Diagnostic and treatment behaviour in children with chronic respiratory symptoms: relationship with socioeconomic factors

BACKGROUND: The prevalence and severity of asthma is believed to increase with increasing socioeconomic deprivation. The relationship between asthma diagnosis, symptoms, diagnostic accuracy, and socioeconomic deprivation as determined by Townsend scores was determined in Sheffield schoolchildren. METHODS: All 6021 schoolchildren aged 8-9 years in one school year in Sheffield were given a parent respondent survey based on International Survey of Asthma and Allergies in Childhood (ISAAC) questions. RESULTS: 5011/6021 (83.2%) questionnaires were returned. Postcode data were available in 4131 replies (82.4%) and were used to assign a composite deprivation score (Townsend score). Scores were divided into five quintiles, with group 1 being least and group 5 being most deprived. A positive trend was observed from group 1 to group 5 for the prevalence of wheeze in the previous 12 months, wheeze attacks >or=4/year, nocturnal wheeze and cough (all p<0.001), cough and/or wheeze "most times" with exertion (p<0.03), current asthma (p<0.001), and significant asthma symptoms (p<0.001). No significant trend was observed for lifetime wheeze or attacks of speech limiting wheeze. There were no significant trends in the prevalence of current asthmatic children without significant symptoms (overdiagnosis) or children with significant asthma symptoms but no current asthma diagnosis (underdiagnosis) across the social groups. There was a significant negative trend in the ratio of asthma medication to asthma diagnosis from least to most deprived groups (p<0.001). CONCLUSIONS: Asthma morbidity and severity increase according to the level of socioeconomic deprivation. This may be due to differences in environment, asthma management, and/or symptom reporting. Diagnostic accuracy does not vary significantly across deprivation groups but children living in areas of least deprivation and taking asthma medication are less likely to be labelled as having asthma, suggesting diagnostic labelling bias.     

Geographical and socioeconomic variation in the prevalence of asthma symptoms in English and Scottish children.

BACKGROUND: There has been controversy over the relation between poverty and asthma in the community. The aim of this analysis was to disentangle geographical and socioeconomic variation in asthma symptoms. METHODS: The analysis is based on parental reports of symptoms from data collected in 1990 and 1991. Children aged 5-11 years from three populations (English representative sample, Scottish representative sample, and an English inner city sample) were included. Of 17 677 eligible children, between 14 490 (82.0%) and 15 562 (88.0%) children were available for analysis according to symptom group. RESULTS: Wheezy symptoms were less prevalent in the Scottish sample than in the English samples and asthma attacks were most prevalent in the English representative sample. Asthma attacks were less prevalent in inner city areas than in the English representative sample (OR 0.79, 95% CI 0.66 to 0.95), but persistent wheeze and other respiratory symptoms were more prevalent (OR 1.95, 95% CI 1.65 to 2.32 and OR 1.67, 95% CI 1.52 to 1.84, respectively). The prevalence of persistent wheeze was higher in children whose father's social class was low and in those living in areas with a high Townsend score (an index of poverty) than in other children (p<0.001). Of the 14 areas with the highest Townsend score, 13 had an OR above 1 and six had an OR significantly higher than the reference area. CONCLUSIONS: Persistent wheeze is more prevalent in poor areas than in less deprived areas. This may indicate that poverty is associated with severe asthma or that a high percentage of persistent asthma symptoms in inner city areas are unrecognised and untreated.     

Childhood asthma in South London: trends in prevalence and use of medical services 1991-2002

BACKGROUND: Hospital admission rates for asthma in Britain rose during the 1980s and fell during the 1990s, but less is known about recent trends in the prevalence of asthma. METHODS: In 1991 and 2002 the same questionnaire was distributed to parents of all school pupils in year 3 (aged 7-8 years) in the London borough of Croydon. Parents of currently wheezy children were then invited for home interview (100% targeted in 1991, 66% in 2002). RESULTS: The prevalence of wheeze during the previous year increased from 12.9% in 1991 to 17.8% in 2002 (prevalence ratio 1.39 (95% CI 1.23 to 1.56)). Increases were observed in frequent (1.54 (95% CI 1.16 to 2.03)) and infrequent attacks, severe speech limiting episodes (2.25 (95% CI 1.34 to 3.77)), and night waking (1.36 (95% CI 1.07 to 1.72)), and in the reported use of steroids (19.9% v 64.1% of currently wheezy children). Nevertheless, the proportions reporting a visit to the GP at his/her surgery for wheeze in the previous year (prevalence ratio 1.15 (95% CI 0.91 to 1.45)) or an outpatient visit (0.98 (95% CI 0.49 to 1.94)) changed little and an increase in reported casualty attendance (1.66 (95% CI 0.89 to 3.07)) was non-significant. CONCLUSIONS: There is evidence of an increase in the prevalence of asthma among British primary school children between 1991 and 2002. The absence of a corresponding increase in health service utilisation data may reflect more widespread prophylactic treatment and/or changes in the use and provision of medical services.     

Prevalence and incidence of respiratory symptoms in relation to indoor dampness: the RHINE study

BACKGROUND: An association between indoor dampness and respiratory symptoms has been reported, but dampness as a risk factor for the onset or remission of respiratory symptoms and asthma is not well documented. METHOD: This follow up study included 16 190 subjects from Iceland, Norway, Sweden, Denmark, and Estonia who had participated in the European Community Respiratory Health Survey (ECRHS I). Eight years later the same subjects answered a postal questionnaire that included questions on respiratory symptoms and indicators of indoor dampness. RESULTS: Subjects living in damp housing (18%) had a significantly (p<0.001) higher prevalence of wheeze (19.1% v 26.0%), nocturnal breathlessness (4.4% v 8.4%), nocturnal cough (27.2% v 36.5%), productive cough (16.6% v 22.3%) and asthma (6.0% v 7.7%). These associations remained significant after adjusting for possible confounders. Indoor dampness was a risk factor for onset of respiratory symptoms but not for asthma onset in the longitudinal analysis (OR 1.13, 95% CI 0.92 to 1.40). Remission of nocturnal symptoms was less common in damp homes (OR 0.84, 95% CI 0.73 to 0.97). CONCLUSIONS: Subjects living in damp housing had a higher prevalence of respiratory symptoms and asthma. Onset of respiratory symptoms was more common and remission of nocturnal respiratory symptoms was less common in subjects living in damp housing.     

Increase in diagnosed asthma but not in symptoms in the European Community Respiratory Health Survey

BACKGROUND: Information on the epidemiology of asthma in relation to age is limited and hampered by reporting error. To determine the change in the prevalence of asthma with age in young adults we analysed longitudinal data from the European Community Respiratory Health Survey. METHODS: A self-administered questionnaire was completed by 11 168 randomly selected subjects in 14 countries in 1991-3 when they were aged 20-44 years and 5-11 years later from 1998 to 2003. Generalised estimating equations were used to estimate net change in wheeze, nocturnal tightness in chest, shortness of breath, coughing, asthma attacks in the last 12 months, current medication, "diagnosed" asthma, and nasal allergies. RESULTS: Expressed as change in status per 10 years of follow up, subjects reporting asthma attacks in the previous 12 months increased by 0.8% of the population (95% CI 0.2 to 1.4) and asthma medication by 2.1% (95% CI 1.6 to 2.6), while no statistically significant net change was found in reported symptoms. Reported nasal allergies increased, especially in the youngest age group. CONCLUSIONS: As this cohort of young adults has aged, there has been an increase in the proportion treated for asthma but not in the proportion of those reporting symptoms suggestive of asthma. Either increased use of effective treatments has led to decreased morbidity among asthmatic subjects or those with mild disease have become more likely to label themselves as asthmatic.     

The home environment and asthma symptoms in childhood: two population based case-control studies 13 years apart

BACKGROUND: Prevalence surveys of asthma and/or wheezing among all children aged between 7 1/2 and 8 1/2 attending state and private schools in the London Borough of Croydon were conducted in February 1978 and February 1991. Two population based case-control studies drawn from the survey responders were used to investigate the association between childhood wheeze and characteristics of the home environment and to assess whether changes in these characteristics between 1978 and 1991 may have contributed to an increase in the population prevalence of wheeze among school children. METHODS: Information on exposure to potential indoor environmental risk factors was obtained from parents by home interview and compared between cases-that is, children with frequent (> or = 5) or in-frequent (1-4) attacks of asthma or wheezing in the past 12 months- and controls, with adjustment for study. Changes in exposure over time were assessed by comparing control groups. RESULTS: Between 1978 and 1991 the population prevalence odds of wheeze increased by 20% (OR 1.20; 95% CI 1.04 to 1.39). Change in parental smoking, gas cooking, pet ownership, and central heating did not appear to explain the rise. Use of non-feather pillows was positively associated with childhood wheeze even after adjusting for other risk factors and after re-coding from non-feather to feather cases thought to have changed pillow in response to symptoms (OR 1.54; 95% CI 1.13 to 2.10). The proportion of control children reportedly using non-feather pillows was 44% in 1978 and 67% in 1991. CONCLUSIONS: Increased use of non-feather pillows was the only domestic indoor exposure studied which appeared to explain a modest rise in prevalence of wheeze from 1978 to 1991. Our analysis attempts to address behavioural change in response to the child's symptoms but an artifact arising from lifelong avoidance of feather bedding in atopic families cannot be entirely discounted.


     

Respiratory symptoms in older people and their association with mortality

BACKGROUND: A study was undertaken to assess the prevalence of reported respiratory symptoms in a population aged over 75 years and their association with mortality. METHODS: A total of 14 458 people aged 75 years and over participating in a trial of health screening of older people in general practice answered questions on three respiratory symptoms: cough, sputum production, and wheeze. The association of symptoms with mortality was examined for all cause and respiratory causes of death taking account of potential confounders. RESULTS: Coughing up phlegm in winter mornings had a prevalence of 27.0% (95% confidence interval (CI) 26.8 to 27.2). Those with this symptom had an adjusted hazard ratio for all cause mortality of 1.35 (95% CI 1.21 to 1.50), p<0.001 and for respiratory specific mortality of 2.01 (95% CI 1.66 to 2.41), p<0.001. Phlegm at any time of the day in winter had a prevalence of 16.5% (95% CI 16.3 to 16.7) with hazard ratios for all cause and respiratory specific mortality of 1.28 (95% CI 1.15 to 1.42) and 2.28 (95% CI 1.92 to 2.70), p<0.001. Wheeze or whistling from the chest had a prevalence of 14.3% (95% CI 14.1 to 14.5) with hazard ratios of 1.45 (95% CI 1.31 to 1.61) and 2.86 (95% CI 2.45 to 3.35), p<0.001. CONCLUSIONS: The prevalence of respiratory symptoms is widespread among elderly people and their presence is a strong predictor of mortality.     

Trends in the prevalence of respiratory symptoms and treatment in Dutch children over a 12 year period: results of the fourth consecutive survey

BACKGROUND: Although there is considerable evidence that the prevalence of childhood asthma has increased over the last decades, it is not clear if this trend is still ongoing. A study was undertaken to investigate whether previously observed trends in the prevalence of respiratory symptoms, physician visits, medication use, and absence from school in Dutch children aged 8-9 years persisted in 2001. METHODS: Parents of 1154 children aged 8-9 years eligible for a routine physical examination in 2001 were asked to complete a questionnaire on the respiratory health of their child. RESULTS: In 2001, 1102 children (95.5%) participated in the survey. Similarly high response rates were obtained in the surveys of 1989, 1993 and 1997, with 1794, 1526 and 1670 children aged 8-9 years participating in the respective surveys. The decreasing trend previously observed for recent wheeze between 1989 and 1997 persisted into 2001, particularly in boys. After increasing between 1989 and 1997, the prevalence of shortness of breath with wheeze decreased between 1997 and 2001. The proportion of wheezy children using medication increased between 1989 and 2001 in boys (42.9% v 64.8%; p = 0.003), but the increase was not statistically significant in girls (34.0% v 45.7%; p = 0.096). CONCLUSION: The prevalence of recent wheeze in Dutch school children has declined steadily since 1989. The rising prevalence of medication use in symptomatic children over time may reflect better asthma control and may partly explain the concurrently decreasing trend in the prevalence of asthma symptoms in our study population.     

Bronchial hyperresponsiveness and the development of asthma and COPD in asymptomatic individuals: SAPALDIA cohort study

BACKGROUND: Bronchial hyperresponsiveness (BHR) is a common feature of asthma. However, BHR is also present in asymptomatic individuals and its clinical and prognostic significance is unclear. We hypothesised that BHR might play a role in the development of chronic obstructive pulmonary disease (COPD) as well as asthma. METHODS: In 1991 respiratory symptoms and BHR to methacholine were evaluated in 7126 of the 9651 participants in the SAPALDIA cohort study. Eleven years later 5825 of these participants were re-evaluated, of whom 4852 performed spirometric tests. COPD was defined as an FEV1/FVC ratio of <0.70. RESULTS: In 1991 17% of participants had BHR, of whom 51% were asymptomatic. Eleven years later the prevalence of asthma, wheeze, and shortness of breath in formerly asymptomatic subjects with or without BHR was, respectively, 5.7% v 2.0%, 8.3% v 3.4%, and 19.1% v 11.9% (all p<0.001). Similar differences were observed for chronic cough (5.9% v 2.3%; p = 0.002) and COPD (37.9% v 14.3%; p<0.001). BHR conferred an adjusted odds ratio (OR) of 2.9 (95% CI 1.8 to 4.5) for wheezing at follow up among asymptomatic participants. The adjusted OR for COPD was 4.5 (95% CI 3.3 to 6.0). Silent BHR was associated with a significantly accelerated decline in FEV1 by 12 (5-18), 11 (5-16), and 4 (2-8) ml/year in current smokers, former smokers and never smokers, respectively, at SAPALDIA 2. CONCLUSIONS: BHR is a risk factor for an accelerated decline in FEV1 and the development of asthma and COPD, irrespective of atopic status. Current smokers with BHR have a particularly high loss of FEV1.     

Asthma in preschool children: prevalence and risk factors

BACKGROUND: The prevalence of asthma in children has increased in many countries over recent years. To plan effective interventions to reverse this trend we need a better understanding of the risk factors for asthma in early life. This study was undertaken to measure the prevalence of, and risk factors for, asthma in preschool children. METHODS: Parents of children aged 3-5 years living in two cities (Lismore, n=383; Wagga Wagga, n=591) in New South Wales, Australia were surveyed by questionnaire to ascertain the presence of asthma and various proposed risk factors for asthma in their children. Recent asthma was defined as ever having been diagnosed with asthma and having cough or wheeze in the last 12 months and having used an asthma medication in the last 12 months. Atopy was measured by skin prick tests to six common allergens. RESULTS: The prevalence of recent asthma was 22% in Lismore and 18% in Wagga Wagga. Factors which increased the risk of recent asthma were: atopy (odds ratio (OR) 2.35, 95% CI 1.49 to 3.72), having a parent with a history of asthma (OR 2.05, 95% CI 1.34 to 3.16), having had a serious respiratory infection in the first 2 years of life (OR 1.93, 95% CI 1.25 to 2.99), and a high dietary intake of polyunsaturated fats (OR 2.03, 95% CI 1.15 to 3.60). Breast feeding (OR 0.41, 95% CI 0.22 to 0.74) and having three or more older siblings (OR 0.16, 95% CI 0.04 to 0.71) decreased the risk of recent asthma. CONCLUSIONS: Of the factors tested, those that have the greatest potential to be modified to reduce the risk of asthma are breast feeding and consumption of polyunsaturated fats.     

Prevalence of atopy, asthma symptoms and diagnosis, and the management of asthma: comparison of an affluent and a non-affluent country

BACKGROUND: The prevalence of childhood asthma and of atopy varies widely between countries. However, few studies have compared the pattern of diagnosis and management of asthma, or the role of atopy in predisposing to asthma between a less affluent country and a more affluent country. The aim of this study was to compare the prevalence of symptoms, diagnosis, and management of asthma, and the prevalence of atopy as measured by skin prick tests in Nigeria and Australia using a standardised methodology. METHODS: Respiratory history was collected using a validated questionnaire administered to parents, and atopy was measured with skin prick tests in 654 Australian and 566 Nigerian children aged 8-11 years (70% consent rate in Australia, 60% in Nigeria). RESULTS: Wheeze and persistent cough were less prevalent in Nigeria (10.2% and 5.1%, respectively) than in Australia (21.9% and 9.6%, respectively), caused less morbidity, and were less likely to be labelled or treated as asthma than in Australia. There was no significant difference in the overall prevalence of atopy between the two countries (Australia 32. 5%, Nigeria 28.2%). Atopy was a strong risk for wheeze in both countries (odds ratio (OR) 3.4 (95% CI 2.3 to 5.1) in Australia, 1.8 (95% CI 1.0 to 3.3) in Nigeria), especially atopy to house dust mites (OR 3.1 (95% CI 2.1 to 4.7) in Australia, 2.4 (95% CI 1.3 to 4. 3) in Nigeria). CONCLUSION: Although there was a similar prevalence of atopy in both countries, Australian children had a higher prevalence of asthma symptoms. Further studies are needed to determine why atopic children in Australia are more at risk of developing asthma. Such studies will have important implications for the prevention of asthma.     

Asthma and incident cardiovascular disease: the Atherosclerosis Risk in Communities Study

Background: A possible association between asthma and cardiovascular disease has been described in several exploratory studies. Methods: The association of self-reported, doctor diagnosed asthma and incident cardiovascular disease was examined in a biracial cohort of 45–64 year old adults (N = 13501) followed over 14 years. Results: Compared with never having asthma, the multivariate adjusted hazard ratio (HR) of stroke (n = 438) was 1.50 (95% CI 1.04 to 2.15) for a baseline report of ever having asthma (prevalence 5.2%) and 1.55 (95% CI 0.95 to 2.52) for current asthma (prevalence 2.7%). The relative risk of stroke was 1.43 (95% CI 1.03 to 1.98) using a time dependent analysis incorporating follow up reports of asthma. Participants reporting wheeze attacks with shortness of breath also had greater risk for stroke (HR = 1.56, 95% CI 1.18 to 2.06) than participants without these symptoms. The multivariate adjusted relative risk of coronary heart disease (n = 1349) was 0.87 (95% CI 0.66 to 1.14) for ever having asthma, 0.69 (95% CI 0.46 to 1.05) for current asthma at baseline, and 0.88 (95% CI 0.69 to 1.11) using the time dependent analysis. Conclusions: Asthma may be an independent risk factor for incident stroke but not coronary heart disease in middle aged adults. This finding warrants replication and may motivate a search for possible mechanisms that link asthma and stroke.     

Maternal food consumption during pregnancy and asthma, respiratory and atopic symptoms in 5-year-old children

BACKGROUND: Associations between maternal vitamin E, vitamin D and zinc intakes during pregnancy and asthma, wheeze and eczema in 5-year-old children have previously been reported. A study was undertaken to investigate whether maternal intake of specific foods during pregnancy is associated with asthma and allergic outcomes in the same children. METHODS: A longitudinal birth cohort study was conducted in 1,924 children born to women recruited during pregnancy. Maternal diet during pregnancy was assessed by food frequency questionnaire (FFQ). Cohort children were followed up at 5 years by symptom questionnaire and FFQ. Food groups of interest were fruit, vegetables, fruit juice, whole grain products, fish, dairy products and fat spreads. Trends across outcome groups defined by level of food intake are presented. RESULTS: 1,253 children participated at 5 years and maternal FFQ data were available for 1,212. No consistent associations were found between childhood outcomes and maternal intake of the analysed foods except for apples and fish. Maternal apple intake was beneficially associated with ever wheeze (OR highest vs lowest tertile 0.63, 95% CI 0.42 to 0.95), ever asthma (OR 0.54, 95% CI 0.32 to 0.92) and doctor-confirmed asthma (OR 0.47, 95% CI 0.27 to 0.82) in the children. Maternal fish consumption was beneficially associated with doctor-confirmed eczema (OR >or=1/week vs never 0.57, 95% CI 0.35 to 0.92). CONCLUSION: There was no evidence for associations between maternal intake of most foods during pregnancy and asthma, respiratory and allergic outcomes in 5-year-old children, except for apples and fish. Consumption of apples and fish during pregnancy may have a protective effect against the development of childhood asthma and allergic disease.     

Asthma and atopy in overweight children

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 (chi(2) trend 7.9, p = 0.005), wheeze ever (chi(2) trend 10.4, p = 0.001), and cough (chi(2) trend 12.3, p<0.001). These were not significant in boys. 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.     

Wheeze, asthma diagnosis and medication use: a national adult survey in a developing country

BACKGROUND: As relatively little is known about adult wheeze and asthma in developing countries, this study aimed to determine the predictors of wheeze, asthma diagnosis, and current treatment in a national survey of South African adults. METHODS: A stratified national probability sample of households was drawn and all adults (>14 years) in the selected households were interviewed. Outcomes of interest were recent wheeze, asthma diagnosis, and current use of asthma medication. Predictors of interest were sex, age, household asset index, education, racial group, urban residence, medical insurance, domestic exposure to smoky fuels, occupational exposure, smoking, body mass index, and past tuberculosis. RESULTS: A total of 5671 men and 8155 women were studied. Although recent wheeze was reported by 14.4% of men and 17.6% of women and asthma diagnosis by 3.7% of men and 3.8% of women, women were less likely than men to be on current treatment (OR 0.6; 95% confidence interval (CI) 0.5 to 0.8). A history of tuberculosis was an independent predictor of both recent wheeze (OR 3.4; 95% CI 2.5 to 4.7) and asthma diagnosis (OR 2.2; 95% CI 1.5 to 3.2), as was occupational exposure (wheeze: OR 1.8; 95% CI 1.5 to 2.0; asthma diagnosis: OR 1.9; 95% CI 1.4 to 2.4). Smoking was associated with wheeze but not asthma diagnosis. Obesity showed an association with wheeze only in younger women. Both wheeze and asthma diagnosis were more prevalent in those with less education but had no association with the asset index. Independently, having medical insurance was associated with a higher prevalence of diagnosis. CONCLUSIONS: Some of the findings may be to due to reporting bias and heterogeneity of the categories wheeze and asthma diagnosis, which may overlap with post tuberculous airways obstruction and chronic obstructive pulmonary disease due to smoking and occupational exposures. The results underline the importance of controlling tuberculosis and occupational exposures as well as smoking in reducing chronic respiratory morbidity. Validation of the asthma questionnaire in this setting and research into the pathophysiology of post tuberculous airways obstruction are also needed.     

Effects on patients with asthma of eradicating visible indoor mould: a randomised controlled trial

BACKGROUND: It is not clear whether associations between respiratory symptoms and indoor mould are causal. A randomised controlled trial was conducted to see whether asthma improves when indoor mould is removed. METHODS: Houses of patients with asthma were randomly allocated into two groups. In one group, indoor mould was removed, fungicide was applied and a fan was installed in the loft. In the control group, intervention was delayed for 12 months. Questionnaires were administered and peak expiratory flow rate was measured at baseline, 6 months and 12 months. RESULTS: Eighty-one houses were allocated to the intervention group and 83 to the control group; 95 participants in 68 intervention houses and 87 in 63 control houses supplied follow-up information. Peak expiratory flow rate variability declined in both groups, with no significant differences between them. At 6 months, significantly more of the intervention group showed a net improvement in wheeze affecting activities (difference between groups 25%, 95% CI 3% to 47%; p = 0.028), perceived improvement of breathing (52%, 95% CI 30% to 74%; p<0.0001) and perceived reduction in medication (59%, 95% CI 35% to 81%; p<0.0001). By 12 months the intervention group showed significantly greater reductions than the controls in preventer and reliever use, and more improvement in rhinitis (24%, 95% CI 9% to 39%; p = 0.001) and rhinoconjunctivitis (20%, 95% CI 5% to 36%; p = 0.009). CONCLUSIONS: Although there was no objective evidence of benefit, symptoms of asthma and rhinitis improved and medication use declined following removal of indoor mould. It is unlikely that this was entirely a placebo effect.     

Health effects of passive smoking. 3. Parental smoking and prevalence of respiratory symptoms and asthma in school age children

BACKGROUND: A systematic quantitative review of the evidence relating parental smoking to the prevalence of asthma and respiratory symptoms was conducted amongst school age children. METHODS: Sixty relevant studies were identified after consideration of 1593 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified 25 studies of asthma, 41 of wheeze, 34 of chronic cough, seven of chronic phlegm and six of breathlessness which were included in a quantitative overview. RESULTS: The pooled odds ratios for either parent smoking were 1.21 (95% CI 1.10 to 1.34) for asthma, 1.24 (95% CI 1.17 to 1.31) for wheeze, 1.40 (95% CI 1.27 to 1.53) for cough, 1.35 (95% CI 1.13 to 1.62) for phlegm, and 1.31 (95% CI 1.08 to 1.59) for breathlessness. Adjustment for confounding had little effect. Evidence of heterogeneity between studies appeared largely explicable by publication bias with a superfluity of small studies with large odds ratios. However, excluding these had little effect on the pooled odds ratios. The prevalence of all symptoms increased with the number of parents who smoked. While maternal smoking had a greater effect than paternal smoking, the effect of father only was clearly significant. CONCLUSIONS: The relationship between parental smoking and respiratory symptoms seems very likely to be causal given statistical significance, robustness to adjustment for confounding factors, consistency of the findings in different countries, and evidence of dose response. The raised risk in households where the father, but not the mother, smoked argues for a postnatal effect.


     

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town

BACKGROUND: Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects. METHODS: A cross sectional survey was conducted of children aged 8-10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels. RESULTS: A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV(1)) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV(1) after exercise were 3.1% (95% CI -1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively). CONCLUSIONS: Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.     

Long term effects of antenatal betamethasone on lung function: 30 year follow up of a randomised controlled trial

BACKGROUND: Antenatal betamethasone is routinely used for the prevention of neonatal respiratory distress syndrome in preterm infants. However, little is known of the long term effects of exposure to antenatal betamethasone on lung function in adulthood. METHODS: Five hundred and thirty four 30 year olds whose mothers had participated in the first and largest randomised controlled trial of antenatal betamethasone were followed. Lung function was assessed by portable spirometric testing. The prevalence of asthma symptoms was assessed using the European Community Respiratory Health Survey questionnaire. RESULTS: Fifty (20%) betamethasone exposed and 53 (19%) placebo exposed participants met the criteria for current asthma (relative risk 0.98 (95% CI 0.74 to 1.30), p = 0.89). 181 betamethasone exposed and 202 placebo exposed participants had acceptable spirometric data. There were no differences in lung function between betamethasone and placebo exposed groups (mean (SD) forced vital capacity in the betamethasone and placebo groups 105.9 (12.0) v 106.6 (12.6)% predicted, difference = -0.7 (95% CI -3.2 to 1.8), p = 0.59; mean (SD) forced expiratory volume in 1 second in the betamethasone and placebo groups 98.9 (13.4) v 98.5 (13.6)% predicted, difference = 0.3 (95% CI -2.4 to 3.1, p = 0.80)). CONCLUSIONS: Antenatal exposure to a single course of betamethasone does not alter lung function or the prevalence of wheeze and asthma at age 30.