NEW ORLEANS—An increased risk of asthma and allergies was found among breast-fed infants in a study reported at the 57th Annual Meeting of the American Academy of Allergy, Asthma, and Immunology. Other highlights include data linking antibiotic use in infancy to asthma and asthma to irritable bowel syndrome.

IL-5 AND EOTAXIN

Interleukin 5 (IL-5) and eotaxin cooperate to recruit eosinophils into the airways of patients with stable asthma and are also associated with eosinophilic exacerbations, reported a research team led by Do-Jin Kim of Soonchuhyang University Hospital in Seoul, South Korea.

The researchers examined sputum samples from 29 patients experiencing asthma exacerbations, 16 patients with stable asthma, and 22 healthy subjects. IL-5 and eotaxin levels were higher in patients with eosinophilic exacerbations than in patients with stable asthma. In contrast, these levels were not increased in patients with neutrophilic exacerbations. Compared with the healthy subjects, the patients with stable asthma had significantly higher IL-5 levels but similar eotaxin concentrations.

There was good correlation among IL-5 levels, eotaxin concentrations, and eosinophil numbers in the patients with stable asthma but not in those with eosinophilic exacerbations.

Corticosteroid treatment significantly decreased eosinophil and IL-5 levels in patients with eosinophilic exacerbations but did not affect eotaxin concentrations.

BREAST-FEEDING MAY INCREASE THE ASTHMA/ALLERGY RISK

Breast-feeding was associated with a statistically significant increase in the risk of developing allergies and asthma in childhood, reported Malcolm R. Sears and colleagues from McMaster University in Hamilton, Canada, and the University of Otago in Dunedin, New Zealand.

A total of 1,037 children were followed for signs of asthma until age 21 years; they underwent skin testing for 11 common allergens at ages 13 and 21 years. Of the overall group, 504 subjects had been breast-fed for four weeks or more, 70 had been breast-fed for less than four weeks, and 463 had not been breast-fed.

Because the latter two groups had similar outcomes, they were combined into a single “non—breast-fed” group.

At age 13, the children who had been breast-fed for four weeks or more had a significantly higher incidence of positive skin tests to cat allergen (18.0% vs 8.4%), house dust mite (35.5% vs 24.2%), or any tested allergen (52.7% vs 37.8%) than did the children in the non—breast-fed group. These differences remained significant at age 21 years. The children in the breast-fed group also had a significantly higher incidence of asthma by age 9 years (11.8% vs 6.5%).

The adjusted relative risks of current asthma at age 9 years, mite sensitivity, and sensitivity to any allergen were significantly increased among the breast-fed infants (2.40, 1.70, and 1.94, respectively). The association between breast-feeding and cat sensitivity was dependent on family history of atopic disease: Infants in the breast-fed group with such a family history had a relative risk of cat allergy of 1.68; the relative risk was 5.27 in those without such a history.

ANTIBIOTIC USE IN INFANCY: A RISK FACTOR FOR WHEEZING?

Antibiotic use in the first year of life may be a risk factor for the development of wheezing later in infancy and childhood, according to findings from a recent prospective study.

Two thirds of the 251 children who were enrolled in the study had received antibiotics for respiratory and nonrespiratory diseases during the first year of life, reported Margo Maria Hagendorens and colleagues from the University of Antwerp in Belgium. The investigators focused their analysis on the 50 infants who received antibiotics for nonrespiratory illnesses and the 83 infants who had not received antibiotics.

The prevalence of wheezing during the first year of life was significantly higher among the infants who had received antibiotics for nonrespiratory causes than among those who had not been given antibiotics (22% vs 8%). The two groups did not differ in the prevalence of the other respiratory symptoms examined (ie, atopy, chronic cough, hypersecretory airways, and bronchitis with or without wheezing).

ASTHMA LINKED TO IRRITABLE BOWEL SYNDROME

New findings suggest that asthma patients may face an increased risk of irritable bowel syndrome. This association may reflect a common etiological factor related to inappropriate smooth muscle contraction or shared pathological features among the two diseases, explained Nicholas Powell and colleagues from the University of Birmingham in the United Kingdom.

The researchers examined population-based data on 1,511 asthma patients and 8,998 subjects without asthma. A significantly higher prevalence of irritable bowel syndrome was found among the asthma patients than among the other subjects (5.9% vs 3.7%). The rates by age are shown in Figure 1.

Figure 1 Incidence of Irritable Bowel Syndrome by Age

Data extracted from Powell N, Beech T, Huntley B, et al. Association between asthma and irritable bowel syndrome [abstract]. J Allergy Clin Immunol. 2001;107:301. Abstract 986.

Additional studies showed that the association between asthma and irritable bowel syndrome was found among both men and women and among all three treatment subgroups (ie, asthma patients given a ß-agonist, those receiving both a ß-agonist and an inhaled corticosteroid, and those using no medication).

—Kristin Della Volpe