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Biomedical subjects

P Burney

Publications and source records attributed to P Burney.

At least 37 records · Page 2Linked to original sources
PubMed2001

Does living on a farm during childhood protect against asthma, allergic rhinitis, and atopy in adulthood?

Recent studies of children suggest that factors encountered in a farm environment might protect against the development of allergy. However, it remains uncertain whether living on a farm in childhood is associated with a decreased risk of atopic diseases in adulthood. We analyzed data from 6,251 randomly selected adults 20 to 44 yr of age participating in the European Community Respiratory Health Survey (ECRHS). Subjects answered a detailed questionnaire and underwent specific IgE measurements to five allergens. After adjustment for potential confounders, including pet exposure in childhood, number of siblings, severe respiratory infection in childhood, and parental history of allergy, living on a farm in childhood was associated with a reduced risk of atopic sensitization in adulthood (OR = 0.76, CI 95% = 0.60-0.97). Compared with other adults, those who had lived on a farm as a child were less frequently sensitized to cat (OR = 0.63, CI 95% = 0.41-0.96) and to Timothy grass (OR = 0.68, CI 95% = 0.50-0.94), and were at lower risk of having nasal symptoms in the presence of pollen (OR = 0.80, CI 95% = 0.64-1.02). The protective effect of farming environment in childhood observed in this population-based sample of young adults provides evidence in favor of the hypothesis that environmental factors encountered in childhood may have a lifelong protective effect against the development of allergy.

Adult↗
PubMed2001

Occupation, chronic bronchitis, and lung function in young adults. An international study.

We studied the relationship between occupational exposures, chronic bronchitis, and lung function in a general population survey in 14 industrialized countries, including 13,253 men and women aged 20 to 44 yr. We studied associations between occupational group, occupational exposures, bronchitis symptoms (cough and phlegm production for at least 3 mo each year), FEV(1), and nonspecific bronchial responsiveness (NSBR) separately in lifetime nonsmokers, cigarette smokers, and ex-smokers. Occupational exposure to vapors, gas, dust, or fumes, estimated with a job exposure matrix (JEM), was associated with chronic bronchitis among current smokers only (prevalence ratio (PR): 1.2 to 1.7). The interaction of occupational exposure with smoking, however, was not statistically significant (p > 0.1). Self-reported exposure was related to chronic bronchitis in all smoking groups. An increased risk for chronic bronchitis was found in agricultural, textile, paper, wood, chemical, and food processing workers, being more pronounced in smokers. Lung function and NSBR were not clearly related to occupational exposures. Findings were similar for asthmatic and nonasthmatic subjects. In conclusion, occupational exposures contributed to the occurrence of chronic (industrial) bronchitis in young adults. Fixed airflow limitation was not evident, probably due to the relatively young age of this population.

Adult↗
PubMed2001

Symptoms of asthma, bronchial responsiveness and atopy in immigrants and emigrants in Europe. European Community Respiratory Health Survey.

Migration studies on asthma may provide information on its environmental causes. The European Community Respiratory Health Survey has potential advantages due to the number of countries involved, standardized collection of information, assessment of directionality of migration, and availability of physiological data on bronchial responsiveness and atopy. Prevalence rates of symptoms associated with asthma were compared for immigrants, emigrants and nonmigrants living in centres mostly in western Europe. Similar analyses were carried out for bronchial responsiveness (provocative concentration causing a 20% fall in forced expiratory volume in one second and slope) and atopy. Medication and use of health services were also explored. Overall, 1,678 (8.6%) of 19,516 participants were immigrants in the 18 countries participating in the study, of whom 581 were emigrants from one of the participating countries. Rates of asthma symptoms were higher in immigrants (odds ratio (OR): 1.21, 95% confidence interval (CI): 1.00-1.51) and emigrants (OR: 1.31, 95% CI: 0.96-1.51) compared to nonmigrants after controlling for area, sex, age and smoking status. However, bronchial responsiveness and atopy were equally distributed between immigrants, emigrants and nonmigrants. Use of health services was observed to be similar in migrants and nonmigrants with asthma. In the European Community Respiratory Health Survey, migrants reported more asthma symptoms, but had similar bronchial responsiveness, atopy, and use of health services when compared with the nonmigrant population.

Adult↗
PubMed2001

Variations in the prevalence across countries of chronic bronchitis and smoking habits in young adults.

The present work aims to assess the international variation in the prevalence of chronic bronchitis and its main risk factor, smoking habits, in young adults of 35 centres from 16 countries. Respiratory symptoms and pulmonary function were assessed in 17,966 subjects (20-44 yrs), randomly selected from the general population, in the frame of the European Community Respiratory Health Survey. The median prevalence of chronic bronchitis was 2.6%, with wide variations across countries (p<0.001; 0.7-9.7%). The prevalence of current smokers ranged 20.1-56.9%, (p<0.001) with a median value of 40%. Current smoking was the major risk factor for chronic bronchitis, especially in males. Its effect increased according to number of pack-yrs: in males, the odds ratio of chronic bronchitis was 3.51 (95% confidence interval (CI) 2.31-5.32) in 1-14 pack-yrs smokers and increased to 17.32 (9.97-30.11) in > or = 45 pack-yrs smokers with respect to nonsmokers. Only 30% of the geographical variability in prevalence could be explained by differences in smoking habits, suggesting that other environmental and/or genetic factors may play an important role. In conclusion, chronic bronchitis is a substantial health problem even in young adults. The impressive prevalence in current smokers in most countries highlights the need to improve the quality of prevention.

Adult↗
PubMed2001

Determinants of cough in young adults participating in the European Community Respiratory Health Survey.

Cough is a common symptom that affects a large proportion of the general population. The aim of this investigation was to identify determinants of nocturnal, nonproductive and productive cough in population samples from different countries. In a cross-sectional international population survey, 18,277 subjects (20-48 yrs) from 16 countries answered an interview-led questionnaire. Total and specific immunoglobulin-E was measured and spirometry was performed. Three types of cough were defined: nocturnal, nonproductive and productive cough. The relation of the independent variables to cough was estimated by means of logistic regression for each centre or country and combined across centre or country by random-effects meta-analysis. The median prevalence of nocturnal, nonproductive and productive cough in the different centres was 30.7%, 10.2% and 10.2%, respectively. Nocturnal and nonproductive cough were related to female sex (adjusted odds ratio (OR)=2.08 and 1.27, respectively), while nocturnal and productive cough were related to rhinitis (OR=1.46 and 1.61, respectively). All three types of cough were related to asthma, tobacco smoking, environmental tobacco smoke and obesity. Females are more likely to report nocturnal and nonproductive cough than males. Cough was related to treatable disorders, like asthma and rhinitis, as well as avoidable factors, such as tobacco smoking and environmental tobacco smoke.

Adult↗
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↗
PubMed2000

Differences in incidence of reported asthma related to age in men and women. A retrospective analysis of the data of the European Respiratory Health Survey.

Sex differences in asthma prevalence and morbidity, assessed with different methods in different populations, have raised several hypotheses about the different susceptibility to asthma in men and women. However, information on the incidence of asthma by age and sex is limited. The aim of this study was to estimate the age- and sex-specific incidence of asthma from birth to 44 yr of age in men and women across several countries, and to evaluate the main factors influencing asthma incidence in young adults. The data of the European Community Respiratory Health Survey, an international, cross-sectional, population-based survey, which were collected in 16 countries from 1991 to 1993 according to a common protocol, and which pertained to 18,659 subjects, were analyzed retrospectively, using the reported age of the first attack as the onset of asthma. During childhood, girls had a significantly lower risk of developing asthma than did boys (relative risk [RR]: 0.74 and 0.56 in the 0- to 5-yr and 5- to 10-yr age classes, respectively). Around puberty, the risk was almost equal in the two sexes (RR = 0.84; 95% confidence interval [CI]: 0.65 to 1.10 in the 10 to 15-yr age class). After puberty, the risk in women was always significantly higher than that in men (RR: 1.38 to 5.91). This pattern was consistent in all of the 16 countries studied, and was not influenced by recall or cohort effects. When the effects of airway caliber and smoking were studied with a case-control design, the results showed that women's greater susceptibility to asthma in early adulthood was at least partly, explained by their smaller airway caliber (the OR decreased from 2. 04 [95% CI: 1.32 to 3.15] to 1.47 [95% CI: 0.89 to 2.44] after controlling for height-adjusted FEV(1)); while smoking did not increase the risk. This analysis strongly confirms that the incidence of asthma shows a sex reversal during puberty, and suggests that airway caliber, in addition to hormonal factors, could play an important role in explaining the different patterns of asthma incidence in men and women.

Adolescent↗
PubMed2000

International assessment of the internal consistency of respiratory symptoms. European Community Respiratory Health Study (ECRHS).

We aimed to assess cross-cultural validity of the reporting of respiratory symptoms in the European Community Respiratory Health Study (ECRHS). A random sample of subjects from the general population (aged 20-44 yr), from 35 centers in 15 countries, answered a questionnaire and underwent allergy tests and airway challenge with methacholine. The overall response rate to the questionnaire was 60% (n = 16,635). Exploratory factor analysis was used to identify how symptoms were grouped (i.e., to specify factor structure), using data from the United Kingdom. Subsequently, a confirmatory factor analysis of the prespecified structure for the United Kingdom was assessed for each country in consecutive nested models, increasing at each step the number of parameters forced to be equal to the United Kingdom, and assessing the goodness of fit. Variables were clustered in the same four groups (factors) in all countries. The four factors, mutually adjusted, were associated with either bronchial responsiveness, atopy, or smoking, which provides coherence for the separation of the four factors. In the confirmatory factor analysis, when the load of each of the symptoms in the corresponding factor was prespecified, all countries except Spain showed an adequate fit; in Spain there were differences in answers concerning asthma treatment. We conclude that the ECRHS multilingual translated respiratory symptoms questionnaire shows high internal consistency, suggesting that international comparisons are not affected by errors due to cross-cultural variations in the reporting of symptoms.

Adult↗
PubMed2000

Comparison of asthma prevalence in the ISAAC and the ECRHS. ISAAC Steering Committee and the European Community Respiratory Health Survey. International Study of Asthma and Allergies in Childhood.

International and regional prevalence comparisons are required to test and generate hypotheses regarding the causes of increasing asthma prevalence in various age groups worldwide. The International Study of Asthma and Allergies in Childhood (ISAAC) is the first such study in children and the European Community Respiratory Health Survey (ECRHS) is the first such study in adults. Therefore, a comparison of the findings of these two surveys was conducted, for the 17 countries in which both surveys were undertaken. There was a strong correlation between the ISAAC and ECRHS prevalence data, with 64% of the variation at the country level, and 74% of the variation at the centre level, in the prevalence of "wheeze in the last 12 months" in the ECRHS phase I data being explained by the variation in the ISAAC phase I data. There was also generally good agreement in the international patterns observed in the two surveys for self-reported asthma (74% of country level and 36% of centre level variation explained), self-reported asthma before age 14 yrs (64 and 26%), hay fever (61 and 73%) and eczema (41 and 50%). Thus although there were differences in the absolute levels of prevalence observed in the two surveys, there is good overall agreement between the International Study of Asthma and Allergies in Childhood and European Community Respiratory Health Survey study findings with regard to international prevalence patterns. These findings, therefore, add support to the validity of the two studies, which provide a new picture of global patterns of asthma prevalence from child- to adulthood, and identify some of the key phenomena which future research must address.

Adolescent↗
PubMed1999

Occupational asthma in Europe and other industrialised areas: a population-based study. European Community Respiratory Health Survey Study Group.

BACKGROUND: There are no large population-based studies on occupational asthma, and few estimates of the proportion of asthma attributed to occupation, even though asthma is the most common occupational respiratory disorder in industrialised countries. METHODS: We assessed data on 15,637 people aged 20-44, randomly selected from the general population of 26 areas in 12 industrialised countries. Asthma was assessed by methacholine challenge test and by questionnaire data on respiratory symptoms and use of medication. Occupation was defined by job-titles and a job exposure matrix was constructed. FINDINGS: Highest risk of asthma, defined as bronchial hyperresponsiveness and reported asthma symptoms or medication, was shown for farmers (odds ratio 2.62 [95% CI 1.29-5.35]), painters (2.34 [1.04-5.28]), plastic workers (2.20 [0.59-8.29]), cleaners (1.97 [1.33-2.92]), spray painters (1.96 [0.72-5.34]), and agricultural workers (1.79 [1.02-3.16]). Similar risks were shown for asthma defined as reported asthma symptoms or medication. The most consistent results across countries were shown for farmers and cleaners. Excess asthma risk was associated with high exposure to biological dusts, mineral dusts, and gases and fumes. The proportion of asthma among young adults attributed to occupation was 5%-10%. INTERPRETATION: The prevalence of occupational asthma in women and in specific occupations has been underestimated. Given a mean prevalence of asthma of about 5%, about 0.2%-0.5% of young adults become asthmatics or have their asthma exacerbated because of their occupations.

Adult↗
PubMed1999

The association of smoking with sensitization to common environmental allergens: results from the European Community Respiratory Health Survey.

BACKGROUND: Smoking is a risk factor for sensitization to some occupational allergens, but its association with sensitization to common environmental allergens remains unclear. OBJECTIVE: We sought to determine the association of smoking with total IgE levels and with sensitization to 3 common environmental allergens in data from the European Community Respiratory Health Survey. METHODS: A detailed smoking history and blood sample for determination of serum total IgE and specific IgE levels to house dust mite, grass, and cat allergens was obtained from 13,002 randomly selected young adults living in the areas served by 34 centers in 14 countries. Associations with smoking status and amount smoked were determined. Because there was evidence of heterogeneity between centers in the association of age, sex, and smoking with sensitization, odds ratios (ORs) were determined for each center and combined by using random-effects meta-analysis. RESULTS: Compared with lifetime nonsmokers, current smokers were at an increased risk of sensitization to house dust mite allergen (OR, 1.13; 95% confidence interval [CI], 1.02-1.26) but a decreased risk of sensitization to grass (OR, 0.76; 95% CI, 0.67-0.88) and cat allergens (OR, 0.69; 95% CI, 0.59-0.80). Exclusion of those with symptoms suggestive of current asthma strengthened the association of smoking with sensitization to house dust mite allergen (OR, 1.29; 95% CI, 1.11-1. 50). The geometric mean total IgE level was higher in smokers and was higher among those who currently smoked the most compared with those who smoked less than 5 cigarettes per day. CONCLUSION: The association between smoking and sensitization to common environmental allergens is different for different allergens.

Adult↗
PubMed1999

Role of current and childhood exposure to cat and atopic sensitization. European Community Respiratory Health Survey.

BACKGROUND: Clinical and population studies have shown that exposure and sensitization to allergens derived from furred pets, particularly cats, represent an important risk factor of allergic respiratory disease and also a significant risk factor for asthma. OBJECTIVE: In the framework of the multicenter European Community Respiratory Health Survey an analysis of the association of current and childhood exposure to cat with atopic sensitization to cat was conducted. METHODS: This study included cross-sectional data from 35 centers representing 16 countries. Altogether, 18,097 subjects were included, of whom 13,509 (75%) provided a blood sample for the measurement of specific IgE. Exposure data and data for potential confounders were extracted from an interviewer-led questionnaire. RESULTS: The prevalence of sensitization to cat (serum specific IgE >0.35 kU/L) was 9%. Among those who did not report allergic symptoms in the presence of pets or house dust, those who owned cats were significantly more likely to be sensitized to cats than were those who did not (odds ratio [95% confidence interval] 1.57 [1.20-2.06]. Childhood exposure to pets including cats was associated with lower sensitization to cats in adulthood, particularly among those with a positive family history of atopy (odds ratio [95% confidence interval] 0.68 [0.51-0.93]. Positive correlations were found between the community prevalence of cat and the prevalences of sensitization to cat, respiratory symptoms, physician-diagnosed asthma, and current asthma medication. CONCLUSIONS: Current cat ownership represents a significant risk for sensitization to cat if cats are allowed indoors. Our results support the hypothesis that childhood exposure to pets, including cats, might modulate immunologic mechanisms and reduce sensitization to cat in adulthood. The significant correlation found between the community prevalence of cat ownership and community prevalence of specific sensitization to cat represents the first documentation of such a relationship.

Adult↗
PubMed1999

Childhood environment and adult atopy: results from the European Community Respiratory Health Survey.

BACKGROUND: Previous literature has indicated that environmental exposures in childhood influence development of atopic sensitization. OBJECTIVE: We sought to study the association between childhood environment and adult atopy. METHODS: Thirteen thousand nine hundred thirty-two subjects aged 20 to 44 years from 36 areas in Europe, New Zealand, the United States, and Australia took part in the European Community Respiratory Health Survey, answering interviewer-led questionnaires and providing blood tests for measurement of specific IgE to grass, house dust mite, cat, and Cladosporium allergens. RESULTS: Atopy was negatively associated with family size (OR = 0. 93; 95% CI = 0.90-0.96 per 1 sib), partly attributable to an independent protective effect of a greater number of brothers (OR = 0.92; 95% CI = 0.89-0.95 per 1 brother). Accounting for total number of siblings, no further influence was detected for number of older or younger siblings. Bedroom sharing was associated with a lower prevalence of atopy, particularly to cat allergen. A protective effect of family size and bedroom sharing could only be detected in subjects reporting no parental allergy (family size, test for interaction P =.012). The presence of a dog in the home in childhood was negatively associated with adult atopy (OR = 0.85, 95% CI = 0. 78-0.92), an effect that remained after adjustment for parental allergy, sibling allergy, and adult pet ownership. CONCLUSION: Subjects from large families with brothers, shared bedrooms, and dogs in childhood were less often atopic as adults. Our findings are consistent with the hypothesis that infectious agents could inhibit development of atopy during childhood. However, in subjects with a strong genetic predisposition, environmental factors in childhood are possibly of less importance.

Adult↗
PubMed1999

Sensitization to individual allergens and bronchial responsiveness in the ECRHS. European Community Respiratory Health Survey.

Little is known about the relation of bronchial responsiveness (BHR) to sensitization to individual allergens, or its variation between countries. Data were obtained for BHR, specific immunoglobulin E and confounding variables from 11,215 subjects, aged 20-44 yrs at the start of the European Community Respiratory Health Survey, in 34 centres in 15 countries. The relation of BHR to sensitization to cat, house dust mite, timothy grass and Cladosporium was estimated by means of multiple regression for each centre, and combined across centres by random effects meta-analysis, controlling for baseline lung function, height, sex, season of testing, age, smoking and age/sex and age/smoking interactions. BHR was greater, on average, in those sensitized to cat (p=0.023), house dust mite (p<0.001) and timothy grass (p=0.018), but not to Cladosporium (p=0.60), and increased with degree of sensitization (p<0.001). All relations showed heterogeneity between centres, although to a lesser extent in the relation to sensitization to house dust mite. More variation in bronchial responsiveness was explained by sensitization and degree of sensitization to the individual allergens than by atopy defined as any positive test in each centre, but the relative importance of each allergen varied. The use of atopy as a single variable in relation to bronchial hyperresponsiveness may be misleading.

Adult↗