Epidemiological study of wheeze,doctor diagnosed asthma,and cough in preschool children in Leicestershire.

OBJECTIVE--To determine the cumulative prevalences of wheeze and doctor diagnosed asthma and the point prevalences of recurrent cough and wheeze in children aged 5 years and under. DESIGN--Questionnaire survey of population based random sample of children registered on regional authority''s child health index for immunisation; questionnaire completed by parents. SETTING--Leicestershire. SUBJECTS--1650 white children born in 1985-9 who were surveyed in 1990. MAIN OUTCOME MEASURES--Cumulative prevalences of wheeze and doctor diagnosed asthma and point prevalences of recurrent cough and wheeze by age and sex. RESULTS--There were 1422 replies (86.2%; 726 for boys, 696 for girls). Overall, 11.0% (95% confidence interval 9.4% to 12.6%) of children had formally been diagnosed as having asthma, the cumulative prevalence in boys (12.7%) being somewhat higher than in girls (9.2%) (age adjusted odds ratio 1.47, p = 0.03). As expected, the cumulative prevalence of asthma increased significantly with age (7.5% (13/173) in children under 1 year, 15.9% (61/383) in children of 4 years and over; p < 0.001). The cumulative prevalence of wheeze overall was 15.6% (13.7% to 17.5%), being higher in boys (17.6%) than in girls (13.5%) (odds ratio 1.38, p = 0.03). The overall prevalence of recurrent cough without colds was 21.8% (19.6% to 23.9%), with a non-significant excess in boys (23.1% v 20.4%). The overall prevalence of wheezing attacks during the previous 12 months was 13.0% (11.3% to 14.8%) with a non-significant excess in boys (14.5% v 11.5%). CONCLUSIONS--These findings are baseline results and emphasise the importance of studying the age group of interest rather than relying on the recall of parents of school age children.     

Prevalence of asthma symptoms in schoolchildren, and climate in west European countries: an ecologic study

The aim of the present study was to estimate the associations between the prevalence of asthma symptoms in schoolchildren and meteorological variables in west European countries that participated in the International Study of Asthma and Allergies in Children (ISAAC), Phase III 1997–2003. An ecologic study was carried out. The prevalence of asthma was obtained from this study from 48 centers in 14 countries, and meteorological variables from those stations closest to ISAAC centers, together with other socioeconomic and health care variables. Multilevel mixed-effects linear regression models were used. For schoolchildren aged 6–7 years, the prevalence rate of asthma decreased with an increase in mean annual sunshine hours, showed a positive association with rainy weather, and warm temperature, and a negative one with relative humidity and physician density (PD). Current wheeze prevalence was stronger in autumn/winter seasons and decreased with increasing PD. Severe current wheeze decreased with PD. For schoolchildren aged 13–14 years, the prevalence rates of asthma and current wheeze increased with rainy weather, and these rates decreased with increased PD. Current wheeze, as measured by a video questionnaire, was inversely associated with sunny weather, and nurse density. Severe current wheeze prevalence was stronger during autumn/winter seasons, decreased with PD, and indoor chlorinated public swimming pool density, and increased with rainy weather. Meteorological factors, including sunny and rainy weather, and PD may have some effect on the prevalence rates of asthma symptoms in children from west European countries.     

Sunny hours and variations in the prevalence of asthma in schoolchildren according to the International Study of Asthma and Allergies (ISAAC) Phase III in Spain

The objective of this study was to estimate the relationship between the prevalence of asthma in schoolchildren aged 6?C7?years and 13?C14?years and the mean annual sunny hours (MASH) in Spain, and to explore predictive models for asthma prevalence. The prevalence of asthma was obtained from the International Study of Asthma and Allergies (ISAAC) Phase III 2002?C2003, and climate and socio-economic variables from official sources. Nine centres were studied and a further four centres, two of which are in ISAAC, to test the predictive models. Logistic regression was used to estimate adjusted prevalence rates of asthma for each centre, and multiple regression models to study the effects of MASH and other meteorological and socio-economic variables. The adjusted prevalence rate of asthma decreased 0.6% [95% confidence interval (CI) 0.4?C0.8%] for the 6-7?years group and 1.1% (95% CI 0.8?C1.3%) for the 13?C14?years group with an increase in the MASH of 100?h. Relative humidity was negatively associated with asthma in the older age group, and gross province product per capita (GPP) was positively associated with asthma in the younger age group. The predictive models, which included MASH, gender, relative humidity, and GPP, anticipated prevalence rates of asthma without significant differences between the levels observed and those expected in 9 of the11 measurements carried out. The results indicate that sunny hours have a protective effect on the prevalence of asthma in schoolchildren.     

Prevalence of asthma in Melbourne schoolchildren: changes over 26 years.

OBJECTIVES--To determine the prevalence of asthma in the past 12 months in Melbourne schoolchildren aged 7, 12, and 15 years and to compare the prevalence of a history of asthma with that of 26 years ago. DESIGN--A questionnaire on respiratory symptoms was distributed to children for completion by parents and return to the school. Subjects were selected by a stratified cluster design. SETTING--Government and non-government schools in the greater Melbourne area, Australia. SUBJECTS--10,981 children. Parents completed questionnaires for 3324 children aged 7, 2899 aged 12, and 2968 aged 15. The overall response rate was 90%. MAIN OUTCOME MEASURES--History of wheeze or asthma in the past 12 months and in lifetime. RESULTS--The prevalences of wheeze in the past 12 months were 23.1%, 21.7%, and 18.6% for 7, 12, and 15 year olds respectively. A history of wheeze was more common in boys than in girls at age 7 (443/1711 v 324/1614) and 12 (418/1767 v 322/1718) but not at age 15. Overall, 78% (1548) of those reporting wheeze also reported a history of asthma and 83% (1611) had used a bronchodilator. The prevalence of a history of asthma among 7 year olds was 46% compared with 19.1% in the 1964 survey, an increase of 141%. CONCLUSIONS--The current prevalence of asthma in Melbourne schoolchildren is high and has risen substantially over the past 26 years.     

Respiratory symptoms and atopy in Aberdeen schoolchildren: evidence from two surveys 25 years apart.

OBJECTIVE--To estimate changes in the prevalence of respiratory symptoms and the reported diagnoses of asthma, eczema, and hay fever in primary school children in Aberdeen between 1964 and 1989. DESIGN--Determination of incidence prevalence and prevalence from survey data. SETTING--Aberdeen, Scotland. PARTICIPANTS--2743 primary school children (aged 8-13) from 1964 and 4003 [corrected] from 1989. MAIN OUTCOME MEASURES--Survey data on whether, according to the parent or guardian, the child wheezed or was troubled with shortness of breath; the number of episodes of breathlessness in the past year; and whether asthma, eczema, or hay fever had ever been diagnosed. RESULTS--Questionnaires were completed by the parents of 2510 children in 1964 and 3403 children in 1989. The prevalence of wheeze rose from 10.4% in 1964 to 19.8% in 1989, and the prevalence of episodes of shortness of breath increased from 5.4% to 10.0%. In both surveys wheeze and shortness of breath were more prevalent in boys than in girls. The reported diagnosis of asthma rose from 4.1% to 10.2%, hay fever from 3.2% to 11.9%, and eczema from 5.3% to 12%. The proportion of boys suffering from eczema rose from 47.7% to 60.0%. Hay fever showed a similar increase, from 49.4% to 60.1%, in boys over the 25 year period. Though the parents of a higher proportion of children with wheeze were aware of the diagnosis of asthma in 1989, because of the increased prevalence of wheeze the absolute number of parents of wheezy children who were not aware of a diagnosis of asthma increased from 7.4% to 9.6% of the population studied. CONCLUSION--The higher diagnosis rate for asthma is due not simply to changes in diagnostic fashion but reflects an increase over the past 25 years in the prevalence of respiratory symptoms, which in turn may reflect a more general change in the prevalence of atopy, the increase in which was particularly noticeable in boys. This increase explains some of the increase in hospital admission rates for children with asthma.     

Climate and prevalence of atopic eczema in 6- to 7-year-old school children in Spain. ISAAC PhASE III

Atopic eczema (AE) is a chronic skin disease. Recent reports indicate that the worldwide prevalence of AE is increasing and that various environmental factors are implicated in its aetiology. Climatic conditions have been related with AE prevalence, and Spain has varying climatic conditions. The aim of this study is to document the possible climatic influence on the prevalence of AE in schoolchildren aged 6–7 years in three different climatic regions in Spain. We conducted a cross-sectional population-based survey of 28,394 schoolchildren aged 6–7 years from 10 Spanish centres in three different climatic regions. The mean participation rate was 76.5%. AE prevalence was assessed using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and the Spanish Academy of Dermatology criteria used in Spain to diagnose AE. The data, including annual temperature, precipitation, relative humidity and the annual number of sunny hours per climatic region, were obtained from the Spanish National Institute of Meteorology. Different AE prevalences were found in all three climatic regions studied: Atlantic, 32.9; Mediterranean 28.3; and Continental 31.2 per 100 children studied (p < 0.005). AE was positively associated with precipitation and humidity, and was negatively associated with temperature and the number of sunny hours. The results show that AE is significantly dependent on meteorological conditions.     

Increased Risk of Wheeze and Decreased Lung Function after Respiratory Syncytial Virus Infection

Background

A relationship between hospitalization for respiratory syncytial virus (RSV) bronchiolitis and asthma development has been suggested in case-control studies.

Objective

The aim of this study was to assess the risk of current wheeze, asthma, and lung function at school age in infants previously hospitalized for RSV bronchiolitis compared to non-hospitalized children.

Methods

For this study, data from a prospective birth cohort of unselected, term-born infants (n = 553), of whom 4 (0.7%) were hospitalized for RSV bronchiolitis, and a prospective patient cohort of 155 term infants hospitalized for RSV bronchiolitis were used. Respiratory outcomes at age 6 in children hospitalized for RSV bronchiolitis were compared to non-hospitalized children.

Results

The risk of current wheeze was higher in hospitalized patients (n = 159) compared to non-hospitalized children (n = 549) (adjusted odds ratio (OR) 3.2 (95% CI 1.2–8.1). Similarly, the risk of current asthma, defined as a doctor’s diagnosis of asthma plus current symptoms or medication use, was higher in hospitalized patients (adjusted OR 3.1 (95% CI 1.3–7.5). Compared to non-hospitalized children, RSV bronchiolitis hospitalization was associated with lower lung function (mean difference FEV1% predicted −6.8 l (95% CI (−10.2 to −3.4).

Conclusions and Clinical Relevance

This is the first study showing that hospitalization for RSV bronchiolitis during infancy is associated with increased risk of wheezing, current asthma, and impaired lung function as compared to an unselected birth cohort at age 6.     

Prevalence of asthma in adults in Busselton,Western Australia.

OBJECTIVE--To estimate whether the prevalence of asthma in adults increased over a nine year interval. DESIGN--Serial cross sectional studies of the population with a protocol that included both subjective and objective measurements. SETTING--Busselton, Western Australia. SUBJECTS--A random sample of 553 subjects aged 18-55 years in 1981, and of 1028 subjects aged 18-55 years in 1990. MAIN OUTCOME MEASURES--Respiratory symptoms measured by self administered questionnaire, bronchial responsiveness measured by bronchial challenge with histamine, and allergy measured by skin prick tests. RESULTS--Symptoms with increased prevalence were those with significant association with allergy in this population. Recent wheeze increased from 17.5% to 28.8% (p < 0.001) and diagnosed asthma increased from 9.0% to 16.3% (p < 0.001). The increase was greatest in subjects less than 30 years old. The prevalence of shortness of breath coming on at rest and of hay fever also increased significantly, but the prevalence of shortness of breath on exertion, chronic cough, bronchial hyperresponsiveness, current asthma (defined as recent wheeze plus bronchial hyperresponsiveness), and allergy did not increase. The severity of bronchial responsiveness did not change significantly in any symptom group. CONCLUSIONS--Young adults showed a significant increase in reporting of symptoms related to allergy but not in the prevalence of current asthma. The increase in symptoms may be due to increased awareness of asthma in this community, to changed treatment patterns, or to increased exposures to allergens.     

Household environmental tobacco smoke and risks of asthma,wheeze and bronchitic symptoms among children in Taiwan

Background

Although studies show that maternal smoking during pregnancy increases the risks of respiratory outcomes in childhood, evidence concerning the effects of household environmental tobacco smoke (ETS) exposure remains inconsistent.

Methods

We conducted a population-based study comprised of 5,019 seventh and eighth-grade children in 14 Taiwanese communities. Questionnaire responses by parents were used to ascertain children''s exposure and disease status. Logistic regression models were fitted to estimate the effects of ETS exposures on the prevalence of asthma, wheeze, and bronchitic symptoms.

Results

The lifetime prevalence of wheeze was 11.6% and physician-diagnosed asthma was 7.5% in our population. After adjustment for potential confounders, in utero exposure showed the strongest effect on all respiratory outcomes. Current household ETS exposure was significantly associated with increased prevalence of active asthma, ever wheeze, wheeze with nighttime awakening, and bronchitis. Maternal smoking was associated with the increased prevalence of a wide range of wheeze subcategories, serious asthma, and chronic cough, but paternal smoking had no significant effects. Although maternal smoking alone and paternal smoking alone were not independently associated with respiratory outcomes, joint exposure appeared to increase the effects. Furthermore, joint exposure to parental smoking showed a significant effect on early-onset asthma (OR, 2.01; 95% CI, 1.00-4.02), but did not show a significant effect on late-onset asthma (OR, 1.17; 95% CI, 0.36-3.87).

Conclusion

We concluded that prenatal and household ETS exposure had significant adverse effects on respiratory health in Taiwanese children.     

Overweight/Obesity and Respiratory and Allergic Disease in Children: International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two

BackgroundChildhood obesity and asthma are increasing worldwide. A possible link between the two conditions has been postulated.MethodsCross-sectional studies of stratified random samples of 8–12-year-old children (n = 10 652) (16 centres in affluent and 8 centres in non-affluent countries) used the standardized methodology of ISAAC Phase Two. Respiratory and allergic symptoms were ascertained by parental questionnaires. Tests for allergic disease were performed. Height and weight were measured, and overweight and obesity were defined according to international definitions. Prevalence rates and prevalence odds ratios were calculated.ResultsOverweight (odds ratio = 1.14, 95%-confidence interval: 0.98; 1.33) and obesity (odds ratio = 1.67, 95%-confidence interval: 1.25; 2.21) were related to wheeze. The relationship was stronger in affluent than in non-affluent centres. Similar results were found for cough and phlegm, rhinitis and eczema but the associations were mostly driven by children with wheeze. There was a clear association of overweight and obesity with airways obstruction (change in FEV1/FVC, −0.90, 95%-confidence interval: −1.33%; −0.47%, for overweight and −2.46%, 95%-confidence interval: −3.84%; −1.07%, for obesity) whereas the results for the other objective markers, including atopy, were null.ConclusionsOur data from a large international child population confirm that there is a strong relation of body mass index with wheeze especially in affluent countries. Moreover, body mass index is associated with an objective marker of airways obstruction (FEV1/FVC) but no other objective markers of respiratory and allergic disorders.     

Asthma,Airway Symptoms and Rhinitis in Office Workers in Malaysia: Associations with House Dust Mite (HDM) Allergy,Cat Allergy and Levels of House Dust Mite Allergens in Office Dust

A prevalence study was conducted among office workers in Malaysia (N= 695). The aim of this study was to examine associations between asthma, airway symptoms, rhinitis and house dust mites (HDM) and cat allergy and HDM levels in office dust. Medical data was collected by a questionnaire. Skin prick tests were performed for HDM allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cat allergen Felis domesticus. Indoor temperature and relative air humidity (RH) were measured in the offices and vacuumed dust samples were analyzed for HDM allergens. The prevalence of D. pteronyssinus, D. farinae and cat allergy were 50.3%, 49.0% and 25.5% respectively. Totally 9.6% had doctor-diagnosed asthma, 15.5% had current wheeze and 53.0% had current rhinitis. The Der p 1 (from D. pteronyssinus) and Der f 1 (from D. farinae) allergens levels in dust were 556 ng/g and 658 ng/g respectively. Statistical analysis was conducted by multilevel logistic regression, adjusting for age, gender, current smoking, HDM or cat allergy, home dampness and recent indoor painting at home. Office workers with HDM allergy had more wheeze (p= 0.035), any airway symptoms (p= 0.032), doctor-diagnosed asthma (p= 0.005), current asthma (p= 0.007), current rhinitis (p= 0.021) and rhinoconjuctivitis (p< 0.001). Cat allergy was associated with wheeze (p= 0.021), wheeze when not having a cold (p= 0.033), any airway symptoms (p= 0.034), doctor-diagnosed asthma (p= 0.010), current asthma (p= 0.020) and nasal allergy medication (p= 0.042). Der f 1 level in dust was associated with daytime breathlessness (p= 0.033) especially among those with HDM allergy. Der f 1 levels were correlated with indoor temperature (p< 0.001) and inversely correlated with RH (p< 0.001). In conclusion, HDM and cat allergies were common and independently associated with asthma, airway symptoms and rhinitis. Der f 1 allergen can be a risk factor for daytime breathlessness.     

Factors associated with difference in prevalence of asthma in children from three cities in China: multicentre epidemiological survey

Objective To determine the factors associated with difference in prevalence of asthma in children in different regions of China.Design Multicentre epidemiological survey.Setting Three cities in China.Participants 10 902 schoolchildren aged 10 years.Main outcome measures Asthma and atopic symptoms, atopic sensitisation, and early and current exposure to environmental factors.Results Children from Hong Kong had a significantly higher prevalence of wheeze in the past year than those from Guangzhou and Beijing (odds ratio 1.64, 95% confidence interval 1.35 to 1.99). Factors during the first year of life and currently that were significantly associated with wheeze were cooking with gas (odds ratio 2.04, 1.34 to 3.13), foam pillows (2.58, 1.66 to 3.99), and damp housing (1.89, 1.26 to 2.83). Factors protecting against wheeze were cotton quilts and the consumption of fruit and raw vegetables.Conclusion Environmental factors and diet may explain the differences in prevalence of asthma between children living in different regions of China.     

Increased prevalence of symptoms of rhinitis but not of asthma between 1990 and 2008 in Swedish adults: comparisons of the ECRHS and GA²LEN surveys

Background

The increase in asthma prevalence until 1990 has been well described. Thereafter, time trends are poorly known, due to the low number of high quality studies. The preferred method for studying time trends in prevalence is repeated surveys of similar populations. This study aimed to compare the prevalence of asthma symptoms and their major determinants, rhinitis and smoking, in Swedish young adults in 1990 and 2008.

Methods

In 1990 the European Community Respiratory Health Survey (ECRHS) studied respiratory symptoms, asthma, rhinitis and smoking in a population-based sample (86% participation) in Sweden. In 2008 the same symptom questions were included in the Global Allergy and Asthma European Network (GA²LEN) survey (60% participation). Smoking questions were however differently worded. The regions (Gothenburg, Uppsala, Umeå) and age interval (20–44 years) surveyed both in 1990 (n = 8,982) and 2008 (n = 9,156) were analysed.

Results

The prevalence of any wheeze last 12 months decreased from 20% to 16% (p<0.001), and the prevalence of “asthma-related symptoms” was unchanged at 7%. However, either having asthma attacks or using asthma medications increased from 6% to 8% (p<0.001), and their major risk factor, rhinitis, increased from 22% to 31%. Past and present smoking decreased.

Conclusion

From 1990 to 2008 the prevalence of obstructive airway symptoms common in asthma did not increase in Swedish young adults. This supports the few available international findings suggesting the previous upward trend in asthma has recently reached a plateau. The fact that wheeze did not increase despite the significant increment in rhinitis, may at least in part be due to the decrease in smoking.     

The Novel 10-Item Asthma Prediction Tool: External Validation in the German MAS Birth Cohort

Background

A novel non-invasive asthma prediction tool from the Leicester Cohort, UK, forecasts asthma at age 8 years based on 10 predictors assessed in early childhood, including current respiratory symptoms, eczema, and parental history of asthma.

Objective

We aimed to externally validate the proposed asthma prediction method in a German birth cohort.

Methods

The MAS-90 study (Multicentre Allergy Study) recorded details on allergic diseases prospectively in about yearly follow-up assessments up to age 20 years in a cohort of 1,314 children born 1990. We replicated the scoring method from the Leicester cohort and assessed prediction, performance and discrimination. The primary outcome was defined as the combination of parent-reported wheeze and asthma drugs (both in last 12 months) at age 8. Sensitivity analyses assessed model performance for outcomes related to asthma up to age 20 years.

Results

For 140 children parents reported current wheeze or cough at age 3 years. Score distribution and frequencies of later asthma resembled the Leicester cohort: 9% vs. 16% (MAS-90 vs. Leicester) of children at low risk at 3 years had asthma at 8 years, at medium risk 45% vs. 48%. Performance of the asthma prediction tool in the MAS-90 cohort was similar (Brier score 0.22 vs. 0.23) and discrimination slightly better than in the original cohort (area under the curve, AUC 0.83 vs. 0.78). Prediction and discrimination were robust against changes of inclusion criteria, scoring and outcome definitions. The secondary outcome ‘physicians’ diagnosed asthma at 20 years'' showed the highest discrimination (AUC 0.89).

Conclusion

The novel asthma prediction tool from the Leicester cohort, UK, performed well in another population, a German birth cohort, supporting its use and further development as a simple aid to predict asthma risk in clinical settings.     

Updated Prevalences of Asthma,Allergy, and Airway Symptoms,and a Systematic Review of Trends over Time for Childhood Asthma in Shanghai,China

Background

The prevalence of asthma among Shanghai children has increased over time. This increase might be associated with changes in environmental exposures. Investigation of the time-trend of asthma and current prevalences is essential to understanding the causes.

Objective

To estimate the current prevalences of asthma, allergies and other respiratory symptoms among Shanghai preschool children, and to investigate the time-trend of childhood asthma prevalence of from 1990 to 2011.

Methods

From April 2011 to April 2012, the CCHH (China, Children, Homes, Health) cross-sectional study was conducted in Shanghai. Questionnaires were distributed to 17,898 parents or guardians of preschool children from 72 kindergartens in 5 districts. Previous similar studies were also summarized by a systematic literature review.

Results

From a total of 14,884 questionnaires for 3–7 year old children, prevalences of the following diseases and symptoms were calculated: asthma 10.2%, wheeze (ever) 28.1%, pneumonia (ever) 33.5%, otitis media 11.0%, rhinitis (ever) 54.1%, hay fever 12.2%, eczema (ever) 22.7%, and food allergy 15.7%. Urban children had higher prevalences of most symptoms than suburban children. The prevalence of asthma has increased significantly, almost five-fold, from 2.1% in 1990 to 10.2% in the present study. The prevalence of asthma in boys was higher than in girls in the present study and in all reviewed studies.

Conclusions

Asthma, allergy and airway symptoms are common among preschool children in Shanghai. The prevalence of childhood asthma in Shanghai has increased rapidly from 1990 to 2011.     

Home environment and severe asthma in adolescence: a population based case-control study.

OBJECTIVE--To investigate the effects of the home environment on the risk of severe asthma during adolescence. DESIGN--A questionnaire based case-control study drawn from a cross sectional survey of allergic diseases among secondary school pupils in Sheffield in 1991. SUBJECTS--763 children whose parents had reported that over the previous 12 months they had suffered either 12 or more wheezing attacks or a speech limiting attack of wheeze. A further 763 children were frequency matched for age and school class to act as controls. Analysis was restricted to 486 affected children and 475 others born between 1975 and 1980 who had lived at their present address for more than three years. RESULTS--Independent associations with severe wheeze were seen for non-feather bedding, especially foam pillows (odds ratio 2.78; 95% confidence interval 1.89 to 4.17), and the ownership of furry pets now (1.51; 1.04 to 2.20) and at birth (1.70; 1.20 to 2.40). These estimates were derived from subjects whose parents denied making changes in the bedroom or avoiding having a pet because of allergy. Parental smoking, use of gas for cooking, age of mattress, and mould growth in the child''s bedroom were not significantly associated with wheezing. CONCLUSIONS--Either our study questionnaire failed to detect the avoidance or removal of feather bedding by allergic families or there is some undetermined hazard related to foam pillows. Synthetic bedding and furry pets were both widespread in this population and may represent remediable causes of childhood asthma.     

West Sweden Asthma Study: Prevalence trends over the last 18 years argues no recent increase in asthma

Asthma prevalence has increased over the last fifty years, but the more recent changes have not been conclusively determined. Studies in children indicate that a plateau in the prevalence of asthma may have been reached, but this has not yet been confirmed in adults. Epidemiological studies have suggested that the prevalence of asthma in adults is approximately 7-10% in different parts of the western world.We have now performed a large-scale epidemiological evaluation of the prevalence of asthma and respiratory symptoms in adults between the ages of 16-75 in West Sweden. Thirty thousand randomly chosen individuals were sent a detailed questionnaire focusing on asthma and respiratory symptoms, as well possible risk factors. Sixty-two percent of the contacted individuals responded to the questionnaire. Asthma prevalence, defined as asthma diagnosed by a physician, was 8.3%. Moreover, the prevalence of respiratory symptoms was lower compared to previous studies. The most common respiratory symptom was any wheeze (16.6%) followed by sputum production (13.3%). In comparison with studies performed 18 years ago, the prevalence of asthma has not increased, and the prevalence of most respiratory symptoms has decreased. Therefore, our data argues that the continued increase in asthma prevalence that has been observed over the last half century is over.     

Asthma as a link between chest illness in childhood and chronic cough and phlegm in young adults

The link between chest illnesses in childhood to age 7 and the prevalence of cough and phlegm in the winter reported at age 23 was investigated in a cohort of 10 557 British children born in one week in 1958 (national child development study). Both pneumonia and asthma or wheezy bronchitis to age 7 were associated with a significant excess in the prevalence of chronic cough and phlegm at age 23 after controlling for current smoking. This excess was largely attributable to the association of cough and phlegm at age 23 with a history of asthma or wheezy bronchitis from age 16. When adjustment was made for recent wheezing, current cigarette consumption, previous smoking habit, and passive exposure to smoke the relative odds of cough or phlegm, or both, in subjects with a history of childhood chest illness was 1·11 (95% confidence interval 0·97 to 1·27). When analysed separately asthma, wheezy bronchitis, and pneumonia up to age 7 did not significantly increase the prevalence of either cough or phlegm.The explanation for the observed continuity between chest illness in childhood and respiratory symptoms in later life may lie more in the time course of functional disturbances related to asthma than in the persistence of structural lung damage.     

An ADAM33 Polymorphism Associates with Progression of Preschool Wheeze into Childhood Asthma: A Prospective Case-Control Study with Replication in a Birth Cohort Study

Background

The influence of asthma candidate genes on the development from wheeze to asthma in young children still needs to be defined.

Objective

To link genetic variants in asthma candidate genes to progression of wheeze to persistent wheeze into childhood asthma.

Materials and Methods

In a prospective study, children with recurrent wheeze from the ADEM (Asthma DEtection and Monitoring) study were followed until the age of six. At that age a classification (transient wheeze or asthma) was based on symptoms, lung function and medication use. In 198 children the relationship between this classification and 30 polymorphisms in 16 asthma candidate genes was assessed by logistic regression. In case of an association based on a p<0.10, replication analysis was performed in an independent birth cohort study (KOALA study, n = 248 included for the present analysis).

Results

In the ADEM study, the minor alleles of ADAM33 rs511898 and rs528557 and the ORMDL3/GSDMB rs7216389 polymorphisms were negatively associated, whereas the minor alleles of IL4 rs2243250 and rs2070874 polymorphisms were positively associated with childhood asthma. When replicated in the KOALA study, ADAM33 rs528557 showed a negative association of the CG/GG-genotype with progression of recurrent wheeze into childhood asthma (0.50 (0.26-0.97) p = 0.04) and no association with preschool wheeze.

Conclusion

Polymorphisms in ADAM33, ORMDL3/GSDMB and IL4 were associated with childhood asthma in a group of children with recurrent wheeze. The replication of the negative association of the CG/GG-genotype of rs528557 ADAM33 with childhood asthma in an independent birth cohort study confirms that a compromised ADAM33 gene may be implicated in the progression of wheeze into childhood asthma.     

Long term prognosis in preschool children with wheeze: longitudinal postal questionnaire study 1993-2004

Objectives To follow a population of preschool children with and without parent reported wheeze over a period of 6-11 years to determine prognosis and its important predictive factors.Design Longitudinal series of five postal surveys based on the international study of asthma and allergies in childhood questionnaire carried out between 1993 and 2004.Setting Two general practice populations, south Manchester.Participants 628 children aged less than 5 years at recruitment and those with at least six years’ follow-up data.Main outcome measures Parent completed questionnaire data for respiratory symptoms and associated features.Results Of 628 children included in the study, 201 (32%) had parent reported wheeze at the first observation (baseline), of whom 27% also reported the symptom on the second occasion (persistent asthma). The only important baseline predictors of persistent asthma were exercise induced wheeze (odds ratio 3.94, 95% confidence interval 1.72 to 9.00) and a history of atopic disorders (4.44, 1.94 to 10.13). The presence of both predictors indicated a likelihood of 53.2% of developing asthma; if only one feature was present this decreased to 17.2%, whereas if neither was present the likelihood was 10.9%. Family history of asthma was not predictive of persistent asthma among children with preschool wheeze.Conclusion Using two simple predictive factors (baseline parent reported exercise induced wheeze and a history of atopic disorders), it is possible to estimate the likelihood of future asthma in children presenting with preschool wheeze. The absence of baseline exercise induced wheeze and a history of atopic disorders reduces the likelihood of subsequent asthma by a factor of five.