Increase in asthma and a high prevalence of bronchitis: results from a population study among adults in urban and rural Vietnam

Underdiagnosis and misclassification of COPD in Sweden - A Nordic Epilung study

INTRODUCTION

The prevalence of COPD tends to level off in populations with decreasing prevalence of smoking but the extent of underdiagnosis in such populations needs further investigation.

AIM

To investigate underdiagnosis and misclassification of COPD with a focus on socio-economy, lifestyle determinants and healthcare utilization.

METHOD

The 1839 participants were selected from two ongoing large-scale epidemiological research programs: The Obstructive Lung Disease in Northern Sweden Studies and the West Sweden Asthma Study. COPDGOLD was defined according to the fixed post-bronchodilator spirometric criteria FEV1/FVC<0.70 in combination with respiratory symptoms.

RESULTS

Among the 128 participants who fulfilled the criteria for COPDGOLD, the underdiagnosis was 83.6% (n = 107) of which 57.9% were men. The undiagnosed participants were younger, had higher FEV1% of predicted and less frequently a family history of bronchitis. One in four of the undiagnosed had utilized healthcare and had more frequently utilized healthcare due to a burden of respiratory symptoms than the general population without COPD. Underdiagnosis was not related to educational level. Misclassification of COPD was characterized by being a woman with low education, ever smoker, having respiratory symptoms and having a previous asthma diagnosis.

CONCLUSION

In the high income country Sweden, the underdiagnosis of COPD was highly prevalent. Reduced underdiagnosis can contribute to risk factor modification, medical treatment and self-management strategies in early stages of the disease, which may prevent disease progression and improve the quality of life among those affected. Therefore, there is a need to increase the use of spirometry in primary care to improve the diagnostic accuracy.

Updated estimation of the burden of fungal disease in Vietnam

BACKGROUND

Anecdotally, the burden of fungal diseases in Vietnam is rapidly rising, but there has been no updated estimate on this issue since a previous report in 2015.

OBJECTIVES

In this study, we aimed at estimating the incidence and prevalence of serious fungal infections for the year 2020.

METHODS

We made estimates with a previously described methodology, using reports on the incidence and prevalence of various established risk factors for fungal infections from local, regional or global sources.

RESULTS

We estimated 2,389,661 cases of serious fungal infection occurred in Vietnam in 2020. The most common condition was recurrent vaginal candidiasis (4047/100,000 women annually). Among people living with HIV, we estimated 451 cases of cryptococcal meningitis, 1030 of pneumocystis pneumonia, 166 of histoplasmosis and 1612 of talaromycosis annually. Candidaemia incidence was estimated at 12/100,000 population each year. Owing to its high burden of tuberculosis and respiratory diseases, Vietnam had high rates of severe infections caused by Aspergillus species. Incidence of invasive aspergillosis is 24/100,000 population, allergic bronchopulmonary aspergillosis 78/100,000 and severe asthma with fungal sensitisation 102/100,000. Five-year period prevalence of chronic pulmonary aspergillosis is 120/100,000 population /5-year period. Mucormycosis, fungal keratitis and tinea capitis were estimated at 192, 14,431 and 201 episodes each year, respectively.

CONCLUSIONS

The number of patients with mycoses in Vietnam is likely underestimated due to a lack of local data and limited diagnostic capacity, but at least 2.5% of the population might have some form of serious fungal disease.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

The Cotton Dust-Related Allergic Asthma: Prevalence and Associated Factors among Textile Workers in Nam Dinh Province, Vietnam

Objective: To determine the prevalence of cotton dust-related allergic asthma and associated factors among textile workers in Nam Dinh province, Vietnam. Methods: A cross-sectional study was performed with 1082 workers in two textile garment companies using the asthma diagnostic criteria of the GINA (Global Initiative for Asthma) 2016 guidelines. Results: Among study participants, 11.9% had suspected asthma symptoms, 7.4% were diagnosed with asthma, and 4.3% (3.6% in men and 4.5% in women) were diagnosed with cotton dust-related allergic asthma. Overweight, seniority more than 10 years, history of asthma, allergic rhinitis, family history of allergy, and exposure to cotton dust from more than one hour per day in the working environment were found to be important predictors of cotton dust-related allergic asthma among textile workers. Conclusions: Textile workers in two companies in Nam Dinh, Vietnam had a high prevalence of dust-related allergic asthma compared to estimates from the general population. There is a need to design appropriate measures of prevention, screening, and care for dust-related asthma in the textile industry. Further evaluation with better exposure assessment is necessary.

Bronchial hyperresponsiveness is common in Hanoi, Vietnam: Asthma probably underdiagnosed

BACKGROUND

Bronchial hyperresponsiveness (BHR) is a key pathophysiological feature of asthma. Methacholine challenge test (MCT) is a common bronchoprovocation test useful for confirming a diagnosis of asthma. Studies of BHR in the general population of Asian countries are rare.

AIM

To estimate prevalence and determinants of BHR in Hanoi, Vietnam, and to study the association between BHR and symptoms common in asthma and previously diagnosed asthma.

METHODS

1500 out of 5872 randomly selected adults in urban and rural Hanoi, who had participated in a questionnaire survey (83% participated), were randomly selected and invited to clinical examinations. Totally 684 subjects (46%) participated. MCT was performed in 366 subjects. BHR was defined as a FEV₁-decrease of ≥20% from baseline following methacholine inhalations (PC₂₀). Cut offs used in the analyses were PC₂₀ ≤ 1 mg/ml, ≤2 mg/ml and ≤8 mg/ml.

RESULTS

The prevalence of BHR was 16.4% at doses ≤8 mg/ml, while 9.6% reacted on doses ≤2 mg/ml. PC₂₀ ≤ 2 mg/ml was associated with FEV₁ <80% of predicted. PC₂₀ ≤ 2 mg/ml, but not PC₂₀ ≤ 8 mg/ml, was associated with multi-sensitization to airborne allergens. BHR defined as PC₂₀ ≤ 8 mg/ml was associated with age >45y. The combination of asthmatic wheeze (wheezing with breathlessness apart from colds) and BHR, irrespectively of magnitude of BHR, was more common than the combination of BHR with previously diagnosed asthma.

CONCLUSIONS

The results indicate BHR to be more common in Hanoi than previously found in south-east Asia. Although the prevalence of physician diagnosed asthma has increased in Vietnam, our results indicate that asthma still may be underdiagnosed in Vietnam.

Chronic respiratory disease surveys in adults in low- and middle-income countries: A systematic scoping review of methodological approaches and outcomes

BACKGROUND

Chronic respiratory diseases (CRDs) contribute significantly towards the global burden of disease, but the true prevalence and burden of these conditions in adults is unknown in the majority of low- and middle-income countries (LMICs). We aimed to identify strategies - in particular the definitions, study designs, sampling frames, instruments, and outcomes - used to conduct prevalence surveys for CRDs in LMICs. The findings will inform a future RESPIRE Four Country ChrOnic Respiratory Disease (4CCORD) study, which will estimate CRD prevalence, including disease burden, in adults in LMICs.

METHODS

We conducted a scoping review to map prevalence surveys conducted in LMICs published between 1995 and 2018. We followed Arksey and O'Malley's six-step framework. The search was conducted in OVID Medline, EMBASE, ISI Web of Science, Global Health, WHO Global Index Medicus and included three domains: CRDs, prevalence and LMICs. After an initial title sift, eight trained reviewers undertook duplicate study selection and data extraction. We charted: country and populations, random sampling strategies, CRD definitions/phenotypes, survey procedure (questionnaires, spirometry, tests), outcomes and assessment of individual, societal and health service burden of disease.

RESULTS

Of 36 872 citations, 281 articles were included: 132 from Asia (41 from China). Study designs were cross-sectional surveys (n = 260), cohort studies (n = 11) and secondary data analysis (n = 10). The number of respondents in these studies ranged from 50 to 512 891. Asthma was studied in 144 studies, chronic obstructive pulmonary disease (COPD) in 112. Most studies (100/144) based identification of asthma on symptom-based questionnaires. In contrast, COPD diagnosis was typically based on spirometry findings (94/112); 65 used fixed-ratio thresholds, 29 reported fixed-ratio and lower-limit-of-normal values. Only five articles used the term 'phenotype'. Most studies used questionnaires derived from validated surveys, most commonly the European Community Respiratory Health Survey (n = 47). The burden/impact of CRD was reported in 33 articles (most commonly activity limitation).

CONCLUSION

Surveys remain the most practical approach for estimating prevalence of CRD but there is a need to identify the most predictive questions for diagnosing asthma and to standardise diagnostic criteria.

Factors affecting healthcare pathways for chronic lung disease management in Vietnam: a qualitative study on patients' perspectives

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and asthma rank among the leading causes of respiratory morbidity, particularly in low- and middle-income countries. This qualitative study aimed to explore the healthcare pathways of patients with chronic respiratory disease, and factors influencing their ability to access healthcare in Vietnam, where COPD and asthma are prevalent.

METHODS

We conducted 41 in-depth interviews among patients, including 31 people with COPD, eight with asthma and two with asthma-COPD overlap syndrome. Participants were recruited at provincial- or national-level health facilities in two urban and two rural provinces in Vietnam. The interviews were audio-recorded, transcribed, and analysed using thematic analysis.

RESULTS

Patients' healthcare pathways were complex and involved visits to multiple health facilities before finally obtaining a definitive diagnosis at a provincial- or national-level hospital. Access to healthcare was affected considerably by participants' limited knowledge of their respiratory conditions, the availability of social support, especially from family members, the costs of healthcare as well as health system factors (including the coverage of public health insurance, the distance to health facilities, and attitude of healthcare providers).

CONCLUSION

The study demonstrated the need for improved access to timely diagnosis and treatment of chronic lung disease within the lower level of the health system. This can be achieved by enhancing the communication skills and diagnostic capacity of local healthcare workers. Health education programmes for patients and caregivers will contribute to improved control of lung disease.

Relationships between symptom control, medication management, and health literacy of patients with asthma in Vietnam

Background

Asthma is a significant health issue among Vietnamese adults in both urban and rural areas. The disease needs serious concern to minimize impact and improve the situation.

Objective

This study aimed to describe the level of health literacy, symptom control, and medication management and determine the relationships among them in patients with asthma in Da Nang, Vietnam.

Methods

A cross-sectional descriptive study was conducted among 84 patients with asthma. The questionnaires were used in this study, including demographic form, the Short-Form Health Literacy questionnaire (HL-SF12), Asthma Control Test (ACT), and Medication Adherence Reporting Scale for Asthma (MARS-A). Pearson product-moment correlation was applied to determine the relationship between health literacy, symptom control, and medication management.

Results

The score revealed for general-health literacy, symptom control, and medication management were 28.70 (SD = 9.66), 17.72 (SD = 4.67), and 3.63 (SD = 0.75), respectively. Health literacy level had moderate positive relationships with symptom control (r = 0.41) and medication management (r = 0.44).

Conclusion

The patients had limited health literacy, partially controlled symptom, and poor adherence to the medication. Health literacy level had moderate positive relationships with symptom control and medication management. These findings are crucial for effective treatment and management of the disease in Vietnam. To improve medication management and symptom control among patients with asthma, nurses should concern patients' health literacy level.

The triad of current asthma, rhinitis and eczema is uncommon among adults: Prevalence, sensitization profiles, and risk factors

BACKGROUND

Coexistence of asthma, rhinitis, and eczema has been studied in children, but data are lacking in adults. As new treatments emerge, epidemiological data on the coexistence are needed.

AIMS

To study the prevalence of concomitant asthma, rhinitis and eczema in the general adult population and among those sensitized to aeroallergens, and to study associations between background characteristics and risks of phenotypes of asthma, rhinitis, and eczema.

METHODS

In the West Sweden Asthma Study, phenotypes and sensitization profiles of 1103 randomly selected adults (16-75 years) were assessed. The methods included measures of serum-IgE and structured interviews on asthma, rhinitis, eczema, their associated symptoms, and relevant risk factors.

RESULTS

Among all participants and in those sensitized, 2% and 6% had concomitant asthma, rhinitis, and eczema, respectively, and the condition did not differ by age or sex. Corresponding figures for asthma and rhinitis, but not eczema, was 8% and 19%, respectively. Determinants of coexistence of the three conditions were family history of asthma/allergy, body mass index, and occupational exposure to gas, dust and fumes. Allergic sensitization in those with asthma, rhinitis and eczema was found in 78%, in those with asthma and rhinitis but not eczema in 65%, in those with asthma and eczema but not rhinitis in 40%, while only 5% were sensitized among those having asthma only.

CONCLUSIONS

In the general adult population about 2% have concomitant asthma, rhinitis, and eczema. Of sensitized adults, about 6% has coexistence of the three conditions.

Non-response did not affect prevalence estimates of asthma and respiratory symptoms - results from a postal questionnaire survey of the general population

BACKGROUND

A high participation rate is warranted in order to ensure validity in surveys of the general population. However, participation rates in such studies have declined during the last decades.

OBJECTIVE

To evaluate the reasons for and potential effects of non-response in a large population-based survey about asthma and respiratory symptoms in Northern Sweden.

METHODS

Within the Obstructive Lung Disease In Norrbotten (OLIN) studies, a random sample of 12,000 adults aged 20-79 was invited to a postal questionnaire survey about asthma, allergic rhino-conjunctivitis and respiratory symptoms in 2016. Three reminders were sent. A random sample of 500 non-responders was invited to a telephone interview.

RESULTS

The participation rate in the initial mailing was 41.4%, and 9.2%, 5.0%, and 2.6% in the subsequent three reminders and totally 58.3% (n = 6854) responded. Of 500 non-responders selected for telephone interviews, 320 were possible to reach and 272 participated. Male sex, younger age, and current smoking were associated with both late and non-response. The prevalence of asthma and most respiratory symptoms did not differ significantly between responders and non-responders while allergic rhino-conjunctivitis and smoking was more common among non-responders. Reminders increased the participation rate but did not alter risk ratios for smoking and occupational exposures. Reasons for non-response were mainly lack of time and having forgotten to answer.

CONCLUSIONS

With a response rate of 58.3%, neither the prevalence estimates of asthma, respiratory symptoms nor the associations to risk factors were affected by non-response, while allergic rhino-conjunctivitis and smoking was underestimated in this Swedish population.

Urbanisation and asthma in low-income and middle-income countries: a systematic review of the urban-rural differences in asthma prevalence

BACKGROUND

Urbanisation has been associated with temporal and geographical differences in asthma prevalence in low-income and middle-income countries (LMICs). However, little is known of the mechanisms by which urbanisation and asthma are associated, perhaps explained by the methodological approaches used to assess the urbanisation-asthma relationship.

OBJECTIVE

This review evaluated how epidemiological studies have assessed the relationship between asthma and urbanisation in LMICs, and explored urban/rural differences in asthma prevalence.

METHODS

Asthma studies comparing urban/rural areas, comparing cities and examining intraurban variation were assessed for eligibility. Included publications were evaluated for methodological quality and pooled OR were calculated to indicate the risk of asthma in urban over rural areas.

RESULTS

Seventy articles were included in our analysis. Sixty-three compared asthma prevalence between urban and rural areas, five compared asthma prevalence between cities and two examined intraurban variation in asthma prevalence. Urban residence was associated with a higher prevalence of asthma, regardless of asthma definition: current-wheeze OR:1.46 (95% CI:1.22 to 1.74), doctor diagnosis OR:1.89 (95% CI:1.47 to 2.41), wheeze-ever OR:1.44 (95% CI:1.15 to 1.81), self-reported asthma OR:1.77 (95% CI:1.33 to 2.35), asthma questionnaire OR:1.52 (95% CI:1.06 to 2.16) and exercise challenge OR:1.96 (95% CI:1.32 to 2.91).

CONCLUSIONS

Most evidence for the relationship between urbanisation and asthma in LMICs comes from studies comparing urban and rural areas. These studies tend to show a greater prevalence of asthma in urban compared to rural populations. However, these studies have been unable to identify which specific characteristics of the urbanisation process may be responsible. An approach to understand how different dimensions of urbanisation, using contextual household and individual indicators, is needed for a better understanding of how urbanisation affects asthma.

PROSPERO REGISTRATION NUMBER

CRD42017064470.

Air Pollution in a Nationally Representative Sample: Findings from the National Adult Tobacco Survey of Lao PDR

In Southeast Asia, household air pollution (HAP) from solid fuel use is the leading cause of disability-adjusted life years (DALYs), a risk which is compounded by exposure to other sources of indoor and outdoor air pollution including secondhand tobacco smoke (SHS). The purpose of this study was to measure the individual and combined prevalence of exposure to household and community sources of air pollution in a national sample of adults in Lao PDR. We analyzed data from the 2012 National Adult Tobacco Survey (NATSL) of Lao PDR-a multi-stage stratified cluster sample of 9706 subjects from 2822 households located in all 17 provinces. Our findings indicate a high prevalence of exposure to household air pollution from cooking fires (78%) and SHS exposure in the home (74.5%). More than a third (32.8%) reported exposure to both inside the home. Exposure to outdoor sources of smoke from cooking, trash, and crop fires was substantial (30.1% to 56.0%). The aggregation of exposures from multiple sources of household air pollution raises the need for initiatives that establish programmatic linkages in the health, environmental, and agricultural sectors to provide a comprehensive strategy to reduce risk factors for respiratory disease in Lao PDR and the region.

Changes in the prevalence of asthma and respiratory symptoms in western Sweden between 2008 and 2016

BACKGROUND

Asthma is a common chronic inflammatory disease of the airways, with a noticeable increase in prevalence during the second half of the 20th century. Recent studies assessing the prevalence trends among adults have been inconsistent. We investigated the changes in the prevalence of asthma, respiratory symptoms, and risk factors between 2008 and 2016 in western Sweden.

METHODS

The West Sweden Asthma Study (WSAS) is a population-based study which started in 2008 (WSAS I) and then repeated in 2016 (WSAS II) in western Sweden. Randomly selected individuals aged 16-75 years (N = 18 087 in 2008 and N = 24 534 in 2016) completed a questionnaire regarding obstructive lung diseases, respiratory symptoms, potential risk factors, and also questions from the GA² LEN survey.

RESULTS

The prevalence of reported ever asthma, physician-diagnosed asthma, use of asthma medication, and current asthma increased significantly from 9.6% to 11%, 8.3% to 10%, 8.6% to 9.8%, and 8.1% to 9.1%, respectively, between 2008 and 2016. There were also increases in the prevalence of respiratory symptoms during the same period. The greatest increase occurred in young adults aged 16-25 years. Female gender, allergic rhinitis, obesity, and family history of asthma remained the strongest risk factors for asthma in 2016 as it was in 2008.

CONCLUSION

There were moderate increases in asthma and respiratory symptoms in adults in western Sweden between 2008 and 2016, the greatest increase occurring in younger adults. The potential risk factors for asthma remained the same during the study period.

Acupoint herbal patching for bronchitis: A protocol systematic review of randomized controlled trials

BACKGROUND

Acupoint herbal patching (AHP) is widely used for symptom management in patients with acute and chronic bronchitis. The purpose of this protocol review is to evaluate the safety and efficacy of AHP for the treatment of bronchitis.

METHODS AND ANALYSIS

This protocol of systematic review will be conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P). The databases searched will include PubMed, Embase, CENTRAL, Web of Science, 3 Korean medical databases (OASIS, Korea Med, and KMBASE), and the Chinese database China National Knowledge Infrastructure (CNKI). Randomized controlled trials (RCTs) or quasi-RCTs using AHP for bronchitis will be considered. The selection of the studies, data abstraction, and validations will be performed independently by 3 researchers.

CONCLUSION

The conclusion of the review will provide evidence that AHP is an effective intervention in patients with bronchitis.

ETHICS AND DISSEMINATION

As individuals were not involved, ethical approval is not required. Findings will be published in a peer-reviewed journal. This systematic review may inform the treatment of bronchitis patients in clinical practice.

REGISTRATION

This systematic review has been registered with the International Prospective Register of Systematic Reviews (PROSPERO). The reference number is CRD42018110380.

Pattern of Cardiovascular Comorbidity in COPD in a Country with Low-smoking Prevalence: Results from Two-population-based Cohorts from Sweden

Cardiovascular diseases are the most common comorbidities in COPD, due to common risk factors such as smoking. The prevalence of current smokers in Sweden has decreased over four decades to around 10%. The aim of the present study was to investigate the prevalence, distribution and associations of cardiovascular comorbidities in COPD by disease severity in two large areas of Sweden, both with low-smoking prevalence. Data from clinical examinations in 2009-2012, including spirometry and structured interview, from two large-scale population studies, the West Sweden Asthma Study (WSAS) and the OLIN Studies in Northern Sweden, were pooled. COPD was defined using post-bronchodilator spirometry according to the fixed ratio FEV₁/FVC <0.70 and the lower limit of normal (LLN^5th percentile) of the ratio of FEV₁/FVC. Of the 1839 subjects included, 8.7% and 5.7% had COPD according to the fixed ratio and the LLN criterion. Medication for heart disease or hypertension among those with moderate-to-severe COPD was more common than among those without COPD (fixed ratio definition of COPD: 51% vs. 23%, p < 0.001; LLN definition: 42% vs. 24%, p = 0.002). After adjusting for known risk factors for COPD, including smoking, age, socio-economic status, and occupational exposure for gas, dust and fumes, only heart failure remained significantly, and independently, associated with COPD, irrespective of the definitions of COPD. Though a major decrease in smoking prevalence, the pattern of cardiovascular comorbidities in COPD still remains similar with previously performed studies in Sweden and in other Westernized countries as well.

Epidemiology of chronic airway disease: results from a cross-sectional survey in Beijing, China

Background

Although the epidemiology of chronic airway disease (CAD) has been investigated in several population-based studies, the findings of these studies are diverse. We aimed to investigate the prevalence of CAD and its associated factors in urban northern China.

Methods

A cross-sectional study was conducted among 29,359 Chinese adults aged ≥20 years. All participants were randomly recruited from two urban communities in Beijing and asked to complete a self-administered questionnaire that enquired about the demographic characteristics as well as the diagnosis of CAD and CAD-related symptoms.

Results

In all, 26,166 participants completed the questionnaire, with the response rate being 89.1%. The prevalence of diagnosed CAD was 9.0% among men and 7.2% among women, with a total prevalence of 8.1%. Furthermore, 11.5% of the investigated subjects had CAD-related symptoms. Women had a lower risk of developing wheezing, cough, dyspnea, and diagnosed CAD than men (P<0.05). The frequency of CAD-related symptoms and diagnosed CAD was greater among elderly persons than among those who were younger (P<0.01). Subjects with a smoking habit were more susceptible to CAD-related symptoms and diagnosed CAD (P<0.01). Additionally, individuals with CAD-related symptoms were more likely to be diagnosed with CAD, compared to those without these symptoms (P<0.01).

Conclusions

CAD is a common respiratory disease in urban northern China. Female gender might be a protective factor against CAD, while age and smoking are risk factors for the disease.

Knowledge on self-management and levels of asthma control among adult patients in Ho Chi Minh City, Vietnam

Background

Most asthma patients in Vietnam have poorly controlled asthma. Besides reasons related to the health care system and health care providers, knowledge on the self-management of patients has also contributed to this situation.

Purpose

To assess knowledge on asthma self-management among adult asthma patients in Ho Chi Minh City.

Patients and methods

A cross-sectional study with convenience sampling was conducted among 322 ambulatory patients using questionnaires filled in via a face-to-face interview. The questionnaires enquired about: 1) sociodemographic details, 2) the Global Initiative for Asthma 2017 criteria of asthma control, 3) the Asthma Control Test, and 4) the Asthma Self-Management Questionnaire (ASMQ). Knowledge on asthma self-management was determined by the ASMQ score. The relationship between this knowledge and demographic factors and asthma control levels was determined.

Results

The knowledge on asthma self-management was low, with a mean raw ASMQ score of 4.3 (maximum 14); this is equivalent to 30 in a transformed score (maximum 100). Only 0.3% of these patients had good knowledge, 16.2% had adequate knowledge, and 83.5% had poor knowledge. Of all participants, 52% stated erroneously that asthma can be cured, 30% were confused about control and rescue medications, 68% failed to correctly describe the inhalation technique, and only 15.5% could answer correctly about the management of an exacerbation. Although most participants had poor asthma control, the higher the patient’s level of control, the better the ASMQ score. Conversely, patients with better knowledge of asthma self-management (ASMQ score ≥50) had better asthma control based on the Asthma Control Test score. Also, a higher education level was associated with more knowledge on asthma self-management.

Conclusion

In these patients, the level of knowledge on asthma self-management was low and significantly correlated with the level of asthma control. There is a clear need to improve knowledge in order to improve asthma control in Vietnam.

Implementation of GINA guidelines in asthma management by primary care physicians in Vietnam

Background

Asthma control is suboptimal in Vietnam. Lack of knowledge of primary care physicians (PCPs) for asthma management may potentially be one of the causes.

Purpose

The aim of this study was to assess the knowledge and practice of PCPs’ asthma management based on the Global Initiative for Asthma (GINA) guidelines (2015 update).

Methods

A cross-sectional study with convenience sampling was conducted among PCPs in an urban and rural area of Vietnam using questionnaires related to asthma patients daily practice: use of spirometry and the asthma control test (ACT), prescription of asthma medications, and frequency of consultations. Five asthma case scenarios were also used to ask participants to classify GINA-defined levels of asthma control and to choose the initial or adjusted treatment options based on the current situation. All scenarios are common in Vietnam, ie, three cases for adults, one case for children, and one case for pregnant women.

Results

Of the 327 completed questionnaires, 201 questionnaires could be analyzed. Most PCPs consulted their asthma patients on a weekly to monthly basis. Approximately 50% used spirometry for asthma care and only 25% used ACT. For asthma treatment, oral short-acting beta agonists and oral steroids were still commonly used and long-acting beta agonists alone were prescribed by 70%. Regarding GINA-defined levels of asthma control, 24% of the responders had ≥50% of correct answers, 21% had no correct answers, 2% had all five correct answers, and 20–42% had a correct answer for each of the five questions. Regarding treatment choice, 22% had ≥50% of correct answers, 14% had a wrong answer for all nine questions, and no respondent had a correct answer for ≥8 questions.

Conclusion

The percentage of PCPs in Vietnam who had implemented GINA 2015 was low. Some drugs with a high risk of side effects were still being prescribed. There is a need to improve both knowledge and daily practice. Additional studies should determine why these guidelines are not largely adopted by PCPs in Vietnam.

Occupational exposure to chemicals drives the increased risk of asthma and rhinitis observed for exposure to vapours, gas, dust and fumes: a cross-sectional population-based study

OBJECTIVES

Occupational exposure to the composite measure vapours, gases, dusts and fumes (VGDF), contribute to the burden of asthma and rhinitis. The objective was to evaluate occupational exposure to VGDF, which is further divided into the components chemicals, organic and inorganic dust in relation to asthma and rhinitis.

METHODS

Previously examined participants from three population-based cohorts in the Obstructive Lung disease In Northern Sweden (OLIN) studies were re-examined during 2002-2004. In total, 4036 participated in a structured interview and answered a questionnaire on occupational exposures.

RESULTS

Occupational exposure to VGDF increased the risk of asthma, and concomitant asthma and rhinitis. Exposure to chemicals, but not dust, showed a similar pattern. Exposure to chemicals increased the risks (OR, 95% CI) of rhinitis without asthma (1.29, 1.10 to 1.52), asthma without rhinitis (1.42, 1.15 to 1.77) and concomitant asthma and rhinitis (1.60, 1.31 to 1.96) when adjusted for confounders such as age, smoking habits, body mass index and sex. The association between exposure to chemicals and asthma and rhinitis remained independent of exposure to dust and was also so when excluding exposure to isocyanates and welding fumes. The results were similar for women and men, as well as for never-smokers and participants without a history of allergy.

CONCLUSIONS

In this cross-sectional population-based study, occupational exposure to chemicals contributed substantially to the increased risk of asthma and rhinitis observed for occupational exposure to VGDF.

Chronic bronchitis in West Sweden - a matter of smoking and social class

BACKGROUND

Although chronic bronchitis is associated with impaired quality of life, hospitalisations and increased mortality, it has been less in focus after the introduction of the term chronic obstructive pulmonary disease (COPD). There are no recent published data on the prevalence of chronic bronchitis from the Scandinavian countries.

AIM

The main aim of the present study was to estimate the prevalence of chronic bronchitis in West Sweden by using data from a large-scale epidemiological study of the general population. A further aim was to identify current risk factors for chronic bronchitis in a population with a major decrease in the proportion of smokers.

METHODS

From the 18,087 questionnaire responders out of 30,000 invited to participate at the West Sweden Asthma Study, 2,000 subjects were randomly selected and invited to detailed clinical examinations performed during 2009-2013. A total of 1,172 subjects aged 17-79 participated in the examinations which included, among others, spirometry and structured interviews. Chronic bronchitis was defined according to reported symptoms.

RESULTS

The overall prevalence of chronic bronchitis was 7.2% (men 7.6%; women 6.8% ns), and it was 8.7% in subjects older than age 60. Chronic bronchitis was strongly associated with smoking, defined both as current smoking status and pack-years. Other risk factors were increasing age, low socio-economic class and urban living. Of those with chronic bronchitis, 22% fulfilled the GOLD criteria of COPD.

CONCLUSION

The prevalence of chronic bronchitis was somewhat lower than found by studies in Sweden in the 1980s and the prevalence was now similar in men and women. Although smoking was still the dominating risk factor for chronic bronchitis, the relative importance of smoking had decreased parallel with a decreasing smoking prevalence, while the relative importance of other factors than smoking had increased compared to previous studies.

Does urban extent from satellite images relate to symptoms of asthma, rhinoconjunctivitis and eczema in children? A cross-sectional study from ISAAC Phase Three

OBJECTIVE

The relationship between urbanisation and the symptom prevalence of asthma, rhinoconjunctivitis and eczema is not clear, and varying definitions of urban extent have been used. Furthermore, a global analysis has not been undertaken. This study aimed to determine whether the symptom prevalence of asthma, rhinoconjunctivitis and eczema in centres involved in the International Study of Asthma and Allergies in Childhood (ISAAC) were higher in urban than rural centres, using a definition of urban extent as land cover from satellite data.

METHODS

A global map of urban extent from satellite images (MOD500 map) was used to define the urban extent criterion. Maps from the ISAAC centres were digitised and merged with the MOD500 map to describe the urban percentage of each centre. We investigated the association between the symptom prevalence of asthma, rhinoconjunctivitis and eczema and the percentage of urban extent by centre.

RESULTS

A weak negative relationship was found between the percentage of urban extent of each ISAAC centre and current wheeze in the 13-14-year age group. This association was not statistically significant after adjusting for region of the world and gross national income. No other relationship was found between urban extent and symptoms of asthma, rhinoconjunctivitis and eczema.

CONCLUSIONS

In this study, the prevalence of symptoms of asthma, rhinoconjunctivitis and eczema in children were not associated with urbanisation, according to the land cover definition of urban extent from satellite data. Comparable standardised definitions of urbanisation need to be developed so that global comparisons can be made.

Prevalence and risk factors of COPD among never-smokers in two areas of Sweden - Occupational exposure to gas, dust or fumes is an important risk factor

BACKGROUND

Although active tobacco smoking is the main risk factor for COPD, COPD is not uncommon also among never-smokers. Different study locations along with different spirometric definitions of COPD have historically yielded different prevalence estimates of the disease.

AIM

To study current prevalence and risk factors of COPD among never-smokers in two areas of Sweden.

METHODS

Data collected in 2008-2012 within the West Sweden Asthma Study and Obstructive Lung Disease in Northern Sweden Studies was pooled. The study population consisted of 1839 subjects who participated in spirometry and interviews. COPD was defined as post-bronchodilator a) FEV(1)/(F)VC < 0.7, b) FEV(1)/FVC < 0.7 and c) FEV(1)/FVC < lower limit of normal.

RESULTS

Of the 1839 subjects, 967 (52.6%) were never-smokers. Among the never-smoking subjects, the prevalence of COPD according to definitions a-c was 7.7%, 4.9% and 3.0%, respectively. The corresponding prevalence of GOLD grade ≥2 was 2.0%, 1.4% and 1.3%. No significant difference in prevalence between the two study areas was observed. In never-smokers, occupational exposure to gas, dust or fumes (GDF) was significantly associated with both COPD (OR 1.85, 95% CI 1.03-3.33), and GOLD ≥2 (OR 4.51, 1.72-11.9) according to definition a), after adjusting for age, educational level and exposure to passive smoking at work.

CONCLUSION

Depending on definition, prevalence of COPD among never-smokers was 3.0-7.7%, whereas GOLD ≥2 was present in 1.3-2.0%. Occupational exposure to GDF remained independently and significantly associated with COPD regardless of spirometric definition of the disease.

Defining Chronic Cough: A Systematic Review of the Epidemiological Literature

Purpose

Recent evidence suggests a global burden of chronic cough in general populations. However, the definitions vary greatly among epidemiological studies, and none have been validated for clinical relevance. We aimed to examine previous epidemiological definitions in detail and explore the operational characteristics.

Methods

A systematic review was conducted for epidemiological surveys that reported the prevalence of chronic cough in general adult populations during the years 1980 to 2013. A literature search was performed on Pubmed and Embase without language restriction. Epidemiological definitions for chronic cough were classified according to their components, such as cutoff duration. Meta-analyses were performed for the male-to-female ratio of chronic cough prevalence to explore operational characteristics of epidemiological definitions.

Results

A total of 70 studies were included in the systematic review. The most common epidemiological definition was identified as 'cough ≥3 months' duration without specification of phlegm (n=50); however, it conflicted with the cutoff duration in current clinical guidelines (cough ≥8 weeks). Meta-analyses were performed for the male-to-female ratio of chronic cough among 28 studies that reported sex-specific prevalence using the most common definition. The pooled male-to-female odds ratio was 1.26 (95% confidence interval 0.92-1.73) with significant heterogeneity (I²=96%, P<0.001), which was in contrast to clinical observations of female predominance from specialist clinics. Subgroup analyses did not reverse the ratio or reduce the heterogeneity.

Conclusions

This study identified major issues in defining chronic cough in future epidemiological studies. The conflict between epidemiological and clinical diagnostic criteria needs to be resolved. The unexpected difference in the gender predominance between the community and clinics warrants further studies. Clinical validation of the existing definition is required.

Chronic cough: an Asian perspective. Part 1: Epidemiology

Asia is one of the most diverse and dynamic continents. Due to recent rapid industrialisation and urbanisation, morbidity patterns are likely to be diverse in Asian populations. Chronic cough is a disease condition resulting from host-environmental interactions, and is associated with a high global epidemiological burden. However, the underlying epidemiology remains unclear, particularly in Asia. We performed a literature search to identify peer-reviewed articles on chronic cough in community-based adult Asian populations that have been published between January 2000 and June 2015. In this review, we aim to examine the epidemiological characteristics and determinants of chronic cough in several geographical areas of Asia.

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

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

Operational definitions of asthma in recent epidemiological studies are inconsistent

OBJECTIVE

The 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.

METHODS

We 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.

RESULTS

Of 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.

CONCLUSIONS

There 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.

Prevalence of COPD by disease severity in men and women in northern Vietnam

The prevalence of COPD and its risk factor pattern varies between different areas of the world. The aim of this study was to investigate the prevalence of COPD by disease severity in men and women and risk factors for COPD in northern Vietnam. From all 5782 responders to a questionnaire survey, a randomly selected sample of 1500 subjects was invited to a clinical follow-up study. The methods included a structured interview using a modified GA2LEN study questionnaire for registration of symptoms and possible determinants of disease. Spirometry was performed before and after bronchodilation. The age distribution of the sample was 23-72 years. Of 684 subjects attending, 565 completed acceptable spirometric measurements. The prevalence of COPD defined by the GOLD criteria was 7.1%; in men 10.9% and in women 3.9% (p = 0.002). Of those 3.4% had a mild disease, 2.8% a moderate and 0.9% a severe disease. In ages >50 years, 23.5% of men and 6.8% of women had COPD. Among smokers aged >60 years (all men), 47.8% had COPD. None of the women with COPD had been smokers. Increasing age, smoking and male sex were the dominating risk factors, although male sex lost its significance in a multivariate setting. The prevalence of COPD among adults in northern Vietnam was 7.1% and was considerably higher among men than women. The prevalence increased considerably with age. Increasing age and smoking, the latter among men only, were the most important determinants of COPD.

Epidemiology of adult asthma in Asia: toward a better understanding

Asia is the world's most dynamic area. Asthma is a major chronic disease in Asia, like other continents. However, unlike childhood asthma, the epidemiological burden of asthma in Asian adults has been unclear. Here we reviewed the currently available literatures on the epidemiology of adult asthma in the Asian community populations. Adult asthma prevalence was generally lower in Asian than in Europe, but the increasing trends suggested the disease burden to rise in the near future. However, for better understanding, it may be essential to prepare for the Asian multinational network for the standardization and collaboration of research.

How are 'urban' and 'rural' defined in publications regarding asthma and related diseases?

BACKGROUND

Global variations in the prevalence of asthma and related diseases have suggested that environmental factors are causative, and that factors associated with urbanisation are of particular interest. A range of definitions for 'urban' and 'rural' have been used in articles on asthma and related diseases, making it difficult to assess their importance as aetiological factors. This study sets out to examine such definitions used in the literature.

METHODS

Medical and social science databases were searched for articles that made distinctions of 'urban' and/or 'rural' in the context of asthma and related diseases.

RESULTS

The search identified 73 articles and categorised four types of definitions. A specific definition of urban or rural was used in 19 (26%) articles. Nine (12%) articles used non-specific and/or administrative definitions. There were 23 (32%) articles that described locations as 'urban' or 'rural' but did not indicate if the description defined 'urban' or 'rural'. Distinctions were made between urban and rural locations without a description or definition in 22 (30%) articles.

CONCLUSIONS

There is substantial variation in the definitions of 'urban' and 'rural' in articles regarding asthma and related diseases. It would be advantageous to have clearer and more precise definitions of 'urban' and 'rural' which could facilitate aetiological research and also comparisons between locations, especially in international studies.

Sensitization to airborne allergens among adults and its impact on allergic symptoms: a population survey in northern Vietnam

Background

The knowledge about allergic sensitization and its relationship with clinical symptoms and diseases among adults in South-East Asia is poor. The aim of this study was to investigate the prevalence and pattern of allergic sensitization and the association with asthma and allergic rhinitis in adults in urban and rural Vietnam.

Methods

Among 5,782 responders to a questionnaire survey in northern Vietnam, a random sample was invited to a clinical follow-up and 684 (46%) participated. The methods included a structured interview using a modified GA²LEN study questionnaire on symptoms and possible determinants for diseases. Skin prick test (SPT) with ten common airborne indoor and outdoor allergens, lung function test, and methacholine test was performed among subjects ≤60 years of age.

Results

In total, one third of subjects had a positive SPT reaction to at least one allergen, 36.9% of men and 31.0% of women (n.s.). The most common sensitizer was the storage mite B. tropicalis (men 27.7%; women 18.7%) followed by house dust mite D. pteronyssinus (men 16.5%; women 10.6%), and D. farinae (men 15.3%; women 6.3%), and cockroach (men 16.5%; women 10.2%). Sensitization to all major allergens were significantly more common among men and among subjects ≤45 years compared with women and subjects >45 years, respectively. The prevalence of sensitization to animals, pollen and molds were low. The majority of cockroach-sensitized subjects were also sensitized to mites. Sensitization to any allergen and all major allergens were significantly associated with rhinitis, but not with asthma. However, bronchial hyper-reactivity was significantly associated with increasing number of positive SPTs (p = 0.047).

Conclusions

Among adults in northern Vietnam sensitization to mite and cockroach most common in both rural and urban areas. The dominant sensitizer was the storage mite B. tropicalis, which should be included in future studies and also in clinical practice, owing to its association with clinical symptoms. As in the Western world allergic sensitization was associated with rhinitis and bronchial hyper-reactivity. The lack of association with asthma in South-East Asia needs to be studied further.

Cross-sectional epidemiological survey of asthma in Jinan, China

BACKGROUND AND OBJECTIVE

The prevalence and control of asthma in all ages are seldom known in Jinan, China. This study aims to determine the prevalence, related factors and control of asthma in populations of all ages in Jinan, China.

METHODS

A cross-sectional epidemiological questionnaire survey was performed with all members from approximately 4500 randomly selected families from 60 communities in the urban area and in 40 villages in the rural area. The completed questionnaires were focused on asthma, asthma-like respiratory symptoms and asthma control.

RESULTS

A total of 13,645 individuals were interviewed in the survey, and the number of effective questionnaires reached 13,419. The asthma prevalence of all ages in Jinan was 1.1%. Atopy, asthma family history, household size and age were independent factors related to asthma. The control of asthma in Jinan was suboptimal in a high proportion of patients and even worse in the rural area.

CONCLUSIONS

The asthma prevalence for all ages in Jinan was relatively low compared with that in western countries; however, local asthma control fell markedly short from the goals of the Global Initiative for Asthma (GINA) criteria for asthma management, which may be attributed to the poor adherence to GINA guidelines, especially the underuse of preventative medication of inhaled corticosteroids.

Urban vs. rural factors that affect adult asthma

In this review, our aim was to examine the influence of geographic variations on asthma prevalence and morbidity among adults, which is important for improving our understanding, identifying the burden, and for developing and implementing interventions aimed at reducing asthma morbidity. Asthma is a complex inflammatory disease of multifactorial origin, and is influenced by both environmental and genetic factors. The disparities in asthma prevalence and morbidity among the world's geographic locations are more likely to be associated with environmental exposures than genetic differences. In writing this article, we found that the indoor factors most consistently associated with asthma and asthma-related symptoms in adults included fuel combustion, mold growth, and environmental tobacco smoke in both urban and rural areas. Asthma and asthma-related symptoms occurred more frequently in urban than in rural areas, and that difference correlated with environmental risk exposures, SES, and healthcare access. Environmental risk factors to which urban adults were more frequently exposed than rural adults were dust mites,high levels of vehicle emissions, and a westernized lifestyle.Exposure to indoor biological contaminants in the urban environment is common.The main risk factors for developing asthma in urban areas are atopy and allergy to house dust mites, followed by allergens from animal dander. House dust mite exposure may potentially explain differences in diagnosis of asthma prevalence and morbidity among adults in urban vs. rural areas. In addition, the prevalence of asthma morbidity increases with urbanization. High levels of vehicle emissions,Western lifestyles and degree of urbanization itself, may affect outdoor and thereby indoor air quality. In urban areas, biomass fuels have been widely replaced by cleaner energy sources at home, such as gas and electricity, but in most developing countries, coal is still a major source of fuel for cooking and heating, particularly in winter. Moreover, exposure to ETS is common at home or at work in urban areas.There is evidence that asthma prevalence and morbidity is less common in rural than in urban areas. The possible reasons are that rural residents are exposed early in life to stables and to farm milk production, and such exposures are protective against developing asthma morbidity. Even so, asthma morbidity is disproportionately high among poor inner-city residents and in rural populations. A higher proportion of adult residents of nonmetropolitan areas were characterized as follows:aged 55 years or older, no previous college admission, low household income, no health insurance coverage, and could not see a doctor due to healthcare service availability, etc. In rural areas, biomass fuels meet more than 70% of the rural energy needs. Progress in adopting modern energy sources in rural areas has been slow. The most direct health impact comes from household energy use among the poor, who depend almost entirely on burning biomass fuels in simple cooking devices that are placed in inadequately ventilated spaces. Prospective studies are needed to assess the long-term effects of biomass smoke on lung health among adults in rural areas.Geographic differences in asthma susceptibility exist around the world. The reason for the differences in asthma prevalence in rural and urban areas may be due to the fact that populations have different lifestyles and cultures, as well as different environmental exposures and different genetic backgrounds. Identifying geographic disparities in asthma hospitalizations is critical to implementing prevention strategies,reducing morbidity, and improving healthcare financing for clinical asthma treatment. Although evidence shows that differences in the prevalence of asthma do exist between urban and rural dwellers in many parts of the world, including in developed countries, data are inadequate to evaluate the extent to which different pollutant exposures contribute to asthma morbidity and severity of asthma between urban and rural areas.

Allergic rhinitis in northern vietnam: increased risk of urban living according to a large population survey

BACKGROUND

Little is known about prevalence and risk factors of allergic rhinitis and chronic nasal symptoms among adults in Vietnam. We aimed to estimate the prevalence, risk factor patterns and co-morbidities of allergic rhinitis and chronic nasal symptoms in one urban and one rural area in northern Vietnam.

METHODS

A cross-sectional questionnaire survey was conducted from August 2007 to January 2008 in urban Hoankiem and rural Bavi in Hanoi among adults aged 21-70 years. Of 7008 randomly selected subjects, 91.7% participated in Bavi and 70.3% in Hoankiem.

RESULTS

Allergic rhinitis ever or chronic nasal symptoms were reported by 50.2%. The prevalence of allergic rhinitis ever was considerably higher in Hoankiem compared to Bavi, 29.6% vs 10.0% (p < 0.001). Allergic rhinitis ever and chronic nasal symptoms were both significantly associated with asthma and respiratory symptoms, respectively (p < 0.001). Exposure to gas, dust or fumes at work was significantly associated with allergic rhinitis ever, OR 1.57 (95% CI 1.34 - 1.84), nasal blocking, OR 1.90 (95% CI 1.68 - 2.15) and runny nose, OR 1.32 (95% CI 1.17 - 1.49), while somewhat surprisingly no association with smoking was found. Female sex was a significant risk factor for both nasal blocking and runny nose.

CONCLUSIONS

Allergic rhinitis ever was considerably more common in the urban area. Nasal blocking and runny nose was each reported by about one third of the studied sample with no major urban-rural difference. Further, exposure to air pollution at work was significantly associated with allergic rhinitis ever, nasal blocking and runny nose.