Background Asthma is considered to be associated with elevated levels of exhaled nitric oxide (FeNO). The nature of this relationship and how it is influenced by atopy are still not resolved. Methods The Isle of Wight birth cohort (N¼1456) was reassessed at 18 years of age. Participants able to attend the research centre were assessed by questionnaires, skin prick testing and FeNO in order to explore the interrelationship between asthma, atopy and FeNO.

A better understanding of how gender and atopic status influence rhinitis during adolescence emerges from this study. Application of such knowledge could help to improve clinical recognition, judge prognosis and ultimately improve management of this common condition.

Allergic sensitization continues to increase over childhood into adolescence although the majority of children who were not sensitized at 4 years remain non-sensitized throughout childhood and adolescence. The presence of sensitization at 4 years predicted later sensitization to additional allergens.

Background Parent of origin effect is important in understanding the genetic basis of childhood allergic diseases and to improve our ability to identify high risk children. Objective To investigate parent of origin effect in childhood allergic diseases. Methods The Isle of Wight Birth Cohort (n=1,456) has been examined at 1, 2, 4, 10 and 18-years. Information on prevalence of asthma, eczema, rhinitis and environmental factors was obtained using validated questionnaires. Skin prick tests were carried out at ages 4, 10 and 18 year, and total IgE at 10 and 18 years. Parental history of allergic disease was assessed soon after the birth of the child when maternal IgE was also measured. Prevalence ratios (PR) and their 95% confidence intervals (CI) were estimated, applying log-linear models, adjusted for confounding variables. Results When stratified for sex of the child, maternal asthma was associated with asthma in girls [PR:1.91 (CI:1.34–2.72), p=0.0003], but not in boys [PR:1.29 (CI:0.85–1.96), p=0.23), while paternal asthma was associated with asthma in boys [PR:1.99 (CI:1.42–2.79), p<0.0001], but not in girls [PR: 1.03 (0.59–1.80) p=0.92). Maternal eczema increased the risk of eczema in girls [PR: 1.92 (CI: 1.37–2.68); p=0.0001] only, while paternal eczema did the same for boys (PR: 2.07 (CI:1.32–3.25); P=0.002). Similar trends were observed when the effect of maternal and paternal allergic disease was assessed for childhood atopy and when maternal total IgE was related to total IgE in children at age 10 and 18 years. Conclusions The current study indicates a sex dependent association of parental allergic conditions with childhood allergies; maternal allergy increasing the risk in girls and paternal allergy in boys. This has implications for childhood allergy prediction and prevention.

We found only a minimal reduction in the prevalence of eczema during childhood and adolescence. During adolescence, more girls develop eczema and more boys outgrow it suggesting a role for gender-specific pubertal factors.

BackgroundAdolescence is a period of change, which coincides with disease remission in a significant proportion of subjects with childhood asthma. There is incomplete understanding of the changing characteristics underlying different adolescent asthma transitions. We undertook pathophysiological characterization of transitional adolescent asthma phenotypes in a longitudinal birth cohort.MethodsThe Isle of Wight Birth Cohort (N = 1456) was reviewed at 1, 2, 4, 10 and 18-years. Characterization included questionnaires, skin tests, spirometry, exhaled nitric oxide, bronchial challenge and (in a subset of 100 at 18-years) induced sputum. Asthma groups were “never asthma” (no asthma since birth), “persistent asthma” (asthma at age 10 and 18), “remission asthma” (asthma at age 10 but not at 18) and “adolescent-onset asthma” (asthma at age 18 but not at age 10).ResultsParticipants whose asthma remitted during adolescence had lower bronchial reactivity (odds ratio (OR) 0.30; CI 0.10 -0.90; p = 0.03) at age 10 plus greater improvement in lung function (forced expiratory flow 25-75% gain: 1.7 L; 1.0-2.9; p = 0.04) compared to persistent asthma by age 18. Male sex (0.3; 0.1-0.7; p < 0.01) and lower acetaminophen use (0.4; 0.2-0.8; p < 0.01) independently favoured asthma remission, when compared to persistent asthma. Asthma remission had a lower total sputum cell count compared to never asthma (31.5 [25–75 centiles] 12.9-40.4) vs. 47.0 (19.5-181.3); p = 0.03). Sputum examination in adolescent-onset asthma showed eosinophilic airway inflammation (3.0%, 0.7-6.6), not seen in persistent asthma (1.0%, 0–3.9), while remission group had the lowest sputum eosinophil count (0.3%, 0–1.4) and lowest eosinophils/neutrophils ratio of 0.0 (Interquartile range: 0.1).ConclusionAsthma remission during adolescence is associated with lower initial BHR and greater gain in small airways function, while adolescent-onset asthma is primarily eosinophilic.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-014-0153-7) contains supplementary material, which is available to authorized users.

Background Understanding of adolescent-onset asthma remains limited. We sought to characterise this state and identify associated factors within a longitudinal birth cohort study. Methods The Isle of Wight Whole Population Birth Cohort was recruited in 1989 (N=1456) and characterised at 1, 2, 4, 10 and 18-years. “Adolescent-onset asthma” was defined as asthma at age 18 without prior history of asthma, “persistent-adolescent asthma” as asthma at both 10 and 18 and “never-asthma” as those without asthma at any assessment. Results Adolescent-onset asthma accounted for 28.3% of asthma at 18-years and was of similar severity to persistent-adolescent asthma. Adolescent-onset asthmatics showed elevated bronchial hyper-responsiveness (BHR) and atopy at 10 and 18-years. BHR in this group at 10 was intermediate to that of never-asthmatics and persistent-adolescent asthma. By 18 their BHR, bronchodilator reversibility and sputum eosinophilia was greater than never-asthmatics and comparable to persistent-adolescent asthma. At 10, males who later developed adolescent-onset asthma had reduced FEV1 and FEF25–75, while females had normal lung function but then developed impaired FEV1 and FEF25–75 in parallel with adolescent asthma. Factors independently associated with adolescent-onset asthma included atopy at 10 (OR = 2.35; 95% CI = 1.08–5.09), BHR at 10 (3.42; 1.55–7.59), rhinitis at 10 (2.35; 1.11–5.01) and paracetamol use at 18-years (1.10; 1.01–1.19). Conclusions Adolescent-onset asthma is associated with significant morbidity. Predisposing factors are atopy, rhinitis and BHR at age 10 while adolescent paracetamol use is also associated with this state. Awareness of potentially modifiable influences may offer avenues for mitigating this disease state.

Breastfeeding has been linked with increased forced vital capacity (FVC) in children but not in older adolescents. Our aim was to investigate the effects of breastfeeding duration and infant weight gain on FVC in both developmental periods.In a birth cohort, information on breastfeeding duration was collected at 1 and 2 yrs; spirometric tests were conducted at 10 and 18 yrs. To estimate the effect of breastfeeding duration on FVC at 18 yrs of age, we used linear models; to analyse repeated FVC measurements at 10 and 18 yrs of age, we used linear mixed models. Links between breastfeeding, infant weight gain and FVC at 10 and 18 yrs of age were analysed through path analyses.Among 808 breastfed children, 49% were breastfed for o4 months. At 18 yrs of age the augmenting effect of breastfeeding on FVC was reduced with increased height. Linear mixed models identified that breastfeeding duration was associated with increased FVC. Path analysis suggested a direct effect of breastfeeding on FVC at 10 yrs of age, but an indirect effect at 18 yrs of age via FVC at 10 yrs of age. Although inversely related to breastfeeding, a higher weight gain in infants led to taller adolescents and, in turn, resulted in increased FVC.In conclusion, a longer duration of breastfeeding contributes to lung health in childhood and adolescence.