Respiratory symptoms among residents of a heavy-industry province in China: prevalence and risk factors

Risk perception among residents living near industries in Godawari Municipality of Lalitpur, Nepal

The industrial sector stands out as a significant contributor to environmental pollution. Those who reside in close proximity to industrial areas commonly harbor concerns about potential health and environmental hazards. This study aimed to find out the perception of risk and self-reported health impacts among individuals living near industries in Godawari Municipality, Lalitpur, Nepal. Conducted as a community-based cross-sectional study, it involved 270 households. Face-to-face interviews were employed, utilizing a pretested structured questionnaire. The study zone encompassed the communities of Godawari Municipality within a 3-kilometer radius of industrial sites. Specifically, stone mines, stone crushers, and brick kilns were purposefully selected, while study participants were randomly sampled using a random table. Data analysis was performed using IBM SPSS, incorporating both univariate and bivariate techniques. Among those residing near industrial zones, a mere 9.6 % reported experiencing wheezing or whistling in the past 12 months. A substantial 36.3% consistently felt stressed due to industrial activities in their vicinity. Approximately half (51.9 %) of the participants indicated that the contaminated air in the area had adverse effects on human health. Furthermore, a palpable perception of elevated risk was associated with the proximity of industries (p<0.001). Over half of the participants perceived a notable risk stemming from the presence of industries near their homes, largely due to pollutants. These individuals also disclosed various health repercussions and expressed significant apprehension regarding their future well-being in the area. The implications of these findings are substantial, particularly for local-level planning and the development of industrial sites. Addressing the concerns surrounding people's heightened perception of risk from nearby industries is pivotal in fostering harmonious coexistence and informed decision-making.

Risk factors of chronic cough in China: a systematic review and meta-analysis

OBJECTIVES

Risk factors of chronic cough in China have not been systematically analyzed and we hypothesized that risk factors of chronic cough might have distinct characteristics in China. Hence, we performed this meta-analysis focusing on the potential risk factors of chronic cough in China.

METHODS

We searched 7 databases for studies published before May 8, 2021. This systematic review was performed in accordance with the PRISMA checklist.

RESULTS

A total of 33 eligible articles were identified and included in this systematic review, and 28 studies were included in the meta-analysis. Our results showed that allergy (OR: 3.72; 95% CI: 1.85-7.47), nasal/sinusitis diseases (OR: 3.56; 95% CI: 2.02-6.29), family history of allergy (OR = 1.74; 95% CI: 1.59-1.90), family history of chronic respiratory diseases (OR = 1.67; 95% CI: 1.47-1.91), exposure to pollutants (OR = 1.60; 95% CI: 1.26-2.04), passive smoking (OR = 1.44; 95% CI: 1.32-1.57), and exposure to pets (OR = 1.37; 95% CI: 1.18-1.58) were risk factors for chronic cough in China.

CONCLUSIONS

Our study indicated some potential risk factors of chronic cough in China, which provides useful epidemiological information for managing chronic cough in China and is worthy as a reference for future global investigations.

Prevalence of chronic cough in China: a systematic review and meta-analysis

Background

Individual studies have indicated variable prevalence for chronic cough, but thus far, there has been no systematic report on the prevalence of this condition.

Methods

In this study, we performed a systematic review and meta-analysis by searching databases including PubMed, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Chinese biomedical literature service system, Wanfang Database, and VIP database, for studies on chronic cough in China published before December 28, 2020. A random effects model was used to calculate pooled prevalence estimates with 95% confidence interval [95%CI], weighted by study size.

Results

Fifteen studies with 141,114 community-based adults were included in the study, showing a prevalence of 6.22% (95% CI 5.03–7.41%). And 21 studies with 164,280 community-based children were included, presenting a prevalence of 7.67% (95% CI 6.24–9.11%). In subgroup meta-analyses, the prevalence in adults was 4.38% (95% CI 2.74–6.02%) in southern China and 8.70% (95% CI 6.52–10.88%) in northern China. In the children population, the prevalence in northern China was also higher than in southern China (northern vs. southern: 7.45% with a 95% CI of 5.50–9.41%, vs. 7.86% with a 95% CI of 5.56–10.16%).

Conclusions

Our population-based study provides relatively reliable data on the prevalence of chronic cough in China and may help the development of global strategies for chronic cough management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01847-w.

The effects of indoor and outdoor air pollution on the prevalence of adults' respiratory diseases in four Chinese cities: a comparison between 2017-2018 and 1993-1996

Background

Over the past decades, both ambient and household air pollution have changed in several aspects, including the emission sources and the concentrations of pollutants, in many Chinese cities. It is unknown whether these changes are associated with changes in health conditions, especially given changes in other factors due to rapid economic growth.

Methods

Two cross-sectional surveys were conducted in two periods spanning more than twenty years (1993–1996 vs. 2017–2018) in four Chinese cities of Chongqing, Wuhan, Lanzhou, and Guangzhou. Data were collected regarding adults’ respiratory disease, smoking status, education, occupation, and household characteristics. Ambient air pollution data were obtained for each study. We first used logistic regression models to construct the district-specific adjusted disease prevalences. In the second stage, first-difference regression models were employed to examine whether the change in respiratory diseases prevalences was associated with the change in outdoor air pollution and indoor air pollution surrogates.

Results

A total of 7,557 and 9,974 households were participating in Period 1 (1993–1996) and Period 2 (2017–2018), respectively. Compared to Period 1, we found substantial reductions in the ambient air pollution concentrations, and a suggestive improvement in cooking-related indoor air pollution in Period 2. We observed decreases in the district-specific covariate-adjusted prevalences of both asthma and chronic bronchitis among participants, with an average reduction of 3.6% (range: 0.0% to 24.3%). From Period 1 to Period 2, one percent decrease in the proportion of cooking with coal was associated with a 19.0% (95% CI, 0.96–37.04%) decrease in the prevalence of males’ chronic bronchitis and a 1.86% (0.69–3.04%) increase in the prevalence of females’ asthma. Little evidence was observed regarding the potential health benefits associated with the decreases in ambient air pollution levels.

Conclusions

The substantial reduction in household use of coal for cooking might be an important contributor to the decrease in adults’ respiratory disease prevalence from 1993–1996 to 2017–2019 in four Chinese cities. Changes in this indoor air pollution source, along with other risk factors for respiratory diseases, may have masked respiratory health benefits associated with reductions in outdoor air pollution levels.

Risk of Acute Respiratory Distress Syndrome Among Older Adults Living Near Construction and Manufacturing Sites

BACKGROUND

Construction and manufacturing sites produce airborne toxins that may affect nearby residents' respiratory health. Living in heavy industrial sites has been linked to respiratory conditions such as asthma and pneumonia. However, limited information is available for risk of acute respiratory distress syndrome (ARDS), a form of acute respiratory failure with high incidence among older adults.

METHODS

We conducted a nationwide ecologic study to investigate associations between annual ZIP code-level changes in industrial activity and annual changes in ZIP code-level hospital admission rates for older community residents. Using adjusted generalized linear mixed models, we analyzed data from nearly 30 million yearly Medicare beneficiaries for the years 2006 through 2012.

RESULTS

We found on average 92,363 hospital admissions for ARDS per year and 646,542 admissions over the course of 7 years. We found that an increase of 10 construction sites per year was associated with a 0.77% (95% confidence interval [CI] = 0.71, 0.84) increase in annual hospital admission rates for ARDS and an increase of 10 manufacturing industries per year was associated with a 1.21% (95% CI = 1.09, 1.33) increase in annual hospital admission rates for ARDS across all ZIP codes. The estimated effect of chemical product manufacturing industry on ARDS was higher than that of total manufacturing industries. Residing in ZIP codes with a high number of construction or manufacturing sites was associated with increased ARDS hospital admissions.

CONCLUSIONS

This nationwide ecologic study of older adults suggests that residence in areas with more construction and manufacturing sites is associated with increased ARDS risk.

Prevalence of respiratory diseases in relation to smoking rate in adults living in four Chinese cities: a comparison between 2017-2018 and 1993-1996

Background

The sustained high prevalence of smoking in China has contributed substantially to the burden of chronic diseases, including respiratory diseases. This study compared the prevalence of smoking and respiratory diseases in Chinese adults between two time periods spanning over 25 years.

Methods

Cross-sectional surveys were performed in four Chinese cities of Chongqing, Lanzhou, Wuhan, and Guangzhou in 1993–1996 (Period 1) and in 2017–2018 (Period 2). Participants completed questionnaires asking smoking status, the presence of asthma and chronic bronchitis, education attainment and household characteristics. Logistic regression models were used to estimate the odds ratios of disease prevalence with regard to active smoking status for men and passive smoking status for women.

Results

Prevalence of asthma, prevalence of chronic bronchitis, and smoking rate, all decreased from Period 1 to Period 2. We observed strong evidence that active smoking increased prevalence for both asthma and chronic bronchitis in men during Period 1, with spatial heterogeneity and modifying effect by college-level education. Home exposure to passive smoking was associated with increased odds of having chronic bronchitis among female participants in Chongqing during Period 2, although the association was not statistically significant.

Conclusions

The prevalence for asthma and chronic bronchitis were lower in 2017–2018 compared to 25 years ago in the same four Chinese cities. Decreased smoking rate may have contribution to the improvement of these respiratory diseases. Male smokers, especially those without college-level education, showed higher prevalence of chronic bronchitis compared to nonsmokers during Period 1.

Evaluation of pulmonary function and respiratory symptoms among workers exposed to 1,3-Butadiene in a petrochemical industry in Iran

This study aimed to evaluate pulmonary function among workers exposed to 1,3-butadiene and was carried out in a petrochemical industry in Iran. The study participants consisted of fifty male workers with current respiratory exposure to 1,3-butadiene and fifty non-exposed workers as the control group. Exposure to 1,3-butadiene was measured according to the NIOSH 1024 method. Respiratory symptom histories were collected through the American Thoracic Society respiratory symptom questionnaire. Lung functions were evaluated using spirometry method. The results showed that exposed participants had significantly higher prevalence rates of all respiratory symptoms compared to the control group. Statistical tests demonstrated a significant difference between pulmonary function tests of exposed and non-exposed personnel. Ultimately, the results of the present study indicate that respiratory exposure to 1,3-butadiene can lead to negative effects on pulmonary functions.

Current Status and Future Directions of Chronic Cough in China

Chronic cough is one of the most common complaints for which patients in China seek medical attention. However, there are no nationwide data on the prevalence and socioeconomic burden of chronic cough. Although approximately 50% of Chinese men smoke, the vast majority of patients presenting for evaluation of chronic cough are never smokers. An equal sex distribution and a middle-aged predominance have been observed in the Chinese chronic cough population, despite demonstration of a higher cough reflex sensitivity in females and older patients. The role of air pollution in the distinct age and sex distribution requires further study. In terms of the etiologies of chronic cough in China, cough-variant asthma, upper airway cough syndrome, nonasthmatic eosinophilic bronchitis, and atopic cough are the most common causes, comprising 75.2% to 87.6% of cases across different regions. Chinese Guidelines for Diagnosis and Treatment of Cough were initially published in 2005, and updated in 2009 and 2016. In addition, the China Cough Coalition was established in 2016. Great progress has been made in both cough-related clinical practice and research in recent years, however, there are still challenges ahead. To facilitate optimal management of chronic cough in China, efforts promoting the dissemination and application of published guidelines will be essential, especially in community-based healthcare and in rural regions. As chronic refractory cough has been identified as a huge challenge to clinicians worldwide, continued international cooperation will be essential in optimizing evaluation and management of chronic cough.

Environmental Exposures and Asthma Development: Autophagy, Mitophagy, and Cellular Senescence

Environmental pollutants and allergens induce oxidative stress and mitochondrial dysfunction, leading to key features of allergic asthma. Dysregulations in autophagy, mitophagy, and cellular senescence have been associated with environmental pollutant and allergen-induced oxidative stress, mitochondrial dysfunction, secretion of multiple inflammatory proteins, and subsequently development of asthma. Particularly, particulate matter 2.5 (PM2.5) has been reported to induce autophagy in the bronchial epithelial cells through activation of AMP-activated protein kinase (AMPK), drive mitophagy through activating PTEN-induced kinase 1(PINK1)/Parkin pathway, and induce cell cycle arrest and senescence. Intriguingly, allergens, including ovalbumin (OVA), Alternaria alternata, and cockroach allergen, have also been shown to induce autophagy through activation of different signaling pathways. Additionally, mitochondrial dysfunction can induce cell senescence due to excessive ROS production, which affects airway diseases. Although autophagy and senescence share similar properties, recent studies suggest that autophagy can either accelerate the development of senescence or prevent senescence. Thus, in this review, we evaluated the literature regarding the basic cellular processes, including autophagy, mitophagy, and cellular senescence, explored their molecular mechanisms in the regulation of the initiation and downstream signaling. Especially, we highlighted their involvement in environmental pollutant/allergen-induced major phenotypic changes of asthma such as airway inflammation and remodeling and reviewed novel and critical research areas for future studies. Ultimately, understanding the regulatory mechanisms of autophagy, mitophagy, and cellular senescence may allow for the development of new therapeutic targets for asthma.

Characteristics of Chinese chronic cough patients

Chronic cough is one of the most common complains for patients seeking medical attention in both general practice and respiratory specialist clinics. Cough variant asthma, eosinophilic bronchitis, upper airway cough syndrome, as well as gastro-esophageal reflux disease are common conditions associated with chronic cough, and cough variant asthma, eosinophilic bronchitis account for a higher proportion of patients with chronic cough in China than in Western countries. An older female predominance has been reported in most Western countries, which may be attributed to a higher cough reflex sensitivity in females, especially those post-menopausal females. However, studies conducted in China showed that patients with chronic cough have a nearly similar gender distribution and most of them are in their late 30s or early 40s, despite the similar gender and age difference in cough reflex sensitivity as Western countries. Environmental and occupational exposures, cigarette smoking, unhealthy lifestyle might play a role in the distinct age and gender distribution of Chinese chronic cough patients, yet further study is needed to clarify it.

Residents' Self-Reported Health Effects and Annoyance in Relation to Air Pollution Exposure in an Industrial Area in Eastern-Estonia

Eastern Estonia has large oil shale mines and industrial facilities mainly focused on electricity generation from oil shale and shale oil extraction, which produce high air pollution emissions. The "Study of the health impact of the oil shale sector-SOHOS" was aimed at identifying the impacts on residents' health and annoyance due to the industrial processing. First, a population-wide survey about health effects and annoyance was carried out. Second, the total and oil shale sectors' emitted concentrations of benzene, phenol, and PM2.5 were modelled. Third, the differences between groups were tested and relationships between health effects and environmental pollution studied using multiple regression analysis. Compared to the control groups from non-industrial areas in Tartu or Lääne-Viru, residents of Ida-Viru more frequently (p < 0.05) reported wheezing, chest tightness, shortness of breath, asthma attacks, a long-term cough, hypertension, heart diseases, myocardial infarction, stroke, and diabetes. All health effects except asthma were reported more frequently among non-Estonians. People living in regions with higher levels of PM2.5, had significantly higher odds (p < 0.05) of experiencing chest tightness (OR = 1.13, 95% CI 1.02-1.26), shortness of breath (1.16, 1.03-1.31) or an asthma attack (1.22, 1.04-1.42) during the previous year. People living in regions with higher levels of benzene had higher odds of experiencing myocardial infarction (1.98, 1.11-3.53) and with higher levels of phenol chest tightness (1.44, 1.03-2.00), long-term cough (1.48, 1.06-2.07) and myocardial infarction (2.17, 1.23-3.83). The prevalence of adverse health effects was also higher among those who had been working in the oil shale sector. Next to direct health effects, up to a quarter of the residents of Ida-Viru County were highly annoyed about air pollution. Perceived health risk from air pollution increased the odds of being annoyed. Annoyed people in Ida-Viru had significantly higher odds of experiencing respiratory symptoms during the last 12 months, e.g., wheezing (2.30, 1.31-4.04), chest tightness (2.88, 1.91-4.33 or attack of coughing (1.99, 1.34-2.95).

Particulate Matter and Respiratory Symptoms among Adults Living in Windhoek, Namibia: A Cross Sectional Descriptive Study

This study aimed to estimate the prevalence of respiratory symptoms and to assess respiratory health risks associated with Particulate Matter (PM) exposure among the residents of Windhoek, Namibia. Objectives: To measure particulate pollution concentration in Windhoek through monitoring of particulate matter concentration and to identify any associations between particulate pollution, individual location, and respiratory health among the Windhoek resident’s. Methods: an adapted standardized self-administered questionnaire was used to collect respiratory health related data as well as previous exposure, while PM monitoring was done using the ASTM (American Standard Test Method) D1739 reference method. Results: A high prevalence was observed for cough (43%), breathlessness (25%), and asthma (11.2%). PM was found to be a significant risk factor for episodes of coughing and phlegm, while high PM exposure category had an increased odds ratio (OR) for episodes of phlegm and cough (OR: 2.5, 95% CI (95% confidence intervals): 0.8–8.0). No association was observed between location and respiratory health outcomes. Conclusions: The study found high levels of PM concentration across all Windhoek suburbs which were above the German, American, and Environmental Protection Agency (EPA). Enactment of legislation relating to the control and monitoring of PM related emissions at the point of generation is required at both a country and city level.

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.

Environmental Exposure and Genetic Predisposition as Risk Factors for Asthma in China

Asthma is the most common chronic pulmonary disease worldwide and places a considerable economic burden on society. China is the world's largest developing country and has the largest population. China has undergone dramatic changes in the past few decades. The traditional lifestyle and living environment have changed in ways that directly affect the prevalence of asthma. The prevalence of asthma is lower in Chinese children and adults than in developed countries, but the prevalence has been on the rise during the past 30 years. The prevalence significantly varies among different parts of China. Polymorphisms of multiple genes, outdoor air pollution caused by PM2.5, PM10, SO₂, NO₂, environmental tobacco smoke, and coal, indoor pollution, and inhaled allergens, such as house dust mites, pollen, and cockroach particles, are risk factors for asthma.

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.

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.

Monosodium glutamate intake, dietary patterns and asthma in Chinese adults

Objectives

Emerging evidence shows that diet is related to asthma. The aim of this analysis was to investigate the association between monosodium glutamate (MSG) intake, overall dietary patterns and asthma.

Methods

Data from 1486 Chinese men and women who participated in the Jiangsu Nutrition Study (JIN) were analyzed. In this study, MSG intake and dietary patterns were quantitatively assessed in 2002. Information on asthma history was collected during followed-up in 2007.

Results

Of the sample, 1.4% reported ever having asthma. MSG intake was not positively associated with asthma. There was a significant positive association between ‘traditional’ (high loadings on rice, wheat flour, and vegetable) food pattern and asthma. No association between ’macho’ (rich in meat and alcohol), ‘sweet tooth’ (high loadings on cake, milk, and yoghurt) ‘vegetable rich’ (high loadings on whole grain, fruit, and vegetable) food patterns and asthma was found. Smoking and overweight were not associated with asthma in the sample.

Conclusion

While a ‘Traditional’ food pattern was positively associated with asthma among Chinese adults, there was no significant association between MSG intake and asthma.

OBSTRUCTIVE LUNG DISEASE AND EXPOSURE TO BURNING BIOMASS FUEL IN THE INDOOR ENVIRONMENT

It is estimated that up to half of the world's population burns biomass fuel (wood, crop residues, animal dung and coal) for indoor uses such as cooking, lighting and heating. As a result, a large proportion of women and children are exposed to high levels of household air pollution (HAP). The short and long term effects of these exposures on the respiratory health of this population are not clearly understood. On May 9-11, 2011 NIH held an international workshop on the "Health Burden of Indoor Air Pollution on Women and Children," in Arlington, VA. To gather information on the knowledge base on this topic and identify research gaps, ahead of the meeting we conducted a literature search using PubMed to identify publications that related to HAP, asthma, and chronic obstructive pulmonary disease (COPD). Abstracts were all analyzed and we report on those considered by the respiratory sub study group at the meeting to be most relevant to the field. Many of the studies published are symptom-based studies (as opposed to objective measures of lung function or clinical examination etc.) and measurement of HAP was not done. Many found some association between indoor exposures to biomass smoke as assessed by stove type (e.g., open fire vs. liquid propane gas) and respiratory symptoms such as wheeze and cough. Among the studies that examined objective measures (e.g. spirometry) as a health outcome, the data supporting an association between biomass smoke exposure and COPD in adult women are fairly robust, but the findings for asthma are mixed. If an association was observed between the exposures and lung function, most data seemed to demonstrate mild to moderate reductions in lung function, the pathophysiological mechanisms of which need to be investigated. In the end, the group identified a series of scientific gaps and opportunities for research that need to be addressed to better understand the respiratory effects of exposure to indoor burning of the different forms of biomass fuels.

Past dust and GAS/FUME exposure and COPD in Chinese: the Guangzhou Biobank Cohort Study

The impact of occupational dust and gas/fume exposure on chronic obstructive pulmonary disease (COPD) in developing countries has not been quantified. We examined the relationship between past dust and fume exposure and prevalence of COPD and respiratory symptoms in a cross-sectional analysis of a large Chinese population sample. Participants in the Guangzhou Biobank Cohort Study (n = 8216; 27.3% men, mean age 61.9 ± 6.8 years) had spirometry and a structured interview including exposures, symptoms, and lifestyle. Self-reported intensity and duration of dust and gas/fume exposure was used to derive cumulative exposure. COPD was diagnosed from spirometry using lower limit of normal based on prediction equations. COPD was associated with high exposure to dust or gas/fume (exposed: 87/1206 v non-exposed: 191/3853; adjusted odds ratio: 1.41; 95% confidence interval (CI) 1.06, 1.87) with no evidence of effect modification by smoking. Respiratory symptoms were associated with exposures to dust and gas/fume, with adjusted odds ratios for chronic cough/phlegm of 1.57 (1.13, 2.17) and 1.39 (1.20, 1.60) for dyspnoea. The overall population attributable fraction for COPD due to occupational exposure was 10.4% (95% CI -0.9%, 19.5%). Occupational dust and gas/fume exposure is associated with an increased prevalence of COPD in this Chinese sample, independent of smoking. The population attributable fraction in Chinese is similar to that in Western populations.

Roles of pollution in the prevalence and exacerbations of allergic diseases in Asia

The prevalence of asthma and allergic diseases has been found to be increasingly rapidly, especially in developing countries. Environmental factors have been found to be important contributors to the manifestations of allergic diseases. Air pollution has been extensively studied in different regions of the world. The levels of ambient air pollutants in many Asian countries are very high when compared with those in developed Western countries. However, the prevalence of asthma was relatively low across many Asian countries. Many studies have clearly documented that environmental air pollution is an important factor resulting in exacerbations of asthma. In particular, levels of traffic-related pollutants are increasing rapidly across many Asian countries in parallel with the level of urbanization and economic development. The loss of protective factors associated with a rural environment will further contribute to the adverse effect on patients with allergic diseases such as asthma. In this review the roles of air pollution were examined in relation to the inception and exacerbations of allergic diseases in Asia.

Low traffic and respiratory symptoms among smoking females: the Hordaland Health Study

The main aim of this study was to evaluate the prevalence of respiratory symptoms among men and women separately in areas with relatively low traffic density. Data on respiratory symptoms were collected from questionnaires in the Hordaland Health Study. A total of 16,412 individuals, 40 to 45 years, were asked to participate (response rate: 55% for men and 66% for women). Women residing in areas with the highest traffic density had increased prevalence of daily cough (18% vs 8.2%, p < .01), of cough with sputum (8.8% vs 2.8%, p < .01), and of chronic cough (11% vs 4.7%, p < .01) compared with women residing in areas with lower traffic density. The differences were most pronounced for smoking females. There were no similar findings among men. In conclusion, even within areas with relatively low environmental air pollution, respiratory symptoms was related to traffic density among smoking females.

Do indoor environments influence asthma and asthma-related symptoms among adults in homes?: a review of the literature

This review summarizes the results of epidemiological studies focusing on the detrimental effects of home environmental factors on asthma morbidity in adults. We reviewed the literature on indoor air quality (IAQ), physical and sociodemographic factors, and asthma morbidity in homes, and identified commonly reported asthma, allergic, and respiratory symptoms involving the home environment. Reported IAQ and asthma morbidity data strongly indicated positive associations between indoor air pollution and adverse health effects in most studies. Indoor factors most consistently associated with asthma and asthma-related symptoms in adults included fuel combustion, mold growth, and environmental tobacco smoke. Environmental exposure may increase an adult's risk of developing asthma and also may increase the risk of asthma exacerbations. Evaluation of present IAQ levels, exposure characteristics, and the role of exposure to these factors in relation to asthma morbidity is important for improving our understanding, identifying the burden, and for developing and implementing interventions aimed at reducing asthma morbidity.

A review of equity issues in quantitative studies on health inequalities: the case of asthma in adults

BACKGROUND

The term 'inequities' refers to avoidable differences rooted in injustice. This review examined whether or not, and how, quantitative studies identifying inequalities in risk factors and health service utilization for asthma explicitly addressed underlying inequities. Asthma was chosen because recent decades have seen strong increases in asthma prevalence in many international settings, and inequalities in risk factors and related outcomes.

METHODS

A review was conducted of studies that identified social inequalities in asthma-related outcomes or health service use in adult populations. Data were extracted on use of equity terms (objective evidence), and discussion of equity issues without using the exact terms (subjective evidence).

RESULTS

Of the 219 unique articles retrieved, 21 were eligible for inclusion. None used the terms equity/inequity. While all but one article traced at least partial pathways to inequity, only 52% proposed any intervention and 55% of these interventions focused exclusively on the more proximal, clinical level.

CONCLUSIONS

Without more in-depth and systematic examination of inequities underlying asthma prevalence, quantitative studies may fail to provide the evidence required to inform equity-oriented interventions to address underlying circumstances restricting opportunities for health.

Air pollution and children's respiratory symptoms in six cities of Northern China

OBJECTIVE

The associations between air pollution and children's respiratory health in the high pollution range have not yet been clearly characterized. We evaluated the effects of outdoor air pollution on respiratory morbidity in children selected from multiple sites in a heavy industrial province of northeastern China.

METHODS

The study included 11,860 children aged 3-12 years, selected from 18 districts of 6 cities in Liaoning province, the participation rate is 89.9%. Informed consent and written responses to surveys about children's historic and current health status, personal and household characteristics, and other information were obtained from parents. A two-stage regression approach was applied in data analyses.

RESULTS

There were wide gradients for TSP (188-689 μg/m(3)), SO(2) (14-140 μg/m(3) and NO(2) (29-94 μg/m(3)) across the 18 districts of 6 cities. The three air pollutants significantly increased the prevalence of persistent cough (21-28%), persistent phlegm (21-30%) and current asthma (39-56%) for each interquartile range increment (172 μg/m(3) for TSP, 69 μg/m(3) for SO(2), 30 μg/m(3) for NO(2)), showing larger between-city effects than within-city. Rates of respiratory symptoms were significantly higher for children with younger age, atopy, respiratory disease in early age, family history of asthma or chronic bronchitis, and tobacco smoke exposure.

CONCLUSION

The high levels of outdoor air pollution in north China are positively associated with children's respiratory symptoms, the associations with TSP appear to be stronger than SO(2) and NO(2).

Respiratory health symptoms among students exposed to different levels of air pollution in a Turkish city

In this study, we aimed to investigate the frequency of respiratory health symptoms among high school students attending schools at industrial, urban and rural areas in a Turkish city. Three schools located in different zones of the city having different pollution characteristics were chosen based on the pollutant distribution maps using Geographical Information Systems (GIS) software. A cross-sectional survey was performed among 667 high school students in the schools. Outdoor and indoor nitrogen dioxide (NO(2)) and ozone (O(3)) concentrations were also measured by passive samplers in the same schools to investigate possible routes of exposure. Chronic pulmonary disease (OR = 1.49; 95%CI: 1.11-1.99; p = 0.008), tightness in the chest (OR = 1.57; 95%CI: 1.22-2.02; p = 0.001), morning cough (OR = 1.81 95%CI: 1.19-2.75; p = 0.006) were higher among students in the industrial zone where nitrogen dioxide and ozone levels were also highest. There were no indoor sources of nitrogen dioxide and ozone exists in the schools except for the dining hall. As a conclusion, this study has noticed that air pollution and respiratory health problems among high school students are high in industrial zones and the use of passive samplers combined with GIS is an effective tool that may be used by public health researchers to identify pollutant zones and persons at risk.

Passive smoking and chronic obstructive pulmonary disease: cross-sectional analysis of data from the Health Survey for England

OBJECTIVES

There is increasing evidence that passive smoking is associated with chronic respiratory diseases, but its association with chronic obstructive pulmonary disease (COPD) requires more study. In this cross-sectional analysis of data from 3 years of the Health Survey for England, the association between passive smoking exposure and risk of COPD is evaluated.

DESIGN

Cross-sectional analysis of the 1995, 1996 and 2001 Health Surveys for England including participants of white ethnicity, aged 40+ years with valid lung function data. COPD was defined using the lower limit of normal spirometric criteria for airflow obstruction. Standardised questions elicited self-reported information on demography, smoking history, ethnicity, occupation, asthma and respiratory symptoms (dyspnoea, chronic cough, chronic phlegm, wheeze). Passive smoking was measured by self-report of hours of exposure to cigarette smoke per week.

RESULTS

Increasing passive smoke exposure was independently associated with increased risk of COPD, with adjusted OR 1.05 (95% CI 0.93 to 1.18) for 1-19 h and OR 1.18 (95% CI 1.01 to 1.39) for 20 or more hours of exposure per week. Similar patterns (although attenuated and non-significant) were observed among never smokers. More marked dose-response relationships were observed between passive smoking exposure and respiratory symptoms, but the most marked effects were on the development of clinically significant COPD (airflow obstruction plus symptoms), where the risk among never smokers was doubled (OR 1.98 (95% CI 1.03 to 3.79)) if exposure exceeded 20 h/week.

CONCLUSION

This analysis adds weight to the evidence suggesting an association between passive smoking exposure and COPD.