Asthma risk increases for overweight and obese youths
■ The likelihood of developing the disease is not as high for obese blacks as it is for other ethnic/racial groups studied.
When treating overweight and obese youths, physicians should keep in mind that an elevated body-mass index increases one's likelihood of having asthma, said the lead author of a recent study.
But the extent to which weight impacts a patient's risk of developing the disease depends, in part, on the individual's ethnicity or race, said Mary Helen Black, PhD. She is a research scientist biostatisticianin the Dept. of Research and Evaluation at Kaiser Permanente Southern California in Pasadena, Calif.
Among youths, the odds of having current asthma are greatest for blacks, according to a study published online Jan. 17 in the journal Obesity. The study, co-written by Black, defines people with current asthma as those diagnosed with the condition in the past year and who have at least one asthma-specific medication on their medical records.
Black youths were nearly twice as likely to have current asthma compared with whites of the same age. But when researchers grouped participants by BMI levels, they found that the risk of developing the disease did not increase as much for overweight and obese blacks as it did for other groups studied.
For example, extremely obese blacks (BMI of 35 kg/m2 or greater) were about 1.6 times as likely to develop the disease as blacks with a healthy weight. Extremely obese whites were nearly two times as likely to have asthma as whites with normal BMI levels.
The study did not identify why weight had a greater impact on asthma risk for some ethnicities and races. But Black said it is possible that certain factors, such as the environment in which black children live, play a larger role in the likelihood of developing asthma than do elevated BMI levels.
"This research contributes to the growing evidence that there is a relationship between childhood obesity and asthma, and suggests that factors related to race and ethnicity ... may modify this relationship," Black said.
About 24.6 million Americans have asthma, according to 2009 data from the Centers for Disease Control and Prevention. The disease is more common among children under 18 than in adults. Nearly one in 10 children has asthma compared with 7.7% of adults. Prevalence is particularly high among black youths; about one in six has the condition.
Researchers for the Obesity study examined data on 681,122 people ages 6 to 19 who received health care in medical offices and hospitals owned by Kaiser Permanente Southern California between Jan. 1, 2007, and Dec. 31, 2009. Pregnant adolescents were excluded from the assessment.
Researchers found that 11% of participants had asthma (link). Although Hispanics were least likely to be diagnosed with the disease, their risk of developing asthma increased as BMI levels rose.
Watching for asthma symptoms
Black encourages physicians to keep an eye on potential signs of asthma in their overweight Hispanic patients, even though the population in general has a low prevalence of the disease. Such symptoms include frequent coughing, especially at night, and breathing problems that worsen after physical activity, according to the CDC.
Researchers found that overweight and obese youths with asthma are more likely to receive medical care for asthma-related problems than normal-weight participants with the disease.
Those with elevated BMI levels also are more frequently prescribed inhaled and oral corticosteroids than normal-weight youths with asthma, the study said. Use of such medications has been shown to increase people's risk of developing diabetes in some instances, Black said.
"Because of the inherent diabetes risk of obese youth, doctors might want to think about what medications they're using to treat" overweight patients with asthma, she said.