Asthma In Epidemiological Studies Research Articles

Estudio de prevalencia de asma en población general en España

IntroductionAsthma is a disease with high prevalence, which affects all age groups and generates high health and social care costs. Studies carried out in a number of populations show great variability in its prevalence, even in geographically close populations, with data suggesting a relevant influence of socio-economic factors. At present, we do not have reliable data on the prevalence of this disease in the adult population of Spain. The objectives of this study are to estimate the prevalence of asthma in the Spanish population for those aged 18-79, to describe the variability between autonomous communities, to estimate the prevalence of under and overdiagnosis, to analyse the prevalence of uncontrolled asthma and steroid-dependent asthma, to evaluate the health care cost, to identify the most frequent phenotypes and to establish a starting point to evaluate the temporal trend with subsequent studies. MethodsA cross-sectional, two-stage study will be carried out, including patients from 50 catchment areas. The study will be carried out in 3 phases: 1) screening and confirmation in the clinical history, in which patients with a previously correctly established diagnosis of asthma will be identified; 2) diagnosis of asthma to evaluate patients without a confirmed or excluded diagnosis; 3) characterization of asthma, where the characteristics of the asthmatic patients will be analysed, identifying the most frequent phenotypes. DiscussionIt seems necessary and feasible to carry out an epidemiological study of asthma in Spain to identify the prevalence of asthma, to optimize healthcare planning, to characterize the most frequent phenotypes of the disease, and to evaluate inaccurate diagnoses.

Prevalence and associated factors for asthma in adults in Quito: a cross-sectional study.

Although several epidemiological studies of asthma have been carried out in Ecuador in the last two decades, none of these has estimated the prevalence of asthma in adult populations. To estimate the prevalence of asthma symptoms in adults in the city of Quito and to identify possible associated factors. A cross-sectional study was conducted on subjects older than 18 years residing in the Metropolitan District of Quito. The Global Asthma Network (GAN) questionnaire was applied to collect information on asthma symptoms and sociodemographic and lifestyle data. Bivariate and multivariate analyses with logistic regression were used to identify asthma-related factors. 2,476 subjects answered the questionnaire (80.9% women, mean age 40 years). The prevalence of wheezing in the last 12 months, asthma ever, and asthma diagnosed by a doctor were 6.3%, 1.9% and 1.6%, respectively. The prevalence of rhinitis ever and eczema ever was 13.7% and 5.5%. The presence of mould at home (OR: 2.13; 95% CI: 1.48 -3.06; p <0.001), cat at home (OR: 1.06; 95% CI: 1.06 -2.13; p <0.022) and rhinitis at some time (OR: 3.65; 95% CI: 2.53 - 5.29; p <0.022) were associated with the presence of wheezing in the last 12 months. Our study shows that, compared to other cities in Latin America, the prevalence of asthma in adults in Quito is relatively low. Along with the presence of rhinitis, factors related to housing quality are closely linked to the occurrence of asthma in adult populations.

Diet Modifications in Primary Prevention of Asthma. Where Do We Stand?

The steep increase in asthma prevalence, observed worldwide in recent decades, has created an urgent need to search for effective methods of its prevention. Among other environmental factors, changes in diet habits and the potential influence of individual food components on immunological processes have been extensively studied as a potential method of intervention in primary prevention of asthma. The preventive role of some nutrients has been confirmed: unpasteurized milk reduced the risk of asthma in epidemiological studies, vitamin D supplementation was effective in preventing the transient forms of wheezing in small children and high maternal intake of fish oil reduced the risk of persistent wheeze and asthma in children. However, not all studies provided consistent results, and many food ingredients are still pending for defining their role in asthma development. Moreover, a novel approach looking not only at single food ingredients, but the whole dietary patterns and diversity has recently been proposed. In this paper, we discuss the current role of nutrients in asthma primary prevention and the reasons for inconsistencies in the study results. We look at single diet components, but also the whole dietary patterns. We describe the proposed mechanisms of action at different stages of life, identify the role of modifiers and delineate future perspectives on the application of nutrients in targeting strategies for asthma primary prevention.

Setting definitions of childhood asthma in epidemiologic studies

The definitions of childhood asthma differ among epidemiological studies. We aimed to compare the diagnostic accuracy and agreement of previous asthma definitions and to evaluate questionnaire-driven asthma definition patterns. Data on 808 participants aged 7-12years from 20 schools were analyzed. Asthma definitions based on symptoms assessed by questionnaire, parent-reported medical asthma diagnosis, current use of asthma medication, airway reversibility after bronchodilatation, and increased (≥35ppb) levels of exhaled nitric oxide (eNO) were compared with a gold standard (medical diagnosis of asthma with asthma symptoms in the past 12months and/or airway reversibility). Concordance was assessed by Cohen's kappa. Data-driven analysis was applied to the questionnaire, and six scores were determined "asthma," "rhinitis," "cough," "non-specific respiratory symptoms," "treated asthma," and "uncontrolled asthma." Tree decisions were built using these scores. Definitions of asthma based on respiratory symptoms, airway reversibility, and parent-reported medical diagnosis had a low sensitivity but high specificity. Agreement between reported and objective measures was poor. Parent-reported medical asthma diagnosis, but not reversibility or eNO, was able to predict questionnaire-driven symptom patterns. Decision trees indicated that those with recent non-specific respiratory symptoms had a higher probability of positive bronchodilation. A standardized operational definition of asthma should include a composite score based on reported asthma medical diagnosis, symptoms, and lung function.

Monitoring Particulate, PAH, Allergen and Microbial Exposures in Asthmatic Kids

The overall goal of the PRISMS Program is to develop sensor-based measurement and informatics platforms of environmental, physiological, and behavioral factors for epidemiological studies of asthma...

Adult Asthma Scores—Development and Validation of Multivariable Scores to Identify Asthma in Surveys

One of the questions in epidemiology is the identification of adult asthma in studies. To develop and validate multivariable scores for adult asthma identification in epidemiological studies and to explore cutoffs to rule in/rule out asthma, compared with asthma diagnosed by a physician after clinical examination and diagnostic tests, blinded to the self-administered questions. We analyzed data (n= 711 adults) from a nationwide population-based study. The predictors were self-administered questions identified in a literature review (the Adult Asthma Epidemiological Score [A2 score]) and from the Global Allergy and Asthma Network of Excellence (GA2LEN) questionnaire (the GA2LEN Asthma Epidemiological Score [GA2LEN score]). Scores were developed using exploratory factor analysis. Internal consistency, discriminative power, and diagnostic accuracy were assessed. The A2 score comprises 8 questions (including "Did a physician confirm you had asthma?") and the GA2LEN score comprises 6 questions (including "Have you ever had asthma?"). Both had high Cronbach α (0.89 and 0.85, respectively, for the A2 score and the GA2LEN score) and good area under the receiver-operating characteristic curve (90.4% and 89.0%). The scoring is the sum of positive answers. Asthma is present (rule in) for scores of 4 or more (specificity, 99.2%; PPV, 93.3% and 91.7%; accuracy, 89.4% and 87.4%, respectively, for the A2 score and the GA2LEN score). Asthma is excluded (rule out) for A2 scores of 0 to 1 and a GA2LEN score of 0 (sensitivity, 93.1%; NPV, 98.2% and 98.0%; accuracy 89.4% and 82.8%, respectively, for the A2 score and the GA2LEN score). These practical scores can be used to rule in/rule out asthma in epidemiological studies and clinical screening/triage settings. They may help physicians in primary care or other specialties to screen patients with asthma using a simple score with a high level of discrimination and to identify the best candidates to be referred for a diagnostic workup. Moreover, their use may contribute to reducing the inconsistencies of operational definitions of asthma across studies and surveys.

An epidemiological study of asthma and its risk factors in school going children in Bhavnagar city, Gujarat, India

Background: Asthma is a common disease worldwide with significant ethnic and regional variations. This study will provide evidence about the prevalence of asthma and will highlight level of problem in community. The objective of the study was to estimate prevalence of asthma and determine the presence of environmental risk factors among children with asthma.Methods: This study was conducted in school-going children of standard 5 to 8 in Bhavnagar city in 2015. Sample size was 1428. All schools of Bhavnagar city were listed and required number of schools were selected randomly and approached for consent. Study forms were filled up by personal interview and physical examination followed by house to house visits. Data entry and analysis were done using software Epi info 7. Chi square test was calculated. Multiple logistic regression was carried out by backward step-wise Likelihood Ratio (LR) method. Adjusted OR for significant variable was then calculated.Results: Total prevalence of asthma was 9% (129/1428). Out of these, 61.18% were female and 38.82% were male children. It was found 36.43% in age group of 11 years and 47.3% in children of lower socio economic class. The adjusted odds ratio for male gender was 0.631 and for smoking were 2.353.Conclusions: Female children are 1.58 times more likely to develop asthma than male children. Children whose family members smoke are 2.35 times more likely to develop asthma.

A new model of wheezing severity in young children using the validated ISAAC wheezing module: A latent variable approach with validation in independent cohorts.

BackgroundThe International Study of Asthma and Allergies in Children (ISAAC) Wheezing Module is commonly used to characterize pediatric asthma in epidemiological studies, including nearly all airway cohorts participating in the Environmental Influences on Child Health Outcomes (ECHO) consortium. However, there is no consensus model for operationalizing wheezing severity with this instrument in explanatory research studies. Severity is typically measured using coarsely-defined categorical variables, reducing power and potentially underestimating etiological associations. More precise measurement approaches could improve testing of etiological theories of wheezing illness.MethodsWe evaluated a continuous latent variable model of pediatric wheezing severity based on four ISAAC Wheezing Module items. Analyses included subgroups of children from three independent cohorts whose parents reported past wheezing: infants ages 0–2 in the INSPIRE birth cohort study (Cohort 1; n = 657), 6-7-year-old North American children from Phase One of the ISAAC study (Cohort 2; n = 2,765), and 5-6-year-old children in the EHAAS birth cohort study (Cohort 3; n = 102). Models were estimated using structural equation modeling.ResultsIn all cohorts, covariance patterns implied by the latent variable model were consistent with the observed data, as indicated by non-significant χ2 goodness of fit tests (no evidence of model misspecification). Cohort 1 analyses showed that the latent factor structure was stable across time points and child sexes. In both cohorts 1 and 3, the latent wheezing severity variable was prospectively associated with wheeze-related clinical outcomes, including physician asthma diagnosis, acute corticosteroid use, and wheeze-related outpatient medical visits when adjusting for confoundersConclusionWe developed an easily applicable continuous latent variable model of pediatric wheezing severity based on items from the well-validated ISAAC Wheezing Module. This model prospectively associates with asthma morbidity, as demonstrated in two ECHO birth cohort studies, and provides a more statistically powerful method of testing etiologic hypotheses of childhood wheezing illness and asthma.

Update of an occupational asthma-specific job exposure matrix to assess exposure to 30 specific agents

ObjectivesWe aimed to update an asthmagen job exposure matrix (JEM) developed in the late 1990s. Main reasons were: the number of suspected and recognised asthmagens has since tripled; understanding of...

Adolescent versus parent reports on asthma and asthma symptoms.

Epidemiological studies of asthma in adolescence commonly rely on self-reports. This study aimed to compare adolescent and parent reports regarding the presence of asthma and asthma symptoms in two ethnic groups, Jews and Arabs, living in the same country. Eighth-grade pupils attending five schools in Tel Aviv and four schools in two Arab cities in Israel were asked to complete the self-report International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire in the classroom. Their parents were interviewed by telephone using the parental ISAAC questionnaire. We assessed prevalence rates of asthma and asthma symptoms according to adolescent and parent responses. Agreement between adolescents and parents was assessed by Cohen's kappa coefficient. Adolescents reported more asthma and asthma symptoms than their parents in both the Jewish (327 adolescent-parent pairs) and the Arab (335 adolescent-parent pairs) groups. Both groups showed moderate adolescent-parent chance-corrected agreement for current asthma (kappa 0.59 in Jews, 0.52 in Arabs, P = 0.60) and lifetime asthma (kappa 0.53 Jews, 0.44 in Arabs, P = 0.33); and slight to fair chance-corrected agreement for asthma symptoms. There were no statistically significant differences between the Jewish and Arab populations in chance-corrected agreement for any of the parameters assessed. Jewish and Arab adolescents more often report asthma and asthma symptoms than do their parents. This seems to be a cross-cultural phenomenon. Therefore, particular attention should be paid to the source of information when comparing prevalence of asthma and asthma symptoms across studies. Pediatr Pulmonol. 2017;52:154-159. © 2016 Wiley Periodicals, Inc.

The correlation between the bronchial hyperresponsiveness to methacholine and asthma like symptoms by GINA questionnaires for the diagnosis of asthma.

BackgroundIn epidemiological studies of asthma, questionnaires to differentiate asthmatics from non-asthmatics have proven to be cost-effective and convenient. The aim of this study was to analyze the association between hyperresponsiveness to methacholine and the validity of five items for the asthma like questionnaire recommended by the Global Initiative for Asthma (GINA).MethodsA total of 680 subjects who visited the pulmonology department with suspected symptoms of asthma were enrolled. All participants completed five items questionnaires and underwent methacholine bronchial provocation tests (MBPT). The diagnostic value of the questionnaire was assessed through analysis of the sensitivity, specificity, and positive and negative predictive values.ResultsMultivariate logistic regression analysis showed that questionnaires about wheezing, exercise induced dyspnea and pollution-induced dyspnea were useful for differentiating asthmatics from non-asthmatics (adjusted odds ratio (OR) =2.0, 95% confidence interval (CI) 1.3-3.0; OR =2.3, 95% CI 1.5-3.5; OR =2.0, 95% CI 1.3-3.0) respectively. A total symptom score of higher than 1 was associated with the highest sensitivity (98.4%) and lowest specificity (9.4%). In contrast, a total symptom score of more than 5 was associated with the highest specificity (91.9%) and lowest sensitivity (18.5%)ConclusionsAlthough questionnaires are not a sufficiently accurate method for diagnosing asthma, properly selected questionnaire can be used as effective strategies in situations such as private clinics or large population based epidemiologic studies.

Operational definitions of asthma in recent epidemiological studies are inconsistent.

ObjectiveThe best combination of questions to define asthma in epidemiological asthma studies is not known. We summarized the operational definitions of asthma used in prevalence studies and empirically assess how asthma prevalence estimates vary depending on the definition used.MethodsWe searched the Thomson Reuters ISI Web of knowledge and included (1) cross-sectional studies (2) on asthma prevalence (3) conducted in the general population and (4) containing an explicit definition of asthma. The search was limited to the 100 most-cited papers or published since January 2010. For each paper, we recorded the asthma definition used and other variables. Then we applied the definitions to the data of the Portuguese National Asthma survey (INAsma) and of the 2005–2006 National Health and Nutrition Examination Survey (NHANES) computing asthma prevalence estimates for the different definitions.ResultsOf 1738 papers retrieved, 117 were included for analysis. Lifetime asthma, diagnosed asthma and current asthma were defined in 8, 12 and 29 different ways, respectively. By applying definitions of current asthma on INAsma and NHANES data, the prevalence ranged between 5.3%-24.4% and 1.1%-17.2%, respectively.ConclusionsThere is considerable heterogeneity in the definitions of asthma used in epidemiological studies leading to highly variable estimates of asthma prevalence. Studies to inform a standardized operational definition are needed. Meanwhile, we propose a set of questions to be reported when defining asthma in epidemiological studies.

P16 Severity and burden of asthma in Scotland–a full population study using the Prescribing Information system

In contrast to many epidemiological studies of asthma that have been limited to samples assumed to be representative of the national population from which they are drawn we have used...

Prevalence of asthma, local risk factors and agreement between written and video questionnaires among Turkish adolescents

BackgroundThere is currently no standard tool for the measurement of asthma in epidemiological studies. The objectives of this study were to determine the prevalence of asthma, to describe the potential local risk factors, and to assess the agreement between written and video questionnaires in 13- to 14-year-old schoolchildren. MethodsWe performed a cross-sectional study involving 5427 adolescents in 26 schools. Prevalence of asthma symptoms were evaluated using the International Study of Asthma and Allergies in Childhood (ISAAC) written and video questionnaire. The adolescents were asked additional questions for risk factors of asthma. ResultsThe prevalence of lifetime wheeze, wheeze in the last 12 months and doctor-diagnosed asthma with written questionnaire were found as 13.5%, 6.3% and 11.2% respectively. Prevalence of lifetime wheeze, wheeze in the last 12 months, wheeze after exercise in the last 12 months, with video questionnaire were found as 9.6%, 5.5%, 11.9% and 1.9% respectively. The proportion of total agreement between the two questionnaires was high (0.77–0.81) with poor kappa value (0.25–0.50). In multivariate analysis, family history of atopy, stuffed toys and accompaniment of children to their parents after school hours in textile industry were found as risk factors for asthma. In addition kind of bird, such as canary was found as a risk factor. ConclusionPrevalence of asthma is moderate in Turkey. Agreement between the two questionnaires was high. Accompaniment of children to their parents in textile industry is a newly-described risk factor for asthma.

Associations of body fat percent and body mass index with childhood asthma by age and gender

High body mass index (BMI) has been shown to be associated with asthma, but the pattern of this association is still unclear and may differ by gender or stage of puberty. BMI is only a proxy of adiposity, whereas estimation of body fat percent (BF%) by the bioimpedance technique is considered an accurate measure of adiposity. We investigated whether BMI and BF% behave differently in their association with asthma between genders, before and during adolescence. In this cross-sectional study of 10,981 schoolchildren, we used logistic regression models to examine the pattern of association of BMI and BF% with asthma. In the case of BF%, both the highest (odds ratio [OR]: 1.68, 95% confidence interval [95% CI]: 1.21-2.30) and lowest (OR: 1.59, 95% CI: 1.13-2.23) z-score categories conferred an increased adjusted risk for active asthma. The likelihood ratio test (LRT) of nonlinearity yielded significant results (P < 0.01) for BF%. In contrast, the LRT for BMI yielded a nonsignificant result (P = 0.45) indicating a linear association of asthma with BMI. A unit increase in BMI z-score conferred an increase in the adjusted odds of active asthma (OR: 1.14, 95% CI: 1.02-1.27). In the case of BF%, the adjusted ORs for active asthma at the highest and lowest z-score categories in both genders, before and during adolescence, were similarly elevated, exhibiting a U-shape pattern. In contrast to the linear association observed with BMI, BF% displayed a U-shaped association with asthma and may be the preferred measure of adiposity in epidemiological studies of asthma in children.

The Cockroach Allergen Bla g 1 Forms Alpha Helical Capsules with an Internal Lipid Binding Cavity: Implications for Allergenicity

The cockroach allergen Bla g 1 is a marker of cockroach exposure that has been widely used in epidemiologic studies of asthma. Bla g 1 is produced in the digestive tract and has a novel structure comprising tandem amino acid repeats. The goal was to determine the structure of Bla g 1 and to investigate its biological function.

Extra-Intestinal Manifestation ofHelicobacter pyloriInfection: Allergic Diseases Including Asthma, Atopy and Idiopathic Urticaria

Helicobacter pylori (H. pylori) infection is known to be negatively associated with allergic diseases including asthma in epidemiologic studies, mainly from the western countries. Bronchial asthma and allergic diseases are initiated by T-cells producing T-helper type 2 (Th2) cytokines (e.g. interleukin-4 (IL-4) and IL-5), which is inhibited by Th1 responses. H. pylori infection appears to inhibit Th2 responses, as well as to drive Th1 inflammation, and recent studies using experimental models of allergic airway disease elucidated a direct link between H. pylori infection and suppression of allergic airway disease through the induction of regulatory T cells. H. pylori has been implicated as a factor in idiopathic urticaria. Its eradication, however, has been shown conflicting results only. Therefore, routine H. pylori eradication for patients with chronic urticaria is not recommended. In Korea, prevalence of H. pylori infection shows a decreasing trend, and studies on association of H. pylori infection with asthma is warranting in the population. (Korean J Med 2013;84:774-780)

The role of Helicobacter pylori infection in the development of allergic asthma

Asthma is one of the most prevalent chronic diseases in developed countries, with steady increases in asthma prevalence evident, particularly in the last few decades. As genetic factors are unlikely to contribute to the rise in asthma prevalence, changes in lifestyle and exposure to environmental stimuli have been proposed to account for this trend. The ‘disappearing microbiota’ hypothesis postulates that major shifts in the human microbiome, resulting from dramatic lifestyle changes, account for the increase in asthma prevalence. In this context, persistent gastric colonization with the human-specific pathogen Helicobacter pylori has been negatively associated with the occurrence of asthma in epidemiological studies. In addition, experimental models of allergic airway disease revealed a direct link between infection with H. pylori and suppression of allergic airway disease through the induction of regulatory T cells. These and other new insights hold the promise of opening up new avenues toward the development of innovative, new strategies directed at asthma treatment and prevention.

Predictors of asthma control

One strategy to improve asthma control is to identify risk factors for uncontrolled asthma in epidemiologic studies and then consider those risk factors as potential targets for intervention. This article reviews predictors of impairment based on validated tools and predictors of severe asthma exacerbations. Indirectly modifiable risk factors for poor asthma control include older age in adults, lower socioeconomic status, and poor perception of dyspnea. Modifiable risk factors for poor asthma control include allergy triggers, low adherence, comorbidities, absence of specialty care, and various aspects of asthma self-management education. Intervention strategies are suggested for predictors that are directly or indirectly modifiable. It is hoped that attention to these factors will improve asthma control and reduce the burden of disease.

A Comparison of Three Methods to Measure Asthma in Epidemiologic Studies: Results from the Danish National Birth Cohort

Asthma is a heterogeneous outcome and how the condition should be measured to best capture clinically relevant disease in epidemiologic studies remains unclear. We compared three methods of measuring asthma in the Danish National Birth Cohort (n>50.000). When the children were 7 years old, the prevalence of asthma was estimated from a self-administered questionnaire using parental report of doctor diagnoses, ICD-10 diagnoses from a population-based hospitalization registry, and data on anti-asthmatic medication from a population-based prescription registry. We assessed the agreement between the methods using kappa statistics. Highest prevalence of asthma was found using the prescription registry (32.2%) followed by the self-report (12.0%) and the hospitalization registry (6.6%). We found a substantial non-overlap between the methods (kappa = 0.21–0.38). When all three methods were combined the asthma prevalence was 3.6%. In conclusion, self-reported asthma, ICD-10 diagnoses from a hospitalization registry and data on anti-asthmatic medication use from a prescription registry lead to different prevalences of asthma in the same cohort of children. The non-overlap between the methods may be due to different abilities of the methods to identify cases with different phenotypes, in which case they should be treated as separate outcomes in future aetiological studies.