Nonmedical interventions for asthma prevention still in dispute

About 7.1 million children nationwide have asthma. Inhaled steroid and beta-agonists remain the gold standard for treating asthma, but because these medications have some adverse events and can be costly, recent research has also focused on nonmedical approaches – such as the efficacy of diet and exercise choices – that aim more at preventing asthma episodes than at treating them when they occur.

Smaller cohort studies have suggested so for years, and one study published recently in the Journal of the American Dietetic Association also came to that conclusion. In the PANACEA study, which was a cross-sectional study of 700 children, researchers from Athens, Greece, concluded that, “Unhealthy lifestyle behaviors, such as salty snack eating and television/video-game viewing, were strongly associated with the presence of asthma symptoms.”

Another paper published in the same journal by researchers from Scotland and the United Kingdom said increasing maternal nutrient intake in utero may be a possible measure to reduce the prevalence of childhood asthma, but that paper concluded that more data are needed.

“Much of the data are inconclusive because the studies are observational and have reported associations, not causality,” one of the U.K. study researchers, Graham S. Devereux, MD, PhD, said in an interview with Infectious Diseases in Children. “While it is hoped that the reported associations are evidence of causality, it is still possible that the associations are a consequence of confounding by other lifestyle factors. Until randomized placebo-controlled trials demonstrate that actually changing diet reduces the likelihood of childhood asthma, we have to be cautious in interpreting the published studies.”

Dietary interventions

The Greek researchers said although salty snack intake and television viewing have been implicated in the presence of asthma, results have been conflicting. The work of Demosthenes B. Panagiotakos, PhD, and colleagues of Harokopio University in Greece revealed that there was nearly a five times higher likelihood of consuming salty snacks more than three times per week among children having asthma symptoms vs. children without asthma symptoms. This association was even more prominent in children who watched TV or played video games more than 2 hours per day.

The researchers also said children who consumed a “Mediterranean diet” were less likely to report asthma symptoms, consistent with previous studies. The Mediterranean diet has a high content of vegetables, fresh fruits, cereals and olive oil, with a high intake of beta-carotene, vitamins C and E and various important protective substances such as selenium, flavonoids and polyphenols with marked antioxidant activity.

“We now have evidence that some components of the diet, like fruits, vegetables and fish, due to their high content in antioxidants, seem to be beneficial for asthma symptomatology in children,” Panagiotakos told Infectious Diseases in Children.

In the paper, Panagiotakos and colleagues said, “Since the prevalence of asthma is quite high in industrialized populations, and has continued to increase during the past years, future interventions and public health messages should be focused on changing these behaviors from the early stages of life, by informing parents, guardians, teachers and any other person that could teach children a healthier lifestyle.”

In the second paper, researchers from the University of Aberdeen, United Kingdom, reviewed three dietary factors that have been hypothesized to explain the increase in asthma — an increasing ratio of omega-6 to omega-3 polyunsaturated fatty acid (PUFA) consumption, changing vitamin D status and a change in the rate of antioxidants consumed. Although there is insufficient clinical evidence for the use of nutritional supplements to complement conventional asthma treatments, the researchers said ongoing studies may change this picture. They also reviewed a small number of studies of maternal diet that suggests that dietary modification during pregnancy may reduce the incidence of childhood asthma.

“The generally weak observational and very limited interventions data suggest that whilst there are associations between diet and asthma, the nature of the associations [with PUFA, antioxidants, nutrients and food], the timing [antenatal, infancy, childhood, adulthood], and the therapeutic potential of the associations are far from clear,” Devereux said.

Future studies should consider the use of dietary interventions to increase the intake of nutrients highlighted by birth cohorts (vitamin E, PUFA, vitamin D, zinc) to capture the complexity of dietary nutrient intake, he said.

“If shown to be efficacious, such a dietary intervention could be the basis for a low-cost, safe public health intervention to rapidly reduce the prevalence of asthma in children and, ultimately, adults, with obvious beneficial consequences for the well-being of individuals and society as a whole,” Devereux said. “Until the results of ongoing and planned trials are available, the practical consequences of research linking diet with asthma are minimal.”

Exercise as prevention

While the same can be said for the scientific evidence linking exercise and asthma prevention, many who have asthma anecdotally report less asthma symptoms when they are in good physical condition, as the Greek research indicated.

And, in a Cochrane review published in 2005, Ram and colleagues looked at 13 controlled studies involving 455 participants, and they concluded that exercise improves cardiopulmonary function but has not been shown to improve asthmatic lung function.

Infectious Diseases in Children Editorial Board member Matthew J. Greenhawt, MD, said physical fitness in and of itself is not a recognized treatment or pretreatment for asthma, adding that attacks may be triggered by exercise in some, and care must be taken to manage these individuals appropriately with pre-exercise treatment or post-treatment.

“Physical activity can be beneficial in many ways. It can raise endorphins, it can help to open up areas of atelectasis though forced deep breathing, and it can increase lung capacity. These can all help contribute to healthy lungs,” Greenhawt said.

“Exercise can stimulate endorphins,” Infectious Diseases in Children Editorial Board member Gary Rachelefsky, MD, said. “People with asthma shouldn’t avoid exercise; they should do things to prevent the onset of their asthma flare-ups, like staying on their medicine, properly warming up, etc. Many people experience bronchospasms while running, but it often is triggered by surrounding cold, dry air, so one way to prevent that is with a short-acting beta-agonist.”

Environmental interventions

Asthma attacks are often triggered by allergens such as pollen, dust and animal dander. Rachelefsky said reducing exposure to these triggers is another common sense way to avoid flare-ups.

“Avoiding cigarette smoke, [fresh] paint in the house, [using] fireplaces, controlling dust mite exposure, these things have been shown to alter the course of asthma,” he said.

Simply managing environmental factors through changing furnace and air conditioner filters and using a high efficiency particulate air (HEPA) grade replacement can reduce dust mite exposures, as can washing one’s bedding in hot water regularly. Vacuuming regularly may also have a positive effect on reducing certain exposures.

Greenhawt said monitoring peak flow is a “superb method” to help prevent asthma flare-ups.

“By assessing your peak expiratory effort on a daily basis, you will be able to monitor small down-trends in your performance, and be more aware of when a change in your pulmonary status is occurring,” he said. “This will enable you to get to your doctor sooner to start an established management of a flare-up.”

The importance of screening

The American College of Allergy, Asthma and Immunology (ACAAI) is also offering ways to monitor the potential for flare-ups during its 15th annual Nationwide Asthma Screening Program in May.

The program, which is being held during National Asthma Awareness Month, offers free screenings at more than 200 locations for those who have symptoms such as wheezing, coughing and shortness of breath that occur frequently, during exercise or at night.

“Many people who cough at night or get short of breath when they exercise don’t think they are at risk for conditions like asthma,” allergist John Winder, MD, chair of the ACAAI Nationwide Asthma Screening Program, said in a press release about the program. “But these symptoms shouldn’t be taken lightly, and anyone who experiences breathing problems should attend a free screening to see an allergist who can help identify the source of their suffering.”

During the screenings, adults will complete a 20-question Life Quality Test developed by the ACAAI. Children aged younger than 15 years will take a special test called the Kids’ Asthma Check that allows them to answer questions themselves about any breathing problems. Another version of the check is available for parents of children aged up to 8 years to complete on their child’s behalf.

Participants will take a lung function test that involves blowing into a tube and will meet with an allergist to determine whether they should seek a thorough examination and diagnosis.

Data lacking

In the meantime, current evidence provides no strongly successful nonmedical strategy for dealing with asthma.

“It must be understood that much of the data [surrounding nonmedicinal interventions to prevent asthma] is limited by lack of prospective studies and difficulty in controlling for all the variables that could confound the data,” Greenhawt said.

Although more studies are needed, it will likely be difficult to pinpoint any one nonmedicinal intervention over another as being responsible for reducing symptoms because a cascade of factors triggers asthma flare-ups, he said. – by Colleen ZacharyczukFor a list of asthma screening locations and dates or to take online versions of the Life Quality Test and Kids’ Asthma Check, visit www.allergyandasthmarelief.org.

For more information:

• Allan K. J Am Diet Assoc. 2011;111:258-268.
• Arvaniti F. J Am Diet Assoc. 2011;111:251-257.
• Halterman JS. Arch Pediatr Adolesc Med. 2011;165:262-268.
• Ram FS. Cochrane Database Syst Rev. 2005;4:CD001116.

Disclosures: Drs. Greenhawt, Panagiotakos and Rachelefsky report no relevant financial disclosures.

Can counseling about avoiding asthma flare-ups and proper medication use lead to better outcomes?

A school-based program that included school-nurse delivery of daily asthma-control medications and a smoke-reduction counseling program for caregivers of children living with a smoker can help reduce asthma symptom flares.

In a study published in the Archives of Pediatrics and Adolescent Medicine (2011;165:262-268), our team showed that a program that provided medication at school and included smoke reduction counseling reduced asthma flare-ups.

The study included 530 children who had moderate to severe asthma. The program featured two parts: 1) monitoring of children as they took their asthma medications at school; and 2) counselors who visited homes of participating children and counseled families on the effect of smoke exposure on asthmatic children. Our controls received standard care, including their regular visits to the doctor and no home interventions.

We found that children in the intervention group had fewer visits to the doctor for acute exacerbations, more symptom-free days and fewer days with limited activity. This was true even independent of any change in the child’s exposure to smoke.

This intervention is widely applicable, and strategies to evaluate costs and develop strategies for implementing the program more widely are needed.

Jill Halterman, MD, MPH, of the University of Rochester in New York.

Disclosure: Dr. Halterman reports no relevant financial disclosures.

Asthma control is not just about the medication, it is about the medical care process. For a long time, that process has focused on a patient going to a doctor, but the [study from Dr. Halterman and colleagues] suggests that if you modify the process and incorporate other factors, you can raise awareness, increase patient compliance and achieve better outcomes.

Although the cost of programs such as these is often cited as a barrier to implementation, there have been studies that have shown school-based interventions to be cost-effective. For programs similar to those described in Dr. Halterman’s study, the first step may be to start with a school nurse-primary care partnership in schools that have full-time or at least part-time nurses.

These are complicated issues and are easier said than done. An interesting follow-up to this study would be a cost-benefit analysis that examined reductions in visits to the emergency room following programs like these.

Julia Graham Lear, PhD, of George Washington University School of Public Health.

Disclosure: Dr. Graham Lear reports no relevant financial disclosures.