November 11, 2013

Study: Greater asthma risk for overweight, obese adults

A new Kaiser Permanente Southern California study indicates the risk for overweight and obese adults is even greater during the fall and winter months.

Researchers have repeatedly established the link between obesity and an increased risk of severe asthma attacks, but a new Kaiser Permanente Southern California study indicates the risk for overweight and obese adults is even greater during the fall and winter months.

In the study, which was published in the Journal of Allergy and Clinical Immunology: In Practice, researchers examined the frequency of asthma exacerbations in relation to patients’ Body Mass Index (BMI). Exacerbations are defined as asthma attacks that require medications that go into the bloodstream, such as oral medication, rather than inhaled steroids that go straight to the lungs.

“As with previous studies, our research found that asthma exacerbations were more frequent with increased BMI in all seasons,” said lead study author Michael Schatz, MD, MS, an allergist and researcher at Kaiser Permanente San Diego. “But the research also revealed that they were particularly likely to occur in overweight or obese adults in the fall and winter, which is a new addition to our knowledge of the disease.”

Children who are overweight or obese were also found to be at greater risk for asthma exacerbations, but the time of year was not as clearly associated with significantly greater incidences of severe asthma events.

For adult patients who have asthma, the findings suggest the need to more closely monitor their condition during the fall and winter months.

Researchers noted that further investigation is needed to hone in on potential reasons for the increase in asthma exacerbations for overweight and obese patients in the fall and winter. In particular, they suggested investigating factors such as the increase in viral infections at that time of year, vitamin D levels, and reduced responsiveness to inhaled steroid medications in overweight and obese patients.

The study involved examining the medical records of 28,000 patients, ranging in age from 5 to 56 years, who were continuously enrolled in the Kaiser Permanente Southern California Health Plan in 2008 and 2009. The study cohort included 17,316 adult patients, with 80 percent being overweight or obese, and 10,700 children of whom 46 percent were overweight or obese.

Kaiser Permanente can deliver transformational health research in part because it has the largest private electronic health system in the world. This system connects researchers to one of the most extensive collections of medical data available that measures patients’ health over a prolonged period of time.

By demonstrating greater risks for severe asthma episodes during the fall and winter seasons in overweight or obese adults, these findings add to our understanding of asthma care and may help patients better manage their condition.