FRIDAY, Feb. 22 (HealthDay News) -- Even a small amount of extra weight can have a negative effect on the lung function of Hispanic and black children, according to a new study.

However, this is not the case for white children, the researchers noted. As a result, they suggested that differences in the distribution of body fat could help explain the greater prevalence of asthma in these minority groups. The study authors said their findings could help doctors identify and treat children with airway obstruction.

"While it has been well documented that Hispanics and African-Americans -- particularly those who live in urban settings -- have a higher prevalence of asthma and obesity, there is less understanding of the lung function in overweight asthmatic minority children," senior study author Dr. Deepa Rastogi, an attending physician in the division of respiratory and sleep medicine at the Children's Hospital at Montefiore in New York City, explained in a Montefiore news release.

"What we have learned from this study is that even small increases in weight can negatively impact lung function," Rastogi added.

In conducting the study, published in the February issue of the Journal of Asthma, the researchers examined the medical records of 980 children living in the Bronx ranging in age from 7 to 20. The records were collected from January 2003 to December 2007.

Although white children tend to be obese before they experience airway obstruction due to excess weight, the study revealed that just being overweight can have a negative effect on lung function among minority children.

"This information may prove to be helpful in the clinic," noted Rastogi, who is also an assistant professor of pediatrics at Albert Einstein College of Medicine of Yeshiva University. "Physicians might want to measure the degree of airway obstruction in Hispanic and African-American children who are both overweight or obese and asthmatic. Early identification of a drop in lung function can assist in better patient management."

While the study showed a connection between being overweight and having airway problems, it didn't establish a cause-and-effect relationship.

Although asthma is usually attributed to environmental factors such as secondhand smoke and exposure to dust or mold, the study authors suggested ethnic differences in body shape and upper body fat distribution may shed light on this discrepancy. Weight gain in Hispanics and blacks may be associated with increased abdominal fat, they explained. This extra belly fat could increase the prevalence of asthma in these minority groups.

The researchers noted previous research has shown that waist circumference is linked to the severity of asthma. Waist size, they added, also has an inverse relationship with lung function.

More information

The U.S. Centers for Disease Control and Prevention provides tips for parents on how to help their children maintain a healthy weight.

SOURCE: Montefiore Medical Center, news release, Feb. 19, 2013

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