Overweight teens and children are more likely to have asthma than their normal-weight peers, according to a new study.

But the strength of that association varies by race and ethnicity, according to Kaiser Permanente researchers writing in the journal Obesity.

The new study, which included more than 681,000 children between ages 6 and 19, found the connection between asthma and being overweight was weaker for African Americans, a group that has the highest prevalence of asthma, than for other racial and ethnic groups.

Researchers found the strongest connection in Hispanic youth.

"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, particularly for Hispanic youth, may modify this relationship," said lead author Mary Helen Black, of the Kaiser Permanente Southern California Department of Research & Evaluation.

"The study's large and diverse population, which is broadly representative of the Southern California region, allowed us to examine a wide range of BMI categories in relation to asthma among youth from five racial/ethnic groups."

Researchers’ findings were based on electronic health records of children and adolescents in the Kaiser Permanente Southern California health plan from 2007 to 2009.

Researchers also found that being overweight or obese was associated with more frequent visits to the doctor or emergency department for asthma. In addition, overweight or obese youth with asthma used more inhaled and oral corticosteroid asthma drugs, when compared to healthy weight youth.