by V. Kumar

Created on: October 12, 2009   Last Updated: October 14, 2009

Though the relationship between obesity is still not fully understood, we now have enough evidence to conclusively say that obesity worsens asthma.

In recent times, some major research and studies have shown that the presence of obesity in asthmatic patients worsens their symptoms while reducing weight tends to bring some relief. This is not a totally new revelation. Statistics show that almost three fourth of all asthma patients that need emergency hospitalization are obese. However, due to a lack of clear understanding, obesity was not considered a predisposing factor for asthma.

Now, we are beginning to get more clues as to how obesity might be impacting asthma. One of them is through the mechanical impact of obesity on lung volumes. The pressure of excess fat makes it difficult for lungs to expand fully. As a result, the severely obese often tend to breathe more frequently, with a lesser tidal volume of air. This increased effort of breathing makes them particularly vulnerable to the obstruction of airways as happens in asthma. Hence, in a case of strong attack of asthma, the obese become more deficient of oxygen and require hospitalization more frequently.

Simultaneously, other aspects of asthma and obesity are also coming to light. It has been observed that obese persons have a higher concentration of 'leptin'. Asthmatic obese children have been observed to have a higher concentration of this substance than their peers. Leptin and other substances produced by fat tissue in the body like adiponectin and plasminogen activator-inhibitor sensitize the airways to allergens, thereby making obese people vulnerable to asthma.

Pioneering work in this regard is under way in Harvard School of Public Health. This is what the co-author of this study, Jeffrey Fredberg, has to say, "Obesity has the capacity to impact lung function in a variety of ways. None of them are good and all of them are poorly understood. More research is needed to explain the relationship between asthma and obesity."

In summary, the impact of obesity on asthma is adverse, and the combination of the two makes life more miserable. However, it is still too early to say that obesity predisposes to asthma in the same way it predisposes to heart diseases and diabetes. For that we will need a better understanding of asthma and obesity both, and require adequate scientific evidence. In spite of this limitation, the physicians are already advising their asthma patients to also take care of their obesity, in order to keep things under control.

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