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Li W, Long C, Fan T, Anneser E, Chien J, Goodman JE. Gas cooking and respiratory outcomes in children: A systematic review. GLOBAL EPIDEMIOLOGY 2023; 5:100107. [PMID: 37638371 PMCID: PMC10446006 DOI: 10.1016/j.gloepi.2023.100107] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 08/29/2023] Open
Abstract
The most recent meta-analysis of gas cooking and respiratory outcomes in children was conducted by Lin et al. [93] in 2013. Since then, a number of epidemiology studies have been published on this topic. We conducted the first systematic review of this epidemiology literature that includes an in-depth evaluation of study heterogeneity and study quality, neither of which was systematically evaluated in earlier reviews. We reviewed a total of 66 relevant studies, including those in the Lin et al. [93] meta-analysis. Most of the studies are cross-sectional by design, precluding causal inference. Only a few are cohort studies that could establish temporality and they have largely reported null results. There is large variability across studies in terms of study region, age of children, gas cooking exposure definition, and asthma or wheeze outcome definition, precluding clear interpretations of meta-analysis estimates such as those reported in Lin et al. [93]. Further, our systematic study quality evaluation reveals that a large proportion of the studies to date are subject to multiple sources of bias and inaccuracy, primarily due to self-reported gas cooking exposure or respiratory outcomes, insufficient adjustment for key confounders (e.g., environmental tobacco smoke, family history of asthma or allergies, socioeconomic status or home environment), and unestablished temporality. We conclude that the epidemiology literature is limited by high heterogeneity and low study quality and, therefore, it does not provide sufficient evidence regarding causal relationships between gas cooking or indoor NO2 and asthma or wheeze. We caution against over-interpreting the quantitative evidence synthesis estimates from meta-analyses of these studies.
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Affiliation(s)
- Wenchao Li
- Gradient, One Beacon St., 17 Floor, Boston, MA 02108, United States of America
| | - Christopher Long
- Gradient, One Beacon St., 17 Floor, Boston, MA 02108, United States of America
| | - Tongyao Fan
- Penn State College of Medicine, Department of Pharmacology, 500 University Drive, Hershey, PA 17033, United States of America
| | - Elyssa Anneser
- Gradient, One Beacon St., 17 Floor, Boston, MA 02108, United States of America
| | - Jiayang Chien
- Gradient, One Beacon St., 17 Floor, Boston, MA 02108, United States of America
| | - Julie E. Goodman
- Gradient, One Beacon St., 17 Floor, Boston, MA 02108, United States of America
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Tutino M, Granell R, Curtin JA, Haider S, Fontanella S, Murray CS, Roberts G, Arshad SH, Turner S, Morris AP, Custovic A, Simpson A. Dog ownership in infancy is protective for persistent wheeze in 17q21 asthma-risk carriers. J Allergy Clin Immunol 2023; 151:423-430. [PMID: 36273658 DOI: 10.1016/j.jaci.2022.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND Asthma-associated single nucleotide polymorphisms from large genome-wide association studies only explain a fraction of genetic heritability. Likely causes of the missing heritability include broad phenotype definitions and gene-environment interactions (GxE). The mechanisms underlying GxE in asthma are poorly understood. Previous GxE studies on pet ownership showed discordant results. OBJECTIVES We sought to study the GxE between the 17q12-21 locus and pet ownership in infancy in relation to wheeze. METHODS Wheezing classes derived from 5 UK-based birth cohorts (latent class analysis) were used to study GxE between the 17q12-21 asthma-risk variant rs2305480 and dog and cat ownership in infancy, using multinomial logistic regression. A total of 9149 children had both pet ownership and genotype data available. Summary statistics from individual analyses were meta-analyzed. RESULTS rs2305480 G allele was associated with increased risk of persistent wheeze (additive model odds ratio, 1.37; 95% CI, 1.25-1.51). There was no evidence of an association between dog or cat ownership and wheeze. We found significant evidence of a GxE interaction between rs2305480 and dog ownership (P = 8.3 × 10-4) on persistent wheeze; among dog owners, the G allele was no longer associated with an increased risk of persistent wheeze (additive model odds ratio, 0.95; 95% CI, 0.73-1.24). For those without pets, G allele was associated with increased risk of persistent wheeze (odds ratio, 1.61; 95% CI, 1.40-1.86). Among cat owners, no such dampening of the genetic effect was observed. CONCLUSIONS Among dog owners, rs2305480 G was no longer associated with an increased risk of persistent wheeze (or asthma). Early-life environmental exposures may therefore attenuate likelihood of asthma in those carrying 17q12-21 risk alleles.
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Affiliation(s)
- Mauro Tutino
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, The University of Manchester, Manchester Academic Health Science Centre, and Manchester University NHS Foundation Trust, Manchester, United Kingdom.
| | - Raquel Granell
- MRC Integrative Epidemiology Unit, Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - John A Curtin
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, The University of Manchester, Manchester Academic Health Science Centre, and Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Sadia Haider
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Sara Fontanella
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Clare S Murray
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, The University of Manchester, Manchester Academic Health Science Centre, and Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Graham Roberts
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom; NIHR Southampton Biomedical Research Centre, University Hospitals Southampton NHS Foundation Trust, Southampton, United Kingdom; David Hide Asthma and Allergy Research Centre, Isle of Wight, United Kingdom
| | - S Hasan Arshad
- NIHR Southampton Biomedical Research Centre, University Hospitals Southampton NHS Foundation Trust, Southampton, United Kingdom; David Hide Asthma and Allergy Research Centre, Isle of Wight, United Kingdom; Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Stephen Turner
- Child Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Andrew P Morris
- Centre for Genetics and Genomics Versus Arthritis, Division of Musculoskeletal and Dermatological Sciences, The University of Manchester, Manchester, United Kingdom
| | - Adnan Custovic
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Angela Simpson
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, The University of Manchester, Manchester Academic Health Science Centre, and Manchester University NHS Foundation Trust, Manchester, United Kingdom
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Ji X, Yao Y, Zheng P, Hao C. The relationship of domestic pet ownership with the risk of childhood asthma: A systematic review and meta-analysis. Front Pediatr 2022; 10:953330. [PMID: 35935350 PMCID: PMC9352935 DOI: 10.3389/fped.2022.953330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/04/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND OBJECTIVE The relationship between pet ownership and childhood asthma remains controversial. In recent years, there have been increasing studies with large sample size. Therefore, we conducted this systematic review and meta-analysis to evaluate the relationship between pet ownership and childhood asthma. METHOD Relevant research was retrieved from PubMed, Cochrane, EMBASE, and Web of science. The retrieval was as of October 1, 2021. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included studies. Stata 15.0 was used to conduct the meta-analysis. RESULTS A total of 60 studies with large sample size published between 1995 and 2021 were included in this systematic review and meta-analysis, which included 18 cohort studies and 42 case-control studies covering 27 countries and 1,871,295 children. As shown by meta-analysis results, cat ownership (OR = 1.18, 95%CI: 1.05∼1.33) and dog ownership (OR = 1.12, 95%CI: 1.0 0∼1.24) have a significant bearing on the occurrence of childhood asthma. Pet ownership was also positively correlated with the occurrence of severe childhood asthma (OR = 1.15, 95%CI: 1.11∼1.20). CONCLUSION Pet ownership, especially cats and dogs, is associated with the occurrence of asthma in children.
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Affiliation(s)
- Xiaoyi Ji
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Suzhou, China.,Department of Pediatric, Jiaxing Maternal and Child Health Hospital, Jiaxing, China
| | - Yuan Yao
- Department of Radiology, Jiaxing Maternal and Child Health Hospital, Jiaxing, China
| | - Ping Zheng
- Department of Pediatric, Jiaxing Maternal and Child Health Hospital, Jiaxing, China
| | - Chuangli Hao
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Suzhou, China
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Indoor Microbial Exposures and Chronic Lung Disease: From Microbial Toxins to the Microbiome. Clin Chest Med 2021; 41:777-796. [PMID: 33153695 DOI: 10.1016/j.ccm.2020.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Effects of environmental microbial exposures on human health have long been of interest. Microbes were historically assumed to be harmful, but data have suggested that microbial exposures can modulate the immune system. We focus on the effects of indoor environmental microbial exposure on chronic lung diseases. We found contradictory data in bacterial studies using endotoxin as a surrogate for bacterial exposure. Contradictory data also exist in studies of fungal exposure. Many factors may modulate the effect of environmental microbial exposures on lung health, including coexposures. Future studies need to clarify which method of assessing environmental microbial exposures is most relevant.
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Yen YC, Yang CY, Wang TN, Yen PC, Ho CK, Mena KD, Lee TC, Chen KS, Lin YC, Chen PS. Household airborne endotoxin associated with asthma and allergy in elementary school-age children: a case-control study in Kaohsiung, Taiwan. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:19502-19509. [PMID: 32212084 PMCID: PMC7244453 DOI: 10.1007/s11356-020-07899-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
To evaluate the association between the presence of asthma and allergy, and airborne endotoxin in homes of school-age children in Kaohsiung City, Taiwan, with a case-control study design by matching the age and class exposure. Data collection of home visits included an interviewer-administered questionnaire and air sampling of participants' homes for endotoxin, bacteria, and fungi, as well as temperature and relative humidity measurements. Endotoxin was detected in all air samples with a median value of 0.67 EU m-3. In the adjusted logistic regression model, household airborne endotoxin was associated with higher prevalence of asthma and allergy; OR = 4.88 (95% CI 1.16-20.55) for Q3 (between 0.67 and 1.97 EU m -3) vs. Q1 (< 0.31 EU m -3), with statistical significance. Airborne fungi were associated with higher prevalence of asthma and allergy; OR = 4.47 (95% CI 1.13-17.69) for Q3 (between 314 and 699 CFU m -3) vs. Q1 (< 159 CFU m -3) in adjusted logistic regression models. Airborne endotoxin and fungi were significantly associated with children's asthma and allergy.
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Affiliation(s)
- Yu-Chuan Yen
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chun-Yuh Yang
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tsu-Nai Wang
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Pei-Chun Yen
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chi-Kung Ho
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Kristina D Mena
- Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Tzu-Chi Lee
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Health Promotion and Health Education, National Taiwan Normal University, Taipei, Taiwan
| | - Kang-Shin Chen
- Institute of Environmental Engineering, College of Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Yuan-Chung Lin
- Institute of Environmental Engineering, College of Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Pei-Shih Chen
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan.
- Institute of Environmental Engineering, College of Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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Howard E, Orhurhu V, Huang L, Guthrie B, Phipatanakul W. The Impact of Ambient Environmental Exposures to Microbial Products on Asthma Outcomes from Birth to Childhood. Curr Allergy Asthma Rep 2019; 19:59. [PMID: 31781873 PMCID: PMC7088961 DOI: 10.1007/s11882-019-0890-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Purpose of Review Asthma is a chronic respiratory condition with increasing domestic and worldwide prevalence that burdens individuals and the healthcare system with high costs associated with long-term treatments and acute emergency room (ER) visits. It can be triggered by ambient microbes, including bacteria, viruses, and fungi. In this review, we examine the outcomes of asthma patients in relation to environmental exposures to ambient microbe products, focusing on whether exposure leads to asthma development from birth to childhood and if particular microbes are associated with worsened asthma exacerbations. Recent Findings Bacterial endotoxin is more prominent in homes with pets and may cause cytokine cascades that lead to asthma exacerbation. However, some studies have demonstrated a protective effect with early exposure. Patients with positive Aspergillus skin testing are more prone to moderate-severe or severe-uncontrolled asthma. Fungal sensitization is also associated with earlier onset of asthma and demonstrates a dose-dependent relationship of symptom severity and duration. Among viruses, rhinovirus has the greatest association with decreased lung function, severe asthma, and asthma-related hospital admissions. Distribution of microbial products and associated asthma symptoms depends on the geographical climate. Genetic variations among individuals also mitigate the effects of microbial products on asthma development and symptom severity. Summary Microbial products of bacteria, fungi, and viruses are associated with the development of asthma, more severe asthma symptoms, and worse outcomes. However, some early exposure studies have also demonstrated a protective effect. Bacterial and fungal products are related to decreased lung function and earlier onset of asthma. Viral products are related to asthma-associated hospital admissions; and the climate and patient genetics can also temper or intensify the relationships between microbial products, asthma development, and asthma symptom severity. Further research should focus on the effects of early microbe exposure and its interaction with human immune systems and asthma-related outcomes.
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Affiliation(s)
- Evin Howard
- Bouvé College of Health Sciences, Graduate School of Nursing, Northeastern University, Boston, MA, USA
| | - Vwaire Orhurhu
- Department of Anesthesia, Critical Care, & Pain Medicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - Lisa Huang
- Department of Anesthesia, Critical Care, & Pain Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Barbara Guthrie
- Bouvé College of Health Sciences, Graduate School of Nursing, Northeastern University, Boston, MA, USA
| | - Wanda Phipatanakul
- Division of Asthma, Allergy, & Immunology, Harvard Medical School, Children's Hospital Boston, Boston, MA, USA.
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Shamsollahi HR, Ghoochani M, Jaafari J, Moosavi A, Sillanpää M, Alimohammadi M. Environmental exposure to endotoxin and its health outcomes: A systematic review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 174:236-244. [PMID: 30831472 DOI: 10.1016/j.ecoenv.2019.02.046] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
Exposure to endotoxin occurs environmentally and occupationally. There are several differences between them in terms of the variety and severity of health outcomes, possible exposed groups and type and route of exposure. Occupational exposures caused adverse health outcomes in almost all cases, but there is disparity in the incidence of significant health outcomes due to environmental exposure to endotoxin. This study has therefore endeavoured to investigate health outcomes from environmental exposure to endotoxin. A systematic review was conducted of three databases and non-occupational studies reporting the environmental concentration of endotoxin, and observed health outcomes in exposed groups were included in the review (n = 27). The studies showed that first exposure to endotoxin occurs in infancy by the inhalation route. Inhalation is the only exposure route that can induce inflammation as the main symptom of exposure to endotoxin. The studies included were conducted using four approaches: molecular immunology, measurement of lung volumes, clinical sensitisation test and diagnosis of asthmatic and respiratory symptoms such as wheezing. By the immunological approach, all the included studies reported that environmental exposure to endotoxin, especially at a younger age, has a protective effect on the incidence of asthma in adolescence. The main disparity observed was in studies using the approach of diagnosed asthma. Overall, however, they confirm the protective effect of exposure to endotoxin although, in the case of children with non-atopic asthma, the results could be different.
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Affiliation(s)
- Hamid Reza Shamsollahi
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mahboobeh Ghoochani
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
| | - Jalil Jaafari
- Department of Environmental Health Engineering, School of Health, Guilan University of Medical Sciences, Rasht, Iran.
| | - Azam Moosavi
- Department of Biochemistry, School of Medicine, Alborz University of Medical Sciences, Alborz, Iran.
| | - Mika Sillanpää
- Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli, Finland.
| | - Mahmood Alimohammadi
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Center for Water Quality Research (CWQI), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran; Health Equity Research Center (HERC), Tehran University of Medical Sciences, Tehran, Iran.
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Olaniyan T, Dalvie MA, Röösli M, Naidoo R, Künzli N, de Hoogh K, Parker B, Leaner J, Jeebhay M. Asthma-related outcomes associated with indoor air pollutants among schoolchildren from four informal settlements in two municipalities in the Western Cape Province of South Africa. INDOOR AIR 2019; 29:89-100. [PMID: 30339304 DOI: 10.1111/ina.12511] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/31/2018] [Accepted: 10/13/2018] [Indexed: 06/08/2023]
Abstract
The health impact of indoor air pollution in informal settlement households has not been extensively studied in South Africa. This cross-sectional study investigated the association between asthma and common indoor exposures among schoolchildren from four informal settlements located in two municipalities in the Western Cape Province. A total of 590 children, aged 9-11 years, were recruited. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was administered to caregivers. Pulmonary function assessment included spirometry and fractional exhaled nitric oxide (FeNO). Phadiatop test for atopy was done. The prevalence of doctor-diagnosed asthma was 3.4% (n = 20) among whom only 50% were on treatment. The prevalence of current wheeze was 12.9%, and 17.6% had airway obstruction (FEV1 < lower limit of normal), while 10.2% had airway inflammation (FeNO > 35 ppb). In adjusted logistic regression models, dampness, visible mold growth, paraffin use for cooking, and passive smoking were associated with a twofold to threefold increased risk in upper and lower airway outcomes. The strongest association was that of visible mold growth with rhinitis (adjusted odds ratio-aOR 3.37, 95% CI: 1.69-6.71). Thus, there is a need for improved diagnosis of childhood asthma and Indoor Air Quality in informal settlement households.
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Affiliation(s)
- Toyib Olaniyan
- Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Mohamed Aqiel Dalvie
- Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Martin Röösli
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Rajen Naidoo
- University of Kwazulu-Natal, Durban, South Africa
| | - Nino Künzli
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Kees de Hoogh
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Bhawoodien Parker
- Department of Environmental Affairs and Developmental Planning, Western Cape Government, Cape Town, South Africa
| | - Joy Leaner
- Department of Environmental Affairs and Developmental Planning, Western Cape Government, Cape Town, South Africa
| | - Mohamed Jeebhay
- Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
- Division of Occupational Medicine, University of Cape Town, Cape Town, South Africa
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Oluwole O, Rennie DC, Senthilselvan A, Dyck R, Afanasieva A, Kirychuk S, Katselis G, Lawson JA. The association between endotoxin in house dust with atopy and exercise-induced bronchospasm in children with asthma. ENVIRONMENTAL RESEARCH 2018; 164:302-309. [PMID: 29554621 DOI: 10.1016/j.envres.2018.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 03/05/2018] [Accepted: 03/07/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Studies have reported protective and adverse associations between microbial exposure and childhood asthma. However, among children with asthma the relationships between endotoxin and exercise-induced bronchospasm (EIB) is less clear. OBJECTIVE We investigated the association between exposure to endotoxin in house dust with atopy and EIB in children with asthma. METHODS A cross-sectional survey was conducted among schoolchildren (aged 7-17 years) in the province of Saskatchewan, Canada. A subpopulation with asthma (n = 116) were identified from 335 participants using a validated asthma algorithm. We determined atopy among the asthma subpopulation by skin prick testing (SPT) while EIB was evaluated using exercise challenge testing (ECT). Dust samples were collected from mattress and play area floors, and endotoxin was measured in dust extracts. Logistic regression analyses were used to explore associations between endotoxin with atopy and EIB. RESULTS Among the 116 children with asthma, 99 completed SPT and all had completed ECT. Of these, 71/99 (71.7%) were atopic and 26/116 (22.4%) had EIB. Exposure to high play area endotoxin concentration [adjusted odds ratio (aOR) = 0.15, 95% CI: 0.03-0.85] and load (aOR = 0.11, 95% CI: 0.02-0.73) were negatively associated with atopy. In contrast, EIB was positively associated with high mattress endotoxin concentration (aOR = 6.01, 95% CI: 1.20-30.13). CONCLUSION Indoor microbial endotoxin exposure has varied associations with atopy and exercise-induced bronchospasm among children with asthma.
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Affiliation(s)
- Oluwafemi Oluwole
- Department of Community Health and Epidemiology, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK, Canada S7N 2Z4; Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4.
| | - Donna C Rennie
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4; College of Nursing, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK, Canada S7N 2Z4.
| | | | - Roland Dyck
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, Canada S7N 0W8.
| | - Anna Afanasieva
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4.
| | - Shelley Kirychuk
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, Canada S7N 0W8.
| | - George Katselis
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, Canada S7N 0W8.
| | - Joshua A Lawson
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, Canada S7N 2Z4; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, Canada S7N 0W8.
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10
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Oluwole O, Rennie DC, Senthilselvan A, Dyck R, Afanasieva A, Kirychuk S, Katselis G, Lawson JA. The association between endotoxin and beta-(1 → 3)-D-glucan in house dust with asthma severity among schoolchildren. Respir Med 2018; 138:38-46. [PMID: 29724391 DOI: 10.1016/j.rmed.2018.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 03/13/2018] [Indexed: 01/19/2023]
Abstract
BACKGROUND Asthma severity can be affected by microbial exposures. However, less is known about the specific indoor agents aggravating the disease in children. We examined the associations between indoor endotoxin and beta-(1 → 3)-D-glucan exposures and asthma severity in children with asthma. METHODS A clinical cross-sectional study of schoolchildren (aged 7-17 years) was conducted in the province of Saskatchewan, Canada. Children with asthma (n = 116) were identified from 335 participants using a combination of survey responses and objective clinical assessments. We then ascertained asthma severity based on recommended guidelines (continuous daytime asthma symptoms, frequent nighttime asthma symptoms, and ≤ 60% predicted FEV1). Levels of indoor endotoxin and beta-(1 → 3)-D-glucan were measured in dust samples obtained from play area floors and child's mattresses. RESULTS The study population of 116 children with asthma was comprised of 75.9% mild asthma and 24.1% moderate/severe asthma. Higher mattress endotoxin concentration was associated with increased odds of moderate/severe asthma [adjusted odds ratio (aOR) = 11.40, 95% confidence interval (CI): 1.45-89.43] while higher beta-(1 → 3)-D-glucan concentration (aOR = 0.16, 95% CI: 0.03-0.89) and load (aOR = 0.10, 95% CI: 0.02-0.72) in play areas were inversely associated with moderate/severe asthma. Furthermore, higher mattress endotoxin concentration was associated with lower FVC (p = 0.01) and FEV1 (p = 0.03). These associations were not seen for beta-(1 → 3)-D-glucan. CONCLUSION Our results showed differential effects of microbial exposures on childhood asthma severity and further highlight domestic endotoxin exposure effects on respiratory health outcomes in children with asthma.
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Affiliation(s)
- Oluwafemi Oluwole
- Department of Community Health and Epidemiology, University of Saskatchewan, 104 Clinic Place Saskatoon, SK, S7N 2Z4, Canada; Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada.
| | - Donna C Rennie
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada; College of Nursing, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK, S7N 2Z4, Canada
| | | | - Roland Dyck
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, S7N 0W8, Canada
| | - Anna Afanasieva
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada
| | - Shelley Kirychuk
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, S7N 0W8, Canada
| | - George Katselis
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, S7N 0W8, Canada
| | - Joshua A Lawson
- Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, 104 Clinic Place, PO Box 23, Saskatoon, SK, S7N 2Z4, Canada; Department of Medicine, College of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, S7N 0W8, Canada
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Schwarze PE, Ovrevik J, Låg M, Refsnes M, Nafstad P, Hetland RB, Dybing E. Particulate matter properties and health effects: consistency of epidemiological and toxicological studies. Hum Exp Toxicol 2016; 25:559-79. [PMID: 17165623 DOI: 10.1177/096032706072520] [Citation(s) in RCA: 252] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Identifying the ambient particulate matter (PM) fractions or constituents, critically involved in eliciting adverse health effects, is crucial to the implementation of more cost-efficient abatement strategies to improve air quality. This review focuses on the importance of different particle properties for PM-induced effects, and whether there is consistency in the results from epidemiological and experimental studies. An evident problem for such comparisons is that epidemiological and experimental data on the effects of specific components of ambient PM are limited. Despite this, some conclusions can be drawn. With respect to the importance of the PM size-fractions, experimental and epidemiological studies are somewhat conflicting, but there seems to be a certain consistency in that the coarse fraction (PM10-2.5) has an effect that should not be neglected. Better exposure characterization may improve the consistency between the results from experimental and epidemiological studies, in particular for ultrafine particles. Experimental data indicate that surface area is an important metric, but composition may play an even greater role in eliciting effects. The consistency between epidemiological and experimental findings for specific PM-components appears most convincing for metals, which seem to be important for the development of both pulmonary and cardiovascular disease. Metals may also be involved in PM-induced allergic sensitization, but the epidemiological evidence for this is scarce. Soluble organic compounds appear to be implicated in PM-induced allergy and cancer, but the data from epidemiological studies are insufficient for any conclusions. The present review suggests that there may be a need for improvements in research designs. In particular, there is a need for better exposure assessments in epidemiological investigations, whereas experimental data would benefit from an improved comparability of studies. Combined experimental and epidemiological investigations may also help answer some of the unresolved issues.
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Affiliation(s)
- P E Schwarze
- Norwegian Institute of Public Health, Oslo, Norway.
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Jalava PI, Happo MS, Huttunen K, Sillanpää M, Hillamo R, Salonen RO, Hirvonen MR. Chemical and microbial components of urban air PM cause seasonal variation of toxicological activity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:375-87. [PMID: 26245811 DOI: 10.1016/j.etap.2015.06.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 05/06/2023]
Abstract
The chemical and microbial composition of urban air particulate matter (PM) displays seasonal variation that may affect its harmfulness on human health. We studied the in vitro inflammatory and cellular metabolic activity/cytotoxicity of urban air particulate samples collected in four size-ranges (PM10-2.5, PM2.5-1, PM1-0.2, PM0.2) during four seasons in relatively clean urban environment in Helsinki, Finland. The composition of the same samples were analyzed, including ions, elements, PAH compounds and endotoxins. In addition, microbial contribution on the detected responses was studied by inhibiting the endotoxin-induced responses with Polymyxin B both in the PM samples and by two different bacterial strains representing Gram-positive and -negative bacteria. Macrophage cell line (RAW 264.7) was exposed to the size segregated particulate samples as well as to microbe samples for 24h and markers of inflammation and cytotoxicity were analyzed. The toxicological responses were dependent on the dose as well as size range of the particles, PM10-2.5 being the most potent and smaller size ranges having significantly smaller responses. Samples collected during spring and autumn had in most cases the highest inflammatory activity. Soil components and other non-exhaust particulate emissions from road traffic correlated with inflammatory responses in coarse particles. Instead, PAH-compounds and K(+) had negative associations with the particle-induced inflammatory responses in fine particles, suggesting the role of incomplete biomass combustion. Endotoxin content was the highest in PM10-2.5 samples and correspondingly, the largest decrease in the responses by Polymyxin B was seen with the very same samples. We found also that inhibitory effect of Polymyxin B was not completely specific for Gram-negative bacteria. Thus, in addition to endotoxin, also other microbial components may have a significant effect on the toxicological responses by ambient particulate matter.
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Affiliation(s)
- Pasi I Jalava
- University of Eastern Finland, Department of Environmental Science, PO Box 1627, FI-70211 Kuopio, Finland.
| | - Mikko S Happo
- University of Eastern Finland, Department of Environmental Science, PO Box 1627, FI-70211 Kuopio, Finland
| | - Kati Huttunen
- University of Eastern Finland, Department of Environmental Science, PO Box 1627, FI-70211 Kuopio, Finland
| | - Markus Sillanpää
- Finnish Meteorological Institute, Air Quality Research, PO Box 503, FI-00101 Helsinki, Finland
| | - Risto Hillamo
- Finnish Meteorological Institute, Air Quality Research, PO Box 503, FI-00101 Helsinki, Finland
| | - Raimo O Salonen
- National Institute for Health and Welfare, Department of Environmental Health, PO Box 95, FI-70701 Kuopio, Finland
| | - Maija-Riitta Hirvonen
- University of Eastern Finland, Department of Environmental Science, PO Box 1627, FI-70211 Kuopio, Finland; National Institute for Health and Welfare, Department of Environmental Health, PO Box 95, FI-70701 Kuopio, Finland
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Patelarou E, Tzanakis N, Kelly FJ. Exposure to indoor pollutants and Wheeze and asthma development during early childhood. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:3993-4017. [PMID: 25872014 PMCID: PMC4410229 DOI: 10.3390/ijerph120403993] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/25/2015] [Accepted: 04/03/2015] [Indexed: 11/16/2022]
Abstract
Background: This review aimed to summarize existing epidemiological evidence of the association between quantitative estimates of indoor air pollution with early childhood respiratory disease. Methods: We carried out a systematic literature search of peer-reviewed epidemiological studies undertaken in “westernized” countries that have assessed exposure to indoor pollutants and asthma and wheeze from infancy up to the age of 5. Results: The search, between January 2004 and February 2014 yielded 1840 studies for consideration. Following application of eligibility criteria to titles and abstracts 22 independent studies were deemed relevant for further review. Two additional studies were next identified through examination of the references’ lists of these studies. Of these 24 selected studies, 16 adopted a prospective cohort design and 8 were case-control studies. Fourteen studies assessed exposure to bio-aerosols, 8 studies assessed exposure to specific air chemicals and two studies assessed exposure to bio-aerosols and air chemicals. Furthermore, 11 studies examined the association of exposure with asthma and 16 with wheeze. Findings indicate that existing studies have reported contradictory effects of indoor pollutants levels and occurrence of asthma/wheeze. Conclusion: Additional research to establish causality and evaluate interventions to prevent disease onset is needed.
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Affiliation(s)
- Evridiki Patelarou
- Florence Nightingale School of Nursing and Midwifery, King's College London, London SE18WA, UK.
| | - Nikolaos Tzanakis
- Department of Thoracic Medicine, Medical School, University of Crete, Heraklion 71414, Greece.
| | - Frank J Kelly
- MRC-PHE Centre for Environment and Health, NIHR Environmental Hazards Health Protection Research Unit, King's College London, London SE19NH, UK.
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Vlaski E, Lawson JA. Urban-rural differences in asthma prevalence among young adolescents: The role of behavioural and environmental factors. Allergol Immunopathol (Madr) 2015; 43:131-41. [PMID: 24485936 DOI: 10.1016/j.aller.2013.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 09/21/2013] [Indexed: 01/11/2023]
Abstract
BACKGROUND Asthma prevalence has been reported to be lower in rural areas compared to urban areas, although this has been inconsistent. This study aims to identify the influence of urban-rural residence on asthma prevalence in adolescents in the Republic of Macedonia and to investigate characteristics that may explain observed associations. METHODS Following International Study of Asthma and Allergies in Childhood protocol, a national sample of Macedonian urban and rural dwelling adolescents (12-16 years) was recruited in 2006. Self-completed questionnaires were used to collect data on wheeze and asthma as well as personal, environmental and dietary characteristics. Following descriptive and multiple logistic regression analyses, a mediation analysis approach was performed to help explain observed associations. RESULTS A lower prevalence of current wheeze and ever-diagnosed asthma was observed in rural compared to urban dwelling adolescents (4.9% vs. 7.2% and 1.2% vs. 1.9%, respectively). After adjustment for potential confounders, the associations, although still protective, were not statistically significant (wheeze: OR=0.74, 95%CI=0.46-1.21; asthma: OR=0.97, 95%CI=0.38-2.46). The associations between urban-rural status with current wheeze and asthma were mediated by region of the country (wheeze 9%; asthma 19%) and by diet (>5% change for both wheeze and asthma). Having a dog resulted in a strengthening of the association between urban-rural status and current wheeze by 11.9%. CONCLUSIONS The prevalence of asthma and wheeze was lower in rural dwelling Macedonian adolescents and the association was mediated by the region of the country with diet likely to be part of the reason for this mediating effect.
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Affiliation(s)
- E Vlaski
- Department of Pulmonology and Allergology, University Children's Clinic, Skopje, Republic of Macedonia.
| | - J A Lawson
- Department of Medicine, Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, SK, Canada
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15
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Lin W, Brunekreef B, Gehring U. Meta-analysis of the effects of indoor nitrogen dioxide and gas cooking on asthma and wheeze in children. Int J Epidemiol 2013; 42:1724-37. [PMID: 23962958 DOI: 10.1093/ije/dyt150] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Since the meta-analysis on the association between indoor nitrogen dioxide (NO2) and childhood respiratory illness in 1992, many new studies have been published. The quantitative effects of indoor NO2 on respiratory illness have not been estimated in a formal meta-analysis since then. We aimed to quantify the association of indoor NO2 and its main source (gas cooking) with childhood asthma and wheeze. METHODS We extracted the association between indoor NO2 (and gas cooking) and childhood asthma and wheeze from population studies published up to 31 March 2013. Data were analysed by inverse-variance-weighted, random-effects meta-analysis. Sensitivity analyses were conducted for different strata. Publication bias and heterogeneity between studies were investigated. RESULTS A total of 41 studies met the inclusion criteria. The summary odds ratio from random effects meta-analysis for asthma and gas cooking exposure was 1.32 [95% confidential interval (CI) 1.18-1.48], and for a 15-ppb increase in NO2 it was 1.09 (95% CI 0.91-1.31). Indoor NO2 was associated with current wheeze (random effects OR 1.15; 95% CI 1.06-1.25). The estimates did not vary much with age or between regions. There was no evidence of publication bias. CONCLUSIONS This meta-analysis provides quantitative evidence that, in children, gas cooking increases the risk of asthma and indoor NO2 increases the risk of current wheeze.
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Affiliation(s)
- Weiwei Lin
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands and Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
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Abstract
PURPOSE OF REVIEW It has been hypothesized that increased cleanliness, reduced family size, and subsequent decreased microbial exposure could explain the increases in global asthma prevalence. This review considers the recent evidence for and against the 'hygiene hypothesis'. RECENT FINDINGS Recent evidence does not provide unequivocal support for the hygiene hypothesis: the hygiene hypothesis specifically relates to atopic asthma, but some of the protective effects (e.g. farm exposures) appear to apply to both atopic and nonatopic asthma; asthma prevalence has begun to decline in some western countries, but there is little evidence that they have become less clean; Latin American countries with high infection rates have high asthma prevalence and the hygiene hypothesis relates to early-life exposures, but exposures throughout life may be important. SUMMARY There is a considerable body of evidence which warrants scepticism about the hygiene hypothesis. However, these anomalies contradict the 'narrow' version of it in which microbial pressure early in life protects against atopic asthma by suppressing T-helper 2 immune responses. It is possible that a more general version of the hygiene hypothesis is still valid, but the aetiologic mechanisms involved are currently unclear.
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Lawson JA, Dosman JA, Rennie DC, Beach JR, Newman SC, Crowe T, Senthilselvan A. Endotoxin as a determinant of asthma and wheeze among rural dwelling children and adolescents: a case-control study. BMC Pulm Med 2012; 12:56. [PMID: 22966977 PMCID: PMC3545854 DOI: 10.1186/1471-2466-12-56] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 08/31/2012] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The association between endotoxin exposure and asthma is complex and has been associated with rural living. We examined the relationship between domestic endotoxin and asthma or wheeze among rural school-aged children (6-18 years) and assessed the interaction between endotoxin and other characteristics with these outcomes. METHODS Between 2005 and 2007 we conducted a case-control study of children 6-18 years in the rural region of Humboldt, Canada. Cases (n = 102) reported doctor-diagnosed asthma or wheeze in the past year. Controls (n = 208) were randomly selected from children without asthma or wheeze. Data were collected to ascertain symptoms, asthma history and indoor environmental exposures (questionnaire), endotoxin (dust collection from the play area floor and child's mattress), and tobacco smoke exposure (saliva collection). Statistical testing was completed using multiple logistic regression to account for potential confounders and to assess interaction between risk factors. A stratified analysis was also completed to examine the effect of personal history of allergy. RESULTS Among children aged 6-12 years, mattress endotoxin concentration (EU/mg) and load (EU/m2) were inversely associated with being a case [odds ratio (OR) = 0.44, 95% confidence interval (CI) = 0.20-0.98; and OR = 0.38, 95% CI = 0.20-0.75, respectively]. These associations were not observed in older children or with play area endotoxin. CONCLUSIONS Our results suggest that endotoxin exposure might be protective for asthma or wheeze. The protective effect is found in younger school-aged, non-allergic children. These results may help explain the inconsistencies in previous studies and suggest that the protective effects of endotoxin in the prevention of atopy and asthma or wheeze are most effective earlier in life.
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Affiliation(s)
- Joshua A Lawson
- Canadian Centre for Health and Safety in Agriculture & Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
- Canadian Centre for Health and Safety in Agriculture Royal University Hospital University of Saskatchewan, 3641-103 Hospital Drive, Saskatoon, SK S7N 0 W8, Canada
| | - James A Dosman
- Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, SK, Canada
| | - Donna C Rennie
- Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, and the College of Nursing, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jeremy R Beach
- Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Stephen C Newman
- Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Trever Crowe
- College of Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ambikaipakan Senthilselvan
- Department of Public Health Sciences, School of Public Health Sciences, University of Alberta, Edmonton, AB, Canada
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Semple S, Garden C, Coggins M, Galea KS, Whelan P, Cowie H, Sánchez-Jiménez A, Thorne PS, Hurley JF, Ayres JG. Contribution of solid fuel, gas combustion, or tobacco smoke to indoor air pollutant concentrations in Irish and Scottish homes. INDOOR AIR 2012; 22:212-23. [PMID: 22007695 PMCID: PMC3573694 DOI: 10.1111/j.1600-0668.2011.00755.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
UNLABELLED There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect of interventions. This study recruited homes in Ireland and Scotland where open combustion processes take place. Open combustion was classified as coal, peat, or wood fuel burning, use of a gas cooker or stove, or where there is at least one resident smoker. Twenty-four-hour data on airborne concentrations of particulate matter<2.5 μm in size (PM2.5), carbon monoxide (CO), endotoxin in inhalable dust and carbon dioxide (CO2), together with 2-3 week averaged concentrations of nitrogen dioxide (NO2) were collected in 100 houses during the winter and spring of 2009-2010. The geometric mean of the 24-h time-weighted-average (TWA) PM2.5 concentration was highest in homes with resident smokers (99 μg/m3--much higher than the WHO 24-h guidance value of 25 μg/m3). Lower geometric mean 24-h TWA levels were found in homes that burned coal (7 μg/m3) or wood (6 μg/m3) and in homes with gas cookers (7 μg/m3). In peat-burning homes, the average 24-h PM2.5 level recorded was 11 μg/m3. Airborne endotoxin, CO, CO2, and NO2 concentrations were generally within indoor air quality guidance levels. PRACTICAL IMPLICATIONS Little is known about indoor air quality (IAQ) in homes that burn solid or fossil-derived fuels in economically developed countries. Recent legislative changes have moved to improve IAQ at work and in enclosed public places, but there remains a real need to begin the process of quantifying the health burden that arises from indoor air pollution within domestic environments. This study demonstrates that homes in Scotland and Ireland that burn solid fuels or gas for heating and cooking have concentrations of air pollutants generally within guideline levels. Homes where combustion of cigarettes takes place have much poorer air quality.
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Affiliation(s)
- S Semple
- Scottish Centre for Indoor Air, Division of Applied Health Sciences, University of Aberdeen, Aberdeen, UK.
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Lawson JA, Dosman JA, Rennie DC, Beach J, Newman SC, Senthilselvan A. The association between endotoxin and lung function among children and adolescents living in a rural area. Can Respir J 2011; 18:e89-94. [PMID: 22187693 PMCID: PMC3267627 DOI: 10.1155/2011/290261] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
UNLABELLED BACKGROUND⁄ OBJECTIVES Knowledge of the effects of domestic endotoxin on children's lung function is limited. The association between domestic endotoxin and asthma or wheeze and lung function among school-age children (six to 18 years of age) was examined. The interaction between endotoxin and other personal and environmental characteristics and lung function was also assessed. METHODS A case-control study was conducted in and around the rural community of Humboldt, Saskatchewan, between 2005 and 2007. Parents of cases reported either doctor-diagnosed asthma or wheeze in the previous year. Controls were randomly selected from those not reporting these conditions. Data were collected by questionnaire to ascertain symptoms and conditions, while spirometry was used to measure lung function including forced vital capacity and forced expiratory volume in 1 s. Dust collected from the child's play area floor and the child's mattress was used to quantify endotoxin, and saliva was collected to quantify cotinine levels and assess tobacco smoke exposure. RESULTS There were 102 cases and 207 controls included in the present study. Lower forced expiratory volume in 1 s was associated with higher mattress endotoxin load among female cases (beta=-0.25, SE=0.07 [P<0.01]). There was a trend toward lower forced vital capacity, which was associated with higher play area endotoxin load among cases with high tobacco smoke exposure (beta=-0.17, SE=0.09 [P<0.10]). CONCLUSIONS Findings indicated that high endotoxin levels present in common household areas of rural children with asthma or wheeze may also affect their lung function. These associations may be potentiated by tobacco smoke exposure and female sex.
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Affiliation(s)
- Joshua A Lawson
- Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Canada.
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Lawson JA, Dosman JA, Rennie DC, Beach J, Newman SC, Senthilselvan A. Relationship of endotoxin and tobacco smoke exposure to wheeze and diurnal peak expiratory flow variability in children and adolescents. Respirology 2011; 16:332-9. [PMID: 21138498 DOI: 10.1111/j.1440-1843.2010.01911.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVE The relationship between endotoxin exposure and asthma severity (wheeze and airways obstruction) is not well described. The effects of endotoxin and tobacco smoke exposure on self-reported wheeze and diurnal PEF variability (DV-PEF) were examined in children aged 6-18 years with asthma or wheeze. METHODS A cross-sectional study was performed in a rural area. From this study, children who reported wheeze in the previous 12 months or a physician diagnosis of asthma (n = 98) were selected for a case-control study. These subjects, who were the basis for the present analysis, completed: (i) a home environmental assessment, including dust collection to measure endotoxin levels: (ii) a clinic visit, including saliva collection to measure cotinine levels; and (iii) 2 week monitoring of twice daily symptom records, including wheeze, and PEF to calculate DV-PEF. RESULTS Among these children, 22.4% reported wheeze during the monitoring period. Greater DV-PEF was associated with higher endotoxin loads in play areas (P < 0.05). The association between salivary cotinine levels and high DV-PEF was modified by gender. In females, higher cotinine levels were associated with an increased risk of high DV-PEF compared with lower cotinine levels (P < 0.05), but this was not observed among males. CONCLUSIONS Higher endotoxin exposure was associated with greater DV-PEF among children with asthma or wheeze. While previous studies have suggested that endotoxin exposure protects against the development of asthma, individuals with the disease should avoid high exposure levels to limit exacerbations. The effect of tobacco smoke exposure on lung health may differ between male and female children.
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Affiliation(s)
- Joshua A Lawson
- Canadian Centre for Health and Safety in Agriculture, Department of Medicine College of Nursing, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Caillaud D, Evrard B, Laurichesse H, Souweine B. Rôle des endotoxines de l’environnement intérieur dans les symptômes asthmatiques. ARCH MAL PROF ENVIRO 2011. [DOI: 10.1016/j.admp.2010.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Loo CJ, Foty RG, Wheeler AJ, Miller JD, Evans G, Stieb DM, Dell SD. Do questions reflecting indoor air pollutant exposure from a questionnaire predict direct measure of exposure in owner-occupied houses? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2010; 7:3270-97. [PMID: 20948960 PMCID: PMC2954581 DOI: 10.3390/ijerph7083270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/14/2010] [Accepted: 08/18/2010] [Indexed: 11/16/2022]
Abstract
Home characteristic questions are used in epidemiological studies and clinical settings to assess potentially harmful exposures in the home. The objective of this study was to determine whether questionnaire-reported home characteristics can predict directly measured pollutants. Sixty home inspections were conducted on a subsample of the 2006 population-based Toronto Child Health Evaluation Questionnaire. Indoor/outdoor air and settled dust samples were analyzed. Mean Fel d 1 was higher (p < 0.0001) in homes with a cat (450.58 μg/g) versus without (22.28 μg/g). Mean indoor NO(2) was higher (p = 0.003) in homes with gas stoves (14.98 ppb) versus without (8.31 ppb). Self-reported musty odours predicted higher glucan levels (10554.37 μg/g versus 6308.58 μg/g, p = 0.0077). Der f 1 was predicted by the home's age, but not by reports of carpets, and was higher in homes with mean relative humidity > 50% (61.30 μg/g, versus 6.24 μg/g, p = 0.002). Self-reported presence of a cat, a gas stove, musty odours, mice, and the home's age and indoor relative humidity over 50% predicted measured indoor levels of cat allergens, NO(2), fungal glucan, mouse allergens and dust mite allergens, respectively. These results are helpful for understanding the significance of indoor exposures ascertained by self-reporting in large epidemiological studies and also in the clinical setting.
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Affiliation(s)
- C.K. Jennifer Loo
- University of Toronto, 1 King’s College Circle, Toronto, Ontario M5S 1A8, Canada; E-Mail: (C.K.J.L.)
| | - Richard G. Foty
- The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada; E-Mail: (R.G.F.)
| | - Amanda J. Wheeler
- Health Canada, 269 Laurier Ave West, Ottawa, Ontario K1A 0K9, Canada; E-Mails: (A.J.W.); (D.M.S.)
| | - J. David Miller
- Chemistry Department, Carleton University, Ottawa, Ontario K1S 5B6, Canada; E-Mail: (J.D.M.)
| | - Greg Evans
- University of Toronto, 200 College Street, Toronto, Ontario M5S 2E5, Canada; E-Mail: (G.E.)
| | - David M. Stieb
- Health Canada, 269 Laurier Ave West, Ottawa, Ontario K1A 0K9, Canada; E-Mails: (A.J.W.); (D.M.S.)
| | - Sharon D. Dell
- The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada; E-Mail: (R.G.F.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-416-813-6248; Fax: +1-416-813-6246
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Subbarao P, Becker A, Brook JR, Daley D, Mandhane PJ, Miller GE, Turvey SE, Sears MR. Epidemiology of asthma: risk factors for development. Expert Rev Clin Immunol 2010; 5:77-95. [PMID: 20476901 DOI: 10.1586/1744666x.5.1.77] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This comprehensive review of the recent literature was undertaken to determine the current state of knowledge of the risk factors involved in the development of asthma in order to focus investigations in a proposed new longitudinal birth cohort study. The origins of asthma appear to lie in the prenatal and early postnatal period, and renewed investigations in this period with long-term close follow-up and objective phenotypic characterization will help to unravel the role of the multiple putative environmental factors in the development of asthma. It is only after understanding these effects that one can hope to design rational prevention studies for asthma.
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Affiliation(s)
- Padmaja Subbarao
- Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Ownby DR, Peterson EL, Williams LK, Zoratti EM, Wegienka GR, Woodcroft KJ, Joseph CLM, Johnson CC. Variation of dust endotoxin concentrations by location and time within homes of young children. Pediatr Allergy Immunol 2010; 21:533-40. [PMID: 20088861 PMCID: PMC4025918 DOI: 10.1111/j.1399-3038.2009.00918.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Endotoxin may affect the development of allergic disease in childhood but little is known about endotoxin variation within homes. We sought to determine endotoxin concentration agreement within homes when five locations were each sampled twice 5 months apart. Endotoxin was measured using the recombinant Limulus factor C assay in dust samples from 585 homes of children enrolled in a prospective study and again in 335 homes 5 months later. The five locations sampled in each home were the child's bedroom floor, child's bed, mother's bedroom floor, mother's bed and living room floor. Concentrations of 4 allergens (Can f 1, Fel d 1, Der f 1 and Bla g 2) were also measured from the child's bedroom floor. In pair-wise comparisons, endotoxin concentrations in all locations within each home were significantly different from all other locations (p < 0.001) except for the child's and mother's bedroom floors (p = 0.272). Spearman correlations between endotoxin concentrations from the different locations were all statistically significant (p < 0.05) but of modest magnitude (r = 0.24-0.54). Similarly, correlations at each site over the 5 month observation interval were statistically significant but modest (r = 0.17-0.44). Pets and season of the year did not affect correlations, although correlations were lower if the floor was not carpeted. Endotoxin concentrations at all locations were minimally correlated with allergen concentrations in both negative and positive directions (r = -0.12 to 0.12). We conclude that a single measurement of endotoxin from a home dust sample provides an imprecise estimate of dust endotoxin concentrations in other locations within the home and over a relatively short observation interval.
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Affiliation(s)
- Dennis R Ownby
- Department of Allergy and Immunology, Medical College of Georgia, Augusta, GA, USA.
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Caillaud D, Evrard B, Laurichesse H, Souweine B. [Role of indoor endotoxins in asthma symptoms]. Rev Mal Respir 2010; 26:893-9. [PMID: 19953033 DOI: 10.1016/s0761-8425(09)73684-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Endotoxin is a collective term designating a characteristic group of chemical constituents of the outer membrane of Gram negative bacteria, the lipopolysaccharides (LPS). BACKGROUND LPS provocation tests in healthy subjects (50 microg) induce asthma-like airflow obstruction with a neutrophilic inflammatory influx, similar to reactions observed in non-atopic asthma. Asthmatic subjects show the same reaction with smaller doses of LPS (20 microg), revealing higher sensitivity to LPS than normal subjects. Low levels (2 microg) of LPS do not induce either airflow obstruction or bronchial hyperreactivity. Among exposed workers, particularly in agriculture, endotoxin is the most significant component of the bioaerosol that is associated with airway disease. In clinical studies, exposure to LPS is associated with severe asthma. Conversely, epidemiological studies, in both urban and rural areas, assessing the relationship between exposure to LPS and asthma and asthma- related symptoms are inconsistent. PERSPECTIVES Longitudinal epidemiological studies, especially in farm children, may confirm the putative protective effects of LPS with respect to atopic asthma. CONCLUSION Exposure to indoor LPS is frequently associated with asthma and asthma-like symptoms in current studies. Their definitive role needs to be confirmed by birth cohort studies currently under way that should define the controversial protective effect of LPS with respect to atopic asthma in farming populations.
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Affiliation(s)
- D Caillaud
- Service de Pneumologie, CHU de Clermont-Ferrand, Hôpital Gabriel Montpied, Clermont-Ferrand, France.
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Rennie DC, Lawson JA, Kirychuk SP, Paterson C, Willson PJ, Senthilselvan A, Cockcroft DW. Assessment of endotoxin levels in the home and current asthma and wheeze in school-age children. INDOOR AIR 2008; 18:447-453. [PMID: 18681911 DOI: 10.1111/j.1600-0668.2008.00543.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
UNLABELLED The relationship between household endotoxin and asthma in children is not clear. To further investigate the relationship between sources of endotoxin and childhood asthma, we conducted a case-control study of children with and without asthma and examined their more frequent household exposures in the home. Children ages 6-13 years with current asthma (n = 70) or wheeze only (n = 19) were sex and age matched (+/-1 year) to 107 controls. Play area and mattress dust were collected for endotoxin analysis. Atopic status was determined by skin prick testing for allergies. A family size of >4 per household was associated with higher endotoxin levels (EU/mg) in the bed dust (P < 0.05). Passive smoking (P < 0.05) and the presence of a cat were associated with higher levels of endotoxin in mattress dust. Endotoxin levels in either the play dust or the bed dust did not differ between cases and controls. Within atopic cases, those with higher endotoxin loads (EU/m2) in bed or play areas were more likely to miss school for chest illness (P < 0.05). In this study, household endotoxin is not a risk factor for current asthma overall but may be associated with increased severity in children with atopic asthma. PRACTICAL IMPLICATIONS This study did not find that household sources of endotoxin were associated with asthma. However, within atopic asthmatics, asthma severity (as measured by a history of being kept home from school because of a chest illness in the past year) was associated with higher levels of endotoxin in dust from the child's bed. There is a need to further investigate the nature of the relationship between household endotoxin and asthma severity in children which could lead to better management of childhood asthma.
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Affiliation(s)
- D C Rennie
- Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatchewan, Canada.
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Abstract
Inner-city residents continue to suffer disproportionate asthma morbidity despite recent progress in reducing asthma morbidity and mortality in other strata of the United States population. Studies over the past decade indicate that the indoor environment is a strong contributor to poor asthma control and asthma-related health care use in inner-city populations. Certain indoor exposures are more common and occur in higher concentrations in inner-city communities than in suburban communities. Identification of "asthmagenic" indoor exposures has paved the way for the development of intervention strategies aimed at reducing asthma morbidity. This article reviews the growing body of evidence that certain indoor environmental exposures contribute to the burden of asthma in the inner city.
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Eberlein B, Gulyas AF, Schultz K, Lecheler J, Flögel S, Wolfmeyer C, Thiessen K, Jakob T, Schuster T, Hollweck R, Ring J, Behrendt H. Domestic allergens and endotoxin in three hospitals offering in-patient rehabilitation for allergic diseases in the alpine mountain climate of Bavaria - The AURA study. Int J Hyg Environ Health 2007; 212:21-6. [PMID: 18155959 DOI: 10.1016/j.ijheh.2007.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 06/27/2007] [Accepted: 09/10/2007] [Indexed: 10/22/2022]
Abstract
Endotoxins and allergens represent the major relevant contents of the atmospheric bioaerosol with regard to the triggering and exacerbation of allergic diseases. In this study, mattress concentrations of endotoxin and indoor allergens were measured in three hospitals in the alpine climate of Bavaria and in adjacent homes. Dust was collected from each of 10 mattresses according to a standardized protocol, and endotoxin was analyzed with the Limulus Amebocyte Lysate (LAL) test, indoor allergens Der p 1, Der f 1 and Fel d 1 were analyzed by ELISAs. The concentration of endotoxin in the mattresses did not differ significantly between different cities. The percentiles of endotoxin were significantly higher in hospitals than in homes. The concentrations of mite allergens (Der p 1 and Der f 1) in the dust were significantly lower in all hospitals than in homes. There was no significant difference of mite allergens between different time points. The concentrations of Fel d 1 were significantly higher in the autumn than in the summer (median: 1376 vs. 478ng/g). No significant differences of Fel d 1 were found between hospitals and homes or between different hospitals. As Fel d 1 concentrations reached levels at which cat allergic patients can experience symptoms, efforts had to be made to reduce the concentrations of Fel d 1 especially in hospitals. In contrast, mite allergens were low in hospitals, which can be clinically beneficial for patients with mite allergies.
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Affiliation(s)
- B Eberlein
- Division of Environmental Dermatology and Allergology, GSF/TUM, Neuherberg, Munich, Germany.
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Marinho S, Simpson A, Lowe L, Kissen P, Murray C, Custovic A. Rhinoconjunctivitis in 5-year-old children: a population-based birth cohort study. Allergy 2007; 62:385-93. [PMID: 17362249 DOI: 10.1111/j.1398-9995.2006.01294.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND There is a paucity of data on the prevalence, risk factors and natural history of rhinitis in early childhood. OBJECTIVE Within the context of a whole-population birth cohort we investigated the prevalence of and risk factors for current rhinoconjunctivitis (CRC) at age 5 years. METHODS Children were followed prospectively to age 5 years [questionnaires (n = 815), skin testing (n = 717), specific immunoglobulin E (n = 478), lung function (n = 711), dry air challenge (n = 556)]. Endotoxin and allergen exposures were measured in dust samples. RESULTS The prevalence of rhinitis ever, current rhinitis and rhinoconjunctivitis was 28.2%, 26.1%, and 12.1%, respectively. Asthma, wheeze and eczema coexisted with CRC (P < or = 0.01). In a multivariate model, maternal asthma (OR 2.38, 95% CI: 1.30-4.38, P = 0.005), paternal hay fever (1.96, 1.11-3.46, P = 0.02) and sensitization to grass (3.46, 1.86-6.42, P < 0.001) and cat (2.42, 1.14-5.18, P = 0.02) remained significant and independent associates of CRC. Whilst almost half of children with CRC were nonatopic, there was little difference in risk factors between atopic and nonatopic CRC. Amongst children with current wheeze, the presence of concurrent CRC had no effect on either severity or frequency of wheezy episodes. There was no difference in specific airway resistance, forced expiratory volume in 1 second (FEV(1)) or airway reactivity between children with and without CRC after adjustment for the presence of wheeze. CONCLUSION Family history of allergic disease and sensitization to inhalant allergens are risk factors for rhinoconjunctivitis in preschool children. In this age group, there is no association between the presence of rhinoconjunctivitis and severity of wheeze, increased airway reactivity and reduced lung function.
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Affiliation(s)
- S Marinho
- University of Manchester, Academic Division of Medicine and Surgery, University Hospital of South Manchester NHS Foundation Trust, Manchester, UK
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Simpson A, John SL, Jury F, Niven R, Woodcock A, Ollier WER, Custovic A. Endotoxin Exposure, CD14, and Allergic Disease. Am J Respir Crit Care Med 2006; 174:386-92. [PMID: 16614348 DOI: 10.1164/rccm.200509-1380oc] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE High endotoxin exposure may reduce the risk of allergic sensitization. OBJECTIVE To determine the relationship between a promoter polymorphism in the CD14 gene (CD14/-159 C to T) and endotoxin exposure in relation to the development of allergic sensitization, eczema, and wheeze within the setting of a birth cohort. METHODS We genotyped 442 children (CD14/-159 C to T; rs2569190). We assessed children for allergic sensitization (IgE > 0.2 kU/L to at least one of seven allergens), eczema (physical examination), and parentally reported wheeze. Endotoxin was measured in house dust. MAIN RESULTS Genotype frequencies were consistent with other populations (TT, 25%; CT, 47%; CC, 28%). Sensitization (present in 33% of children) was not associated with genotype. For children with TT and CT genotypes, there was no association between endotoxin and sensitization (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.71-1.23; p = 0.7; and OR, 0.90; 95% CI, 0.77-1.04; p = 0.16, respectively) or endotoxin and eczema (OR, 0.99; 95% CI, 0.81-1.20; p = 0.89; and OR, 1.38; 95% CI, 0.83-2.30; p = 0.22, respectively). In children with the genotype CC, increasing endotoxin load was associated with a marked and significant reduction in the risk of sensitization (OR, 0.70; 95% CI, 0.55-0.89; p = 0.004) and eczema (OR, 0.73; 95% CI, 0.56-0.95; p = 0.02). However, we observed an increased risk of nonatopic wheeze with increasing endotoxin exposure in children with the CC genotype (OR, 1.42; 95% CI, 1.01-1.99; p = 0.04) but not other genotypes. No effect was seen for atopic wheeze. CONCLUSIONS Increasing endotoxin exposure is associated with reduced risk of allergic sensitization and eczema but with increased risk of nonatopic wheeze in children with the CC genotype at -159 of the CD14 gene. The impact of environmental endotoxin may be enhanced in individuals with this genotype.
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Affiliation(s)
- Angela Simpson
- North West Lung Centre, Wythenshawe Hospital, Manchester M23 9LT, UK
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