Prevent Disease.com - Conflicting Data on Asthma-Obesity Link



		Conflicting Data on Asthma-Obesity Link Excerpt By Suzanne Rostler, Reuters Health NEW YORK (Reuters Health) - The rising rates of asthma among children in affluent nations have perplexed scientists, who have blamed everything from declining rates of breast feeding to greater exposure to cigarette smoke and other pollutants. Now, two new reports in the November issue of Thorax offer conflicting conclusions about the role of body weight, another possible risk factor for the disease. In one study, researchers conclude that increasing rates of asthma appear to be linked to rising rates of obesity among US children. The report found that the heaviest children were 77% more likely to have symptoms of asthma, including wheezing and shortness of breath, compared with the thinnest children. About 15% of the heaviest children were diagnosed with asthma, compared with nearly 9% of the thinnest kids. After taking into account other risk factors, such as exposure to cigarette smoke and not having been breast fed, body weight remained a major risk factor for the chronic respiratory disorder regardless of a child's gender or ethnicity. What's more, the amount of time a child spent watching television and exercising were not linked to asthma, indicating that body weight, not a lack of physical activity, could be the problem. The results are based on interviews with the parents of 7,500 children aged 4-17 years. Children were weighed, measured and tested for a number of other types of allergies. ``Appropriate strategies for the reduction of body weight in children may contribute to a reduced incidence of asthma in childhood,'' Dr. E. von Mutius, from University Children's Hospital in Munich, Germany and co-authors conclude. Exactly how excess body weight can lead to asthma is not clear, but the investigators suggest that obesity, which can lead to inflammation in the body, may also cause inflammation of the airways. Or, the pressure of excess weight on the lungs may compromise the airways. But in a second study, investigators argue that a concurrent rise in rates of asthma and obesity is recent and therefore cannot explain the decades-long increase in asthma rates. They reviewed data from a national study on British children aged 8-9 years, which monitored the incidence of asthma and obesity over a 12-year period. ``The evidence points towards the association between asthma and obesity being of recent origin. This may be explained by obesity being a marker of recent lifestyle differences now associated with both asthma and overweight,'' conclude Dr. S. Chinn and R.J. Rona of King's College in London, UK. In an interview with Reuters Health, Chinn explained that the concurrent rise in rates of both asthma and obesity among children, coupled with consistent findings of a link between the two, have led some researchers to conclude that there is a causal link. ``We found that the increase in overweight and obesity explained none of the increase in asthma,'' Chinn said. She added that several factors are probably causing rates of asthma to rise, and several studies are now underway to determine what those factors might be. SOURCE: Thorax 2001;56:835-838, 845-850. Reference Source 89 For more information on how to prevent other diseases, use PreventDisease.com's "Quick Prevention Resources".