TUESDAY, Jan. 24 (HealthDay News) -- Children with asthma who don't have heartburn and other signs of gastroesophageal reflux don't get additional asthma control from acid-reducing medications, according to new research.

And, taking these medications when there are no digestive issues increases a child's risk of developing a respiratory infection, reports the study.

"There's a strong epidemiological link between acid reflux and asthma," explained study co-author Janet Holbrook, an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore. As a result, current asthma guidelines call for evaluating people with asthma for acid reflux, Holbrook said.

Because definitive tests for excess acid production can cause children discomfort, some doctors may choose to do a trial of acid-suppressing medications called proton pump inhibitors (PPIs). Some common brand names in this class of medication are Prilosec, Prevacid and Nexium.

"Our findings suggest that physicians should not take kids with poorly controlled asthma and test whether PPIs will help," said Holbrook.

Results of the study are published in the Jan. 25 issue of the Journal of the American Medical Association. The study was funded by the U.S. National Institutes of Health and conducted by the American Lung Association Asthma Clinical Research Centers.

Asthma and gastroesophageal reflux (GER or GERD) are common conditions in children. Youngsters with asthma often have symptoms of gastroesophageal reflux. In adults, PPIs seem to help people with asthma who also have symptoms of gastroesophageal reflux, but not those who don't have symptoms, such as frequent heartburn.

The current study included 306 children recruited from 19 centers across the United States between 2007 and 2010. The average age was 11 years. All had poor asthma control despite receiving treatment with inhaled corticosteroids.

The children were randomly assigned to receive either lansoprazole -- a PPI -- or a placebo daily for six months. The dose of lansoprazole was based on the child's weight.

Asthma improvement was assessed through a change in the Asthma Control Questionnaire, which has a scale of 0 to 6. A change of 0.5 is considered clinically significant. Lung function was also measured.

After six months, there were no statistically significant differences between the groups. The average change in the Asthma Control Questionnaire score was only 0.2, and there were no statistically significant changes in lung function, quality of life or rate of asthma flare-ups.

In addition, among 115 children who also had a 24-hour esophageal acid study, 43 percent were found to have elevated levels of acid production. Yet even in this group, treatment with lansoprazole didn't improve asthma symptoms over placebo.

Holbrook said although this study only looked at one PPI, she believes the results would hold true for other medications in this class of drugs.

Children taking lansoprazole had about a 30 percent higher risk of respiratory infections and sore throats in this study. PPIs were also associated with a difference in the risk of activity-related bone fractures, although the difference was not statistically significant, according to an accompanying editorial in the same issue of the journal.

"PPIs do not improve asthma in children who do not have symptoms of GER/GERD, and it is unlikely to be of great benefit even in children who do have such symptoms," said the editorial author, Dr. Fernando Martinez, director of the Arizona Respiratory Center at the University of Arizona in Tucson.

"The substantial increase in use of PPIs in children during the last decade is worrisome and unwarranted," he wrote.

Still, Martinez advised parents not to abruptly discontinue any medications. Parents "should consult their pediatricians, who can best evaluate the clinical situation for each child," he said.

Holbrook agreed and said if a child is on a PPI, it's reasonable for parents to ask why. She noted that these medications may come with an additional risk and cost, and they may not have any additional benefit.

"If your child is on a PPI for asthma, it's not an effective treatment. These medications are approved for the treatment of acid reflux," said Holbrook.

More information

Learn more about asthma treatment from the U.S. National Heart, Lung, and Blood Institute.