42% between 1982 and 1994, according to the Academy.

The reasons for these findings are unknown. "Physicians have observed for a long time that asthmatics tended to be heavier, but the assumption has been that asthmatics restricted their activity and thus gained weight," Held said. But she noted that studies over time in women and children suggest that the obesity comes first, and the youngest children -- whether obese or not -- are more likely to develop asthma if their mothers are obese.

Held's findings were based on questionnaire data from almost 12,000 men collected by the Centers for Disease Control and Prevention for the Household Youth Data File, which links characteristics of children with those of their parents. She divided the data into four groups according to the men's body mass index (BMI). She found that the prevalence of asthma in each group, in percent of men affected from thinnest to heaviest, was 5.30%, 8.09%, 8.93% and 17.31%.

When Held studied whether obese asthmatic men also had asthmatic children, she found that the association between the men's obesity and asthma was stronger than the association between having asthma and having a child with asthma.

Also, countries where people are thinner have a smaller proportion of asthmatics than North America, New Zealand, Australia and the United Kingdom, she said. These are all places where there is a rapid increase in the prevalence of both obesity and asthma.

"Growing evidence indicates that asthma follows the same pattern as other 'diseases of modernization' of increasing risk with increasing overnutrition and overweight," the researchers conclude.

Nonetheless, Held admitted that none of these data prove whether obesity causes asthma or the other way around. "That's obviously the next step (in research), the causal relationship," she said.

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