Longitudinal assessment of airway responsiveness from 1 month to 18 years in the PIAF birth cohort.

The Perth Infant Asthma Follow-up (PIAF) study involves a birth cohort of unselected subjects who have undergone longitudinal assessments of airway responsiveness at 1, 6 and 12 months and 6, 11 and 18 years of age. The aim of this study was to determine the relationship between increased airway responsiveness throughout childhood and asthma in early adult life.Airway responsiveness to histamine, assessed as a dose-response slope (DRS), and a respiratory questionnaire were completed at 1, 6 and 12 months and 6, 11 and 18 years of age.253 children were initially recruited and studied. Airway responsiveness was assessed in 203, 174, 147, 103, 176 and 137 children at the above-mentioned time points, respectively (39 participants being assessed on all test occasions). Asthma at 18 years was associated with increased airway responsiveness at 6, 12 and 18 years, but not during infancy (slope 0.24, 95% CI 0.06-0.42; p=0.01; slope 0.25, 95% CI 0.08-0.49; p=0.006; and slope 0.56, 95% CI 0.29-0.83; p<0.001, respectively).Increased airway responsiveness and its association with asthma at age 18 years is established between infancy and 6 years. We propose that airway responsiveness in early life reflects the initial airway geometry and airway responsiveness later in childhood increasingly reflects immunological responses to environmental influences.

A longitudinal study of lung function from 1†month to 18†years of age.

BACKGROUND: Our hypothesis was that factors associated with wheeze will be associated with changes in lung function trajectory between 1 month and 18 years of age. METHODS: Measurements of lung function were made in individuals aged 1, 6 and 12 months (V'maxFRC), and also at ages 6, 12 and 18 years (FEF(25-75)). Changes in lung function over time relative to sex, a history of asthma, maternal asthma and other factors were explored using random coefficient models. RESULTS: Lung function (maximal flow at functional residual capacity in infants and FEF(25-75) in children) was determined in 241 individuals at 1 month, 192 at 6 months, 164 at 12 months, 106 at 6 years, 183 at 12 years and 141 at 18 years. In the multivariable model, maternal asthma (mean reduction in lung function 9.8%), flow limitation (mean reduction 17.4%), infant atopy (mean reduction 12.6%) and maternal smoking (mean reduction in lung function 8.1%) were acting independently. When interactions with time were sought, the reduction in lung function associated with maternal asthma and infant atopy were consistent over time, but % lung function increased in boys by a mean of 1%/year compared with girls, in flow-limited individuals by 3.0%/year and by 0.9%/year for those exposed to maternal smoking during pregnancy compared to other cohort members. CONCLUSIONS: Decrements in lung function in 18-year-olds associated with maternal asthma and early onset atopy may be determined by 1 month of age. Low initial lung function in some individuals can 'recover' in some settings.

Reduced infant lung function, active smoking, and wheeze in 18-year-old individuals.

UNLABELLED: IMPORTANCE This is the first study to link reduced lung function in early life, before the development of symptoms, to wheeze in 18-year-olds. Additionally, the study gives insight into factors other than reduced lung function that are also associated with persistent wheeze in young adults. OBJECTIVE: To test the hypothesis that reduced lung function in early life is associated with increased risk for persistent wheeze at age 18 years. DESIGN: Birth cohort study. SETTING: Perth, Western Australia. PARTICIPANTS: Individuals followed up from age 1 month to 18 years. MAIN OUTCOME MEASURES: Maximal flow at functional residual capacity (V'maxFRC) was measured in 1-month-old infants who were followed up at ages 6, 12, and 18 years. Based on reported symptoms, individuals were categorized as having remittent wheeze, later-onset wheeze, persistent wheeze, and no wheeze. Smoking status was noted at age 18 years. RESULTS: Of the 253 individuals originally recruited, 150 were followed up at age 18 years; 37 of the 150 had recent wheeze. Compared with the no-wheeze group (n = 96), persistent wheeze (n = 13) was independently associated with reduced percentage of predicted V'maxFRC (mean reduction, 43%; 95% CI, 13-74). Compared with the no-wheeze group, persistent wheeze was also associated with atopy in infancy (odds ratio = 7.1; 95% CI, 1.5-34.5), maternal asthma (odds ratio = 6.8; 95% CI, 1.4-32.3), and active smoking (odds ratio = 4.8; 95% CI, 1.0-21.3). When only wheeze at age 18 years was considered, reduced percentage of predicted V'maxFRC was associated with wheeze at age 18 years only among current smokers (P = .04). CONCLUSIONS AND RELEVANCE: Wheeze persisting from ages 6 to 18 years is associated with multiple factors, including reduced infant lung function, infant-onset atopy, maternal asthma, and active smoking. Wheeze at age 18 years (regardless of previous wheeze status) is associated with active smoking, but only among those with reduced lung function in infancy. These findings give unique insight into the cause of obstructive airways disease in 18-year-olds, and follow-up of this cohort might be expected to further extend our understanding.

A multicenter study on chronic cough in children : burden and etiologies based on a standardized management pathway.

BACKGROUND: While the burden of chronic cough in children has been documented, etiologic factors across multiple settings and age have not been described. In children with chronic cough, we aimed (1) to evaluate the burden and etiologies using a standard management pathway in various settings, and (2) to determine the influence of age and setting on disease burden and etiologies and etiology on disease burden. We hypothesized that the etiology, but not the burden, of chronic cough in children is dependent on the clinical setting and age. METHODS: From five major hospitals and three rural-remote clinics, 346 children (mean age 4.5 years) newly referred with chronic cough (> 4 weeks) were prospectively managed in accordance with an evidence-based cough algorithm. We used a priori definitions, timeframes, and validated outcome measures (parent-proxy cough-specific quality of life [PC-QOL], a generic QOL [pediatric quality of life (PedsQL)], and cough diary). RESULTS: The burden of chronic cough (PC-QOL, cough duration) significantly differed between settings (P = .014, 0.021, respectively), but was not influenced by age or etiology. PC-QOL and PedsQL did not correlate with age. The frequency of etiologies was significantly different in dissimilar settings (P = .0001); 17.6% of children had a serious underlying diagnosis (bronchiectasis, aspiration, cystic fibrosis). Except for protracted bacterial bronchitis, the frequency of other common diagnoses (asthma, bronchiectasis, resolved without specific-diagnosis) was similar across age categories. CONCLUSIONS: The high burden of cough is independent of children's age and etiology but dependent on clinical setting. Irrespective of setting and age, children with chronic cough should be carefully evaluated and child-specific evidence-based algorithms used.

Are prenatal ultrasound scans associated with the autism phenotype? Follow-up of a randomised controlled trial.

An existing randomised controlled trial was used to investigate whether multiple ultrasound scans may be associated with the autism phenotype. From 2,834 single pregnancies, 1,415 were selected at random to receive ultrasound imaging and continuous wave Doppler flow studies at five points throughout pregnancy (Intensive) and 1,419 to receive a single imaging scan at 18 weeks (Regular), with further scans only as indicated on clinical grounds. There was no significant difference in the rate of Autism Spectrum Disorder between the Regular (9/1,125, 0.8 %) and Intensive (7/1,167, 0.6 %) groups, nor a difference between groups in the level of autistic-like traits in early adulthood. There is no clear link between the frequency and timing of prenatal ultrasound scans and the autism phenotype.

Cough in children: definitions and clinical evaluation.

The aetiology and management approach for cough in children differs greatly to that in adults, so the empirical approach commonly used in adults is unsuitable for children. Clinical evaluation of cough in children should include an assessment of environmental factors, particularly tobacco smoke, parental concerns and expectations. Most children with acute cough are likely to have an uncomplicated viral acute respiratory tract infection, but the possibility of a more serious problem, especially aspiration of foreign material, should always be considered. Isolated chronic cough in children is rarely asthma, and the term "cough variant asthma" should not be used. Over-the-counter and prescription medications are ineffective for the symptomatic relief of acute cough. Treatment for chronic cough should be based on aetiology. Because of the favourable natural history of cough, a "positive" response in medication trials should not be assumed to be due to the medication. Children should be reassessed within the expected timeframe of response to therapy.

A new asthma spacer device to improve compliance in children: a pilot study.

OBJECTIVE: This pilot study was designed to compare the acceptance, ease of use, and effects on compliance between currently used spacer devices and the Funhaler--a new small volume spacer device designed to improve adherence to asthma medication in children. METHODOLOGY: A matched questionnaire-based survey was conducted by two interviews of each caregiver by the same person. A total of 32 children were randomly recruited from seven clinics spanning widely differing socioeconomic and geographical areas of Perth, Western Australia. Preschool children taking regular inhaled asthma medication using an existing low volume spacer device and aged between 1.5 and 6 years, took part in the pilot study. Parents completed two matched questionnaires. The first questionnaire was completed at the beginning of the study and the second after 2 weeks' use of the Funhaler spacer. Data collected related primarily to ease of use of the devices, child and parental compliance, and treatment attitudes. During the study, parents were also called at random on one occasion to ascertain whether they had attempted to medicate their child the previous day. RESULTS: Using the Funhaler incentive spacer device, parents reported significantly more success at medicating their children (22/30 always successful) in comparison to using their existing spacer device (3/30). Parental adherence to prescribed frequency and the delivery technique of children were also improved. The children also showed improved satisfaction and willingness to use the device and parents' attitude towards medicating their children was improved with the Funhaler spacer device. CONCLUSIONS: Use of a novel, incentive spacer device (Funhaler) appeared to be associated with increased success and fewer problems in medicating children, improved child and parental adherence, and a more positive attitude towards treatment, suggesting that more extensive long-term efficacy trials with the device are warranted.