Biomedical subjects

C Svanes

Publications and source records attributed to C Svanes.

At least 19 recordsLinked to original sources

PubMed2006

Incidence of asthma and net change in symptoms in relation to changes in obesity.

The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.

Adult↗

PubMed2006

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.

Adult↗

PubMed2006

Sources of variation in forced expiratory volume in one second and forced vital capacity.

Published prediction equations for lung function differ considerably, but the components of population variation responsible for the differences are unknown. Data were analysed for 6,323 never-smoking adults who did not report wheeze or asthma, from 42 centres participating in the European Community Respiratory Health Survey. Means and components of variance were estimated for males and females aged 20-24 yrs, and the relationships with age and height were examined in those aged 25-44 yrs. Mean lung function for those aged 20-24 yrs differed between centres, but variation could not be wholly attributed to differences in population or equipment. The maximum difference in means by equipment type was 101 mL for FVC in males. Equipment differences were not statistically significant adjusted for country, but differences in mean forced expiratory volume in one second and forced vital capacity by country, adjusted for instrument, were statistically significant in males. Differences between centres in relation to age and height had less influence on predicted values. In conclusion, there are unexplained differences in lung function between ethnically similar nonsmoking symptom-free populations. Neither national reference curves nor those based on the same ethnic group can be guaranteed to give accurate norms of lung health.

Adult↗

PubMed2006

Changes in active and passive smoking in the European Community Respiratory Health Survey.

The aim of the present investigation was to study changes and determinants for changes in active and passive smoking. The present study included 9,053 adults from 14 countries that participated in the European Community Respiratory Health Survey II. The mean follow-up period was 8.8 yrs. Change in the prevalence of active and passive smoking was expressed as absolute net change (95% confidence interval) standardised to a 10-yr period. Determinants of change were analysed and the results expressed as adjusted hazard risk ratio (HRR) or odds ratio (OR). The prevalence of active smoking declined by 5.9% (5.1-6.8) and exposure to passive smoking in nonsmokers declined by 18.4% (16.8-20.0). Subjects with a lower educational level (HRR: 0.73 (0.54-0.98) and subjects living with a smoker (HRR: 0.45 (0.34-0.59)) or with workplace smoking (HRR: 0.69 (0.50-0.95)) were less likely to quit. Low socio-economic groups were more likely to become exposed (OR: 2.21 (1.61-3.03)) and less likely to cease being exposed to passive smoking (OR: 0.48 (0.37-0.61)). In conclusion, the quitting rate was lower and the risk of exposure to passive smoking higher among subjects with lower socio-economic status. Exposure to other peoples smoking decreased quitting rates and increased the risk of starting to smoke.

Adult↗

PubMed2005

Hormone replacement therapy, body mass index and asthma in perimenopausal women: a cross sectional survey.

BACKGROUND: Hormone replacement therapy (HRT) and obesity both appear to increase the risk of asthma. A study was undertaken to investigate the association of HRT with asthma and hay fever in a population of perimenopausal women, focusing on a possible interaction with body mass index (BMI). METHODS: A postal questionnaire was sent to population based samples in Denmark, Estonia, Iceland, Norway, and Sweden in 1999-2001, and 8588 women aged 25-54 years responded (77%). Pregnant women, women using oral contraceptives, and women <46 years were excluded. Analyses included 2206 women aged 46-54 years of which 884 were menopausal and 540 used HRT. Stratified analyses by BMI in tertiles were performed. RESULTS: HRT was associated with an increased risk for asthma (OR 1.57 (95% CI 1.07 to 2.30)), wheeze (OR 1.60 (95% CI 1.22 to 2.10)), and hay fever (OR 1.48 (95% CI 1.15 to 1.90)). The associations with asthma and wheeze were significantly stronger among women with BMI in the lower tertile (asthma OR 2.41 (95% CI 1.21 to 4.77); wheeze OR 2.04 (95% CI 1.23 to 3.36)) than in heavier women (asthma: p(interaction) = 0.030; wheeze: p(interaction) = 0.042). Increasing BMI was associated with more asthma (OR 1.08 (95% CI 1.05 to 1.12) per kg/m2). This effect was only found in women not taking HRT (OR 1.10 (95% CI 1.05 to 1.14) per kg/m2); no such association was detected in HRT users (OR 1.00 (95% CI 0.92 to 1.08) per kg/m2) (p(interaction) = 0.046). Menopause was not significantly associated with asthma, wheeze, or hay fever. CONCLUSIONS: In perimenopausal women there is an interaction between HRT and BMI in the effects on asthma. Lean women who were HRT users had as high a risk for asthma as overweight women not taking HRT. It is suggested that HRT and overweight increase the risk of asthma through partly common pathways.

Adult↗

PubMed2005

The association between birth size and atopy in young North-European adults.

BACKGROUND: There is evidence that atopic disorders may begin in intra-uterine life; however, studies of birth characteristics and atopy show conflicting results. METHODS: We wanted to investigate the association of birth weight and head circumference with serum total or specific IgE, allergic rhinitis or eczema while addressing the influence of demographic and geographical factors. In this historic prospective cohort study, data were collected from birth records for 1683 men and women born in 1947-1973, from six Nordic-Baltic populations participating in the European Community Respiratory Health Survey. Blood tests for the measurement of serum total and specific IgE were available for 1494 subjects. In multiple regression analyses, adjustments were made for birth length, gender, age, study centre, adult body mass index, level of education, parental and adult smoking. RESULTS There was no association of birth weight (n=1230) and head circumference (n=285) with serum total IgE, specific IgE antibodies, allergic rhinitis or eczema. There were neither significant interactions by gender or age, nor heterogeneity between the study centres in the analyses of birth weight and adult atopy. CONCLUSION: Birth size was not associated with atopy among adults in this large Nordic-Baltic population study.

Adult↗

PubMed2005

Maternal atopy and changes in parity.

BACKGROUND: Atopic women tend to have fewer children, although atopy may favour conception. OBJECTIVE: To assess whether atopy is associated with the number of new births and whether changes in parity are associated with a change in atopy in a cohort of young women. METHODS: Women had atopy (defined as the presence of serum-specific IgE against common aeroallergens) measured in the European Community Respiratory Health Study during the years 1991--92 (n=4580). About 9 years later, 2844 (62.1%) were recontacted and 2414 (52.7%) had atopy measured again. RESULTS: Atopic women had fewer children at baseline than non-atopic women but the association disappeared at the end of the follow-up. Atopy tended to increase parity during the follow-up, but in a non-statistically significant way (relative risk=1.08; 0.86-1.35, after adjusting for number of children at baseline, age, length of follow-up, education or social class). Prevalence of atopy during the follow-up changed by the same magnitude whatever the birth cohort and the change in the number of children (P for interaction >0.7). CONCLUSION: Atopic women did not have a significantly higher fertility rate but they may postpone having their first child compared with non-atopic women. We are unable to confirm the hypothesis that atopy in women may decrease with successive pregnancies.

Adult↗

PubMed2005

Insomnia is more common among subjects living in damp buildings.

BACKGROUND: Insomnia is a condition with a high prevalence and a great impact on quality of life. Little is known about the relation between and sleep disturbances and the home environment. AIM: To analyse the association between insomnia and building dampness. METHODS: In a cross-sectional, multicentre, population study, 16 190 subjects (mean age 40 years, 53% women) were studied from Reykjavik in Iceland, Bergen in Norway, Umeå, Uppsala, and Göteborg in Sweden, Aarhus in Denmark, and Tartu in Estonia. Symptoms related to insomnia were assessed by questionnaire. RESULTS: Subjects living in houses with reported signs of building dampness (n = 2873) had a higher prevalence of insomnia (29.4 v 23.6%; crude odds ratio 1.35, 95% CI 1.23 to 1.48). The association between insomnia and different indicators of building dampness was strongest for floor dampness: "bubbles or discoloration on plastic floor covering or discoloration of parquet floor" (crude odds ratio 1.96, 95% CI 1.66 to 2.32). The associations remained significant after adjusting for possible confounders such as sex, age, smoking history, housing, body mass index, and respiratory diseases. There was no significant difference between the centres in the association between insomnia and building dampness. CONCLUSION: Insomnia is more common in subjects living in damp buildings. This indicates that avoiding dampness in building constructions and improving ventilation in homes may possibly have a positive effect on the quality of sleep.

Adult↗

PubMed2005

Association of asthma and hay fever with irregular menstruation.

BACKGROUND: There is some evidence that asthmatic women are more likely to have abnormal sex hormone levels. A study was undertaken to determine whether asthma and allergy were associated with irregular menstruation in a general population, and the potential role of asthma medication for this association. METHODS: A total of 8588 women (response rate 77%) participated in an 8 year follow up postal questionnaire study of participants of the ECRHS stage I in Denmark, Estonia, Iceland, Norway, and Sweden. Only non-pregnant women not taking exogenous sex hormones were included in the analyses (n = 6137). RESULTS: Irregular menstruation was associated with asthma (OR 1.54 (95% CI 1.11 to 2.13)), asthma symptoms (OR 1.47 (95% CI 1.16 to 1.86)), hay fever (OR 1.29 (95% CI 1.05 to 1.57)), and asthma preceded by hay fever (OR 1.95 (95% CI 1.30 to 2.96)) among women aged 26-42 years. This was also observed in women not taking asthma medication (asthma symptoms: OR 1.44 (95% CI 1.09 to 1.91); hay fever: OR 1.27 (95% CI 1.03 to 1.58); wheeze preceded by hay fever: OR 1.76 (95% CI 1.18 to 2.64)). Irregular menstruation was associated with new onset asthma in younger women (OR 1.58 (95% CI 1.03 to 2.42)) but not in women aged 42-54 years (OR 0.62 (95% CI 0.32 to 1.18)). The results were consistent across centres. CONCLUSIONS: Younger women with asthma and allergy were more likely to have irregular menstruation. This could not be attributed to current use of asthma medication. The association could possibly be explained by common underlying metabolic or developmental factors. The authors hypothesise that insulin resistance may play a role in asthma and allergy.

Adult↗

PubMed2004

Is birth weight related to lung function and asthma symptoms in Nordic-Baltic adults?

Studies of birth characteristics and respiratory outcomes show contradictory findings. We wanted to investigate the association of birth weight with adult lung function as well as asthma symptoms while addressing the influence of demographic and environmental factors. Data was collected from the birth records of 1683 men and women born in 1947-1973 who were included in 6 Nordic-Baltic population samples investigated within the European Community Respiratory Health Survey (ECRHS). In the adults, an increase in birth weight from below 2500 g to above 4000 g was associated with an increase from 96% to 104% predicted one-second forced expiratory volume (P<0.01) and from 1.00% to 107% predicted forced vital capacity (P<0.01). However, birth weight was not associated with symptoms of asthma. After adjustment for birth length, gender, age, study centre, adult BMI, allergic rhinitis, parental and adult tobacco smoke exposure in multivariate regression analyses, birth weight was not associated with adult lung function or asthma symptoms. Further sub-sample analyses revealed no influence of gestational age, gender, age or geographical area. In this historic prospective cohort study an association was neither found between birth weight and adult lung function nor between birth weight and asthma symptoms.

Adult↗

PubMed2004

An international survey of chronic obstructive pulmonary disease in young adults according to GOLD stages.

BACKGROUND: The recently published GOLD guidelines provide a new system for staging chronic obstructive pulmonary disease (COPD) from mild (stage I) to very severe (stage IV) and introduce a stage 0 (chronic cough and phlegm without airflow obstruction) that includes subjects "at risk" of developing the disease. METHODS: In order to assess the prevalence of GOLD stages of COPD in high income countries and to evaluate their association with the known risk factors for airflow obstruction, data from the European Community Respiratory Health Survey on more than 18,000 young adults (20-44 years) were analysed. RESULTS: The overall prevalence was 11.8% (95% CI 11.3 to 12.3) for stage 0, 2.5% (95% CI 2.2 to 2.7) for stage I, and 1.1% (95% CI 1.0 to 1.3) for stages II-III. Moderate to heavy smoking (> or =15 pack years) was significantly associated with both stage 0 (relative risk ratio (RRR)=4.15; 95% CI 3.55 to 4.84) and stages I+ (RRR=4.09; 95% CI 3.17 to 5.26), while subjects with stages I+ COPD had a higher likelihood of giving up smoking (RRR=1.39; 95% CI 1.04 to 1.86) than those with GOLD stage 0 (RRR=1.05; 95% CI 0.86 to 1.27). Environmental tobacco smoke had the same degree of positive association in both groups. Respiratory infections in childhood and low socioeconomic class were significantly and homogeneously associated with both groups, whereas occupational exposure was significantly associated only with stage 0. All the GOLD stages showed a significantly higher percentage of healthcare resource users than healthy subjects (p<0.001), with no difference between stage 0 and COPD. CONCLUSIONS: A considerable percentage of young adults already suffered from COPD. GOLD stage 0 was characterised by the presence of the same risk factors as COPD and by the same high demand for medical assistance.

Adult↗

PubMed2004

Parental smoking in childhood and adult obstructive lung disease: results from the European Community Respiratory Health Survey.

BACKGROUND: Early exposure to parental smoking appears to influence the development of the airways and predispose to respiratory symptoms. A study was undertaken to determine whether the consequences of parental smoking could be traced in adulthood. METHODS: Information from interviewer-led questionnaires was available for 18 922 subjects aged 20-44 years from random population samples in 37 areas participating in the European Community Respiratory Health Survey. Lung function data were available for 15,901 subjects. RESULTS: In men, father's smoking in childhood was associated with more respiratory symptoms (ORwheeze 1.13 (95% CI 1.00 to 1.28); never smokers: ORwheeze 1.21 (95% CI 0.96 to 1.50)) and there was a dose-dependent association between number of parents smoking and wheeze (one: OR 1.08 (95% CI 0.94 to 1.24); both: OR 1.24 (95% CI 1.05 to 1.47); ptrend = 0.010). A reduced ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) was related to father's smoking (-0.3% (95% CI -0.6 to 0)) and number of parents smoking (ptrend <0.001) among men. In women, mother's smoking was associated with more respiratory symptoms and poorer lung function (ORwheeze 1.15 (95% CI 1.01 to 1.31), never smokers: ORwheeze 1.21 (95% CI 0.98-1.51); FEV1 -24 ml (95% CI -45 to -3); FEV1/FVC ratio -0.6% (95% CI -0.9 to -0.3)). These effects were possibly accounted for by maternal smoking in pregnancy (ORwheeze 1.39 (95% CI 1.17 to 1.65); FEV1 -23 ml (95% CI -52 to 7); FEV1/FVC ratio -0.9% (95% CI -1.3 to -0.4)) as there was no association with paternal smoking among women (interaction by sex, p<0.05). These results were homogeneous across centres. CONCLUSION: Both intrauterine and environmental exposure to parental tobacco smoking was related to more respiratory symptoms and poorer lung function in adulthood in this multicultural study. The age window of particular vulnerability appeared to differ by sex, postnatal exposure being important only in men and a role for prenatal exposure being more evident in women.

Adult↗

PubMed2004

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.

Adult↗

PubMed2004

Obesity and nocturnal gastro-oesophageal reflux are related to onset of asthma and respiratory symptoms.

Several studies have identified obesity as a risk factor for asthma in both children and adults. An increased prevalence of asthma in subjects with gastro-oesophageal reflux (GOR) and obstructive sleep apnoea syndrome has also been reported. The aim of this investigation was to study obesity, nocturnal GOR and snoring as independent risk factors for onset of asthma and respiratory symptoms in a Nordic population. In a 5-10 yr follow-up study of the European Community Respiratory Health Survey in Iceland, Norway, Denmark, Sweden and Estonia, a postal questionnaire was sent to previous respondents. A total of 16,191 participants responded to the questionnaire. Reported onset of asthma, wheeze and night-time symptoms as well as nocturnal GOR and habitual snoring increased in prevalence along with the increase in body mass index (BMI). After adjusting for nocturnal GOR, habitual snoring and other confounders, obesity (BMI >30) remained significantly related to the onset of asthma, wheeze and night-time symptoms. Nocturnal GOR was independently related to the onset of asthma and in addition, both nocturnal GOR and habitual snoring were independently related to onset of wheeze and night-time symptoms. This study adds evidence to an independent relationship between obesity, nocturnal gastro-oesophageal reflux and habitual snoring and the onset of asthma and respiratory symptoms in adults.

Adult↗

PubMed2004

A prospective study of asthma incidence and its predictors: the RHINE study.

The objective of this longitudinal study was to estimate the incidence rate of asthma, and to compare the incidence between subjects with or without baseline reporting of certain respiratory symptoms. A follow-up of the random population samples in the European Respiratory Health Survey (ECRHS) in Sweden, Norway, Denmark, Iceland and Estonia was conducted in 1999-2001, in a population aged 30-54 yrs at follow-up (n=14,731). Asthma was defined as reporting either asthma or physician-diagnosed asthma, and a reported year when asthma symptoms were first noticed. Incidence rates, incidence rate ratios and hazard ratios were calculated with 95% confidence intervals. The incidence rate of asthma was 2.2 cases per 1,000 person-yrs. The incidence was higher among females (2.9 cases.1,000 person-yrs(-1)) than among males (1.5 cases.1,000 person-yrs(-1)). When subjects with baseline reporting of wheezing were excluded, the incidence rate decreased to 1.7 cases.1,000 person-yrs(-1), with a further decrease to 1.5 cases.1,000 person-yrs(-1) after exclusion of subjects with wheezing, nocturnal dyspnoea, chest tightness and cough. There was a strong association between onset of asthma and wheezing at baseline. In this prospective, population-based study, the incidence rate of asthma in the whole population sample ranged 1.5-2.2.1,000 person-yrs(-1), with a higher incidence range among females. The incidence was dependent on the extent to which subjects with respiratory symptoms were excluded from follow-up. Hence, for comparability between studies, the exclusion criteria in the follow-up population must be stated.

Adult↗

PubMed2002

Early exposure to children in family and day care as related to adult asthma and hay fever: results from the European Community Respiratory Health Survey.

BACKGROUND: The literature indicates that early exposure to children in the family and to day care permanently influences the development of allergic disease. A study was undertaken to examine the associations of family size and day care with adult asthma and hay fever and to determine whether these associations are mediated through specific IgE production and whether they vary with allergic predisposition. METHODS: 18,530 subjects aged 20-44 years from 36 areas predominantly in the market economies participated in the European Community Respiratory Health Survey and provided information through interviewer-led questionnaires. 13,932 subjects gave blood samples for measurement of specific IgE. RESULTS: Hay fever was less common in subjects with many siblings (OR=0.92; 95% CI 0.90 to 0.95 per sib). There was a U-shaped relationship between asthma and number of siblings (quadratic effect of siblings, pwheeze=0.014, pFEV(1)=0.016). In subjects without siblings but exposed to children in day care, hay fever was less common (OR=0.76; 95% CI 0.60 to 0.98) and asthma symptoms were more common (ORwheeze=1.48; 95% CI 1.12 to 1.95). Adjustment for specific IgEs did not alter these associations. The inverse association of hay fever with siblings was found in sensitised subjects (OR=0.89; 95% CI 0.84 to 0.94) and in those with parental allergy (OR=0.91; 95% CI 0.85 to 0.97), but not in subjects without such a predisposition (OR=1.02; 95% CI 0.97 to 1.09). CONCLUSION: Subjects exposed to many children at home or in day care experienced less hay fever and more asthma in adulthood. Microbial challenge through children may contribute to a non-allergic immunological development giving less hay fever but more airways infections predisposing to asthma. These effects were not mediated through production of specific IgE. The protective effect of siblings on hay fever was particularly strong in those with an allergic predisposition.

Adult↗

PubMed2001

Asthma and indoor environment in Nepal.

BACKGROUND: The development of asthma seems to be influenced by the adoption of a Western lifestyle. A study was undertaken to assess the importance of indoor environmental factors in Nepal where the lifestyle and home environment differ from that in the West. METHODS: The home environment of 121 schoolchildren with asthma and 126 controls aged 11-17 years was studied. The homes of all participants were investigated and the children and their mothers were interviewed using a standardised questionnaire. Cases and controls were identified from an ISAAC (International Study of Asthma and Allergy in Childhood) based population study of 2330 schoolchildren in Kathmandu, Nepal. RESULTS: Keeping cattle inside the house during the night was related to a lower risk for having asthma (adjusted odds ratio (OR) 0.2 (95% CI 0.1 to 0.5)) while there was no association between asthma and cattle kept outside. Asthma was associated with cigarette smoking by two or more family members (OR 1.9 (95% CI 1.0 to 3.9)) and with the domestic use of smoky fuels (OR 2.2 (95% CI 1.0 to 4.5)). In analyses stratified by sex, passive smoking and the use of smoky fuels were significantly associated with asthma only in boys. CONCLUSIONS: The risk of asthma in Nepalese children was lower in subjects exposed to cattle kept inside the house and higher in subjects exposed to passive smoking and indoor use of smoky fuels. Childhood exposure to microorganisms or allergens from cattle may protect against the development of atopic disease.

Adolescent↗

PubMed2001

The European Community Respiratory Health Survey: what are the main results so far? European Community Respiratory Health Survey II.

The European Community Respiratory Health Survey (ECRHS) was the first study to assess the geographical variation in asthma and allergy in adults using the same instruments and definitions. The database of the ECRHS includes information from approximately 140,000 individuals from 22 countries. The aim of this review is to summarize the results of the ECRHS to date. The ECRHS has shown that there are large geographical differences in the prevalence of asthma, atopy and bronchial responsiveness, with high prevalence rates in English speaking countries and low prevalence rates in the Mediterranean region and Eastern Europe. Analyses of risk factors have highlighted the importance of occupational exposure for asthma in adulthood. The association between sensitization to individual allergens and bronchial responsiveness was strongest for indoor allergens (mite and cat). Analysis of treatment practices has confirmed that the treatment of asthma varies widely between countries and that asthma is often undertreated. In conclusion, the European Community Respiratory Health Survey has shown that the prevalence of asthma varies widely. The fact that the geographical pattern is consistent with the distribution of atopy and bronchial responsiveness supports the conclusion that the geographical variations in the prevalence of asthma are true and most likely due to environmental factors.

Asthma↗