Indoor Air Pollution and Asthma in Hospitalized Children in a Tropical Environment

We performed a hospital-based study to examine a hypothesis that indoor air pollution was associated with acute asthma in young children living in Kuala Lumpur City. A total of 158 children aged 1 month to 5 years hospitalized for the first time for asthma were recruited as cases. Controls were 201 children of the same age group who were hospitalized for causes other than a respiratory illness. Information was obtained from mothers using a standardized questionnaire. Univariate analysis identified two indoor pollution variables as significant factors. Sharing a bedroom with an adult smoker and exposure to mosquito coil smoke at least three nights in a week were both associated with increased risk for asthma. Logistic regression analysis confirmed that sharing a bedroom with an adult smoker (OR = 1.91, 95% Cl 1.13, 3.21) and exposure to mosquito coil smoke (OR = 1.73, 95% Cl 1.02, 2.93) were independent risk factors. Other factors independently associated with acute asthma were previous history of allergy, history of asthma in first-degree relatives, low birth weight, and the presence of a coughing sibling. There was no association between asthma and exposure to kerosene stove, wood stove, aerosol mosquito repellent, type of housing, or crowding. We conclude that indoor air pollution is an avoidable factor in the increasing morbidity due to asthma in children in a tropical environment.     

Effect of Indoor Air Pollution from Biomass and Solid Fuel Combustion on Prevalence of Self-Reported Asthma among Adult Men and Women in India: Findings from a Nationwide Large-Scale Cross-Sectional Survey

Objectives. Increasing prevalence of asthma in developing countries has been a significant challenge for public health in recent decades. A number of studies have suggested that ambient air pollution can trigger asthma attacks. Biomass and solid fuels are a major source of indoor air pollution, but in developing countries the health effects of indoor air pollution are poorly understood. In this study we examined the effect of cooking smoke produced by biomass and solid fuel combustion on the reported prevalence of asthma among adult men and women in India. Methods. The analysis is based on 99,574 women and 56,742 men aged between 20 and 49 years included in India’s third National Family Health Survey conducted in 2005–2006. Effects of exposure to cooking smoke, determined by the type of fuel used for cooking such as biomass and solid fuels versus cleaner fuels, on the reported prevalence of asthma were estimated using multivariate logistic regression. Since the effects of cooking smoke are likely to be confounded with effects of tobacco smoking, age, and other such factors, the analysis was carried out after statistically controlling for such factors. Results. The results indicate that adult women living in households using biomass and solid fuels have a significantly higher risk of asthma than those living in households using cleaner fuels (OR: 1.26; 95%CI: 1.06–1.49; p = .010), even after controlling for the effects of a number of potentially confounding factors. Interestingly, this effect was not found among men (OR: 0.98; 95%CI: 0.77–1.24; p = .846). However, tobacco smoking was associated with higher asthma prevalence among both women (OR: 1.72; 95%CI: 1.34–2.21; p < .0001) and men (OR: 1.35; 95%CI: 1.49–2.25; p < .0001). Combined effects of biomass and solid fuel use and tobacco smoke on the risk of asthma were greater and more significant in women (OR: 2.16; 95%CI: 1.58–2.94; p < .0001) than they were in men (OR: 1.34; 95%CI: 1.04–1.72; p = .024). Conclusions. The findings have important program and policy implications for countries such as India, where large proportions of the population still rely on polluting biomass fuels for cooking and heating. Decreasing household biomass and solid fuel use and increasing use of improved stove technology may decrease the health effects of indoor air pollution. More epidemiological research with better measures of smoke exposure and clinical measures of asthma is needed to validate the findings.     

Bedroom air quality and vacuuming frequency are associated with repeat child asthma hospital admissions

Objective: Indoor environment factors have been associated with risk of asthma exacerbations in children but little is known about their role on asthma hospital readmissions. As children in Western societies continually spend more time indoors, understanding the influence of these factors on asthma exacerbation is important. We examined the role of indoor environmental and lifestyle characteristics on child asthma readmissions. Methods: A hospital-based case–control study recruited 22 children readmitted for asthma and 22 controls not readmitted for asthma. Logistic regression models were used to examine the association between aeroallergens and fungi in the bedroom and indoor lifestyle characteristics factors for asthma readmissions. To determine the best possible set of predictors among a large set of risk factors, we used random forests (RF) techniques. Results: Higher levels of airborne Cladosporium and yeast in the child’s bedroom increased risk of readmission (OR?=?1.68, 95% CI 1.04–2.72 and OR?=?1.52, 95% CI 0.99–2.34, respectively). Carpeted floors in the bedroom and synthetic doonas were also associated with increase in asthma readmissions (OR?=?4.07, 95% CI 1.03–16.06 and OR?=?14.6, 95% CI 1.26–169.4, respectively). In the home, frequent vacuuming using bagged cleaners increased risk of asthma readmission OR?=?15.7 (95% CI 2.82–87.2). Conclusions: Factors in the child’s bedroom play an important role in increasing the risk of asthma hospital readmissions. These findings have major clinical implications as the identified potential risk factors may be modifiable. Further epidemiological studies with larger samples are necessary to evaluate these associations further.     

Childhood asthma and the indoor environment

To investigate the influence of indoor air quality on respiratory health, a questionnaire-based study of 17,962 Canadian schoolchildren in kindergarten through grade 2 was carried out in 1988. The present report focuses on associations between several indoor environmental factors and childhood asthma. Increased reports of physician-diagnosed asthma were significantly associated (p less than 0.001) with exposure to environmental tobacco smoke (OR = 1.4), living in a damp home (OR = 1.5), the use of gas for cooking (OR = 2.0) and the use of a humidifier (OR = 1.7). Wheezing without a diagnosis of asthma also was associated (p less than 0.01) with environmental tobacco smoke (OR = 1.4, home dampness (OR = 1.6) and humidifier use (OR = 1.4), but not with gas cooking. Thus, several modifiable risk factors for respiratory illness may exist in Canadian homes. Further research is required to determine the nature of these cross-sectional observations.     

Risk factors for invasive meningococcal disease in southern Queensland, 2000-2001

AIM: The aim of this paper is to describe the risk factors for invasive meningococcal disease (IMD) in southern Queensland. METHODS: A case control study during the calendar years 2000-2001 was undertaken. RESULTS: Eighty-four laboratory-confirmed cases of IMD were notified. Four patients died and were excluded from the present study. Sixty-two (78%) eligible cases and 79 controls selected from the same age group and medical practice as cases, were interviewed. Univariate analysis found that IMD was associated with sharing bedrooms with two or more people (odds ratio (OR) 4.3; 95% confidence interval (CI) 1.2-17.0, P = 0.01), any exposure to tobacco smoke (smoker or passive exposure; OR 2.3; 95% CI 1.1-4.8, P = 0.02), passive exposure to tobacco smoke (OR 2.4; 95% CI 1.0-5.6, P = 0.03) and recent upper respiratory tract infection (OR 1.9, 95% CI 0.9-4.1, P = 0.06). Children who were breast-fed were less likely to develop IMD (OR 0.3; 95% CI 0.1-1.1, P = 0.04). Attendance at a childcare centre was not associated with an increased risk of IMD. In multivariate analysis, IMD was associated with children under 6 years of age who shared a bedroom with two or more people (OR 7.4; 95% CI 1.5-36.1, P = 0.01) or who had a primary carer who smoked (OR 9.1; 95% CI 2.1-39.9, P = 0.003). DISCUSSION: This is the second Australian study that identifies links between risk of IMD and exposure to cigarette smoke. The risk of IMD in young children could be further reduced if primary caregivers did not smoke. This information may contribute a new perspective to antismoking campaigns.     

Risk Factors for Asthmatic Patients Requiring Intubation. III. Observations in Young Adults

During recent decades, asthma prevalence and mortality have increased rapidly worldwide among children, teenagers, and young adults. Little attention has been placed on the latter group. Therefore, we studied risk factors for intubation in young adults as potential severity markers predictive of death. We analyzed demographic data from a retrospective cohort of hospitalized asthmatic young adults, including all asthmatics aged 20-34 years admitted over a 10-year period (1984-1994) to the University of California, Davis, Medical Center, Sacramento, California. A total of 550 such asthma admissions were reviewed, involving 351 women and 199 men, mean age 27.9 ± 4.2 years. Of this group, 180 young adults were white, 209 were black, 118 were Hispanic, 16 were Asian, and 27 were American Indian. By National Heart, Lung, and Blood Institute guidelines, there were 95 mild, 322 moderate, and 133 severe cases. Thirty-four young adults required intubation for their asthma. Significant risk factors identified for intubation were psychological factors and psychosocial problems odds ratio (OR) 25.0; 95% confidence interval (Cl) 12.4, 50.8, prior intubation (OR 23.6; 95% Cl 7.5, 42.8), language barrier (OR 17.3, 95% Cl 7.9, 38.0), prior asthma emergency room visit in past year (OR 10.2; 95% Cl 4.6, 16.0), crowding (OR 8.5; 95% Cl 4.6, 16.0), prior asthma hospitalization in past year (OR 8.3; 95% CI3.3, 20.8), family dysfunction (OR 7.2; 95% Cl 3.6,14.3), active smoking/secondhand smoke exposure (OR 7.1; 95% Cl 5.1, 9.9), respiratory infection (OR 6.0; 95% Cl 3.2, 11.5), low formal education (OR 5.7; 95% Cl 2.9, 11.2), unemployment (OR 4.9; 95% Cl 2.5, 9.5), steroid dependence (OR 4.6; 95% Cl 3.2, 6.4), and atopy (OR 4.3; 95% Cl 2.1, 8.5). These variables are important determinants of baseline risk factors.     

Prevalence and risk factors for asthma in Poland: results from the PMSEAD study.

BACKGROUND: The prevalence of asthma depends on both hereditary and environmental factors. Knowledge of the effects of environmental and congenital factors on the frequency of occurrence of asthma may provide important clues to its pathogenesis and prevention. OBJECTIVES: The Polish Multicentre Study of Epidemiology of Allergic Diseases was designed to obtain estimates representative of the entire Polish population to assess asthma prevalence and risk factors. METHODS: Thirty-three areas were selected in 11 regions of Poland. Epidemiologic diagnoses of asthma were verified by a single recognized expert in each region on the basis of collected data as well as available medical documentation, in accordance with the 1997 guidelines of the Global Initiative for Asthma. Ambient air concentrations of sulfur dioxide and suspended particulates (black smoke) were measured directly or estimated by statistical modelling. RESULTS: Results were obtained for asthma in 16 238 subjects, including 3268 children (aged 3 to 16 years) and 12 970 adults (17 to 80 years). The overall prevalence of asthma was 8.6% (95% confidence interval [CI], 7.7%-9.6%) among children and 5.4% (95% CI, 5.0%-5.8%) among adults. Several risk factors for asthma were identified: family history of asthma, black smoke, residential exposure to traffic-related air pollution in both children and adults, and damp or overcrowded housing in adults. No statistically significant association was observed for passive smoking in the home, use of gas stoves, pet ownership, or exposure to ambient air pollution with sulfur dioxide. CONCLUSION: Our results show that the prevalence of asthma is associated with several host and environmental factors in the Polish population.     

Wood stove heating, asthma and allergies.

In two German studies household wood or coal stove use was negatively associated with atopic sensitization and allergic rhinitis in childhood. Wood stove heating is strongly related to 'traditional lifestyle and therefore subjected to confounding factors possibly yet not known. The study was conducted to study these factors and the independent impact of early exposure to wood stove heating on subsequent asthma and atopic disease. In a questionnaire survey among 10667 Finnish university students aged 18-25 years, we investigated the association between wood stove heating at age 0-6 years and asthma and allergies up to young adulthood. Adjustment was made for factors related to the heating system and atopic disorders by using multivariate regression. Unadjusted lifetime prevalence rates for physician-diagnosed asthma, allergic rhinoconjunctivitis, atopic dermatitis and self-reported wheezing were lower among subjects with wood stove heating compared to other heating systems. There was a significant negative association between childhood wood stove heating and allergic rhinitis or conjunctivitis in the univariate model (OR 0.61, 95% CI 0.61-0.91), but not for the other diseases. The significant association disappeared in the multivariate analysis after adjusting for various family indoor and outdoor (adjusted OR 0.96, 95% CI 0.77-1.20) factors. The association between wood stove heating and allergic rhinoconjunctivitis was mainly confounded by childhood residential environment, especially the farm environment. Farm environment was found to be the main confounding factor related to association between wood stove heating and asthma, and atopic diseases.     

Respiratory health effects of exposure to environmental tobacco smoke

Tobacco smoke is a major component of indoor air pollution. Exposure to environmental tobacco smoke (ETS) is prevalent worldwide despite growing awareness of its adverse health effects on non-smokers. ETS contains the same toxic substances as identified in mainstream tobacco smoke. Cotinine (a metabolite of nicotine) can be measured in urine and serum of non-smokers exposed to ETS and reflects the degree of exposure. In children, exposure to ETS leads to reduced lung function, increased risk of lower respiratory tract illnesses, acute exacerbation of asthma resulting in hospitalization, increased prevalence of non-allergic bronchial hyperresponsiveness, increased risk for sudden infant death syndrome (SIDS) and possibly increased risk for asthma. Exposure to ETS is responsible for excess cost to the family's financial resources and demands on health services. In adults, exposure to ETS is associated with increased risk of lung cancer, particularly in those with high exposure and acute and chronic respiratory symptoms that improve after the cessation of exposure. Healthcare providers should advocate for non-smokers' rights in the community and support legislation to limit tobacco exposure.     

Household environmental factors and children’s respiratory health: comparison of two cross-sectional studies over 25 years in Wuhan,China

BackgroundOver the recent decades, residential lifestyle and household environment have changed substantially with rapid development of industrialization and urbanization in China. Whether the prevalence of respiratory diseases changed is still lack of evidence. The objective of this study is to assess potential changes in children’s respiratory disease prevalence and associated household environmental factors in Wuhan over a 25-year time interval.MethodsTwo cross-sectional studies in the Period 1 (1993 to 1996) and Period 2 (2017 to 2018) were compared in this research. Elementary school children in period 1 (N=2,517) and in period 2 (N=3,152) were recruited in Wuhan, China. The respiratory health condition, home environmental factors, and family socioeconomic status of each subject were acquired through questionnaire survey using the same protocols in both periods. We used the Chi-square test to analyze the difference of household environmental factors (focused on three indoor air quality determinants) and children’s respiratory health condition between two periods. Logistic regression models were used to assess the impacts of household environmental determinants on children’s respiratory diseases and symptoms between the two studies, by adjusting a set of covariates.ResultsThe three indoor air quality determinants have reduced substantially in prevalence from period 1 to period 2: environment tobacco smoke (ETS) from 86.6% to 45.9%, household coal use from 47.6% to 4.9%, and kitchen smoke from 58.9% to 7.3%. The prevalence of certain respiratory symptoms in children significantly decreased, such as cough with colds (51.1% to 41.6%) and phlegm with colds (22.3% to 17.7%). The prevalence of asthma was 2.5% and 2.4% and that of bronchitis was 27.1% and 29.8% in both periods. Coal use was a risk factor for asthma in period 1 (OR =2.34, 95% CI: 1.30–4.23), while it was not significantly associated with prevalence of asthma in period 2 (OR =0.60, 95% CI: 0.08–4.51).ConclusionsHousehold indoor air quality determinants and respiratory health condition of children in Wuhan has been improved over the last 25 years. At present, kitchen smoke is an important factor affecting the prevalence of wheeze whatever child has a cold or not and reducing exposure to ETS could be beneficial to protect children to be less likely to develop bronchitis.     

Domestic exposure to formaldehyde significantly increases the risk of asthma in young children.

Concern has arisen in recent years about indoor air pollution as a risk factor for asthma. Formaldehyde exposure was examined in relation to asthma among young children (between 6 months and 3 yrs old) in a population-based control study carried out in Perth, Western Australia, between 1997-1999. An association between exposure to formaldehyde and asthma in young children has been suggested. Cases (n=88), whose parents were recruited at Princess Margaret Hospital Accident and Emergency Dept (Perth, Western Australia), were children discharged with asthma as the primary diagnosis. Controls (n=104), who were children in the same age group without asthma diagnosed by a doctor, were identified from birth records through the Health Dept of Western Australia (Perth, Western Australia). Health outcomes for the children were studied using a respiratory questionnaire and skin-prick tests. Formaldehyde, average temperature and relative humidity were measured on two occasions, winter (July-September 1998) and summer (December 1998-March 1999) in the child's bedroom and in the living room. The study found seasonal differences in formaldehyde levels in the children's bedrooms and living rooms with significantly greater formaldehyde exposure during the summer period for case and control subjects. The generalised estimating equation model showed that children exposed to formaldehyde levels of > or = 60 microg x m(-3) are at increased risk of having asthma. The results suggest that domestic exposure to formaldehyde increases the risk of childhood asthma.     

Prevalence and severity of asthma among Indian school children aged between 6 and 14 years: associations with parental smoking and traffic pollution

Objective: Phase three of the International Study of Asthma and Allergy in Children (ISAAC) was carried out at various sites in India. The prevalence of asthma symptoms in school children and the effect of environmental tobacco smoke and traffic pollution on the occurrence of asthma were analysed. Methods: Two groups of school children, aged 6–7?yr and 13–14?yr, participated according to the ISAAC protocol. Schools were randomly selected and responses to the ISAAC questionnaire were recorded. Results: The prevalence of asthma was 5.35% in the 6–7?yr age group and 6.05% in the 13–14?yr age group. The odds ratios (ORs) for the risk of asthma in children with exposure to mild, moderate and heavy traffic pollution compared with minimal traffic pollution were 1.63 (95% CI: 1.43, 1.85), 1.71 (95% CI: 1.49, 1.96) and 1.53 (95% CI: 1.31, 1.78), respectively, in the younger group. Similarly, in the older group, they were 1.19 (95% CI: 1.04, 1.36), 1.51 (95% CI: 1.31, 1.75) and 1.51 (95% CI: 1.29, 1.76). Asthma was associated with maternal smoking [6–7?yr group: OR?=?2.72 (2.05, 3.6); 13–14?yr group: OR?=?2.14 (1.72, 2.66)] and paternal smoking [6–7?yr group: OR?=?1.9 (1.70, 2.11); 13–14?yr group: OR?=?1.21 (1.09, 1.34)]. Conclusions: The prevalence of asthma was lower in the 6–7 than the 13–14?yr age group. Environmental tobacco smoke and traffic pollution were the factors most strongly associated with asthma in Indian children.     

Association of indoor nitrogen dioxide exposure with respiratory symptoms in children with asthma

RATIONALE: Chronic exposure to indoor nitrogen dioxide (NO2) is a public health concern. Over half of U.S. households have a source of NO2, and experimental data suggest potential for adverse respiratory effects. OBJECTIVE: To examine associations of indoor NO2 exposure with respiratory symptoms among children with asthma. METHODS: NO2 was measured using Palmes tubes, and respiratory symptoms in the month before sampling were collected during home interviews of mothers of 728 children with active asthma. All were younger than 12 yr, lived at the sampled home for at least 2 mo, and had asthma symptoms or used maintenance medication within the previous year. MEASUREMENTS: Respiratory symptoms (wheeze, persistent cough, shortness of breath, chest tightness). RESULTS: Mean (SD) NO2 was 8.6 (9.1) ppb in homes with electric ranges and 25.9 (18.1) ppb in homes with gas stoves. In models stratified by housing type (a factor associated with socioeconomic status), gas stove presence and elevated NO2 were each significantly associated with respiratory symptoms, controlling for age, ethnicity, medication, mold/mildew, water leaks, and season of sampling. Among children in multifamily housing, exposure to gas stoves increased likelihood of wheeze (odds ratio [OR], 2.27; 95% confidence interval [95% CI], 1.15, 4.47), shortness of breath (OR, 2.33; 95% CI, 1.12, 5.06), and chest tightness (OR, 4.34; 95% CI, 1.76, 10.69), whereas each 20-ppb increase in NO2 increased both likelihood of any wheeze (OR, 1.52; 95% CI, 1.04, 2.21) or chest tightness (OR, 1.61; 95% CI, 1.04, 2.49), and days of wheeze (rate ratio (RR), 1.33; 95% CI, 1.05, 1.68) or chest tightness (RR, 1.51; 95% CI, 1.18, 1.91). CONCLUSION: Exposure to indoor NO2 at levels well below the Environmental Protection Agency outdoor standard (53 ppb) is associated with respiratory symptoms among children with asthma in multifamily housing.     

Effects of glutathione S-transferase M1, maternal smoking during pregnancy,and environmental tobacco smoke on asthma and wheezing in children

The rise in childhood asthma prevalence suggests a role for environmental factors in the etiology of this evolving epidemic; however, genetics also influence the occurrence of asthma. Glutathione S-transferase (GST) M1 may play a role in asthma and wheezing occurrence among those exposed to tobacco smoke, as it functions in pathways involved in asthma pathogenesis such as xenobiotic metabolism and antioxidant defenses. Effects of GSTM1 genotype, maternal smoking during pregnancy, and childhood environmental tobacco smoke (ETS) exposure on asthma and wheezing were investigated in 2,950 children enrolled in 4th, 7th, and 10th grade classrooms in 12 Southern California communities. The effects of in utero exposure to maternal smoking on asthma and wheezing occurrence were largely restricted to children with GSTM1 null genotype. Among GSTM1 null children, in utero exposure was associated with increased prevalence of early onset asthma (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.0-2.5), asthma with current symptoms (OR 1.7, 95% CI 1.1-2.8), persistent asthma (OR 1.6, 95% CI 1.1-2.4), lifetime history of wheezing (OR 1.8, 95% CI 1.3-2.5), wheezing with exercise (OR 2.1, 95% CI 1.3-3.3), wheezing requiring medication (OR 2.2, 95% CI 1.4-3.4), and emergency room visits in the past year (OR 3.7, 95% CI 1.9-7.3). Among children with GSTM1 (+) genotype, in utero exposure was not associated with asthma or wheezing. Our findings indicate that there are important long-term effects of in utero exposure in a genetically susceptible group of children.     

The role of environmental tobacco smoke in the origins and progression of asthma

Exposure to environmental tobacco smoke (ETS) is a major source of indoor air pollution and causes adverse effects on the respiratory health of individuals with asthma. At least one third of children and adults with asthma are exposed to ETS on a regular basis. There is convincing evidence for a causal relationship between exposure to ETS and development of asthma in children and in nonsmoking adults. Exposure to ETS also worsens asthma control in children and nonsmoking adults who have established asthma. The mechanism by which ETS causes these harmful effects is not established but may involve genetic predisposition, impairment of lung development, and altered lung inflammatory responses. Workplace smoking restrictions and reduced smoking in the home may lower the prevalence of asthma, improve asthma control, and reduce the use of medical services in both children and adults who are exposed to ETS.     

Indoor environmental factors associated with wheezing illness and asthma in South Korean children: phase III of the International Study of Asthma and Allergies in Childhood

Background: The relationship between exposure to indoor environmental pollutants and incidence of asthma and wheezing illness in children is unclear. This study aimed to clarify this relationship by identifying the risk factors associated with these conditions in South Korean children aged 6–7 years. Methods: The parents or guardians of 3810 children aged 6–7 years who had participated in the International Study of Asthma and Allergies in Childhood and met the study criteria completed validated questionnaires regarding their children's asthma and wheezing illness, risk factors and exposure to indoor pollutants. The data were subjected to chi-square and multivariate logistic regression analysis to identify the factors significantly associated with asthma and wheezing illness. Results: Parental history of allergic disease (odds ratio [OR]: 1.729; 95% confidence interval [CI]: 1.447–2.066), living on the basement or semi-basement floor (OR: 1.891; 95% CI: 1.194–2.996) and living in housing that had been remodeled within the last 12 months (OR: 1.376; 95% CI: 1.101–1.720) were found to be significantly associated with wheezing illness. Parental history of allergic disease (OR: 2.189; 95% CI: 1.483–3.231), male sex (OR: 1.971; 95% CI: 1.369–2.838) and positive skin prick test (SPT) result (OR: 1.583; 95% CI: 1.804–3.698) were found to be significantly associated with current asthma. Conclusions: Although the risk factors for current asthma appear to be more related to the non-modifiable risk factors like sex, parental history of allergic diseases, SPT, the two groups are associated with exposure to modifiable indoor environmental factors.     

Recent Advances in the Epidemiologic Investigation of Risk Factors for Asthma: A Review of the 2011 Literature

The present review aims to identify and summarize epidemiologic investigations published during 2011 on the environmental risk factors for asthma. Potentially eligible papers were identified by a MEDLINE search. In total, 1,130 items were retrieved. Based on a broad definition of environment, the following topics were included: obesity, diet, vitamin D, air pollution, farming environment, and social factors. Some of the more relevant contributions included evidence that 1) obesity precedes asthma, 2) fruit consumption is longitudinally associated with a lower risk of asthma and atopy, 3) a comprehensive statewide smoking ban was followed by a reduction in hospital admissions for asthma, 4) asthma is one of the diseases showing the largest burdens due to environmental tobacco smoke, 5) traffic-related urban air pollution is associated with bronchial inflammation as measured by fractional exhaled nitric oxide and uncontrolled asthma, 6) aeroallergens and desert dust may contribute to the short-term effects of air pollution and asthma, and 7) maternal exposure to air pollution before and during pregnancy may alter the immune competence in offspring.     

PM10, and children's respiratory symptoms and lung function in the PATY study

Studies of the impact of long-term exposure to outdoor air pollution on the prevalence of respiratory symptoms and lung function in children have yielded mixed results, partly related to differences in study design, exposure assessment, confounder selection and data analysis. We assembled respiratory health and exposure data for >45,000 children from comparable cross-sectional studies in 12 countries. 11 respiratory symptoms were selected, for which comparable questions were asked. Spirometry was performed in about half of the children. Exposure to air pollution was mainly characterised by annual average concentrations of particulate matter with a 50% cut-off aerodynamic diameter of 10 μm (PM(10)) measured at fixed sites within the study areas. Positive associations were found between the average PM(10) concentration and the prevalence of phlegm (OR per 10 μg·m(-3) 1.15, 95% CI 1.02-1.30), hay fever (OR 1.20, 95% CI 0.99-1.46), bronchitis (OR 1.08, 95% CI 0.98-1.19), morning cough (OR 1.15, 95% CI 1.02-1.29) and nocturnal cough (OR 1.13, 95% CI 0.98-1.29). There were no associations with diagnosed asthma or asthma symptoms. PM(10) was not associated with lung function across all studies combined. Our study adds to the evidence that long-term exposure to outdoor air pollution, characterised by the concentration of PM(10), is associated with increased respiratory symptoms.     

Health impact of indoor mineral particle pollution

Mineral particle air pollution consists of both atmospheric pollution and indoor pollution. Indoor pollution comes from household products, cosmetics, combustion used to heat homes or cook food, smoking, hobbies or odd jobs. There is strong evidence that acute respiratory infections in children and chronic obstructive pulmonary disease in women are associated with indoor biomass smoke. Detailed questioning is essential to identify at risk activities and sampling of airborne particles may help with the identification of pollution risks. Particle elimination depends on the standard of ventilation of the indoor environment. Five per cent of French homes have levels of pollution greater than 180 μg/m3 for PM 10 and 2% for PM 2.5. The principal mineral particle air pollutants are probably silica, talc, asbestos and carbon, whereas tobacco smoke leads to exposure to various ultrafine particles. The toxicity of these particles could be more related to surface exchange than to density. Tissue measurements by electron microscopy and microanalysis of particle samples may identify an uptake of particles similar to those in the environmental sample.     

The effect of biomass fuel exposure on the prevalence of asthma in adults in India – review of current evidence

Introduction: The combustion of biomass fuels is a major source of respiratory disease among individuals in the developing world. Over two million people world-wide rely on biomass fuels to supply their household energy needs with an estimated 1.6 million deaths annually being attributable to biomass smoke exposure. As a developing country, India relies heavily on the use of solid fuels as a source of energy. These materials supply 75% of the country’s domestic energy need and are attributed as the cause of over 600?000 deaths annually. Diseases such as chronic bronchitis and acute lower respiratory tract infections are strongly correlated to biomass smoke exposure. While not as strongly correlated, accumulating evidence suggests that asthma prevalence may be related to solid fuel smoke. Methods: This review examines the current literature linking biomass smoke exposure to the reporting of asthma symptoms. A PubMed search was performed using key terms biomass, asthma, India and respiratory disease. Preference was given to recent articles that surveyed the adult population within India. Results: The reviewed articles showed an increased odds ratio for reporting a diagnosis of asthma or symptoms consistent with asthma following biomass smoke exposure. While the literature supports a strong association between household air pollution and the development of chronic bronchitis and acute lower respiratory tract infections in India, this review establishes a more firm relationship between reported asthma symptoms and biomass smoke exposure. Conclusion: The exposure to biomass fuel smoke results in respiratory diseases in developing countries. Among these diseases, asthma appears to be a preventable pulmonary pathology that is associated with household air pollution. Measures to reduce exposure may decrease the burden of disease which could help advance social and economic progress in these nations. Further research and out-reach efforts are needed to reduce the total burden of lung diseases, including asthma, across the developing world. This reduction could save millions of dollars annually and lower morbidity and mortality in the affected populations.