Obesity May Be Linked to Adult-Onset Asthma in Women
"In a study like the Nurses' Health Study, there are more than 900 variables," says Albert Wu, MD, MPH, in an interview seeking objective commentary on the study. "There are many, many predictive variables and there is the possibility of a spurious association." Wu is associate professor of healthy policy and management and medicine at Johns Hopkins University in Baltimore.
Before recommending weight loss as a strategy to prevent adult-onset asthma, Wu tells WebMD that "the finding needs to be replicated in a study intended to answer the question." In the Nurses' Health Study, Wu says, "there are so many potential associations that there is always the risk of chance, and that it is not a true association." Because the Nurses' Health Study has such a "large number of candidate variables and an equally large number of disease and other health outcomes," he says, "that a finding like this deserves to be replicated."
Other experts also question the study's findings. The authors of an accompanying editorial urge confirming the results in other, more diverse populations. And they ask whether the chicken or the egg came first -- was the asthma a reason the adult nurses were overweight, or were they overweight first?
Michael Schatz, MD, a spokesperson for the American Academy of Asthma, Allergy and Immunology, tells WebMD, "The bottom line is, 'Is it a legitimate risk factor?' ... It is going to take a lot more information before we can determine that."
Camargo acknowledges many of the same study limitations that these critics raise. Moreover, he points out that it took a long time before doctors believed that dust mites and cockroaches played a role in asthma. He worries that it may take a while before doctors are convinced of the role of obesity.
- A new study shows that a high body mass index (BMI) is associated with a higher risk of developing adult-onset asthma.
- Earlier findings have already shown that childhood asthma is more prevalent in overweight populations.
- Some experts point to the limitations of the study, saying that the association could be explained by other variables.