Asthma Watch

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Acetaminophen Use Not a Risk for Asthma After All?
The ongoing debate about the association between the development of asthma and acetaminophen in children is under review due to recent findings, which reject a causal relationship.

In past studies, researchers reported that acetaminophen may be attributing to the international increase of asthma prevalence in children. Although the mechanism behind this phenomenon is not well understood, several clinical pathways have been proposed to be involved. However, although these pathways provide a valid causal link, none have been proven conclusively.

In a letter to the editor of the Journal of Allergy and Clinical Immunology, it was stated that the association was only evident under certain conditions, raising doubt of the true causality. Research which had sought to identify a positive relationship between asthma and acetaminophen use relied only on parents’ ability to recall the child’s medical history of infection and acetaminophen use. Since parents are more likely to remember use for fevers associated with airway infections, it is possible that the infection itself, and not the medication, was the ultimate cause of asthma development.

Led by Eva Schnabel, MD, of the German Research Center for Environmental Health, researchers analyzed long-term data of children followed from infancy until the age of 6 years. Parents recorded all cases of fever, airway, stomach, and urinary tract infections, along with the medications their child used within the first years of life.

Increased frequency of acetaminophen use was weakly associated with an increased risk of childhood asthma. However, this correlation disappeared after adjustments for the frequency of airway infections. Since several studies have shown that viral infections are a predictor for the future development of asthma, researchers concluded that “increased respiratory tract infection morbidity and not (acetaminophen) use during infancy is associated with the later development of asthma.”

Mother’s Stress Levels Predict Child’s Asthma Severity
A study published October 7, 2010, in BioPsychoSocial Medicine, concluded that different levels of emotional stress among mothers, along with the coping mechanisms utilized, seem to play a role in a child’s asthma development.

Researchers surveyed 274 mothers of children with asthma, aged 2 to12 years, using a questionnaire that inquired about their chronic stress/coping behaviors, parenting attitudes, and their children’s disease status. A follow-up survey was conducted 1 year later regarding their child’s disease status, and it was found that anger, chronic irritation, and emotional suppression were associated with more severe asthma in children under 7 years of age. Older children were affected more by the mother’s interference in their personal daily activities.

Jun Nagano, MD, of the Kyushu University of Health Science and colleagues wrote “Clinicians may benefit by considering an alternative strategy of ‘treating the parents to heal the child’ where the mothers of younger children are advised not to be too worried about if they are falling into ‘unfavorable’ parenting styles, but to pay more attention to the reduction of their own stress. Mothers of older children would be encouraged to increase their own well-being via proper egocentric and selfdefensive activities, being careful to avoid too much interference with their child.”

Increased Dosage of Inhaled Corticosteroids May Not Eliminate Need for Rescue Oral Corticosteroids
A review published online October 6, 2010, in the Cochrane Database of Systematic Reviews, reported that the need for oral corticosteroids in asthma exacerbations was not significantly reduced when comparing use of higher dose versus normal dose inhaled corticosteroid (ICS) regimens.

Inadequate asthma control, regardless of regular treatments with ICS, raises the question of whether to increase the dose in an attempt to more effectively treat symptoms and to reduce the overall risk of asthma exacerbations. Because the clinical effects of corticosteroids are dose dependent, the hypothesis is that a higher dose may more efficiently reduce airway reactivity, inflammation, and restore airway integrity.

Investigators reviewed 5 randomized controlled trials comparing regimens, which involved 1250 patients, 28 children and 1222 adults, with mild to moderate asthma. After randomly assigning and comparing ICS dose increases versus stable maintenance dose, no significant difference was found in oral corticosteroid rescue requirement. The reviewers reported that “in adults with asthma on daily maintenance ICS, a self-initiated ICS increase to 1000 to 2000 mcg/day at the onset of an exacerbation is not associated with a statistically significant reduction in the risk of exacerbations requiring oral corticosteroids.”

Maintaining a typical dose, as well as daily compliance of that dose, is currently the most effective method of asthma control. PT