Biomedical subjects

E M Flannery

Publications and source records attributed to E M Flannery.

At least 19 recordsLinked to original sources

PubMed2004

Relationship between socioeconomic status and asthma: a longitudinal cohort study.

BACKGROUND: There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors. METHODS: We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models. RESULTS: No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports. CONCLUSIONS: Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding.

Adolescent↗

PubMed2003

Bronchodilator tolerance: the impact of increasing bronchoconstriction.

Chronic exposure to beta-agonists causes tolerance to their bronchodilator effects, which is best demonstrated during acute bronchoconstriction. The aim of the present study was to assess whether tolerance becomes more evident with increasing bronchoconstriction, as might occur in acute asthma. In a randomised, double-blind, placebo-controlled, crossover study comprising 15 patients, the treatments were salbutamol 400 microg q.i.d. or placebo given via Diskhaler for 28 days with a 2-week washout between treatments. Patients attended on days 14, 21 and 28. Bronchoconstriction was induced on two of these three occasions to achieve a reduction in the forced expiratory volume in one second (FEV1) of 0 (no methacholine), 15 and 30% (using methacholine) in a randomised order. Immediately after this, salbutamol 100 microg, 100 microg and 200 microg was inhaled at 0, 5, and 10 min. FEV1 was measured over 40 min. Dose/response curves were plotted and values for the area under the curve (AUC)0-40 FEV1 were compared between treatments and by degree of bronchoconstriction. Regular salbutamol resulted in attenuation of the acute response to beta-agonist, which was increasingly evident with greater bronchoconstriction. With a reduction in FEV1 of 0, 15 and 30%, the AUC0-40 FEV1 with salbutamol were 11.2, -14.6 and -35.7% respectively, compared to placebo. There was a linear relationship between the magnitude of bronchoconstriction and the between-treatment differences in AUC0-40 FEV1. Increasing bronchoconstriction conferred greater susceptibility to the effects of bronchodilator tolerance.

Acute Disease↗

PubMed2002

House dust mite allergen levels in university student accommodation in Dunedin.

AIM: To quantify the levels of Dermatophagoides pteronyssinus (Der p1) in different university student accommodation in Dunedin, and to assess relationships with housing characteristics and housekeeping practices. METHODS: Dwellings (n=178) were randomly selected from a database of first year university students in Dunedin. Dust samples were collected from both bed and the bedroom floor by standardised procedures. Der p1 levels were quantified by monoclonal antibody ELISA techniques. Details of housing characteristics, occupancy and housekeeping practices were obtained by questionnaire. RESULTS: Geometric mean (95% confidence intervals) Der p1 allergen levels from bedroom floors were: family homes (n=61) 5.58 (3.73-8.36) microg/g; student flats (n=43) 3.89 (2.49-6.07) microg/g; halls of residence (n=74) 0.26 (0.16-0.43) microg/g. Der p1 allergen levels from beds were: family homes 15.85 (9.78-26.57) microg/g; student flats 10.5 (6.41-17.19) microg/g; halls of residence 3.25 (2.33-4.54) microg/g. In all accommodation lower levels of Der p1 were found on the floor compared to the bed (p<0.005). Halls of residence had significantly lower Der p1 levels in both bed and floor (p<0.0005). Higher levels of Der p1 were associated with longer duration of occupancy, a history of condensation or mold in the accommodation, failure to use a hot wash for sheets, mattress age greater than one year and infrequent vacuuming of the bedroom floor. CONCLUSIONS: Wide variations in Der p1 levels were observed between different forms of student accommodation. Higher levels of Der p1 are found in family homes than in student flats or halls of residence.

Antigens, Dermatophagoides↗

PubMed2002

Exhaled NO and assessment of anti-inflammatory effects of inhaled steroid: dose-response relationship.

Exhaled nitric oxide (eNO) is an easily measured marker of airway inflammation. This study was undertaken to evaluate the usefulness of serial eNO in investigating the dose-response relationship for inhaled beclomethasone (BDP), and to compare eNO with other markers of airway inflammation. Following withdrawal of inhaled corticosteroid (ICS) therapy, 65 patients entered a double-blind, parallel-group, placebo-controlled trial of 50, 100, 200 or 500 microg x BDP x day(-1) for eight weeks. eNO and spirometry were performed weekly and a hypertonic saline challenge with sputum induction was performed at the beginning and end of treatment. The relationship between the dose of ICS and changes in eNO and forced expiratory volume in one second (FEV1) was linear at 1 week and at the end of treatment. A linear dose-response relationship was also seen for sputum eosinophils. Changes in eNO correlated significantly with changes in sputum eosinophils. Changes in the provocative dose of saline causing a 15% fall in FEV1 saline did not differ across the treatment groups nor did they correlate with changes in other measurements. Exhaled nitric oxide may be used to assess the dose-response relationship for the anti-inflammatory effects of inhaled beclomethasone. The relationship found in this study was linear over the dose range 0-500 microg x day(-1) soon after commencing therapy and continued over time.

Administration, Inhalation↗

PubMed2001

The predictive value of exhaled nitric oxide measurements in assessing changes in asthma control.

Exhaled nitric oxide (eNO) levels are increased in untreated or unstable asthma and measurements can be made easily. Our aim was to assess the usefulness of eNO for diagnosing and predicting loss of control (LOC) in asthma following steroid withdrawal. Comparisons were made against sputum eosinophils and airway hyperresponsiveness (AHR) to hypertonic saline (4.5%). Seventy-eight patients with mild/moderate asthma had their inhaled steroid therapy withdrawn until LOC occurred or for a maximum of 6 wk. Sixty (77.9%) developed LOC. There were highly significant correlations between the changes in eNO and symptoms (p < 0.0001), FEV(1) (p < 0.002), sputum eosinophils (p < 0.0002), and saline PD(15) (p < 0.0002), and there were significant differences between LOC and no LOC groups. Both single measurements and changes of eNO (10 ppb, 15 ppb, or an increase of > 60% over baseline) had positive predictive values that ranged from 80 to 90% for predicting and diagnosing LOC. These values were similar to those obtained using sputum eosinophils and saline PD(15) measurements. We conclude that eNO measurements are as useful as induced sputum analysis and AHR in assessing airway inflammation, with the advantage that they are easy to perform.

Adolescent↗

PubMed2001

Reversing acute bronchoconstriction in asthma: the effect of bronchodilator tolerance after treatment with formoterol.

Continuous treatment with a short-acting beta2-agonist can lead to reduced bronchodilator responsiveness during acute bronchoconstriction. This study evaluated bronchodilator tolerance to salbutamol following regular treatment with a long-acting beta2-agonist, formoterol. The modifying effect of intravenous corticosteroid was also studied. Ten asthmatic subjects (using inhaled steroids) participated in a randomised, double-blind, placebo-controlled, cross-over study. Formoterol 12 microg b.i.d. or matching placebo was given for 10-14 days with >2 weeks washout. Following each treatment, patients underwent a methacholine challenge to induce a fall in forced expired volume in one second (FEV1) of at least 20%, then salbutamol 100 microg, 100 microg, and 200 microg was inhaled via a spacer at 5 min intervals, with a further 400 microg at 45 min. After a third single-blind formoterol treatment period, hydrocortisone 200 mg was given intravenously prior to salbutamol. Dose-response curves for change in FEV1 with salbutamol were compared using analysis of covariance to take account of methacholine-induced changes in spirometry. Regular formoterol resulted in a significantly lower FEV1 after salbutamol at each time point compared to placebo (p<0.01). The area under the curves (AUCs) for 15 (AUC0-15) and 45 (AUC0-45) min were 28.8% and 29.5% lower following formoterol treatment (p<0.001). Pretreatment with hydrocortisone had no significant modifying effect within 2 h of administration. It is concluded that significant tolerance to the bronchodilator effects of inhaled salbutamol occurs 36 h after stopping the regular administration of formoterol. This bronchodilator tolerance is evident in circumstances of acute bronchconstriction.

Acute Disease↗

PubMed2000

Bronchodilator tolerance and rebound bronchoconstriction during regular inhaled beta-agonist treatment.

There is uncertainty about the development of airway tolerance to beta-agonists and the phenomenon of rebound bronchoconstriction on beta-agonist withdrawal. We have recently completed a study of the regular terbutaline and budesonide treatment in asthma. We report our observations on the effect of starting and stopping terbutaline treatment on morning and evening peak flows. The study was a randomized four-way, double-dummy, cross-over comparison of regular inhaled terbutaline (500-1000 microg four times daily), budesonide, combined treatment and matching placebo. Each treatment was given for 6 weeks following a 4 week single-blind placebo washout. Ipratropium was used for symptom relief. No other asthma medication was permitted during either the treatment or wash-out periods. Evaluable data were obtained from 52 subjects for both placebo and terbutaline treatment. Changes in mean morning and evening peak flows during terbutaline treatment were compared to the baseline peak flows during the last 2 weeks of the preceding washout. The peak flow changes on stopping terbutaline were also analysed. Mean morning peak flow was not significantly different during terbutaline treatment when compared to either baseline or placebo treatment. Evening peak flows were significantly higher during terbutaline treatment [mean increase 23.1 l min(-1) (95% CI = 18.8, 27.4)]. Analysis of the peak flow changes on a day-by-day basis revealed an initial increase in morning peak flows for the first 2 days of treatment of 19.2 and 13.41 min(-1) [increases of 25.0 and 17.31 min(-1) in comparison with the corresponding values during placebo (P<0.01)] followed by a return to baseline. The increase in evening peak flows was also greater for the first 2 days of treatment than for the remainder of the treatment period (P<0.01). On ceasing terbutaline treatment there was a fall in mean morning peak flow below the baseline on the following morning of 21.6 l min(-1) (P<0.05 compared to placebo). The temporary increase in morning peak flows and greater than expected rise in evening peak flows for the first 2 days of treatment suggest the development of tolerance to the bronchodilator effect of terbutaline. Similarly, the fall in morning peak flows on treatment withdrawal suggests rebound bronchoconstriction. These effects are likely to be mediated by downregulation of the beta-receptor during treatment. The clinical significance of these changes is uncertain in view of the stability of overall asthma control during terbutaline treatment, but sudden withdrawal of beta-agonist treatment could conceivably lead to a deterioration in asthma control.

Administration, Inhalation↗

PubMed2000

The influence of polymorphism at position 16 of the beta2-adrenoceptor on the development of tolerance to beta-agonist.

Polymorphism at position 16 of the beta2-adrenoceptor alters receptor down-regulation in vitro. Our aim was to compare the development of tolerance to beta-agonist in homozygous Gly-16 patients with patients harboring the "wild" genotype (homozygous Arg-16) during regular treatment with salmeterol. In a prospective, randomized, double-blind, placebo-controlled, cross-over study, 20 subjects with mild to moderate asthma (10 Gly-16, 10 Arg-16) received 2 weeks of treatment with inhaled salmeterol 100 microg b.i.d. Thereafter, dose responses to inhaled salbutamol were constructed for forced expiratory volume in 1 sec (FEV1), heart rate, QTc interval, serum potassium and glucose, and finger tremor. The protective effect of salbutamol against adenosine monophosphate (AMP) challenge was also measured. Salmeterol resulted in a significant reduction in the area under curve (AUC) for FEV1 (p = 0.01), heart rate (p = 0.01), QTc interval (p = 0.01), and tremor (p = 0.05), and in the maximum responses for FEV1 (p = 0.05), heart rate (p = 0.02), and glucose (p = 0.02). The protective effect of salbutamol against AMP was reduced by 3.61 doubling doses (p < 0.001). However, differences between Gly-16 and Arg-16 patients were small and nonsignificant. Thus, although tolerance is influenced in vitro by polymorphism of the beta2-adrenoceptor, the magnitude of between-genotype differences in vivo is unlikely to be significant.

Adrenergic beta-Agonists↗

PubMed1999

Tolerance to beta-agonists during acute bronchoconstriction.

Previous reports suggest that regular use of beta-agonists does not lead to tolerance to their bronchodilator effects. However, most studies have been conducted in stable asthma. This study investigates whether bronchodilator tolerance can be demonstrated during acute bronchoconstriction. Thirty-four asthmatic subjects were treated with 6 weeks inhaled terbutaline (1 mg q.i.d.), budesonide (400 microg, b.i.d.), both drugs or placebo in a randomized, double-blind, cross-over study. After each treatment methacholine was administered to induce a 20% fall in the forced expiratory volume in one second (FEV1). The response to inhaled salbutamol 100, 100, 200 microg at 5 min intervals) was then measured. Dose-response curves were compared using an analysis of covariance. Pre-methacholine FEV1, the highest pre-methacholine FEV1, the fall in FEV1 induced by methacholine and the logarithm of the provocative dose of methacholine required to induce the 20% fall in FEV1 (PD20) were used as covariates. There was a significantly reduced response to salbutamol after 6 weeks terbutaline treatment: the mean (95% confidence intervals (CI)) area under the dose-response curve was reduced by 36% (24, 47) compared to placebo (p<0.0001). The reduction in bronchodilator response was not affected by concomitant treatment with budesonide. Significant tolerance to the bronchodilator effect of inhaled beta-agonists may be demonstrated when tested during acute bronchoconstriction. Continuous treatment with inhaled beta-agonists may lead to a reduced response to emergency beta-agonist treatment during asthma exacerbations.

Acute Disease↗

PubMed1999

Relationship between fetal growth and the development of asthma and atopy in childhood.

BACKGROUND: A study was undertaken to investigate the relationship between birth anthropometric measures and the subsequent development of asthma, airway hyperresponsiveness, and atopy in later childhood. METHODS: A longitudinal study was performed on 734 subjects (71%) from a cohort of children born in Dunedin, New Zealand in 1972-73. The birth anthropometric measures were available from hospital records and the main outcome measures of reported asthma, skin prick tests, and methacholine hyperresponsiveness were measured at the age of 13 years, while the serum total IgE was measured at 11 years. RESULTS: After adjustment for other factors, infants with a larger head circumference at birth tended to have higher serum total IgE at 11 years of age (p = 0.02) but IgE was not associated significantly with birth length or birth weight. The adjusted odds ratio for raised serum IgE (>150 IU/ml) in infants with a head circumference of 37 cm or more was 3.4 (95% CI 1.4 to 7.9). In contrast, recent asthma symptoms were positively associated with birth length (p = 0. 04) but not with head circumference. The adjusted odds ratio for asthma in the previous two years in infants with a birth length of 56 cm or more was 6.4 (95% CI 2.0 to 19.8). Infants with a birth weight of less than 3.0 kg had an odds ratio for reported asthma of 0.2 (95% CI 0.0-0.6). There were no significant associations of any of the birth parameters with skin prick positivity, reported hay fever, or eczema. CONCLUSIONS: These results suggest that increased fetal growth is related to an increased risk of asthma and atopy in childhood. The precision of the findings is limited by the small numbers in the extreme categories of each birth parameter, but the results are consistent with intrauterine programming of the developing respiratory and immune systems.

Adolescent↗

PubMed1999

Randomised trial of an inhaled beta2 agonist, inhaled corticosteroid and their combination in the treatment of asthma.

BACKGROUND: Although many asthmatic patients are treated with a combination of beta2 agonist and corticosteroid inhalers, the clinical effects of combining the drugs are unknown. Studies on the early asthmatic response to allergen suggest that beta2 agonists may reduce the benefit of inhaled corticosteroids. A study of the effects of combining the drugs on asthma control was undertaken. METHODS: Sixty one subjects with mild to moderate asthma were randomised to a double blind crossover comparison of inhaled budesonide (200-400 microg twice daily), terbutaline (500-1000 microg four times daily), combined treatment, and placebo. Each treatment was given for six weeks following a four week washout period. Ipratropium was used for symptom relief. Treatments were ranked from worst (1) to best (4) based on need for oral steroid, mean morning peak flow, nocturnal awakening, ipratropium use, and asthma symptoms. Lung function and bronchial hyperresponsiveness were measured before and after each treatment. RESULTS: Evaluable data for all four treatments were obtained from 47 subjects. The mean rank of each treatment was: placebo = 2.05; terbutaline = 2.13; budesonide = 2.48; combined treatment = 3.34. Combined treatment was ranked significantly better than any other treatment (p<0.01). Mean (95% CI) morning and evening peak flows were 14 (5 to 23) and 24 (15 to 34) l/min higher, respectively, during combined treatment than during budesonide, and 27 (17 to 37) and 15 (7 to 23) l/min higher than during terbutaline. Asthma symptoms tended to be least frequent during combined treatment but were not significantly different from budesonide alone. There was no significant difference between combined treatment and budesonide alone for lung function and bronchial hyperresponsiveness. CONCLUSIONS: In this group of mild to moderate asthmatic subjects the combination of beta2 agonist and corticosteroid gave better asthma control than either treatment alone. There was no evidence that regular beta2 agonist treatment impaired the beneficial effect of inhaled corticosteroid.

Administration, Inhalation↗

PubMed1998

Asthma control during long-term treatment with regular inhaled salbutamol and salmeterol.

BACKGROUND: The adverse effects of long term treatment of asthma with the short acting beta agonist fenoterol have been established in both epidemiological and clinical studies. A study was undertaken to investigate the efficacy and safety of long term treatment with salbutamol and salmeterol in patients with mild to moderate bronchial asthma. METHODS: In a two centre double dummy crossover study 165 patients were randomly assigned to receive salbutamol 400 micrograms q.i.d., salmeterol 50 micrograms b.i.d., or placebo via a Diskhaler. All patients used salbutamol as required for symptom relief. The study comprised a four week run in and three treatment periods of 24 weeks, each of which was followed by a four week washout. Asthma control was assessed by measuring mean morning and evening peak expiratory flow rate (PEFR), a composite daily asthma score, and minor and major exacerbation rates. Washout assessments included methacholine challenge and bronchodilator dose response tests. Analysis was by intention to treat. RESULTS: Data from 157 patients were analysed. Relative to placebo, the mean morning PEFR increased by 30 l/min (95% CI 26 to 35) for salmeterol but did not change for salbutamol. Evening PEFR increased by 25 l/min (95% CI 21 to 30) and 21 l/min (95% CI 17 to 26), respectively (p < 0.001). Salmeterol improved the asthma score compared to placebo (p < 0.001), but there was no overall difference with salbutamol. Only daytime symptoms were improved with salbutamol. The minor exacerbation rates were 0.29, 0.88, and 0.97 exacerbations/patient/year for salmeterol, salbutamol and placebo, respectively (p < 0.0001 for salmeterol). The corresponding major exacerbation rates were 0.22, 0.51 and 0.40, respectively (p < 0.03 for salmeterol). For salbutamol the asthma score deteriorated over time (p < 0.01), and the time spent in major exacerbation was significantly longer compared with placebo (12.3 days (95% CI 4.2 to 20.4) versus 8.4 days (95% CI 5.2 to 11.6), p = 0.02). There was no evidence of rebound deterioration in asthma control, lung function, or bronchial hyper-responsiveness following cessation of either active treatment, and no evidence of tolerance to salbutamol or salmeterol. CONCLUSIONS: Regular treatment with salmeterol is effective in controlling asthma symptoms and reduces minor more than major exacerbation rates. Salbutamol was associated with improved daytime symptoms but subtle deterioration in asthma control occurred over time. Salbutamol should therefore be used only as required.

Administration, Inhalation↗

PubMed1997

The efficacy of inhaled corticosteroids in the management of non asthmatic chronic airflow obstruction.

AIMS: The aims of this investigation were to evaluate the efficacy of regular inhaled beclomethasone in the control of symptoms and lung function with non-asthmatic smoking related obstructive pulmonary disease and to evaluate the relationship between clinical responses to a short course of oral prednisone and longer term outcomes using inhaled steroid. METHODS: The study was a randomised, double blind, placebo controlled, crossover investigation in 18 patients. The active treatment was inhaled beclomethasone 1000 micrograms given twice daily for three months by metered dose inhaler. At the end of each treatment period, patients received oral prednisone 30 mg/day for ten days. The two treatment phases were separated by a one month washout interval. Peak flow rates, symptom scores and "rescue" bronchodilator use were recorded twice daily. Lung function (FEV1, FVC and lung volumes) and bronchial hyperresponsiveness (PC20 methacholine) were measured at monthly visits. The number of exacerbations requiring intervention therapy were also recorded. RESULTS: There were no consistent benefits attributable to beclomethasone. Lung function was not significantly better as a result of active treatment. Sputum production improved but other symptom scores were similar during active and placebo therapy. Three patients exhibited an increase in FEV1 of 15% or more during active treatment but did not do so when oral prednisone was administered immediately after the period of placebo treatment. A further three patients showed an improvement in FEV1 of 15% or more with oral prednisone but failed to improve during treatment with inhaled beclomethasone. The predictive value of the "trial of steroid" was 0% and 81.3% for positive and negative outcomes respectively. CONCLUSIONS: Our results indicate that in non-asthmatic chronic obstructive pulmonary disease inhaled corticosteroid fails to achieve significant improvements in either lung function or symptoms. The response to a "trial of steroid" using oral prednisone is not clinically helpful in selecting the small number of patients who may subsequently benefit from this form of therapy.

Administration, Inhalation↗

PubMed1997

Comparison of reported prevalences of recent asthma in longitudinal and cross-sectional studies.

A potential source of bias in prevalence rates reported for symptoms and diagnoses of asthma in longitudinal studies could arise if repeated questioning of subjects or previous experience of lung function and airway responsiveness tests increased awareness of respiratory symptoms. We wished to determine the extent of any such bias by comparing reported prevalence rates from a longitudinal and cross-sectional study within similar populations. The prevalences of wheezing in the last year, waking with chest tightness, waking with shortness of breath, waking with coughing, having an attack of asthma in the last year, and current use of medications for asthma were determined using identical questions in two populations. Self-completed questionnaire responses of 946 subjects, 21 yrs of age, participating in the seventh respiratory assessment in the longitudinal Dunedin Multidisciplinary Health and Development Research Study were compared with responses provided by 991 subjects, aged 20-22 yrs, completing a postal questionnaire on one occasion only for the New Zealand section of the European Community Respiratory Health Study. The prevalence rates were not significantly different between the two populations, for all of the reported symptoms and for medication use. Differences in responses between genders were similar in each study, with all responses being more common in females. We conclude that repeated questioning regarding respiratory symptoms and repeated lung function and bronchial challenge testing in a longitudinal study of asthma did not bias prevalence rates compared with those obtained in a similar population of the same age studied on only one occasion.

Adult↗

PubMed1996

Parental and neonatal risk factors for atopy, airway hyper-responsiveness, and asthma.

BACKGROUND: Previous studies have not resolved the importance of several potential risk factors for the development of childhood atopy, airway hyperresponsiveness, and wheezing, which would allow the rational selection of interventions to reduce morbidity from asthma. Risk factors for these disorders were examined in a birth cohort of 1037 New Zealand children. METHODS: Responses to questions on respiratory symptoms and measurements of lung function and airway responsiveness were obtained every two to three years throughout childhood and adolescence, with over 85% cohort retention at age 18 years. Atopy was determined by skin prick tests at age 13 years. Relations between parental and neonatal factors, the development of atopy, and features of asthma were determined by comparison of proportions and logistic regression. RESULTS: Male sex was a significant independent predictor for atopy, airway hyper-responsiveness, hay fever, and asthma. A positive family history, especially maternal, of asthma strongly predicted childhood atopy, airway hyperresponsiveness, asthma, and hay fever. Maternal smoking in the last trimester was correlated with the onset of childhood asthma by the age of 1 year. Birth in the winter season increased the risk of sensitisation to cats. Among those with a parental history of asthma or hay fever, birth in autumn and winter also increased the risk of sensitisation to house dust mites. The number of siblings, position in the family, socioeconomic status, and birth weight were not consistently predictive of any characteristic of asthma. CONCLUSIONS: Male sex, parental atopy, and maternal smoking during pregnancy are risk factors for asthma in young children. Children born in winter exhibit a greater prevalence of sensitisation to cats and house dust mites. These data suggest possible areas for intervention in children at risk because of parental atopy.

Asthma↗

PubMed1995

Relations of bronchial responsiveness to allergy skin test reactivity, lung function, respiratory symptoms, and diagnoses in thirteen-year-old New Zealand children.

BACKGROUND: Many factors have been found to relate univariately to bronchial responsiveness (BR), but their independent relationships are often unclear because many are interrelated. OBJECTIVE: The purpose of this study was to present a multivariate analysis of the closeness of the association of various factors that are related univariately to BR, including allergy skin tests. METHODS: The results of methacholine challenge were transformed into a continuous variable (BRindex), which has a nearly Gaussian distribution. With stepwise multiple regression, the closeness of the association of the independent variables with BRindex was evaluated. RESULTS: Of the 11 skin tests applied, four showed independent relationships to BRindex (mite, cat, dog, and Aspergillus species). The sizes of these skin test reactions were correlated with BRindex, and their sum appeared to maximize the overall correlation of allergy skin tests with BRindex (r = 0.516). The lowness of the ratio of forced expiratory volume in 1 second to vital capacity and of percent predicted forced expiratory volume in 1 second added significantly to the skin tests in correlating with BRindex, (multiple r = 0.621). Adding diagnoses and symptoms increased the multiple r to 0.685. CONCLUSIONS: The size of the reactions to the four skin tests noted above showed much closer correlations with BR than total serum IgE had shown at age 11, and the relationship was present in asthmatic and nonasthmatic subjects.

Adolescent↗

PubMed1995

Relation of the course of bronchial responsiveness from age 9 to age 15 to allergy.

Bronchial responsiveness to methacholine was measured in a birth cohort of New Zealand children at ages 9, 11, 13, and 15. Overall bronchial hyperresponsiveness (BHR) decreased with age. While the response at age 9 was significantly related to responsiveness, symptom severity, and low lung function at age 15, these relationships were much closer when bronchial response levels after age 9 were taken into account. Also, among children who were unresponsive to methacholine at age 15, those with previous BHR had more frequent wheeze and lower lung function than those whose previous tests were all unresponsive. Both the overall tendency to BHR and the tendency to retain BHR were closely related to high serum IgE levels (determined at age 11) and to positive allergy skin tests (determined at age 13). These evidences of allergy, closely related to the severity and course of methacholine response, appeared to be important determinants of the frequency of wheeze and the degree of impairment of lung function at the end of follow-up. In view of the variability in BHR, a single estimate of bronchial responsiveness taken at an arbitrary point in time may not be an accurate index of the overall tendency to BHR.

Adolescent↗

PubMed1994

Sheepskins and bedding in childhood, and the risk of development of bronchial asthma.

BACKGROUND: Sheepskin bedding might increase house dust mite exposure and so explain some of the increasing prevalence of severity of childhood asthma. METHODS: Relationships between use of different types of bedding, and diagnoses of asthma, symptoms of wheezing, skin prick test evidence of house dust mite sensitivity, and airway responsiveness to methacholine, were examined retrospectively in a birth cohort of children followed longitudinally to age 15 years. RESULTS: In the whole cohort, no associations were identified to suggest a causal relationship between use of any type of bedding and development of features of asthma. Although not an a priori hypothesis, we noted that among children with a family history of atopic disease, those who were house dust mite sensitive were more likely to have used an innerspring mattress (29.6% vs 10.2% who had not used an innerspring mattress, p = 0.005). CONCLUSION: In this subgroup, increased airway responsiveness and mite sensitivity were significantly associated with use of innerspring mattresses, although whether this is a causal or secondary association is not certain. Use of a sheepskin in the bed in early childhood was not an additional risk factor for the development of asthma.

Allergens↗