Association between lung function and dyspnoea and its variation in the multinational Burden of Obstructive Lung Disease (BOLD) study.

BACKGROUND: Dyspnoea is a common symptom of respiratory disease. However, data on its prevalence in general populations and its association with lung function are limited and are mainly from high-income countries. The aims of this study were to estimate the prevalence of dyspnoea across several world regions, and to investigate the association of dyspnoea with lung function. METHODS: Dyspnoea was assessed, and lung function measured in 25,806 adult participants of the multinational Burden of Obstructive Lung Disease study. Dyspnoea was defined as ≥2 on the modified Medical Research Council (mMRC) dyspnoea scale. The prevalence of dyspnoea was estimated for each of the study sites and compared across countries and world regions. Multivariable logistic regression was used to assess the association of dyspnoea with lung function in each site. Results were then pooled using random-effects meta-analysis. RESULTS: The prevalence of dyspnoea varied widely across sites without a clear geographical pattern. The mean prevalence of dyspnoea was 13.7 % (SD=8.2 %), ranging from 0 % in Mysore (India) to 28.8 % in Nampicuan-Talugtug (Philippines). Dyspnoea was strongly associated with both spirometry restriction (FVC

Prevalence of and risk factors for respiratory symptoms in an adult urban population.

OBJECTIVE: To determine prevalence of and risk factors for respiratory symptoms in an adult urban Pakistani population.METHODS: We conducted a multi-stage, community-based, cross-sectional survey from May 2014 to August 2015, comprising 1629 adults from 75 random clusters in Karachi using questionnaire-based interviews.RESULTS: Around 60% of participants were females and 43% belonged to the >37 years age group. At least one respiratory symptom was reported by 37.5% of participants. Breathlessness was the most common symptom (25.2%, 95%CI 23.1-27.3), followed by acute wheeze (10.1%, 95%CI 8.7-11.7). Multivariable models revealed that males and those aged >37 years were more likely to report acute and chronic phlegm and bronchitis, and breathlessness. Participants with a higher level of education were less likely to report acute and chronic cough. Participants with >5 years pack-years of smoking were more likely to report acute and chronic cough and breathlessness. Other risk factors included passive smoking, regular use of air conditioning and mosquito coils, wet spots and mould in the house, and exposure to dusty jobs.CONCLUSION: We found breathlessness to be the most prevalent respiratory symptom and identified various risk factors for respiratory symptoms.

Prevalence and risk factors of airflow obstruction in a Caribbean population.

SETTING: The prevalence of airflow obstruction (AO) in the Caribbean population is unknown.OBJECTIVE: To measure the prevalence of and risk factors for AO (post-bronchodilator ratio of forced expiratory volume in 1 sec to forced vital capacity of <0.7) in the Trinidad and Tobago general population using the Burden of Obstructive Lung Disease methodology.DESIGN: National cross-sectional, stratified, cluster sampling of adults aged ≥40 years.RESULTS: AO prevalence was 9.5% among 1104 participants, most of whom were unaware of this. Compared to those aged 40-49 years, the adjusted odds ratio of AO by age group was 2.73 (60-69 years) and 3.30 (≥70 years). Risk factors for AO were unemployment (OR 4.31), being retired (OR 2.17), smoking ≥20 pack-years (OR 1.88) and exposure to dusty jobs for more than 1 year (OR 2.06). Related symptoms were history of wheezing, unscheduled visits to the doctor or admission to hospital for breathing problems and in subjects with at least one respiratory symptom (OR 1.90), at least one risk factor (OR 2.81), either symptoms or risk factors (OR 3.71) and both symptoms and risk factors (OR 5.78) (P < 0.05 in all cases).CONCLUSION: AO prevalence in the general population of Trinidad and Tobago aged ≥40 years was 9.5%, almost all of which was undiagnosed. AO was associated with smoking, age >59 years, lack of employment and working in a dusty job.

Association between chronic airflow obstruction and socio-economic position in Morocco: BOLD results.

BACKGROUND: Chronic obstructive lung disease (COPD) is the third most common cause of death in the world. Factors other than smoking, such as socio-economic status, could be involved in the development of COPD.OBJECTIVE: To investigate the association between chronic airflow obstruction and socio-economic status in Morocco.DESIGN: Questionnaires were administered and spirometry tests performed as part of the BOLD (Burden of Obstructive Lung Disease) Study carried out in Fez, Morocco. Socio-economic status was evaluated using a wealth score (0-10) based on household assets. The ratio of forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) was used to measure airflow obstruction.RESULTS: A total of 760 subjects were included in the analysis. The mean age was 55.3 years (standard deviation [SD] 10.2); the average wealth score was 7.54 (SD 1.63). After controlling for other factors and potential confounders, FEV1/FVC increased by 0.4% (95%CI 0.01-0.78; P < 0.04) per unit increase in wealth score. Ageing, tobacco smoking, underweight, history of tuberculosis and asthma were also independently associated with a higher risk of airflow obstruction.CONCLUSION: Our findings suggest that airflow obstruction is associated with poverty in Morocco. Further investigations are needed to better understand the mechanisms of this association.

Atopy in people aged 40 years and over: Relation to airflow limitation.

BACKGROUND: Previous studies have reached conflicting conclusions about the role of atopy as a risk factor for COPD. In part, this is attributable to variation in the definitions of airflow limitation and the treatment of people with asthma. OBJECTIVE: To establish whether there is any independent association between atopy and post-bronchodilator airflow limitation in the general population aged 40 years and over. METHODS: A cross-sectional survey was conducted in a general population sample of 2415 people aged 40 years and over in Australia. A history of ever being diagnosed with asthma was elicited by questionnaire. Atopy was defined as any skin prick test weal to common aeroallergens ≥4 mm. Airflow limitation was defined as post-bronchodilator spirometric (FEV1 /FVC) ratio

Prevalence of chronic airflow limitation in Kashmir, North India: results from the BOLD study.

BACKGROUND: Data on spirometrically defined chronic airflow limitation (CAL) are scarce in developing countries. OBJECTIVE: To estimate the prevalence of spirometrically defined CAL in Kashmir, North India. METHODS: Using Burden of Obstructive Lung Disease survey methods, we administered questionnaires to randomly selected adults aged ⩾40 years. Post-bronchodilator spirometry was performed to estimate the prevalence of CAL and its relation to potential risk factors. RESULTS: Of 1100 participants initially recruited, 953 (86.9%) responded and 757 completed acceptable spirometry and questionnaires. The prevalence of a forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio less than the lower limit of normal was 17.3% (4.5) in males and 14.8% (2.1) in females. Risk factors for CAL included higher age, cooking with wood and lower educational status. The prevalence of current smoking was 61% in males and 22% in females; most smoked hookahs. CAL was found equally in non-smoking males and females, and was independently associated with the use of the hookah, family history of respiratory disease and poor education. A self-reported doctor's diagnosis of chronic obstructive pulmonary disease was reported in 8.4/1000 (0.9% of females and 0.8% of males). CONCLUSION: Spirometrically confirmed CAL is highly prevalent in Indian Kashmir, and seems to be related to the high prevalence of smoking, predominantly in the form of hookah smoking.

Respiratory hypersensitivity reactions to NSAIDs in Europe: the global allergy and asthma network (GA2 LEN) survey.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most prevalent drugs inducing hypersensitivity reactions. The aim of this analysis was to estimate the prevalence of NSAID-induced respiratory symptoms in population across Europe and to assess its association with upper and lower respiratory tract disorders. METHODS: The GA2 LEN survey was conducted in 22 centers in 15 European countries. Each of 19 centers selected random samples of 5000 adults aged 15-74 from their general population, and in three centers (Athens, Munich, Oslo), a younger population was sampled. Questionnaires including questions about age, gender, presence of symptoms of asthma, allergic rhinitis, chronic rhinosinusitis, smoking status, and history of NSAID-induced hypersensitivity reactions were sent to participants by mail. Totally, 62 737 participants completed the questionnaires. RESULTS: The mean prevalence of NSAID-induced dyspnea was 1.9% and was highest in the three Polish centers [Katowice (4.9%), Krakow (4.8%), and Lodz (4.4%)] and lowest in Skopje, (0.9%), Amsterdam (1.1%), and Umea (1.2%). In multivariate analysis, the prevalence of respiratory reactions to NSAIDs was higher in participants with chronic rhinosinusitis symptoms (Odds Ratio 2.12; 95%CI 1.78-2.74), asthma symptoms in last 12 months (2.7; 2.18-3.35), hospitalization due to asthma (1.53; 1.22-1.99), and adults vs children (1.53; 1.24-1.89), but was not associated with allergic rhinitis. CONCLUSION: Our study documented significant variation between European countries in the prevalence of NSAID-induced respiratory hypersensitivity reactions, and association with chronic airway diseases, but also with environmental factors.

The global burden of chronic respiratory disease in adults.

With an aging global population, chronic respiratory diseases are becoming a more prominent cause of death and disability. Age-standardised death rates from chronic obstructive pulmonary disease (COPD) are highest in low-income regions of the world, particularly South Asia and sub-Saharan Africa, although airflow obstruction is relatively uncommon in these areas. Airflow obstruction is, by contrast, more common in regions with a high prevalence of cigarette smoking. COPD mortality is much more closely related to the prevalence of a low forced vital capacity which is, in turn, associated with poverty. Mortality from asthma is less common than mortality from COPD, but it is also relatively more common in poorer areas, particularly Oceania, South and South-East Asia, the Middle East and Africa. Again this contrasts with the asthma prevalence among adults, which is highest in high-income regions. In high-income areas, mortality due to asthma, which is predominantly an adult problem, has fallen substantially in recent decades with the spread of new guidelines for treatment that emphasise the use of inhaled steroids to control the disease. Although mortality rates have been falling, the prevalence of atopy has been increasing between generations in Western Europe. Changes in the prevalence of wheeze among adults has been more varied and may have been influenced by the reduction in smoking and the increase in the use of inhaled steroids.

The relation of airway obstruction to asthma, chronic rhinosinusitis and age: results from a population survey of adults.

RATIONALE: There is conflicting evidence on whether patients with asthma experience an accelerated decline in lung function with age. We examined the association between postbronchodilator lung function, asthma, chronic rhinosinusitis (CRS), and atopy with age using a large European sample. METHODS: In 17 centers in 11 European countries, case-control studies were nested within representative cross-sectional surveys of adults aged less than 75 years. Representative samples of participants with asthma, CRS or both and controls were assessed for postbronchodilator ventilatory function, smoking history, atopy, and treatment. Multiple regression was used to assess the interactive effects of age and diagnostic group on decline in postbronchodilator ventilatory function. RESULTS: A total of 3337 participants provided adequate data (778 with asthma, 399 with CRS, 244 with both asthma and CRS and 1916 controls who had neither asthma nor CRS). Participants with asthma had lower FEV1 /FVC (-4.09% (95% CI: -5.02, -3.15, P < 0.001) and a steeper slope of FEV1 /FVC against age (-0.14%/annum [95%CI: -0.19, -0.08]) equivalent to smoking 1-2 packs of cigarettes per day. Those with atopy had a slope equivalent to controls. CONCLUSIONS: People with asthma have a steeper decline in postbronchodilator lung function with age, but neither CRS nor atopy alone were associated with such decline.

Geographical variation in the prevalence of sensitization to common aeroallergens in adults: the GA(2) LEN survey.

BACKGROUND: Geographical variation in the prevalence of sensitization to aeroallergens may reflect differences in exposure to risk factors such as having older siblings, being raised on a farm or other unidentified exposures. OBJECTIVE: We wanted to measure geographical variation in skin prick test positivity and assess whether it was explained by differences in family size and/or farm exposure. We also compared prevalence in younger and older subjects. METHODS: Within the Global Allergy and Asthma European Network (GA(2) LEN) survey, we measured the prevalence of skin prick positivity to a panel of allergens, and geometric mean serum total immunoglobulin E (IgE), in 3451 participants aged 18-75 years in 13 areas of Europe. Estimated prevalence was standardized to account for study design. We compared prevalence estimates in younger and older subjects and further adjusted for age, gender, smoking history, farm exposure, number of older siblings and body mass index (BMI). RESULTS: Skin prick test positivity to any one of the measured allergens varied within Europe from 31.4% to 52.9%. Prevalence of sensitization to single allergens also varied. Variation in serum total IgE was less marked. Younger participants had higher skin prick sensitivity prevalence, but not total IgE, than older participants. Geographical variation remained even after adjustment for confounders. CONCLUSION: Geographical variation in the prevalence of skin prick test positivity in Europe is unlikely to be explained by geographical variation in gender, age, smoking history, farm exposure, family size and BMI. Higher prevalence in younger, compared to older, adults may reflect cohort-associated increases in sensitization or the influence of ageing on immune or tissue responses.

The association of asthma, nasal allergies, and positive skin prick tests with obesity, leptin, and adiponectin.

BACKGROUND: Cross-sectional and longitudinal reports show that obese adults have more asthma than non-obese adults. A proposed mechanism is via effects of adipokines (leptin and adiponectin) on the immune system. OBJECTIVE: We wished to measure the associations of asthma and other atopic diseases with serum adipokine levels and to find whether the associations with asthma were strong enough to rule out the possibility that they are secondary to the association of fatness measures with asthma. METHODS: The Global Asthma and Allergy Network of Excellence (GA(2) LEN) clinical follow-up survey is a clinical survey, embedded in a larger multi-centre cross-sectional postal survey, involving, with a case/control design, enrichment of the sample with subjects with asthma and chronic rhinosinusitis (CRS). We recorded serum leptin or adiponectin in 845 men and 1110 women in 15 centres and also anthropometric measures of fatness including body mass index and waist/hip ratio, current asthma, and specific skin prick and IgE sensitisation. We used inverse sampling-probability-weighted rank and regression statistics to measure population associations of disease outcomes with adipokines in males and females, adjusting for confounders (area, age, smoking history, and number of elder siblings) and also mutually adjusting associations with adipokines and fatness measures. RESULTS: One thousand nine hundred and fifty-five subjects aged 16-77 years had information on leptin or adiponectin levels. Leptin and leptin/adiponectin ratio were positively associated with the level of asthma, especially in females (Somers' D of leptin by asthma score, 0.20; 95% CI, 0.08-0.30; P = 0.00079). These associations were attenuated after adjusting for confounders and became non-significant after additionally adjusting for fatness measures and multiple comparisons. CONCLUSIONS AND CLINICAL RELEVANCE: Asthma levels are positively associated with serum leptin. However, we cannot rule out the possibility that this association is secondary to associations of both with fatness measures.

Prevention and control of childhood asthma and allergy in the EU from the public health point of view: Polish Presidency of the European Union.

The leading priority for the Polish Presidency of the Council of the European Union was to reduce health inequalities across European societies, and, within its framework, prevention and control of respiratory diseases in children. This very important paper contain proposal of international cooperation on the prevention, early detection and monitoring of asthma and allergic diseases in childhood which will be undertaken by the EU member countries as a result of EU conclusion developed during the Polish Presidency of the Council of the European Union. This will result in collaboration in the field of chronic diseases, particularly respiratory diseases, together with the activity of the network of national institutions and NGOs in this area. Paper also contains extensive analysis of the socio-economic, political, epidemiological, technological and medical factors affecting the prevention and control of childhood asthma and allergy presented during Experts presidential conference organized in Warsaw-Ossa 21-22 September 2011.

Asthma in adults and its association with chronic rhinosinusitis: the GA2LEN survey in Europe.

BACKGROUND: The prevalence of asthma and its association with chronic rhinosinusitis (CRS) have not been widely studied in population-based epidemiological surveys. METHODS: The Global Allergy and Asthma Network of Excellence (GA(2) LEN) conducted a postal questionnaire in representative samples of adults living in Europe to assess the presence of asthma and CRS defined by the European Position Paper on Rhinosinusitis and Nasal Polyps. The prevalence of self-reported current asthma by age group was determined. The association of asthma with CRS in each participating centre was assessed using logistic regression analyses, controlling for age, sex and smoking, and the effect estimates were combined using standard methods of meta-analysis. RESULTS: Over 52,000 adults aged 18-75 years and living in 19 centres in 12 countries took part. In most centres, and overall, the reported prevalence of asthma was lower in older adults (adjusted OR for 65-74 years compared with 15-24 years: 0.72; 95% CI: 0.63-0.81). In all centres, there was a strong association of asthma with CRS (adjusted OR: 3.47; 95% CI: 3.20-3.76) at all ages. The association with asthma was stronger in those reporting both CRS and allergic rhinitis (adjusted OR: 11.85; 95% CI: 10.57-13.17). CRS in the absence of nasal allergies was positively associated with late-onset asthma. CONCLUSION: Geographical variation in the prevalence of self-reported asthma was observed across Europe, but overall, self-reported asthma was more common in young adults, women and smokers. In all age groups, men and women, and irrespective of smoking behaviour, asthma was also associated with CRS.

Quality of spirometry tests performed by 9893 adults in 14 countries: the BOLD Study.

OBJECTIVE: to determine the ability of participants in the Burden of Obstructive Lung Disease (BOLD) study to meet quality goals for spirometry test session quality and to assess factors contributing to good quality. METHODS: Following 2 days of centralized training, spirometry was performed pre- and post-bronchodilator (BD) at 14 international sites, in random population-based samples of persons aged ≥40 years, following a standardized protocol. The quality of each test session was evaluated by the spirometer software and an expert reading center. Descriptive statistics were calculated for key maneuver acceptability variables. A logistic regression model identified the predictors of acceptable quality test sessions. RESULTS: About 96% of test sessions met our quality goals for a low back-extrapolated volume (BEV), time to peak flow (PEFT), and end-of-test volume (EOTV). The mean forced expiratory time (FET) was 10.4 s. Ninety percent of the maneuvers with the highest FVC had a forced expiratory time (FET) > 6.8 s. About 90% of test sessions had FEV(1) and FVC which were repeatable within 150 mL. Test quality was slightly better for post-BD test sessions when compared to pre-BD. Independent predictors of adequate test quality included female sex, younger age, higher education, lack of dyspnea, higher pre-BD FEV(1), less BD responsiveness, and study site. CONCLUSIONS: Quality goals for spirometry tests were met about 90% of the time in these population-based samples of adults from several countries.

Chronic rhinosinusitis in Europe--an underestimated disease. A GA²LEN study.

BACKGROUND: Chronic rhinosinusitis (CRS) is a common health problem, with significant medical costs and impact on general health. Even so, prevalence figures for Europe are unavailable. In this study, conducted by the GA²LEN network of excellence, the European Position Paper on Rhinosinusitis and nasal Polyps (EP³OS) diagnostic criteria are applied to estimate variation in the prevalence of Chronic rhinosinusitis (CRS) for Europe. METHOD: A postal questionnaire was sent to a random sample of adults aged 15-75 years in 19 centres in Europe. Participants reported symptoms of CRS, and doctor diagnosed CRS, allergic rhinitis, age, gender and smoking history. Definition of CRS was based on the EP³OS diagnostic criteria: the presence of more than two of the symptoms: (i) nasal blockage, (ii) nasal discharge, (iii) facial pain/pressure or (iv) reduction in sense of smell, for >12 weeks in the past year--with at least one symptom being nasal blockage or discharge. RESULTS: Information was obtained from 57,128 responders living in 19 centres in 12 countries. The overall prevalence of CRS by EP³OS criteria was 10.9% (range 6.9-27.1). CRS was more common in smokers than in nonsmokers (OR 1.7: 95% CI 1.6-1.9). The prevalence of self-reported physician-diagnosed CRS within centres was highly correlated with the prevalence of EP³OS-diagnosed CRS. CONCLUSION: This is the first European international multicentre prevalence study of CRS. In this multicentre survey of adults in Europe, about one in ten participants had CRS with marked geographical variation. Smoking was associated with having CRS in all parts of Europe.

Reliability of EP3OS symptom criteria and nasal endoscopy in the assessment of chronic rhinosinusitis--a GA² LEN study.

BACKGROUND: The European Position Paper on Rhinosinusitis and Nasal Polyps (EP3OS) incorporates symptomatic, endoscopic, and radiologic criteria in the clinical diagnosis of chronic rhinosinusitis (CRS), while in epidemiological studies, the definition is based on symptoms only. We aimed to assess the reliability and validity of a symptom-based definition of CRS using data from the GA(2) LEN European survey. METHODS: On two separate occasions, 1700 subjects from 11 centers provided information on symptoms of CRS, allergic rhinitis, and asthma. CRS was defined by the epidemiological EP3OS symptom criteria. The difference in prevalence of CRS between two study points, the standardized absolute repeatability, and the chance-corrected repeatability (kappa) were determined. In two centers, 342 participants underwent nasal endoscopy. The association of symptom-based CRS with endoscopy and self-reported doctor-diagnosed CRS was assessed. RESULTS: There was a decrease in prevalence of CRS between the two study phases, and this was consistent across all centers (-3.0%, 95% CI: -5.0 to -1.0%, I(2) = 0). There was fair to moderate agreement between the two occasions (kappa = 39.6). Symptom-based CRS was significantly associated with positive endoscopy in nonallergic subjects, and with self-reported doctor-diagnosed CRS in all subjects, irrespective of the presence of allergic rhinitis. CONCLUSION: Our findings suggest that a symptom-based definition of CRS, according to the epidemiological part of the EP3OS criteria, has a moderate reliability over time, is stable between study centers, is not influenced by the presence of allergic rhinitis, and is suitable for the assessment of geographic variation in prevalence of CRS.

Forced vital capacity, airway obstruction and survival in a general population sample from the USA.

BACKGROUND: Many studies show a link between forced expiratory volume in 1 s (FEV(1)) and survival in the general population and this has been interpreted as a link between airway obstruction and survival. However, the observation that vital capacity is also associated with survival weakens this interpretation. METHODS: Data on spirometry and survival were taken from the Atherosclerosis Risk in Communities (ARIC) limited access dataset. Survival among 7489 participants with usable spirometry and complete data was regressed against measures of ventilatory function after controlling for many other factors likely to be associated with survival. RESULTS: Survival was strongly associated with forced vital capacity (FVC) after adjustment for FEV(1), but not the other way round. The fully adjusted hazard ratio (HR) associated with high FVC was 0.90 in men (95% CI 0.80 to 1.00; p=0.049) and 0.82 in women (95% CI 0.70 to 0.95; p=0.01). This compares with 0.98 for FEV(1) in men (95% CI 0.90 to 1.07; p.0.72) and 1.01 in women (95% CI 0.89 to 1.15; p=0.84). There was no association between survival and airway obstruction as measured by the FEV(1)/FVC ratio. CONCLUSIONS: FVC but not airway obstruction predicts survival in asymptomatic adults without chronic respiratory diagnoses or persistent respiratory symptoms. The association is not explained by age, anthropometry, smoking, income occupation or blood pressure. As FVC later in life, cardiovascular risk, type II diabetes mellitus and low-grade systemic inflammation are all associated with poor fetal growth, these other conditions may be partly responsible for the poor survival in those with low FVC.

Important research questions in allergy and related diseases: 3-chronic rhinosinusitis and nasal polyposis - a GALEN study.

Chronic rhinosinusitis is one of the most common health care challenges, with significant direct medical costs and severe impact on lower airway disease and general health outcomes. The diagnosis of chronic rhinosinusitis (CRS) currently is based on clinical signs, nasal endoscopy and CT scanning, and therapeutic recommendations are focussing on 2 classes of drugs, corticosteroids and antibiotics. A better understanding of the pathogenesis and the factors amplifying mucosal inflammation therefore seems to be crucial for the development of new diagnostic and therapeutic tools. In an effort to extend knowledge in this area, the WP 2.7.2 of the GA(2)LEN network of excellence currently collects data and samples of 1000 CRS patients and 250 control subjects. The main objective of this project is to characterize patients with upper airway disease on the basis of clinical parameters, infectious agents, inflammatory mechanisms and remodeling processes. This collaborative research will result in better knowledge on patient phenotypes, pathomechanisms, and subtypes in chronic rhinosinusitis. This review summarizes the state of the art on chronic rhinosinusitis and nasal polyposis in different aspects of the disease. It defines potential gaps in the current research, and points to future research perspectives and targets.

Joint effect of obesity and TNFA variability on asthma: two international cohort studies.

Obesity is a risk factor for asthma. Adipose tissue expresses pro-inflammatory molecules including tumour necrosis factor (TNF), and levels of TNF are also related to polymorphisms in the TNF-alpha (TNFA) gene. The current authors examined the joint effect of obesity and TNFA variability on asthma in adults by combining two population-based studies. The European Community Respiratory Health Survey and the Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults used comparable protocols, questionnaires and measures of lung function and atopy. DNA samples from 9,167 participants were genotyped for TNFA -308 and lymphotoxin-alpha (LTA) +252 gene variants. Obesity and TNFA were associated with asthma when mutually adjusting for their independent effects (odds ratio (OR) for obesity 2.4, 95% confidence interval (CI) 1.7-3.2; OR for TNFA -308 polymorphism 1.3, 95% CI 1.1-1.6). The association of obesity with asthma was stronger for subjects carrying the G/A and A/A TNFA -308 genotypes compared with the more common G/G genotype, particularly among nonatopics (OR for G/A and A/A genotypes 6.1, 95% CI 2.5-14.4; OR for G/G genotype 1.7, 95% CI 0.8-3.3). The present findings provide, for the first time, evidence for a complex pattern of interaction between obesity, a pro-inflammatory genetic factor and asthma.

A case-control study of the relation between plasma selenium and asthma in European populations: a GAL2EN project.

BACKGROUND: There is evidence that selenium levels are relatively low in Europe and may be falling. Low levels of selenium or low activity of some of the enzymes dependent on selenium have been associated with asthma. METHODS: The GA(2)LEN network has organized a multicentre case-control study in Europe to assess the relation of plasma selenium to asthma. The network compared 569 cases in 14 European centres with a diagnosis of asthma and reporting asthma symptoms in the last 12 months with 576 controls from the same centres with no diagnosis of asthma and no asthmatic symptoms in the last 12 months. RESULTS: All cases and controls were selected from the same population defined by age and place of residence. Mean plasma selenium concentrations among the controls ranged from 116.3 microg/l in Palermo to 67.7 microg/l in Vienna and 56.1 microg/l among the children in Oslo. Random effects meta-analysis of the results from the centres showed no overall association between asthma and plasma selenium [odds ratio (OR)/10 microg/l increase in plasma selenium: 1.04; 95% confidence interval (CI): 0.89-1.21] though there was a significantly protective effect in Lodz (OR: 0.48; 95% CI: 0.29-0.78) and a marginally significant adverse effect in Amsterdam (OR: 1.68; 95% CI: 0.98-2.90) and Ghent (OR: 1.35; 95% CI: 1.03-1.77). CONCLUSION: This study does not support a role for selenium in protection against asthma, but effect modification and confounding cannot be ruled out.