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Objective To measure scenario participant and faculty self‐reported realism, engagement and learning for the low fidelity, in situ simulations and compare this to high fidelity, centre‐based simulations. Methods A prospective survey of scenario participants and faculty completing in situ and centre‐based paediatric simulations. Results There were 382 responses, 276 from scenario participants and 106 from faculty with 241 responses from in situ and 141 from centre‐based simulations. Scenario participant responses showed significantly higher ratings for the centre‐based simulations for respiratory rate (P = 0.007), pulse (P = 0.036), breath sounds (P = 0.002), heart sounds (P < 0.001) and patient noises (P < 0.001). There was a significant difference in overall rating of the scenario reality by scenario participants in favour of the centre‐based simulations (P = 0.005); however, there was no significant difference when rating participant engagement (P = 0.11) and participant learning (P = 0.77). With the centre‐based scenarios, nurses rated the reality of the respiratory rate (P < 0.001), blood pressure (P = 0.016) and abdominal signs (P = 0.003) significantly higher than doctors. Nurses rated the overall reality higher than doctors for the centre simulations (96.8% vs 84.2% rated as realistic, P = 0.041), which was not demonstrated in the in situ scenarios (76.2% vs 73.5%, P = 0.65). Conclusion Some aspects of in situ simulations may be less ‘real’ than centre‐based simulations, but there was no significant difference in self‐reported engagement or learning by scenario participants. Low fidelity, in situ simulation provides adequate realism for engagement and learning.

The aim of this study was to investigate how breast density interacted with demographic, reproductive, and lifestyle features among Vietnamese women. Mammographic density and established risk factors for breast cancer were collected from 1651 women (345 cancer cases and 1306 normal cases) in Vietnam. The association of breast density categories with potential risk factors was investigated using Spearman’s test for continuous variables and χ2 tests for categorical variables. Independent factors associated with high breast density and breast cancer in specific density groupings were assessed using logistic regression. Results showed that high breast density was significantly associated with young age, low body mass index, low number of children, early age at having the last child, premenopausal status, and increased vegetable consumption. Reproductive factors were key agents associated with breast cancer for women with high breast density, which was not so evident for women with low breast density.

ObjectiveKey components in the assessment of a child in the emergency department (ED) are their heart and respiratory rates. In order to interpret these signs, practitioners must know what is normal for a particular age. The aim of this paper is to develop age-specific centiles for these parameters and to compare centiles with the previously published work of Fleming and Bonafide, and the Advanced Paediatric Life Support (APLS) reference ranges.DesignA retrospective cross-sectional study.SettingThe ED of the Children's Hospital at Westmead, Australia.PatientsAfebrile, Triage Category 5 (low priority) patients aged 0–15 years attending the ED.InterventionsCentiles were developed using quantile regression analysis, with cubic B-splines to model the centiles.Main outcome measuresCentile charts were compared with previous studies by concurrently plotting the estimates.Results668 616 records were retrieved for ED attendances from 1995 to 2011, and 111 696 heart and respiratory rates were extracted for inclusion in the analysis. Graphical comparison demonstrates that with heart rate, our 50th centile agrees with the results of Bonafide, is considerably higher than the Fleming centiles and fits well between the APLS reference ranges. With respiratory rate, our 50th centile was considerably lower than the comparison centiles in infants, becomes higher with increasing age and crosses the lower APLS range in infants and upper range in teenagers.ConclusionsClinicians should consider adopting these centiles when assessing acutely unwell children. APLS should review their normal values for respiratory rate in infants and teenagers.

Aim: To describe the use of diagnostic labels by clinicians for children with autism spectrum disorders (ASD) and calculate the label-specific and overall agreement between diagnostic labels and Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV) diagnoses provided by the same clinician. Methods: State-wide active surveillance was used to ascertain children newly recognised with one or more DSM-IV criteria for autistic disorder aged 0–15 years (incident cases) in New South Wales (NSW) between July 1999 and December 2000. Clinicians were asked to supply a diagnostic label and then complete DSM-IV criteria for each child reported. Results: Questionnaires with diagnostic label and DSM-IV criteria were returned for 348 children. The agreement between labels used and diagnosis based on DSM-IV classification system was the highest for autism (97%) and lower for labels of Asperger disorder, pervasive developmental disorder – not otherwise specified or atypical autism (27%). Kappa overall agreement was 0.31. Level of agreement between label and DSM-IV diagnosis was similar for questionnaires completed by multidisciplinary teams, psychiatrists, paediatricians and psychologists working as part of a team. Conclusion: A lack of agreement between the diagnostic labelling used by clinicians and diagnosis based on DSM-IV criteria indicates a lack of consistency in diagnostic communication that is necessary to provide best clinical care, appropriate services and relevant information to parents and carers.

Background This study was commenced in 1999 with the aim of examining risk factors for autism using established population-based data for comparison. Methods Cases were ascertained using active surveillance and compared with birth data. Results Four risk factors were found to be significantly associated with autism using binary logistic regression analysis; being male [adjusted odds ratio (OR) 4.7, 95% confidence interval (CI) 3.2–7.0], being born prematurely (adjusted OR 2.2, 95% CI 1.5–3.5), having maternal age ≥35 years (adjusted OR 1.7, 95% CI 1.2–2.4) and having a mother born outside Australia (adjusted OR 1.4, 95% CI 1.0–1.9). For analysis completed for pregnancies, rather than live births, multiple birth was also a significant risk factor for one or more children of the pregnancy to be affected by autism (adjusted OR 2.5, 95% CI 1.1–5.5). There was a statistically significant trend towards increasing risk with increasing risk factor ‘dose’ for gestational age (P = 0.019), multiple birth (P = 0.016) and maternal age (P

ObjectiveThis study evaluates the contribution of energy-dense, nutrient-poor ‘extra’ foods to the diets of 16–24-month-old children from western Sydney, Australia.DesignAn analysis of cross-sectional data collected on participants in the Childhood Asthma Prevention Study (CAPS), a randomised trial investigating the primary prevention of asthma from birth to 5 years. We collected 3-day weighed food records, calculated nutrient intakes, classified recorded foods into major food groups, and further classified foods as either ‘core’ or ‘extras’ according to theAustralian Guide to Healthy Eating.SettingPregnant women, whose unborn child was at risk of developing asthma because of a family history, were recruited from all six hospitals in western Sydney, Australia. Data for this study were collected in clinic visits and at participants’ homes at the 18-month assessment.ParticipantsFour hundred and twenty-nine children participating in the CAPS study; 80% of the total cohort.ResultsThe mean consumption of ‘extra’ foods was ∼150 g day− 1and contributed 25–30% of the total energy, fat, carbohydrate and sodium to the diets of the study children. ‘Extra’ foods also contributed around 20% of fibre, 10% of protein and zinc, and about 5% of calcium. Children in the highest quintile of ‘extra’ foods intake had a slightly higher but not significantly different intake of energy from those in the lowest quintile. However, significant differences were evident for the percentage of energy provided by carbohydrate and sugars (higher) and protein and saturated fat (lower). The intake of most micronutrients was also significantly lower among children in the highest quintile of consumption. The intake of ‘extra’ foods was inversely associated with the intake of core foods.ConclusionsThe high percentage of energy contributed by ‘extra’ foods and their negative association with nutrient density emphasise the need for dietary guidance for parents of children aged 1–2 years. These preliminary data on commonly consumed ‘extra’ foods and portion sizes may inform age-specific dietary assessment methods.

Early life exposures may be important in the development of asthma and allergic disease.To test house dust mite (HDM) avoidance and dietary fatty acid modification, implemented throughout the first 5 years of life, as interventions to prevent asthma and allergic disease.We recruited newborns with a family history of asthma antenatally and randomized them, separately, to HDM avoidance or control and to dietary modification or control. At age 5 years, they were assessed for asthma and eczema and had skin prick tests for atopy.Of 616 children randomized, 516 (84%) were evaluated at age 5 years. The HDM avoidance intervention resulted in a 61% reduction in HDM allergen concentrations (microg/g dust) in the child's bed but no difference in the prevalence of asthma, wheeze, or atopy (P.1). The prevalence of eczema was higher in the active HDM avoidance group (26% vs 19%; P = .06). The ratio of omega-6 to omega-3 fatty acids in plasma was lower in the active diet group (5.8 vs 7.4; P.0001). However, the prevalence of asthma, wheezing, eczema, or atopy did not differ between the diet groups (P.1).Further research is required to establish whether other interventions can be recommended for the prevention of asthma and allergic disease.House dust mite avoidance measures and dietary fatty acid modification, as implemented in this trial during infancy and early childhood, did not prevent the onset of asthma, eczema, or atopy in high-risk children.

Objective Proteins are the major effectors of biological structure and function. Oxidation-induced changes to protein structure can critically impair protein function, with important pathologic consequences. This study was undertaken to examine whether oxidation-induced changes to protein structure occur during pediatric cardiopulmonary bypass and to examine the association with postoperative outcome. Methods Elevation of the 3,4-dihydroxyphenylalanine content of a protein relative to its native tyrosine content indicates structural damage due to oxidation. Protein 3,4-dihydroxyphenylalanine/native tyrosine ratios were measured before surgery and up to 6 hours after institution of cardiopulmonary bypass in 24 children undergoing repair of congenital heart disease, who were prospectively selected to form a cyanotic and comparable acyanotic control group. Results were correlated with perioperative variables and postoperative outcomes. Results Elevation of protein 3,4-dihydroxyphenylalanine/tyrosine ratios above baseline (0.48 mmol/mol [SD, 0.11 mmol/mol] vs 0.36 mmol/mol [SD, 0.13 mmol/mol]; P = .001) occurred within 30 minutes of initiating cardiopulmonary bypass in cyanotic but not in acyanotic children and correlated inversely with preoperative arterial oxygen saturation ( R = −0.52; P = .03). Protein 3,4-dihydroxyphenylalanine/tyrosine ratios were also increased above baseline at 120 minutes (0.44 mmol/mol [SD, 0.12 mmol/mol]; P = .007) and 180 minutes (0.40 mmol/mol [SD, 0.14 mmol/mol]; P = .01) after the institution of cardiopulmonary bypass in children who underwent prolonged procedures. Elevation of 3,4-dihydroxyphenylalanine/tyrosine during prolonged procedures was associated with postoperative arrhythmias and the need for increased inotropic support ( P = .001). Conclusions Oxidative injury to proteins occurs during pediatric cardiopulmonary bypass. Cyanotic children are most at risk, particularly those undergoing prolonged procedures, in whom elevation of the protein 3,4-dihydroxyphenylalanine/tyrosine ratio is associated with increased postoperative morbidity.

Objective: To document meat consumption among 18-month-old children, for use in refining population dietary assessment methods and dietary guidance for young children. Design: A secondary analysis of data collected in 1998–2000 from the 18 months follow up of the Childhood Asthma Prevention Study: an intervention trial of omega-3 oil supplementation and house-dust mite reduction, from birth to five years. Subjects and setting: Pregnant women whose unborn children had an atopic family history were recruited from antenatal clinics of six hospitals in western Sydney. Carers of 429 18-month-old children (80% response) satisfactorily completed three-day weighed food records. Main outcome measures: Mean and median intakes per day and portion sizes of various meats and meat products. Statistical analyses: T-tests for comparing gender differences; Pearson correlation and one-way analysis of variance for relationships between meat and nutrient intake. Results: During the recording period 94% of the children ate meat. McDonald's Chicken McNuggets™, beef mince, and beef sausages were the most frequently consumed meats. Median portion sizes ranged from 20–50 g, and were considerably smaller than ‘usual’ portions specified on food frequency questionnaires in common use. Higher meat diets in this age group were not associated with higher intakes of iron or zinc per MJ. Conclusion: The marginally low intakes of iron and zinc in this age group could be improved by greater use of cuts of red meat appropriately prepared for toddlers.

Recently there has been controversy about how many children are affected by autism and whether the incidence of autism is increasing. This paper updates existing reviews and explores the reasons for the controversy.

The objective of this study was to assess whether exposure to house dust mite allergens has an influence on respiratory symptoms and atopy at 18 months of age. A total of 616 women at risk of having a child who would develop asthma because of a family history were recruited from the antenatal clinics of six hospitals in Sydney, Australia. Families were randomized to a house dust mite avoidance group or a control group. Dust was collected from children's beds at regular intervals to measure house dust mite allergen (Der p 1) concentrations which were categorized into quintiles of exposure. At the age of 18 months, 529 children (85.9% of total sample) had an assessment of symptoms by a research nurse blinded to group status. Atopy by skin prick tests and serum IgE were also measured. Atopy to inhaled allergens (p = 0.79) or to Der p 1 was not associated with Der p 1 exposure (p = 0.87). "Doctor diagnosed asthma," "wheeze ever," and "wheeze in the absence of a cold" did not decrease with quintile of exposure...

Objective:To examine statistical models that have been used to predict the cessation of breast–feeding.Setting:In nutritional epidemiology, a knowledge of risk factors that lead to breast-feeding cessation is essential to promote optimal infant health by increasing or sustaining breast–feeding rates. However, a number of methodological issues complicate the measurement of such risk factors. It is important when building multivariate models that variables entered into the model are not intervening variables, factors on the causal pathway or surrogate outcomes. Inclusion of these types of variable can lead to inaccurate models and biased results. A factor often cited to predict breast–feeding is ‘intention to breast–feed’ prior to the birth of the infant, although this factor is directly on the causal decision–making pathway. Another factor often cited is the age of introduction of formula feeding, which is actually part of the outcome variable because formula feeding defines the difference between full, complementary and no breast-feeding. Rather than include these as risk factors in multivariate models, factors removed from the causal pathway such as influences of educational practices, including advice to complementary feed, and beliefs and attitudes of families and health-care practitioners should be measured.Conclusions:The accurate quantification of modifiable risk factors is essential for designing public health education campaigns that are effective in sustaining or increasing breast–feeding duration.

Asthma is a leading cause of morbidity for children and is a major public health problem in Australia. Ecological and temporal data suggest that dietary factors may have a role in recent increases in the prevalence of asthma.The aim of conducting this study was to investigate whether childhood asthma was associated with the ratio of omega 6 (n-6) to omega 3 (n-3) fatty acids in the diet (n-6:n-3).The Western Australian Pregnancy Cohort Study is a prospective birth cohort of 2602 children. Using a nested case-control cross-sectional study design within this cohort, a group of children were identified as cases with current asthma at 6 or at 8 years of age or as controls with no asthma at 6 or at 8 years. Dietary details including n-6 and n-3 fatty acid intake data were collected by parent response to a questionnaire when the children were 8 years old. Logistical regression was used to compare quartiles of n-6:n-3 intake in cases and controls. Adjustment was made for covariates: gender, gestational age, breastfeeding, older siblings, maternal smoking during pregnancy, maternal age, maternal asthma, child's current age in months, body mass index, total energy intake, and antioxidant intake (vitamins A, C, E, and zinc).A response rate of 83% was achieved by providing complete data from 335 children [49% cases with current asthma (n = 166), 51% controls (n = 169)]. Following adjustment for covariates the association between the ratio of n-6:n-3 fatty acids and risk for current asthma was statistically significant (p = 0.022).We found evidence for a modulatory effect of the dietary n-6:n-3 fatty acid ratio on the presence of asthma in children. Our results provide evidence that promotion of a diet with increased n-3 fatty acids and reduced n-6 fatty acids to protect children against symptoms of asthma is warranted.

Studies of maternal asthma in pregnancy have shown an increased risk of adverse neonatal and maternal outcomes such as preeclampsia, hypertension, cesarean delivery, prematurity, low birth weight, and perinatal/neonatal mortality. However, results are not consistent between studies. We studied the association between maternal asthma and various adverse neonatal and maternal outcomes and explored whether there is any evidence that pregnancy exacerbates maternal asthma. The data were collected as part of the Childhood Asthma Prevention Study. Pregnant women with asthma or women whose partners or other children had current symptoms of asthma were recruited at six Sydney hospitals. All women recruited were post 36 weeks gestation and were living within 30 km of the study recruitment center. Information about family history of asthma was collected using a questionnaire at 36 weeks gestation and subsequent information about antenatal and perinatal events was obtained from hospital records. Data from 611 pregnant women were available for analysis, 340 of whom had asthma. Hypertension was significantly more common in asthmatics than in nonasthmatics [OR = 2.16 (1.02-4.6), p < 0.043]. The prevalence of gestational diabetes, labor complications, delivery complications, and adverse neonatal outcomes did not differ significantly between the groups. We also found that the course of maternal asthma usually remains unchanged during pregnancy, but that more severe asthma is likely to get worse. We have confirmed previous observations that women with asthma are at increased risk of hypertension in pregnancy, which is consistent with studies that show that pregnant asthmatic women have a slightly increased risk of preeclampsia. However, we did not find evidence of an increased risk of adverse perinatal outcomes.

Background: In parts of coastal Australia, house dust mite allergen concentrations in homes are often very high with at least 80% of homes in Sydney exceeding concentrations of 10 µg of allergen per gram of fine dust. In this study, we report the relation between characteristics of the home environment and house dust mite allergen concentrations at three sites in Sydney homes. Methods: A total of 616 families were recruited as part of the Childhood Asthma Prevention Study (CAPS). Information about the home environment and structural aspects of the home was collected using a questionnaire. Samples of dust were collected from the parents' bed, the bedroom floor and the living room floor and assayed for Der p 1. Results: A total of 68% of participants' beds, 65% of bedroom floors and 56% of living room floors had Der p 1 concentrations above 10 µg/g, with the highest concentrations of allergen in the bed. The most significant predictor of high Der p 1 concentrations in the bed and floors was the age of the home. We also found that beds with mattresses over two years old and with woollen or synthetic blankets or synthetic quilts had higher Der p 1 concentrations. Carpeted floors had higher Der p 1 concentrations than hard floors. Conclusion: The finding that high Der p 1 allergen concentrations in homes with carpets and older mattresses indicates that control strategies directed at these sources are likely to be effective in reducing exposure. Alternatives such as the use of house dust mite impermeable mattress encasings on older mattresses may also be effective in reducing exposure.

Background: House-dust-mite allergen content differs between houses and is thought to be a function of the housing characteristics and furnishing choices that affect indoor microclimate and mite proliferation. The importance of these features may differ with regional climates. Methods: Concentrations of mite allergen were analysed as a function of housing features. Information on housing features was collected by questionnaire in 50 houses in two towns in a dry inland region of Australia. Mite allergen (Der p 1) was measured by ELISA in dust samples collected on five occasions over 2 years from beds and floors. Results: Der p 1 was detected in all houses. Many housing features did not influence mite allergen concentrations. However, the presence of evaporative cooling increased mite allergen by 3.34-fold in beds (P=0.007) and 3.94-fold in floors (P=0.003). Mite allergen was threefold higher in mattresses >5 years old, and synthetic and feather duvets tended to have higher and lower levels of mite allergen, respectively. Conclusions: In houses in dry, inland regions of Australia, evaporative cooling and older mattresses are associated with higher concentrations of mite allergen. Alternative forms of air conditioning to evaporative cooling may be useful for control of mite allergen in dry regions.

Background Farmers' children in northern Europe have a lower prevalence of atopy, hay fever and asthma than other children. Farms in Australia differ in scale and operation from those in Europe and the prevalence of allergic diseases in children is higher. Objective To investigate whether having lived on a farm as a child in Australia is associated with a lower risk of allergic diseases. Methods Cross-sectional study of children (n = 1500) aged 7-12 years from two rural towns: Wagga Wagga in a mixed farming region, and Moree in a crop farming region. Parents answered a questionnaire and children had a skin prick test for atopy. Results Twenty percent of children had lived on a farm for at least 1 year. The effect of having lived on a farm differed between the towns (P Conclusion Having lived on a farm in Australia can confer protection against atopy in children. Further studies are needed to identify possible protective mechanisms associated with farm animals or to establish whether the protective effect is explained by other related exposures.

Background The patterns of inheritance of asthma have largely been explored using data of symptom history collected by questionnaires which are subject to bias and which may therefore distort the measured relationship. Objective The purpose of this study was to examine family patterns of allergic disease using objective measurements of atopy and of airway hyperresponsiveness (AHR). Methods A large random sample of children aged 8–11 years was studied and 3 months later, their parents were also invited for study. Of the sample of 1655 children, both parents of 661 children were studied. In all subjects, respiratory illness history was measured by questionnaire, atopy by skin tests and AHR by responsiveness to histamine. Results The odds ratio for a child to have AHR if either parent had the same condition was approximately 2.0, which was the same as the odds ratio for wheeze or diagnosed asthma in the presence of the same condition in either parent. The odds ratio for atopy was smaller (approximately 1.4, NS) but the risk of a nonatopic child having AHR if the parent had AHR was 3.0 (P = 0.01). The correlation between weal size in the child and parent was poor and the severity of AHR in the child was only modestly correlated with the severity of AHR in the parent (R = 0.51, P = 0.04). Conclusion The use of objective measurements did not strengthen the association between atopic or asthmatic conditions in the parent and child, but did suggest that atopy and AHR are inherited independently.

Early attendance at daycare has been shown to protect against atopy, as defined by a positive skin prick test. One proposed hypothesis for this association is that early exposure to other children protects against atopy by facilitating the spread of infections among children. An alternative hypothesis is that children attending daycare centers have less atopy due to lower levels of exposure to indoor allergens. Our aim was to determine whether attendance at daycare before age 2 years protects against atopy in Australian preschool age children and to test the two alternative hypotheses, as well as a number of potential confounding factors. We conducted a cross-sectional study of children aged 3–5 years living in one humid coastal city (Lismore, n = 286) and one dry, inland city (Wagga Wagga, n = 364) in New South Wales, Australia, in 1995. Atopy was assessed by skin prick tests to six common allergens. Daycare attendance and other possible risk factors for atopy were measured by a parent-completed questionnaire. Children who attended daycare before age 2 years had a reduced risk of atopy at 3–5 years. The greatest effect was seen in children who attended a daycare center (odds ratio (OR), 0.26; 95% CI, 0.14–0.50) rather than family daycare (OR, 0.66; 95% CI, 0.41–1.04). The results of this study do not support either of the proposed hypotheses, nor can the effect be explained by any of the other potential confounders measured. Further work is needed to determine the exposure that is responsible for the protective effect of daycare attendance on atopy. Pediatr Pulmonol. 2000; 30:377–384. © 2000 Wiley-Liss, Inc.

The aim of this study was to obtain quantitative information from published data on the association between environmental tobacco smoke (ETS) exposure and the prevalence of serious lower respiratory tract infections (LRTI) in infancy and early childhood. We identified 21 relevant publications on the relation between ETS and the prevalence of serious LRTI by reviewing reference lists in relevant reports and by conducting manual and computer searches (Medline database; Dissertation abstracts index of Xerox University Microfilms) of published reports between 1966 and 1995. Thirteen studies were included in a quantitative overview using random effects modeling to derive pooled odds ratios. Sensitivity analyses were conducted to test the decision rules used in extracting odds ratio data. The results of community and hospital studies are broadly consistent and show that the child of a parent who smokes is at approximately twice the risk of having a serious respiratory tract infection in early life that requires hospitalization. This association was pronounced in children younger than age two and diminished after the age of two. The combined odds ratio for hospitalization for lower respiratory tract infections in infancy or early childhood is 1.93 (95% CI 1.66-2.25); the combined odds ratio of prevalence of serious LRTI at age less than 2 years, between 0 and 6 years, and between 3 and 6 years were 1.71 (95% CI 1.33-2.20); 1.57 (1.28-1.91), and 1.25 (0.88-1.78), respectively. There was no evidence of heterogeneity across the studies in these combined odds ratios. We conclude that this meta-analysis provides strong evidence that exposure to ETS causes adverse respiratory health outcomes such as either a serious LRTI or hospitalization for LRTI. New public health campaigns are urgently needed to discourage smoking in the presence of young children.

To explore the natural history of asthma and its relation to allergic responses, we examined the relation between total serum IgE in early adulthood and a history of respiratory symptoms, airway hyperresponsiveness (AHR), and atopy during childhood. We studied 180 subjects aged 18-20 years who had been studied since the age of 8-10 years. We measured wheeze in the previous year by questionnaire, AHR by histamine inhalation test, atopy by skin prick tests, and serum IgE levels by immunoassay. Subjects with AHR in early adulthood had higher IgE levels (mean 257.0 IU/ml) than subjects with past AHR (mean 93.3 IU/ml) or with lifelong normal responsiveness (mean 67.6 IU/ml) (P < 0.001). Subjects who had symptoms had higher IgE levels (mean 125.9 IU/ml) than those who were lifelong asymptomatic (mean 63.1 IU/ml) (P < 0.001). Recent wheeze, AHR, and allergic sensitization all had a positive relation to serum IgE, but IgE was not more predictive of AHR than skin prick tests. The finding that young adults who are sensitized to common allergens are highly likely to have AHR even in the absence of symptoms is further evidence of the fundamental role of IgE-mediated responses in the natural history of AHR throughout childhood and into adulthood.

We have calculated normal standards for lung function of Australian children and have estimated the effects on lung function of passive smoking, current asthma, past asthma, and a current respiratory infection. Three cross-sectional samples of children in school years 3-5 (aged 8-11 years) were studied. The 2765 children were from two rural regions of NSW and from the city of Sydney. Details of passive smoking and respiratory illness were collected by a questionnaire sent to parents. Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), peak expiratory flow rate (PEFR), and forced mid-expiratory flow rate (FEF25-75%) were used as measures of lung function. Airway responsiveness was assessed by histamine inhalation test. Data from 1278 "normal" children were used in regression analysis to calculate prediction models for lung function. Passive smoking was associated with reduced FEV1, PEFR, and FEF25-75%. Children with current asthma had reduced FEV1 and FEF25-75% and children with past asthma had reduced FEF25-75%. Children with a current respiratory infection had reduced FVC, FEV1, PEFR, and FEF25-75%. The effects of these deficits on the future lung function of these children is not known but is likely to be important.

Objective : To investigate whether prevalence of asthma in children increased in 10 years. Design : Serial cross sectional studies of two populations of children by means of standard protocol. Setting : Two towns in New South Wales: Belmont (coastal and humid) and Wagga Wagga (inland and dry). Subjects : Children aged 8-10 years: 718 in Belmont and 769 in Wagga Wagga in 1982; 873 in Belmont and 795 in Wagga Wagga in 1992. Main outcome measures : History of respiratory illness recorded by parents in self administered questionnaire; airway hyperresponsiveness by histamine inhalation test; atopy by skin prick tests; counts of house dust mites in domestic dust. Results : Prevalence of wheeze in previous 12 months increased in Belmont, from 10.4% (75/718) in 1982 to 27.6% (240/873) in 1992 (P Conclusions : We suggest that exposure to higher allergen levels has increased airway abnormalities in atopic children or that mechanisms that protected airways of earlier generations of children have been altered by new environmental fators.

This study evaluates the contribution of energy-dense, nutrient-poor 'extra' foods to the diets of 16-24-month-old children from western Sydney, Australia.An analysis of cross-sectional data collected on participants in the Childhood Asthma Prevention Study (CAPS), a randomised trial investigating the primary prevention of asthma from birth to 5 years. We collected 3-day weighed food records, calculated nutrient intakes, classified recorded foods into major food groups, and further classified foods as either 'core' or 'extras' according to the Australian Guide to Healthy Eating.Pregnant women, whose unborn child was at risk of developing asthma because of a family history, were recruited from all six hospitals in western Sydney, Australia. Data for this study were collected in clinic visits and at participants' homes at the 18-month assessment.Four hundred and twenty-nine children participating in the CAPS study; 80% of the total cohort.The mean consumption of 'extra' foods was approximately 150 g day(-1) and contributed 25-30% of the total energy, fat, carbohydrate and sodium to the diets of the study children. 'Extra' foods also contributed around 20% of fibre, 10% of protein and zinc, and about 5% of calcium. Children in the highest quintile of 'extra' foods intake had a slightly higher but not significantly different intake of energy from those in the lowest quintile. However, significant differences were evident for the percentage of energy provided by carbohydrate and sugars (higher) and protein and saturated fat (lower). The intake of most micronutrients was also significantly lower among children in the highest quintile of consumption. The intake of 'extra' foods was inversely associated with the intake of core foods.The high percentage of energy contributed by 'extra' foods and their negative association with nutrient density emphasise the need for dietary guidance for parents of children aged 1-2 years. These preliminary data on commonly consumed 'extra' foods and portion sizes may inform age-specific dietary assessment methods.

Background: Obesity may be associated with an increase in asthma and atopy in children. If so, the effect could be due to an effect of obesity on lung volume and thus airway hyperresponsiveness. Methods: Data from 5993 caucasian children aged 7–12 years from seven epidemiological studies performed in NSW were analysed. Subjects were included if data were available for height, weight, age, skin prick test results to a common panel of aeroallergens, and a measure of airway responsiveness. History of doctor diagnosed asthma, wheeze, cough, and medication use was obtained by questionnaire. Recent asthma was defined as a doctor diagnosis of asthma ever and wheeze in the last 12 months. Body mass index (BMI) percentiles, divided into quintiles per year age, were used as a measure of standardised weight. Dose response ratio (DRR) was used as a measure of airway responsiveness. Airway hyperresponsiveness was defined as a DRR of ⩾8.1. Adjusted odds ratios were obtained by logistic regression. Results: After adjusting for atopy, sex, age, smoking and family history, BMI was a significant risk factor for wheeze ever (OR = 1.06, p = 0.007) and cough (OR = 1.08, p = 0.001), but not for recent asthma (OR = 1.02, p = 0.43) or airway hyperresponsiveness (OR = 0.97 p = 0.17). In girls a higher BMI was significantly associated with higher prevalence of atopy (χ 2 trend 7.9, p = 0.005), wheeze ever (χ 2 trend 10.4, p = 0.001), and cough (χ 2 trend 12.3, p Conclusions: Higher BMI is a risk factor for atopy, wheeze ever, and cough in girls only. Higher BMI is not a risk factor for asthma or airway hyperresponsiveness in either boys or girls.

Two main types of observational epidemiological studies have been used to question whether breastfeeding protects children from developing atopic disease and asthma. These are cohort studies of random samples of children and cohort studies of children with a family history of asthma or atopy. In each study type, exposure and outcome data are collected either prospectively or retrospectively. In this review, the primary objective was to assess the evidence of whether breastfeeding protects against asthma and atopic disease. As an outcome of this review, an analytical perspective with clinical implications is given. J Hum Lact. 19(3):250-261

The association between snoring, nocturnal cough, and allergic symptoms in young children is not known.To measure the prevalence of habitual snoring and its association with nocturnal cough, asthma, and hay fever in preschool children.A cross-sectional study.Preschool children aged 2 to 5 years.The data were collected in a cross-sectional study. A total of 974 children were randomly selected from two areas of Lismore and Wagga Wagga in New South Wales, Australia.The prevalence of snoring was 10.5%, with no gender difference (p = 0.99) or trend association with age (p = 0.58). The association between snoring and nocturnal cough was highly significant (odds ratio [OR], 3.68; 95% confidence interval [CI], 2.41 to 5.63; p = 0.001). This association was significant in both the nonasthmatic and asthmatic groups when examined separately. Snoring was also significantly associated with asthma (OR, 2.03; 95% CI, 1.34 to 3.10; p = 0.001). In subjects without hay fever, the association between snoring and asthma was also highly significant (41.2% vs 24.8%; OR, 2.12; 95% CI, 1.34 to 3.37; p = 0.001).The prevalence of snoring in preschool children was 10.5% for both genders. Snoring was significantly associated with both nocturnal cough and asthma. Because snoring, asthma, and nocturnal cough may have a common etiology, it is possible that effective treatment of one symptom may lead to reductions in the presence or severity of the other symptoms.

In the future, the important longitudinal studies will be those that divide the broad spectrum of asthma into phenotypic groups in order to provide more precise information about mechanisms and outcomes. Asthmatics who present in a clinical setting often have a combination of two or three different phenotypes, and may have more severe illness as a result, but subjects who are tested in epidemiological studies are frequently characterized by only one phenotype. Although the definition of asthma as a combination of symptoms plus either AHR or reduced lung function has greater predictive isolation for assessing the prognosis of respiratory illness that occurs in childhood (27,40,55,66-68), studies that are able to classify subjects according to their different phenotypes are more likely to lead to a better understanding of the factors that influence prognosis. More importantly, by using this approach, future research studies should be better able to separate the mechanisms whereby therapeutic or environmental interventions influence the prognosis of each phenotype. The potential benefits will be a better understanding and evaluation of the factors that make an important contribution to respiratory health.

We have previously shown that the prevalence of asthma in Australian primary schoolchildren increased substantially between 1982 and 1992.1 Similar increases have been reported in studies of children of different ages and from various geographical regions, spanning periods up to the mid-1990s.2 It is not known whether this trend has continued during the late 1990s and early 2000s. We therefore conducted a third cross sectional study in the same population that was surveyed previously.1 We report here on prevalence trends over the latter 10 year period. We conducted all studies during June and July in primary schools in and around Belmont, a coastal suburb some 150 km north of Sydney, Australia. We invited all children in years 3, 4, and 5 (ages 8-11 years) at selected schools to participate and studied only children who had parental consent. Parents …

Summary Background To interpret individual measurements of house dust mite (MDM) allergen and to design and analyse HDM studies it is necessary to quantify the variability which is inherent in the measurement of this exposure. Objective To estimate the repeatability of one method of HDM allergen measurement. Methods We analysed data from one or more HDM allergen measurements in 215 houses included in four previous studies conducted in Sydney (a high allergen environment) and Busselton. Western Australia (a moderate allergen environment). Samples were collected from the bed by vacuuming above and below the sheets and inside the pillow case and from the bedroom and living room floors by vacuuming a I m2 area for 1 min. Extracts from aliquots of fine dust from each sample were assayed for HDM allergen Der p I using a monoclonal antibody enzyme linked immunosorbent assay (IBLISA). The values for HDM allergen were positively skewed and the suitability of a log transformation was established by the resulting normal distribution and stable within-site variance. Results The range of single determination (within which the true value lies with 95% certainty) was 3-1-fold for samples from the bed and 3.5-fold for samples from the floor. The coefficient of repeatability (the ratio beyond which a change between two estimates is established with 95% certainty) was 4.9 for the bed and 5.8 for the floor. Conculsion We estimate that, to detect a twofold difference or change in allergen levels. 35 houses per group will be required in cross-sectional studies and 30 houses per group in parallel-group, randomized controlled trials. We recommend that beds be sampled by collecting dust from the layer of bedding below the bottom sheet. A single site within the bedroom floor may be taken as representative of this site but this is not true for the living-room floor.

To examine the relationship between bronchial hyperresponsiveness (BHR) and respiratory symptoms associated with asthma, we studied a sample of 380 schoolchildren on three occasions at 2-yr intervals. The age of the children at the first study was 8-10 yr. Respiratory symptoms history was assessed by questionnaire, BHR was measured by a histamine inhalation test and atopy was assessed by skin-prick tests to 13 allergens. The cumulative prevalence of BHR in this sample was 27%. The severity of BHR was categorized as severe, moderate, mild or slight. The distribution of severe, moderate and mild BHR was similar at each of the studies. At the third study, when the children were aged 12-14 yr, the prevalence of slight BHR decreased. Children with severe or moderate BHR at age 8-10 yr were atopic, reported current symptoms during the 4 yr of the study and had a high prevalence of severe or moderate BHR in later studies. In this group, 87% of children had current respiratory symptoms and 73% were using asthma medication at age 12-14 yr. In children with mild or slight BHR when first studied, the prevalence of atopy, continuing respiratory symptoms and medication use was much lower. We conclude that severe or moderate BHR is an important risk factor for ongoing morbidity and that comparisons of the prevalence of this severity of BHR in populations may be more informative than comparisons of BHR defined by present criteria.

Summary In a cross-sectional study of 2363 schoolchildren living in two rural areas of New South Wales, we used a questionnaire to collect details of sex, area of residence, social class, early respiratory illness (ERI), parental history of asthma and recent upper respiratory tract infection (URTI), and we used skin-prick tests to measure atopic status. The relative importance of these factors on the likelihood of children having bronchial hyperresponsiveness (BHR) was assessed using a linear modelling analysis. The extent to which these factors affected the severity of BHR was also examined. We found that social class or recent URTI had no association with BHR, that sex and area of residence (inland or coastal) had a small association and that a history of early respiratory illness, a history of asthma in either parent, and atopic status had an important association with BHR. Atopic status was the most important factor. The proportion of children with atopy, with ERI or with parental asthma increased as the severity of BHR increased. The odds ratio for moderate or severe BHR doubled if either ERI or parental asthma was present in addition to atopy and there was a six-fold increase if all three factors were present together. The identification of these risk factors makes it possible to predict which children in the community are most likely to have BHR, and which children are at high risk for having more severe levels of BHR.

A coastal population mainly reactive to house dust mite was compared with an inland population mainly reactive to other allergens to investigate whether exposure to house dust mite plays a part in initiating childhood asthma. Respiratory symptoms, asthma, bronchial hyperresponsiveness, hay fever and atopy were all more common in the dry inland area than in the humid coastal area. In both areas 38% of children were atopic. Coastal children had more skin reactivity to house dust mites and inland children were more reactive to grass pollen extracts. The findings suggest that the clinical presentation of asthma may be related more to the total burden of aeroallergens than to exposure to a particular allergen.