Scientific review finds asthma drugs suppress child growth

This is a well known potential side effect of inhaled corticosteroids, the most commonly prescribed asthma controller medication.  As indicated in this article, the effect seems "small and non-cumulative".  Moreover, this effect is not seen in all children.  It is critical to re-evaluate asthma periodically to be sure medication is still needed, and to reduce dosing when appropriate.  Dr. Susarla

Scientific review finds asthma drugs suppress child growth

(Reuters) - Corticosteroid drugs given via inhalers to children with asthma may suppress their growth, according to two systematic reviews of scientific studies on the issue.

Health experts who conducted the review and published it in The Cochrane Library journal found that children's growth slowed in the first year of treatment, although the effects were minimized by using lower doses.

Steroid-containing inhalers are prescribed as first-line treatments for adults and children with persistent asthma.

They are the most effective asthma control drugs and have been shown to reduce asthma deaths, hospital visits and improve quality of life by cutting the number and severity of attacks.

Yet their potential effect on children's growth is a source of worry for parents and doctors - a factor which prompted the Cochrane reviewers to analyze the evidence more closely.

"The evidence... suggests that children treated daily with inhaled corticosteroids may grow approximately half a centimeter less during the first year of treatment," said Linjie Zhang at the Federal University of Rio Grande in Brazil, who led the review. "But this effect is less pronounced in subsequent years, is not cumulative, and seems minor compared to the known benefits of the drugs for controlling asthma."

According to data from the World Health Organization (WHO), some 235 million people worldwide suffer from asthma, a chronic disease which inflames and narrows the air passages of the lungs. The disease is common among children.

The first of the two systematic reviews focused on 25 trials involving 8,471 children up to 18 years old with mild to moderate persistent asthma. These trials tested almost all the available inhaled corticosteroids and showed they suppressed growth rates when compared to placebos or non-steroidal drugs.

Fourteen of the trials reported growth over a year and found the average growth rate, which was around 6 to 9 centimeters (2.4 to 3.5 inches)per year in control groups, was about 0.5 cm (0.2 inch) less in the groups of children being treated with inhaled steroids for asthma.

In the second review, researchers looked at data from 22 trials in which children were treated with low or medium doses of inhaled corticosteroids.

Only three trials followed 728 children for a year or more and the reviewers said they showed that using lower doses of inhaled corticosteroids, by about one puff per day, improved growth by around a quarter of a centimeter (0.1 inch) at one year.

Francine Ducharme of the University of Montreal in Canada, who worked on both reviews, said the findings were important and should prompt more frequent and detailed tracking of childhood asthma patients' growth.

"Only 14 percent of the trials we looked at monitored growth in a systematic way for over a year," she said. "This is a matter of major concern given the importance of this topic."

She said her team would recommend the minimal effective dose be used in children with asthma until further data becomes available. "Growth should be carefully documented in all children treated with inhaled corticosteroids, as well in all future trials testing (them) in children," she said.

Experts not directly involved in the reviews cautioned, however, that the growth effects were minimal and should not prompt asthma patients to stop taking their medication.

"These studies confirm what many have suspected, that inhaled steroids can suppress growth in children," said Jon Ayres, a professor of environmental and respiratory medicine at Britain's Birmingham University.

"However, the effect seems... small and non-cumulative and many may consider this a risk worth taking compared to the alternative, which is poorly controlled and therefore potentially life threatening asthma." 

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New research reveals swimming beneficial for young people with asthma

Exercise, particularly swimming, can be a potent way to improve lung function.  This may be particularly beneficial for children and adolescents with asthma.  Dr. Susarla

New research by medical students working in the Breathe Well Centre of Research Excellence at the UTAS School of Medicine has revealed swimming has health benefits for young people with asthma, with no adverse effects on asthma control or exacerbations.

Asthma is a common condition among children and adolescents causing intermittent wheezing, coughing and chest tightness and is the main reason why Tasmanian children present at emergency departments or are hospitalised.

Director of Paediatric Education at the Royal Hobart Hospital Dr Sean Beggs, who assisted in the research, said concerns that physical exercise such as swimming could worsen asthma, had the potential to reduce participation, resulting in reduced physical fitness.

"The review aimed to determine the effectiveness and safety of swimming training in children and adolescents with asthma aged 18 years and under," Dr Beggs said.

"Our research found swimming training is well-tolerated in children and adolescents with stable asthma, and increases physical and cardio-pulmonary fitness as well as lung function."

In 2011, the Asthma Foundation of Tasmania (AFT) provided funding to jointly support students Yi Chao Foong, Hong C Le and Danial Noor, undertaking their first health professional degree, to conduct the asthma review. The review was co-supervised by UTAS' Dr Julia Walters who heads the health services theme within the Centre of Research Excellence.

AFT Chief Executive Officer Cathy Beswick said the outcome of the project would ensure swimmers with respiratory problems achieved the best outcomes when trying to improve their health.

"Anecdotally it is understood swimming is an outstanding form of exercise for children and adults with asthma, but there have been concerns that it might have an impact on asthma control or even induce exacerbations," Ms Beswick said.

"This research provides a strong scientific foundation for deciding who to recommend this form of exercise to and the type of exercise they should undertake."

Ms Beswick said the student scholarship was awarded following an agreement with the UTAS School of Medicine, continuing the Australian Satellite of the Cochrane Airways Group's scholarship scheme.

"The Australian Satellite of the Cochrane Airways Group's scholarship scheme facilitates the activities of the Cochrane Collaboration, which encourages individuals to work together to provide the best evidence for health care," Ms Beswick said.

"Our funding has ensured a future for the scholarship scheme in Tasmania, meaning greater knowledge and insight into asthma and other respiratory diseases in our population."

The Tasmanian asthma research reviewed evidence from eight studies involving 262 participants and combined the results to see if swimming was a safe and beneficial activity for young people.

The review, titled Swimming training for asthma in children and adolescents aged 18 years and under, has been published online together with a podcast of the findings in the Cochrane Library at:

The Cochrane Library is an online collection of accessible high-quality, independent evidence to inform healthcare decision-making around the world.

The NHMRC-funded "Breathe Well" Centre of Research Excellence (CRE) focuses on preserving respiratory health in the community from youth to old age, and optimising respiratory health through innovative approaches to detection and therapy. The CRE houses the official Australian Satellite of the Cochrane Airways Group based in London.

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Strange but true finding, animal airways have "taste buds" that allow them to react to exceedingly bitter substances -- causing the airways to relax, not unlike an asthma inhaler.  Dr. Susarla

Could a bitter compound give clues about asthma?

For a long time, scientists thought the taste receptors that signal sweet, bitter, or salty were found only in our taste buds. Then, things started to get weird.

Six years ago, researchers found taste receptors in the cells of the gut. Even more bizarre, scientists found them in cells that line the airway, and in the muscles that contract during an asthma attack. Basic scientific research began to suggest that bitter chemicals had potential as an asthma treatment. That is when Ronghua ZhuGe, a University of Massachusetts Medical School microbiologist, began to pay attention.

ZhuGe studies cell signaling involved in muscle function, a process that helps regulate blood pressure or airway constriction. He was intrigued when he read about experiments that showed that bitter compounds could cause those muscle cells to relax, pointing to a potential way to quell an asthma attack.

In that initial paper, the researchers called it a paradoxical result. They expected the bitter compounds would have the opposite effect, causing airway cells to contract. That would add to the problems patients experience in diseases caused by airway obstruction, such as asthma. But instead, bitter substances caused the cells to relax. ZhuGe decided to study how the compounds had that effect.

In a study published Tuesday in the journal PLOS Biology, ZhuGe and colleagues tease out the precise cellular mechanisms at work when bitter stuff, such as quinine and denatonium — ZhuGe says it is the most bitter compound that exists — are administered to those airway cells. The scientists took freshly procured muscle airway cells from mice and carefully figured out the complicated signaling that results in the relaxation of the cells. That is the goal with asthma medications, called bronchodilators.

“Definitely, we see a great potential to develop a new class of bronchodilators,” ZhuGe said. “When we compare how effective those compounds are to relax airways, we found we can relax them more completely compared” to existing treatments.

ZhuGe said the prospects are particularly exciting because there are so many bitter compounds that could be tried as potential new asthma treatments. The search will be guided, he hopes, by a more precise understanding of the mechanism at play when airway cells relax in response to a bitter stimulant.

But why did bitter taste receptors end up in our lungs in the first place? ZhuGe said his guess is it could be a protective mechanism; perhaps it is advantageous to have cells relax instead of contract when inhaling a bitter compound.

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