Evaluation of Skin Prick Test Reading Time at 10 versus 15 min in Young Infants.

INTRODUCTION: The optimal time point for reading the mean wheal diameter (MWD) of a skin prick test (SPT) in infants is not established. We aimed to assess if either of two reading time points of the SPT, 10 or 15 min, was superior to detect allergic sensitization (AS) in 6-month-old infants. METHODS: In 1,431 6-month-old infants from the population-based Preventing Atopic Dermatitis and ALLergies in children (PreventADALL) mother-child cohort, the SPT was performed with standard solutions for egg, cow's milk, peanut, wheat, soy, birch, timothy, dog, and cat. The MWD was measured after 10 and 15 min. AS was defined as a positive SPT with MWD ≥2 mm larger than the negative control. RESULTS: Overall, 149 (10.4%) infants were sensitized to at least one allergen at 10 and/or 15 min, while 138 (9.6%) had a positive SPT at 10 min and 141 (9.9%) at 15 min. A total of 12,873 allergen pricks were performed with 212 (1.6%) being positive at any time point, 194 (1.5%) positive at 10 min, and 196 (1.5%) positive at 15 min. The mean (95% CI) histamine MWD of 3.8 (3.8, 3.9) mm at 10 min was significantly larger than the 3.6 (3.6, 3.7) mm at 15 min. DISCUSSION/CONCLUSIONS: Reading the SPT after both 10 and 15 min increased the number of 6-month-old infants with documented AS compared to reading after one time point only. As neither 10 nor 15 min reading time was superior to the other in detecting AS, our results indicate that readings at both time points should be considered. However, the histamine MWD was significantly larger at 10 min compared to 15 min. Reappraisal of SPT reading in infancy may be warranted.

Eoxins: a new inflammatory pathway in childhood asthma.

BACKGROUND: Increased levels of leukotrienes (LTs) in exhaled breath condensate (EBC) are associated with asthma and bronchial hyperresponsiveness (BHR), whereas eicosanoids generated through the 15-lipoxygenase (LO) pathway (15-hydroxyeicosatetraenoic acid [HETE] and eoxins) have been less studied. OBJECTIVE: We investigated whether metabolites of the 5- and 15-LO pathways in EBC are associated with childhood asthma, asthma severity, and clinical parameters. METHODS: The present study included 131 school-aged children (27 children with problematic severe asthma, 80 children with mild-to-moderate asthma, and 24 healthy children) from the Severe Asthma Recognized in Childhood study and 19 children with other nonasthmatic chronic lung diseases. Clinical work-up included spirometry, fractional exhaled nitric oxide measurements, skin prick testing, and methacholine challenge. Eicosanoids were analyzed in EBC by using mass spectrometry and are reported as concentrations (in picograms per milliliter) and eicosanoid/palmitic acid (PA) ratios. RESULTS: Eoxin C4/PA, eoxin D4/PA, eoxin E4/PA, 15-HETE/PA, and LTC4/PA ratios were significantly increased in asthmatic versus healthy children. Eoxin D4/PA and LTE4/PA ratios were also significantly higher in children with BHR. A nonsignificant trend was observed toward higher eoxin/PA ratios with increasing asthma severity. In contrast to asthma, children with chronic lung disease had the highest 15-HETE/PA, LTC4/PA, LTE4/PA, and LTB4/PA ratios. CONCLUSION: The results point to increased activity of the 15-LO inflammatory pathway in childhood asthma. Mass spectrometric analyses of EBC demonstrate that increased eoxin levels not only accompany the increased 5-LO product LTC4 but are also associated with BHR. These markers might represent a new therapeutic target for asthma treatment.

Lung function at 10 yr is not impaired by early childhood lower respiratory tract infections.

The causal relationship between lower respiratory tract infections (LRIs) in early life and reduced lung function later in childhood is unsettled. Therefore, we assessed whether LRIs the first 2 yr of life influenced lung function development from birth to school age. In the prospective Oslo birth cohort, 'the Environment and Childhood Asthma (ECA) study' lung function was measured at birth in 802 infants by tidal flow volume loops and in 664 infants by passive respiratory mechanics and half yearly questionnaires, including LRI questions, were completed until 2 yr of age. The present study includes 607 children with information about LRIs the first 2 yr of life and successfully forced expiratory flow (FEF) volume measurements at the 10-yr follow-up assessment. At 10 yr of age, FEF at 50% of forced vital capacity (FEF(50)) (mean 95% confidence interval) was reduced in children with at least one bronchiolitis (85.0, 80.6-89.5, p = 0.020) or bronchitis (86.2, 82.6-89.8, p = 0.030) or > or =3 LRIs (83.4, 78.1-88.8, p = 0.017) when compared with no LRIs (90.6, 88.8-92.5) by 2 yr of life. The effects were significant in girls only when stratifying for gender. Among girls with later bronchiolitis compliance of the respiratory system (3.64, 3.17-4.10 vs. 4.18, 3.98-4.37, p = 0.031) and the ratio of time to peak tidal expiratory flow to total expiratory time (t(PTEF)/t(E)) measured at birth was significantly reduced (0. 26, 0.23-0.29 vs. 0.32, 0.30-0.33, p = 0.005) when compared with children with no LRIs. Change in lung function from birth (by t(PTEF)/t(E)) to 10 yr of age was not significantly associated with LRIs the first 2 yr of life, and LRIs by 2 yr of life were not significantly associated with lung function at 10 yr of age in regression analyses including lung function at birth and other possible predictors of lung function at 10 yr. In our study, LRIs during the first 2 yr of life did not impair lung function development from birth until 10 yr of age.

Time spent in vigorous physical activity is associated with increased exhaled nitric oxide in non-asthmatic adolescents.

INTRODUCTION: Physical activity (PA) is important in preventing disease, but endurance elite athletes have increased prevalence of asthma and airway inflammation. OBJECTIVES: We aimed to determine if PA was associated with increased fractional exhaled nitric oxide (FENO ) in asthmatic and non-asthmatic adolescents. METHODS: FENO was recorded (Niox Mino®, Aerocrine AB, Stockholm, Sweden) in 169 adolescents (13-14 years) in a nested case-control analysis from the Environment and Childhood Asthma study, Oslo, 92 adolescents with and 77 without asthma. They underwent clinical examination, lung function measurements and treadmill run measuring peak oxygen uptake, and objectively recorded PA for four consecutive days. PA was classified as moderate, vigorous and very vigorous, and total number of hours of each category was recorded for each subject. Associations between FENO and PA were tested using linear robust multiple regression analyses. RESULTS: In non-asthmatic adolescents, FENO was associated with daily hours of vigorous to very vigorous (r=0.27, P=0.02) and very vigorous PAs (r=0.25, P=0.036) in bivariate analyses. In multivariate analyses, FENO was associated with vigorous to very vigorous PA [regression coefficients (95% confidence interval) 1.9 (0.6, 3.1); P=0.004] and more strongly with very vigorous PA [3.9 (1.5, 6.4); P=0.002] in non-asthmatic but not in asthmatic adolescents. Total daily PA was not associated with FENO in either group. Thus, 1 h of very vigorous PA per day increased FENO by 3.9ppb. CONCLUSION: Vigorous to very vigorous PA, contrasting total daily PA, was significantly associated with increased FENO in non-asthmatic adolescents, suggesting that intensive PA may induce airway inflammation independent of asthma.