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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.

Aim To measure the long-term improvement in the documented provision of an asthma action plan (AAP) to children with asthma and wheeze discharged from the Emergency Department following the introduction of the electronic AAP (eAAP) and to determine the need for an electronic pre-school wheeze action plan in our population. Methods A retrospective case note review, from July 2014 to June 2015, of all patients over 12 months old discharged from the Emergency Department or Emergency Medical Unit, with a discharge diagnosis of either asthma or wheeze. The primary outcome was the documentation of an AAP, either recorded electronically as an eAAP or a report of an AAP as part of the patient medical record. Results Two thousand three hundred and forty-two patients were included in the study, 926 with asthma and 1416 with wheeze. The median age was 3.3 years (interquartile range (IQR) 3.5, range 1–15.9 years). The median age of the children with asthma was 5.3 years (IQR 4.6) and of the children with wheeze was 2.5 years (IQR 2.0).Overall, 1683 (71.9%) children had a documented AAP, with a significant difference between those with a discharge diagnosis of asthma (85.9%) compared with wheeze (62.9%), P

Purpose Improved mammographic sensitivity is associated with reduced mammographic density. This study aims to: provide a preliminary report on mammographic density among women in Riyadh; identify risk factors associated with mammographic density; and consider the potential implications for screening practices. Methods Based on a cross-sectional design, we examined a total of 792 women using an area-based mammographic density method (LIBRA). Spearman's correlation, Mann-Whitney U, Kruskal–Wallis and binary logistic regression were used for analyses. Results The study population had a mean age of 49.6 years and a high proportion of participants were overweight or obese (90%). A large number of women had low mammographic density, with a mean dense breast area of 19.1 cm2 and percent density of 10.3 cm2. Slightly more than half of the variations in the dense breast area and percent density models were explained by BMI. In the adjusted analyses, BMI, menopausal status, age at menarche and number of children remained statistically significant predictors. Conclusion Given the high proportion of women with low mammographic density, our findings suggest that women living in Riyadh may not require additional imaging strategies beyond mammography to detect breast cancers. The high proportion of obese women reported here and across Saudi Arabia suggests that mammographic density is less likely to have an adverse impact on mammographic sensitivity. Thus and to improve clinical outcomes among Saudi women, annual mammography and commencing screening at a younger age are suggested. Additional studies are required to shed further light on our findings.

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.

Background: In recent decades the amount of new breast cancer cases in the southern region has been reported to increase more rapidly than in the northernVietnam. The aim of this study is to compare breast cancer risk factors between the two regions and establish if westernized influences have an impact on any reported differences. Method: Data was collected from the two largest oncology hospitals in the north and the south of Vietnam in 2015. Breast density, demographic, reproductive and lifestyle data of 127 cases and 269 controls were collected in the north and 141 cases and 250 controls were gathered from the south. Baseline differences in factors between cases and age-matched controls in each region were assessed using chi-square tests and independent t-tests. Odds ratios (OR) for independent risk factors for breast cancer were obtained from conditional logistic regression. Results: In northern Vietnam significantly increased risks in developing breast cancer were observed for women with age at first menstrual period less than 14 years old (OR=2.1; P

Malnutrition and elevated inflammatory markers have a negative impact on clinical outcomes in cancer patients. Few studies have investigated the associations between inflammatory makers, nutritional status and survival. This study investigates the association between nutritional status, inflammatory markers and overall survival (OS) in patients with advanced cancer. This prospective cohort study recruited 114 adult patients from January 2007 to January 2010. It included patients diagnosed with advanced cancer, good Eastern Cooperative Oncology Group (ECOG) performance status 0–2, a prognosis of more than 3 months and had not received chemotherapy for advanced cancer prior to enrolment. Baseline data were collected prior to commencement of chemotherapy. Patients were followed up from the date of baseline nutritional assessment until the date of death or the date that data were last updated, whichever came first. Malnourished cancer patients had statistically significant higher concentrations of serum C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR) or modified Glasgow Prognostic Score (mGPS) prior to starting chemotherapy. In univariate analyses to predict survival, mGPS 1 or 2 had a hazard ratio (HR) of 1.81 (95 % confidence interval (CI) 1.13–2.89) and NLR ≥ 5 had a HR of 1.13 (95 % CI 1.08–4.60) and malnutrition (HR of 1.66 for Patient-Generated Subjective Global Assessment (PG-SGA) B (95 % CI 1.02–2.71), and HR for severely malnourished patients (PG-SGA C) was 2.73 (95 % CI 1.50–4.96). Inflammatory markers were statistically associated with malnutrition. Malnutrition and mGPS were significant independent predictors of overall survival in patients with advanced cancer.

Purpose Rates of women with breast cancer have increased rapidly in recent years in Vietnam, with over 10,000 new patients contracting the disease every year. This study was conducted to identify demographic, reproductive and lifestyle risk factors for breast cancer in Vietnam. Materials and methods Breast density, demographic, reproductive and lifestyle data of 269 women with breast cancer and 519 age-matched controls were collected in the two largest oncology hospitals in Vietnam (one in the north and one in the south). Baseline differences between cases and controls in all women, premenopausal and postmenopausal women were assessed using chi-squared tests and independent t tests. Conditional logistic regression was used to derive odds ratios (OR) for factors that had statistically significant associations with breast cancer. Results Vietnamese women with breast cancer were significantly more likely to have a breast density > 75% (OR, 1.7), be younger than 14 years at first menstrual period (OR, 2.2), be postmenopausal (OR, 2.0), have less than three pregnancies (OR, 2.1), and have less than two babies (OR, 1.7). High breast density (OR, 1.6), early age at first menstrual period (OR, 2.6), low number of pregnancies (OR, 2.3), hormone use (OR, 1.8), and no physical activities (OR, 2.2) were significantly associated with breast cancer among premenopausal women, while breast density (OR, 2.0), age at first menstrual period (OR, 1.8), number of pregnancies (OR, 2.3), and number of live births (OR, 2.4) were the risk factors for postmenopausal women. Conclusion Breast density, age at first menarche, menopause status, number of pregnancies, number of babies born, hormone use and physical activities were significantly associated with breast cancer in Vietnamese women.

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.

Background Two factors thought to influence the risk of asthma are the promoting effect of sensitization to house dust mites and the preventive effect of increased omega-3 fatty acids. Although house dust mite allergen avoidance has been used as a preventive strategy in several trials, the effect of omega-3 fatty acid supplementation in the primary prevention of asthma and allergic disease is not known. Objective To measure the effects of dietary supplementation with omega-3 fatty acids and house dust mite allergen avoidance in children with a family history of asthma. Methods A total of 616 children at high risk of asthma were enrolled antenatally in a randomized controlled trial, and 526 children remained in the trial at age 3 years. The outcomes were symptoms of allergic disease and allergen sensitization. Results There was a significant 10.0% (95% CI, 3.7-16.4) reduction in the prevalence of cough in atopic children in the active diet group ( P =.003; number needed to treat, 10) but a negligible 1.1% (95% CI, −7.1 to 9.5) reduction cough among nonatopic children. There was a 7.2% (95% CI, 10.11-14.3) reduction in sensitization to house dust mite in the active allergen avoidance group ( P =.05; number needed to treat, 14). No significant differences in wheeze were found with either intervention. Conclusion These results suggest that our interventions, designed to be used in simple public health campaigns, may have a role in preventing the development of allergic sensitization and airways disease in early childhood. This offers the prospect of reducing allergic disease in later life.

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.

Introduction The association between snoring, nocturnal cough, and allergic symptoms in young children is not known. Objective To measure the prevalence of habitual snoring and its association with nocturnal cough, asthma, and hay fever in preschool children. Setting A cross-sectional study. Subjects Preschool children aged 2 to 5 years. Method 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. Results 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). Conclusion 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.

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: Observational studies have linked house dust mite (HDM) exposure and dietary fatty acid intake with asthma in childhood. However, definitive evidence of their role in the etiology of asthma requires a randomized controlled trial. Objective: We hypothesized that the incidence of asthma and allergy in high-risk children would be reduced by avoidance of HDM allergens, supplementation with omega-3 fatty acids, or the combination of these strategies. We present the results of an interim analysis reporting outcomes assessed at 18 months. Methods: A total of 616 pregnant women were randomized to an HDM avoidance intervention, comprising the use of impermeable mattress covers and an acaricide or control and the use of an oil supplement, margarines, and cooking oils containing high levels of omega-3 fatty acids or control. Atopic status was measured by skin prick testing. Symptoms, diagnoses, and medication histories were elicited by means of parental interviews. Results: The diet intervention resulted in a 9.8% absolute reduction (95% CI, 1.5-18.1; P = .02) in the prevalence of any wheeze and a 7.8% absolute reduction (95% CI, 0.5-15.1, P = .04) in prevalence of wheeze of >1 week, but it had no effect on serum IgE, atopy, or doctors' diagnosis of asthma. The HDM avoidance intervention did not affect these outcomes but was associated with a lower use of oral steroids. Conclusion: Increasing dietary omega-3 fatty acids might have a beneficial effect on the prevalence of wheeze during the first 18 months of life. Follow-up to age 5 years, when the effect of the interventions on asthma risk will be assessed, is underway.

BackgroundYoung women are under-represented in cardiovascular disease research, with obesity and cardiometabolic risk factor interventions generally targeting older adults. Furthermore, appropriate study designs for young women remain uncertain. This study aimed to assess the impact of a 12 week multi-disciplinary lifestyle intervention on cardiometabolic risk factors in premenopausal women with abdominal obesity.MethodsWomen aged 18-30 y with abdominal obesity [waist circumference (WC) ≥ 80 cm] were randomised to a 12 week lifestyle intervention (n = 26) of physical activity, nutrition education and cognitive behavioural therapy, or a wait-list control group (n = 17). Both groups completed anthropometric, biochemical, nutrition and fitness testing, at pre (0 weeks) and post (12 weeks), with intervention participants completed follow-up testing at 24 weeks.ResultsResults from a linear mixed model showed no between-group differences, other than increased physical activity in the intervention group, at post. In the intervention group alone, positive within-group changes were observed in WC, waist-hip-ratio (WHR), waist-height-ratio (WHtR), resting heart rate, blood pressure, predicted VO2max, and total energy intake. Most changes were maintained at 24 weeks post-intervention. Similar within-group improvements were observed in control participants in WC, WHR, WHtR, and systolic blood pressure but no changes were detected in physical activity and nutrition.ConclusionsCardiometabolic risk factors were decreased as a result of a lifestyle intervention in young women with abdominal obesity. It is difficult to describe observations in the control group without greater understanding of the behaviour of wait-list participants.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12612001017819.

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: Although many children with asthma may have a remission as they grow and other children who did not have asthma may develop asthma in adult life, knowledge about the factors that influence the onset and prognosis of asthma during adolescence and young adulthood is very limited. Methods: A cohort of 8–10 year old children (n=718) living in Belmont, New South Wales, Australia were surveyed six times at 2 yearly intervals from 1982 to 1992, and then again 5 years later in 1997. From this cohort, 498 subjects had between three and seven assessments and were included in the analysis. Atopy, airway hyperresponsiveness (AHR), and wheeze in the last 12 months were measured at each survey. Late onset, remission, and persistence were defined based on characteristics at the initial survey and the changes in characteristics at the follow up surveys. Results: The proportion of subjects with late onset atopy (13.7%) and wheeze (12.4%) was greater than the proportion with remission of atopy (3.2%) and wheeze (5.6%). Having atopy at age 8–12 years (OR 2.8, 95% CI 1.5 to 5.1) and having a parental history of asthma (OR 2.0, 95% CI 1.02 to 4.13) were significant risk factors for the onset of wheeze. Having AHR at age 8–12 years was a significant risk factor for the persistence of wheeze (OR 4.3, 95% CI 1.3 to 15.0). Female sex (OR 1.9, 95% CI 1.01 to 3.60) was a significant risk factor for late onset AHR whereas male sex (OR 1.9, 95% CI 1.1 to 2.8) was a significant risk factor for late onset atopy. Conclusions: The onset of AHR is uncommon during adolescence, but the risk of acquiring atopy and recent wheeze for the first time continues during this period. Atopy, particularly present at the age of 8–10 years, predicts the subsequent onset of wheeze.

International audience; Objectives: This study aimed to (1) investigate cardiometabolic risk markers in young women (18–30 years) with overweight/obesity, and (2) establish whether the measures of waist circumference and body mass index possess similar associations of cardiometabolic risk. Design: Cross-sectional. Methods: Cardiometabolic risk factors including, anthropometric, metabolic syndrome markers, biochemical , and other health/fitness indicators were assessed in women when classified as overweight/obese by waist circumference [waist circumference 91.9 ± 10.1 cm, age 22.3 ± 3.5 years, n = 38] versus control [n = 30, waist circumference 71.4 ± 3.5 cm, age 20.1 ± 0.9 years], and when classified by body mass index [n = 35, body mass index 32.2 ± 5.2 kg m 2 , age 22.5 ± 3.6 years] versus control [body mass index 21.7 ± 1.9 kg m 2 , age 20.1 ± 0.9 years, n = 33]. Results: Compared with controls, women with overweight/obesity (classified by waist circumference or body mass index) displayed elevated body mass, systolic blood pressure and homeostasis model assessment of insulin resistance, and reduced estimated VO 2max and weekly physical activity, with no differences in self-reported energy intake. The unadjusted odds ratio of being classified with overweight/obesity and an elevated homeostasis model assessment of insulin resistance and/or less than recommended physical activity ranged between 5.1 and 10.0. Receiver operator characteristic curves indicated waist circumference , body mass index and waist-to-height ratio cutoff points of ≥84.2 cm, ≥30.6 kg m −2 and ≥0.5, respectively, for homeostasis model assessment of insulin resistance, and ≥80.6 cm, ≥25.2 kg m −2 and ≥0.46, respectively, for less than recommended physical activity. Conclusions: Waist circumference and body mass index have similar associations with cardiometabolic risk, with greater homeostasis model assessment of insulin resistance and lower physical activity, rather than differences in traditional metabolic syndrome markers, observed in young women with over-weight/obesity.

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.

The fungus Alternaria is known to be allergenic and is one of the most common fungi worldwide. We investigated the extent to which exposure to Alternaria increases the severity of asthma. We undertook a prospective cohort study in Australia of 399 school children who had positive skin tests to one or more aeroallergens. Airway responsiveness to histamine, wheeze, and bronchodilator use in 1 mo was measured five times between 1997 and 1999. Airway hyperresponsiveness was defined as PD(20)FEV(1) = 3.9 micromol histamine. Airborne concentrations of Alternaria spores were measured throughout the study, and mean daily concentrations over 1 mo ranged from 2.2 to 307.7 spores/m(3) of ambient air. Using generalized estimating equations, we found that airway responsiveness, wheeze, and bronchodilator use increased significantly in association with increased spore concentrations and that the increase in airway responsiveness was greater in children sensitized to Alternaria than in other children (p = 0.01). The odds ratio for airway hyperresponsiveness in children sensitized to Alternaria was 1.26 (95% CI, 1.14 to 1.39) after an increase in mean exposure of 100 spore/m(3)/d over 1 mo. These results suggest that Alternaria allergens contribute to severe asthma in regions where exposure to the fungus is high.

Objective: To compare the prevalence and risk factors for wheeze, asthma diagnosis and hayfever in Aboriginal and non-Aboriginal children living in rural towns in Australia. Design and setting: Cross-sectional study in two towns in rural NSW, Australia, 1997. Participants: Primary school children (aged 7-12 years) classified by their parents as being of Aboriginal (n = 158) or of non-Aboriginal (n = 1282) origin. Main outcome measures: Atopy measured by skinprick tests and respiratory symptoms measured by parent-completed questionnaire. Results: Aboriginal children were less likely to be atopic (36.2% v 45.6%; 95% Cl for the difference, -17.6 to -1.3) and to have hayfever (23.3% v 35.2%; 95% Cl for the difference, -19.1 to -4.6) than non-Aboriginal children, but were equally likely to have had wheeze (31.0% v 27.3%) and asthma (39.4% v 39.3%). Among Aboriginal children, having had bronchitis before age two was a strong risk factor for wheeze (adjusted odds ratio (aOR), 9.3; 95% Cl, 2.8-30.2) and asthma (aOR, 19.3; 95% Cl, 4.7-79.3) and having a parent with hayfever was a strong risk factor for hayfever (aOR, 17.9; 95% Cl, 3.5-90.8), but these risk factors were weaker among non-Aboriginal children. Conclusions: Asthma and wheeze are equally prevalent in Aboriginal and non-Aboriginal children living in the same towns, but appear to have a different aetiology.

The Childhood Asthma Prevention Study is a randomized controlled trial to measure whether the incidence of atopy and asthma can be reduced by house dust mite allergen reduction, a diet supplemented with omega-3 fatty acids, or a combination of both interventions. Six hundred and sixteen pregnant women whose unborn children were at high risk of developing asthma because of a family history were randomized prenatally. Study groups are as follows: Group A (placebo diet intervention, no house dust mite reduction), Group B (placebo diet intervention, active house dust mite reduction), Group C (active diet intervention, no house dust mite reduction), and Group D (active diet intervention, active house dust mite reduction). The house dust mite reduction intervention comprises use of physical and chemical methods to reduce allergen contact. The dietary intervention comprises use of a daily oil supplement from 6 months or at onset of bottle-feeding, and use of margarine and cooking oils based on sunflower or canola oils to increase omega-3 dietary intake. Data is collected quarterly until the infant is 1 year old and then half yearly until age 5 years. Questionnaires are used to collect respiratory illness history and information about diet and home environment. Dust is collected from the child's bed and bedroom and playroom floors. Blinded assessments are conducted at 18 months, 3 years, and 5 years. Skin prick tests to common allergens, blood tests, and detailed illness, medication use, and vaccination histories are collected. Primary outcomes will be the development of allergic sensitization and the presence and severity of asthma. This study is designed to measure the effectiveness of allergen reduction and dietary supplementation, both separately and in combination, for the primary prevention of atopy and asthma. The results of this study may have important implications for public health policies to reduce the incidence of childhood asthma. Control Clin Trials 2001;22:333-354

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—A study was undertaken to assess whether the recent increases in prevalence of both asthma and obesity are linked and to determine if obesity is a risk factor for diagnosed asthma, symptoms, use of asthma medication, or airway hyperresponsiveness. METHODS—Data from 1971 white adults aged 17-73 years from three large epidemiological studies performed in NSW were pooled. Doctor diagnosis of asthma ever, history of wheeze, and medication use in the previous 12 months were obtained by questionnaire. Body mass index (BMI) in kg/m2 was used as a measure of obesity. Airway hyperresponsiveness (AHR) was defined as dose of

To evaluate the association between growth in height and growth in lung function, and to identify the potential temporal relationships between airway hyperresponsiveness (AHR), respiratory symptoms, and lung function growth during adolescence and young adulthood, we analyzed data collected from the Belmont cohort. Among the 718 schoolchildren initially studied at 1982 (aged 8-10 yr), 557 were studied between two times and six times at 2-yr intervals until 1992. Baseline lung function, AHR by histamine inhalation test, and recent wheeze by questionnaires, were measured at each visit. We found that between 17 and 19 yr of age, when growth in height had stopped, growth in FEV(1) was approximately 200 ml/yr in boys and 100 ml/yr in girls. Peak growth velocity of height occurred at age 13 both in boys and in girls, whereas peak growth velocity of FEV(1) occurred at the same age only in girls and 1 yr later in boys. Having AHR and recent wheeze at the previous study time were both associated with lower subsequent growth in FEV(1), but not with subsequent growth in FVC. We conclude that lung function continues to grow after the cessation of height growth and that growth in FEV(1) is reduced in subjects with AHR and/or recent wheeze.

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.

Background and Aims: To assess accurately the effect of parental smoking on the respiratory health of New South Wales (NSW) school children, we obtained a large data set by pooling data from seven cross-sectional studies conducted in NSW between 1991 and 1993. Methods: A random sample of 6394 children age eight to 11 years was studied. Respiratory symptoms, family history of asthma and parental smoking history were measured by questionnaire, atopy by skin prick test and airway hyper-responsiveness (AHR) by histamine inhalation test. Results: In total, 58.3% of children had at least one parent who smoked; 38.5% were exposed to maternal smoking. After adjusting for potential confounders, such as atopy, parental history of asthma and bronchitis in the first two years, children who were exposed to maternal smoking had a significantly increased risk of recent wheeze but not of AHR (odds ratios 1.33; 95% CI: 1.2-1.5 and 1.00; 95% CI: 0.9-1.2). Conclusions: The positive association with wheeze and the lack of an association with AHR suggests that exposure to parental smoking leads to wheezing, but does not increase airway responsiveness.

Study objective: Cough is a common symptom in children that is frequently encountered in general practice. However, most of the information on the prevalence of persistent cough has come from studies that use different, often ambiguous, definitions for persistent cough. It is therefore important that a validated questionnaire to accurately measure persistent cough is developed and is appropriate for use in different age groups of children and in different cultures. Such a questionnaire is essential for accurately measuring the prevalence of persistent cough and the factors associated with its occurrence. Design: A parent-administered respiratory questionnaire was developed and administered twice during a 3-week interval pilot study to test repeatability. The questionnaire was then administered to a randomly selected cross-section of Australian children aged 5 to 7 years old and 8 to 11 years old (N 5 511 and N 5 654, respectively), and to 566 Nigerian children aged 8 to 11 years old. Results: The new questionnaire was reliable, with most of the questions having a k value of above 0.6. The prevalence of persistent cough was similar in younger and older Australian children, but significantly less in Nigerian children (p < 0.001). Also, persistent cough was more prevalent in children of high rather than low socioeconomic status among older Australian children (p 5 0.04). Conclusions: The newly developed questionnaire will be an important tool in epidemiological studies for measuring the prevalence, morbidity, and risk factors of persistent cough in childhood. Although our findings showed that persistent cough does not occur more frequently in younger than in older Australian children, it is more frequent in Australian than in Nigerian children. (CHEST 1999; 115:434 ‐ 439)

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.

Background: We urgently need to take steps towards reducing the prevalence of asthma in countries where the prevalence has become unacceptably high in recent years. Because we do not have any good information about causes of the increased prevalence, we cannot act directly to reverse the trend. Therefore we need to take an indirect approach and use known information of etiologic factors to try to reduce asthma in the next generation, while acknowledging that we may be dealing with different factors from those responsible for the increased prevalence. Any successful strategies will also help to ensure that developing countries do not attain such high rates of asthma in their children in coming years. Objective: This article summarizes the roles of the risk factors that identify "high-risk" children, that provide insights into mechanisms, or that have potential for primary prevention. The factors with the most potential for primary prevention are allergen exposure, parental smoking, breast-feeding, and dietary fatty acids. Conclusion: In other health models, information about risk factors has been used in successful public health interventions. It is disappointing that the important risk factors for asthma are well documented but that there have been few trials of primary prevention and no changes in public health policies. (J Allergy Clin Immunol 1999;103:1-10.)

The International Union Against Tuberculosis and Lung Disease questionnaire is widely used in epidemiologic studies of adult asthma. We examined whether the symptom questions could be classified into groups that represent different "syndromes," and whether some questions are better for predicting asthma than others. We analyzed questionnaire data from a population sample of 1,527 adults aged 18 to 55 years using factor analyses to classify the 17 respiratory symptom questions into four different groups that we termed asthma, cough, breathlessness, and urgent medical visit. The urgent medical visit was a subset of asthma. These four "syndromes" had good validity when measured against airway responsiveness to histamine, atopy to common allergens, lung function, smoking status, and body mass index. Questions that predicted asthma syndrome were those that asked about wheeze at rest or following exercise, asthma attack, chest tightness, and shortness of breath at rest. Questions about cough identified a different group of subjects who apparently did not have asthma. Questions of breathlessness did not aggregate with "asthma" or with "cough syndrome." The identification of particular questions that measure different respiratory conditions is important for epidemiologic studies when short questionnaires or more precise definitions are required.

Background: Although lung diseases are a leading cause of premature mortality in Australian Aborigines, little is known about normal lung function in these people. Aim: To develop models for 'normal' spirometric function in rural Australian Aborigines. Method: A cross-sectional population-based study of four rural Aboriginal communities was performed in Queensland, Northern Territory and South Australia, Australia. We studied 261 children aged seven-19 years and 332 adults aged 20-80 years who were free of symptoms and had no clinical signs of chronic lung disease. The outcome measures were forced expiratory volume in one second (FEV 1 ) and forced vital capacity (FVC). Multiple linear regression was used to develop models for FEV 1 and FVC and comparisons were made with Caucasians and indigenous people from other countries. Results: The Aboriginal people studied had FEV 1 and FVC values that were lower (20% and 30% respectively) than those found in Caucasians of the same height, age and gender. As a consequence, they had relatively high FEV 1 /FVC ratios. Those studied also had forced expiratory volumes that were lower than those found in African Americans and other indigenous peoples. Conclusions: Apparently healthy rural Aboriginal people have low forced expiratory volumes when contrasted with Caucasians and indigenous peoples such as African Americans. More research is required to determine if this is 'normal' or a product of the suboptimal environment into which many Aboriginal people are born.

In epidemiological studies, defining asthma as the presence of airway hyperresponsiveness (AHR) plus recent symptoms leaves two groups of subjects whose clinical significance is unclear: those with asymptomatic AHR, and those with symptoms only. The aim of the study was to determine whether subjects with symptoms only differ from the normal and asthmatic groups in the perception of airway obstruction. Six hundred and ninety seven adults completed a questionnaire of symptoms and underwent bronchial challenge with histamine to induce airway obstruction. Recent symptoms included wheeze and morning chest tightness in the last 12 months. AHR was defined as a provoking dose of histamine causing > or = 20% fall in forced expiratory volume in one second (PD20FEV1)