1
|
Medjo B, Atanaskovic-Markovic M, Nikolic D, Spasojevic-Dimitrijeva B, Ivanovski P, Djukic S. Association between pet-keeping and asthma in school children. Pediatr Int 2013; 55:133-7. [PMID: 23421334 DOI: 10.1111/ped.12071] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/03/2013] [Accepted: 02/05/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND The role of pet exposure in childhood asthma and allergy is still controversial. The aim of this study was to investigate the association between pet-keeping during different periods of childhood and asthma and sensitization in school children. METHODS One hundred and forty-nine children aged between 7 and 14 years were enrolled in this study. Seventy-four children had current physician-diagnosed asthma, while 75 children did not have asthma. Pet-keeping was investigated by questionnaire. Allergic sensitization to pet allergen was assessed on skin prick tests and specific serum IgE concentration. Logistic regression analysis was performed, taking into account potential confounders. RESULTS Early, past and current pet-keeping was not significantly associated with asthma. Neither owning a cat nor dog during childhood was associated with asthma. Early pet-keeping, however, was significantly associated with sensitization to pet allergens (adjusted odds ratio [aOR], 24.11; 95% confidence interval [CI]: 3.28-177.27). Further analysis showed that only early cat-keeping was significantly associated with sensitization to cat allergen (aOR, 51.59; 95%CI: 2.28-1167.07). Keeping a cat or a dog after the first year of life was not associated with sensitization to those allergens. CONCLUSIONS Keeping a cat or a dog does not increase risk for asthma. Keeping a cat in the first year of life, however, increases risk of sensitization to cat allergen. Considering that this is a relatively small study, larger, prospective, birth cohort studies are required in Serbia to accurately assess the relationship between pet-keeping, asthma and sensitization.
Collapse
Affiliation(s)
- Biljana Medjo
- Pediatric Intensive Care Unit, University Children's Hospital, Medical Faculty, University of Belgrade, Belgrade, Serbia.
| | | | | | | | | | | |
Collapse
|
2
|
Genuneit J. Exposure to farming environments in childhood and asthma and wheeze in rural populations: a systematic review with meta-analysis. Pediatr Allergy Immunol 2012; 23:509-18. [PMID: 22625206 DOI: 10.1111/j.1399-3038.2012.01312.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Asthma is a chronic respiratory disorder that has become substantially more common over the past decades. One environmental factor for which particularly strong associations with asthma and allergic diseases have been described is exposure to farming environments in childhood. The aim of this systematic review was to update and extend existing narrative reviews, test for heterogeneity of effect across studies, and conduct a meta-analysis to report a summary effect measure. Published relevant literature was searched through PubMed including all articles added to PubMed before September 1, 2011. Articles were included if they reported an epidemiological study on the exposure to a farming environment in childhood and subsequent wheeze or asthma. Heterogeneity of effect measures across studies was evaluated using Cochran's Q and I(2). Random-effects meta-analysis was performed to summarize effect measures for various outcome definitions. In total, 357 retrieved abstracts revealed 52 original articles from 39 studies with data considered for the meta-analysis. Most studies were conducted among children or on childhood onset of disease. Most data were published on doctor-diagnosed asthma or current wheeze. The meta-analysis showed substantial heterogeneity across studies with similar outcome definitions. Nonetheless, the combined effects were statistically significant and showed an approximate 25% lower asthma prevalence among exposed subjects compared with unexposed subjects. The protective 'farm-effect' on asthma was reported in numerous studies. Its underlying factors ought to be studied, and promising efforts have been already made. However, the heterogeneity of the effect across studies should also be investigated because whatever causes it is a potential threat to valid synthesis of evidence and to the detection of specific protective factors.
Collapse
Affiliation(s)
- Jon Genuneit
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany.
| |
Collapse
|
3
|
Dimich-Ward H, Chow Y, Chung J, Trask C. Contact with livestock--a protective effect against allergies and asthma? Clin Exp Allergy 2007; 36:1122-9. [PMID: 16961711 DOI: 10.1111/j.1365-2222.2006.02556.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND A 'protective farm factor' possibly related to livestock exposure is hypothesized to reduce the risk for allergic sensitization. OBJECTIVE The purpose of this study was to determine whether 4-H club youth, who have opportunities for contact with livestock through club activities, have reduced risks of respiratory and allergic symptoms according to residence on a farm or exposure to livestock. METHODS A cross-sectional postal survey was completed by British Columbia 4-H members 8-20 years of age; a subset underwent skin prick testing as well. The association of farm residence and livestock exposure variables with symptoms were evaluated using logistic regression with adjustment for age, sex, cat and/or dog ownership, parental history of allergic disease, parental education, number of older siblings and exposure to smokers at home. RESULTS Questionnaires were completed by 1158 participants (response rate 50.3%); of these, a subset of 317 had skin prick tests (SPTs) (response rate 64.4%). Current residence on a farm was associated with a lower prevalence of ever having wheeze and asthma, as well as symptoms of atopic dermatitis. Variables relating to residence in a farm or rural area with livestock were more strongly associated with respiratory and allergic symptoms than were the livestock exposure variables such as frequency of contact and hours of barn use. The adjusted odds ratios for living in a farm residence in comparison with a rural non-livestock area were 0.49 (95% confidence interval (CI) 0.27-0.89) for diagnosed asthma, 0.51 (95% CI 0.30-0.85) for allergic rhinitis and 0.45 (95% CI 0.24-0.84) for atopic dermatitis. CONCLUSION Our findings suggest that some aspects of the farm environment, not just attributable to contact with livestock, were protective for respiratory and allergic conditions among 4-H youth.
Collapse
Affiliation(s)
- H Dimich-Ward
- Department of Medicine, Respiratory Division, University of British Columbia, Vancouver, BC, Canada.
| | | | | | | |
Collapse
|
4
|
Alfvén T, Braun-Fahrländer C, Brunekreef B, von Mutius E, Riedler J, Scheynius A, van Hage M, Wickman M, Benz MR, Budde J, Michels KB, Schram D, Ublagger E, Waser M, Pershagen G. Allergic diseases and atopic sensitization in children related to farming and anthroposophic lifestyle--the PARSIFAL study. Allergy 2006; 61:414-21. [PMID: 16512802 DOI: 10.1111/j.1398-9995.2005.00939.x] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The prevalence of allergic diseases has increased rapidly in recent decades, particularly in children. For adequate prevention it is important not only to identify risk factors, but also possible protective factors. The aim of this study was to compare the prevalence of allergic diseases and sensitization between farm children, children in anthroposophic families, and reference children, with the aim to identify factors that may protect against allergic disease. METHODS The study was of cross-sectional design and included 14,893 children, aged 5-13 years, from farm families, anthroposophic families (recruited from Steiner schools) and reference children in Austria, Germany, The Netherlands, Sweden and Switzerland. A detailed questionnaire was completed and allergen-specific IgE was measured in blood. RESULTS Growing up on a farm was found to have a protective effect against all outcomes studied, both self-reported, such as rhinoconjunctivitis, wheezing, atopic eczema and asthma and sensitization (allergen specific IgE > or = 0.35 kU/l). The adjusted odds ratio (OR) for current rhinoconjunctivitis symptoms was 0.50 (95% confidence interval (CI) 0.38-0.65) and for atopic sensitization 0.53 (95% CI 0.42-0.67) for the farm children compared to their references. The prevalence of allergic symptoms and sensitization was also lower among Steiner school children compared to reference children, but the difference was less pronounced and not as consistent between countries, adjusted OR for current rhinoconjunctivitis symptoms was 0.69 (95% CI 0.56-0.86) and for atopic sensitization 0.73 (95% CI 0.58-0.92). CONCLUSIONS This study indicates that growing up on a farm, and to a lesser extent leading an anthroposophic life style may confer protection from both sensitization and allergic diseases in childhood.
Collapse
Affiliation(s)
- T Alfvén
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Suzuki K, Kayaba K, Tanuma T, Kitazawa J, Yanagawa H. Respiratory symptoms and hamsters or other pets: a large-sized population survey in Saitama Prefecture. J Epidemiol 2005; 15:9-14. [PMID: 15678920 PMCID: PMC7817372 DOI: 10.2188/jea.15.9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND: Keeping hamsters as pets has been increasing markedly. Clinical reports have suggested that hamster or other pet ownership is associated with respiratory symptoms. However, this association has not been fully investigated by population-based studies in Japan. The aim of the present study was to investigate the relationship between hamster ownership and respiratory symptoms by using a questionnaire. METHODS: During the period of August 1 to 20, 2002, we conducted a cross-sectional survey in Saitama Prefecture, which has a total population of approximately 7 million. First, we selected, proportionally to the population size, 100 areas from 5 administration districts of Saitama Prefecture. From each area, 30 households were chosen: 15 living in detached houses and 15 living in other types of dwelling, such as apartment houses. In this way, 2 groups based on type of dwelling (detached house versus other types) could be studied. A lay away plan was carried out. For the survey, 2 questionnaires were developed. One was a questionnaire dealing with household conditions, including pet keeping. The other sought details regarding individual health and lifestyle conditions. The questionnaire dealing with respiratory symptoms asked “whether the respondents had experienced respiratory symptoms (wheezing and/or breathlessness and/or bad cough) in the last 12 months.” RESULTS: The response rate was 78.9%. There were 7,395 respondents in 2,368 households. There was no association between either dog or cat ownership and respiratory symptoms. In contrast, hamsters kept in the home were positively associated with respiratory symptoms. In a multivariate logistic regression analysis, hamster ownership increased the odds ratio for respiratory symptoms (odds ratio: 1.57; 95% confidence interval: 1.18-2.10). CONCLUSION: This large size population-survey indicated that hamster ownership is associated with respiratory symptoms.
Collapse
Affiliation(s)
- Kyoko Suzuki
- Graduate School of Health Science, Tokyo Medical and Dental University, Bunkyo, Japan.
| | | | | | | | | |
Collapse
|
6
|
Eduard W, Omenaas E, Bakke PS, Douwes J, Heederik D. Atopic and non-atopic asthma in a farming and a general population. Am J Ind Med 2004; 46:396-9. [PMID: 15376208 DOI: 10.1002/ajim.20088] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND In a previous study inverse associations between asthma and exposure to fungal spores and endotoxins in atopic farmers and positive associations with the same factors in non-atopic farmers were documented. No external reference population had been included. We, therefore, compared this farming population with the general population from an adjacent region. METHODS Random samples of a farming (n=2,106) and a rural (n=351) and urban (n=727) general population were selected. Atopy was assessed by serum IgE and asthma by questionnaires. RESULTS The asthma prevalence was 4.0% among farmers, 5.7% in the rural, and 7.6% in the urban population. Atopy was similar (9-10%). Most asthmatics were not atopic, 67-75%. Farmers had asthma less often than the general population OR 0.52 (95% CI 0.36-0.75); both atopic (OR 0.33 (95% CI 0.15-0.69)) and non-atopic asthma (OR 0.60 (95% CI 0.39-0.93)). CONCLUSION This may indicate a protective effect of the farm environment on asthma but a healthy worker effect may also play a role.
Collapse
Affiliation(s)
- Wijnand Eduard
- National Institute of Occupational Health, Oslo, Norway.
| | | | | | | | | |
Collapse
|
7
|
Yemaneberhan H, Flohr C, Lewis SA, Bekele Z, Parry E, Williams HC, Britton J, Venn A. Prevalence and associated factors of atopic dermatitis symptoms in rural and urban Ethiopia. Clin Exp Allergy 2004; 34:779-85. [PMID: 15144471 DOI: 10.1111/j.1365-2222.2004.1946.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Allergic diseases, including atopic dermatitis (AD), are increasingly becoming a clinical problem in developing countries. OBJECTIVE We investigated the prevalence of AD symptoms and the effects of potential environmental aetiologies in rural and urban areas of Jimma in southwestern Ethiopia. METHODS Information on allergic disease symptoms and lifestyle factors was gathered in an interviewer-led cross-sectional questionnaire-based population survey of 9844 urban and 3032 rural participants of all ages. A one-in-four subsample underwent skin prick testing for hypersensitivity to Dermatophagoides pteronyssinus, mixed threshings, and aspergillus. RESULTS Around 95% of those eligible took part in the survey. Lifetime cumulative prevalence of AD symptoms was generally low with an overall prevalence of 1.2%, but was higher in the urban (1.5%) than in the rural area (0.3%; odds ratio (OR)=4.45 [95% CI 2.34-8.47]). AD symptoms were strongly associated with wheeze (adjusted OR=22.03 [15.45-31.42]) and rhinitis symptoms (61.94 [42.66-89.95]). Of several environmental exposures assessed, residence in a house made of brick (rather than mud) walls with wooden (rather than clay) floor, exposure to cigarette smoke as a child, having lived outside of Jimma in the past, and being of the Tigrean ethnic group were associated with an increased risk of AD symptoms. CONCLUSION Although the overall prevalence of AD symptoms was low in this Ethiopian population, a marked urban-rural gradient was evident. Lifestyle factors linked to urbanization were associated with an increased risk of AD symptoms.
Collapse
|
8
|
Sandin A, Björkstén B, Bråbäck L. Development of atopy and wheezing symptoms in relation to heredity and early pet keeping in a Swedish birth cohort. Pediatr Allergy Immunol 2004; 15:316-22. [PMID: 15305940 DOI: 10.1111/j.1399-3038.2004.00166.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The role of pet keeping during infancy for the development of allergy and asthma is still controversial. The objective of this population-based birth cohort study was to assess the development of atopy and different wheezing phenotypes during the first 4 yr of life in relation to heredity and early pet keeping. The cohort comprised all 1228 infants living in a Swedish county who were born over a 1-yr period. The parents replied to repeated questionnaires and 817 of the children were skin prick tested both at 1 and 4 yr. Cat keeping during the first year of life was associated with an increased risk of a positive skin prick test to cat at 1 yr of age [odds ratio (OR) 2.2, 95% confidence interval (CI) 0.9-5.6], but neither with sensitivity nor clinical symptoms of allergy at 4 yr. Dog keeping during the first year of life was associated with an increased risk of early-onset transient wheezing, but only in children with parental asthma (adjusted OR 4.3, 95% CI 1.5-12.1). In contrast, early dog keeping had an inverse association with sensitivity to pollen allergen at 4 yr (adjusted OR 0.3, 95% CI 0.1-0.9) and late-onset wheezing (adjusted OR 0.4, 95% CI 0.2-1.0). Thus, pet keeping during the first year of life was not associated with an increased risk of atopy at 4 yr, although a positive SPT to cat was more common at 1 yr. Our findings may even suggest that dog keeping during the first year of life might provide some protection from pollen allergy and late-onset wheezing and increase the risk of early-onset transient wheezing in children with heredity for asthma.
Collapse
Affiliation(s)
- Anna Sandin
- Department of Paediatrics, Ostersund Hospital, Ostersund, Sweden.
| | | | | |
Collapse
|
9
|
Remes ST, Iivanainen K, Koskela H, Pekkanen J. Which factors explain the lower prevalence of atopy amongst farmers' children? Clin Exp Allergy 2003; 33:427-34. [PMID: 12680856 DOI: 10.1046/j.1365-2222.2003.01566.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The inverse association between farming and atopy in children has been attributed to microbial exposure, especially through livestock. Very little is known about other potential explanatory factors. OBJECTIVE To explore potential differences in lifestyle and environmental factors between farmer and non-farmer families, and whether these factors could explain the association between farming and childhood atopy. METHODS A cross-sectional study, including 366 farmers' and 344 non-farmers' children in eastern Finland. Information regarding exposure and background characteristics was gathered by a written questionnaire. Atopy was defined as having one or more positive skin prick test reactions (> 3 mm) against the six common aeroallergens. RESULTS Regardless of the current farming type, atopy was less frequent among the farmers' children than the non-farmers' children (aOR 0.56, 95% CI 0.40-0.78). Remarkable differences were seen in many lifestyle factors (including diet) between the farmer and non-farmer families, but only a few of the explored factors were associated with atopy. The frequency of current livestock contacts seemed to have an inverse, dose-dependent association with atopy (aOR 0.46, 95% CI 0.22-0.97 for daily vs. no contact). Having lived on a dairy farm in infancy (aOR 0.51, 95% CI 0.28-0.93), or having had cats or dogs in infancy (aOR 0.60, 95% CI 0.42-0.85), decreased the risk of atopy at school age. The inverse association between farming and atopy was not explained by the sociodemographic factors, or by differences in conventional risk factors of atopy. Animal contacts explained partially, but not completely, the association. CONCLUSION Higher frequency of animal contacts is one factor, but probably not the only one, explaining the inverse association of farming and atopy in children. The importance of early life exposures may have recently been over-emphasized, and current exposures discounted, when studying the risk factors of childhood atopy.
Collapse
Affiliation(s)
- S T Remes
- Department of Pediatrics, Kuopio University Hospital, Kuopio University Hospital, Kuopio, Finland.
| | | | | | | |
Collapse
|
10
|
Bukowski JA, Lewis RJ. Is the hygiene hypothesis an example of hormesis? NONLINEARITY IN BIOLOGY, TOXICOLOGY, MEDICINE 2003; 1:155-166. [PMID: 19330119 PMCID: PMC2651604 DOI: 10.1080/15401420391434306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
UNLABELLED The "hygiene hypothesis" has been suggested to explain the rising incidence of allergic disorders in developed countries. The postulated mechanism is that infectious and/or microbial agents stimulate the immune system toward Th1 (allergy fighting) rather than Th2 (allergy promoting) response. This paper reviews the evidence related to early life infectious/microbial exposures and subsequent atopic disorders and evaluates whether these data suggest a hormetic effect. Our review indicates an insufficient and contradictory association for bacterial/viral infections, with protective effects being either absent or specific to certain infections and/or populations. Chronic, heavy parasitic burdens appear to confer protection against atopic disorders, but are associated with considerable pathology. Moreover, light parasitic burden may increase allergic responses (i.e., no "low dose" beneficial effect). In contrast, there is consistent evidence that general microbial exposures, particularly gut commensals, may be protective against allergy development, which is consistent with a hormetic effect (i.e., potentially beneficial effects at low doses and detrimental effects at high levels). CONCLUSION General microbial exposures in relation to the "hygiene hypothesis" may represent a hormetic effect, although further research with more rigorous study methods (i.e., prospective designs and measurement of exposure timing, dose, route, etc.) are needed.
Collapse
Affiliation(s)
- John A. Bukowski
- ExxonMobil Biomedical Science, Inc., 1545 Route 22 East, P.O. Box 971, Annandale, NJ 08801–0971
| | - R. Jeffrey Lewis
- ExxonMobil Biomedical Science, Inc., 1545 Route 22 East, P.O. Box 971, Annandale, NJ 08801–0971
| |
Collapse
|
11
|
Abstract
BACKGROUND The reasons for the increase in childhood asthma over time are unclear. The indoor environment is of particular concern. An adverse role for synthetic bedding on asthma development in childhood has been suggested by cross-sectional studies that have found an association between synthetic pillow use and childhood wheeze. Prospective data on infant bedding have not been available. METHODS Bedding data at 1 month of age were available from an infant survey for children who were participating in a 1995 follow-up study (N = 863; 78% traced). The 1995 follow-up was embedded in a larger cross-sectional survey involving 6,378 seven year olds in Tasmania (N = 92% of eligible). Outcome measures included respiratory symptoms as defined in the International Study of Asthma and Allergies in Childhood protocol. Frequent wheeze was defined as more than 12 wheeze episodes over the past year compared with no wheeze. RESULTS Synthetic pillow use at 1 month of age was associated with frequent wheeze at age 7 (adjusted relative risk [aRR] = 2.5; 95% confidence interval [CI] = 1.2-5.5) independent of childhood exposure. Current synthetic pillow and quilt use was strongly associated with frequent wheeze (aRR = 5.2; CI = 1.3-20.6). Substantial trends were evident for an association of increasing number of synthetic bedding items with frequent wheeze and with increasing wheeze frequency. Among children with asthma, the age of onset of asthma occurred earlier if synthetic bedding was used in infancy. CONCLUSIONS In this cohort, synthetic bedding was strongly and consistently associated with frequent childhood wheeze. The association did not appear to be attributable to bedding choice as part of an asthma management strategy.
Collapse
Affiliation(s)
- Anne-Louise Ponsonby
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia.
| | | | | | | | | | | |
Collapse
|
12
|
Abstract
Symptom persistence in difficult asthmatics may be related to their home environment. If sensitised asthmatics are to benefit from indoor allergen avoidance measures, these must be rigorous and drug adherence satisfactory. This is difficult for many families. The relationship between traffic pollution, asthma diagnosis and symptom severity is persuasive but requires objective validation. Overall, it seems that house dust mite control and tobacco smoke avoidance are important for asthmatics and advice about how to avoid these adverse factors must be given. Whether these measures are effective in difficult asthmatics and whether moving house makes any difference is unknown.
Collapse
Affiliation(s)
- Sejal Saglani
- Respiratory Paediatrics, Great Ormond Street Hospital, London WC1N 3JH, UK
| | | |
Collapse
|
13
|
Abstract
There have been few studies of childhood asthma among families who live in nonmetropolitan settings. This work is part of the baseline assessment conducted before implementing a health education program to study the impact of asthma risk factors (gender, ethnicity, socioeconomic status, asthma severity) on home asthma management. Data analysis yielded no significant differences in home asthma management performed by parents or children with asthma based on the child's gender, ethnicity, asthma severity, or family socioeconomic status. Factors that define the child's experienced asthma pattern, such as activity limitations, number of allergens, and school absenteeism, were associated with the parent's work of asthma management. Trends in the data for the different ethnic and gender subgroups that have implications for clinical practice were identified. Future directions for research to address questions that emerged in this analysis are discussed.
Collapse
Affiliation(s)
- Sharon D Horner
- University of Texas at Austin, School of Nursing, 78701-1499, USA.
| | | | | |
Collapse
|
14
|
Portengen L, Sigsgaard T, Omland Ø, Hjort C, Heederik D, Doekes G. Low prevalence of atopy in young Danish farmers and farming students born and raised on a farm. Clin Exp Allergy 2002; 32:247-53. [PMID: 11929489 DOI: 10.1046/j.1365-2222.2002.01310.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Recent studies have shown that in several countries atopic sensitization to common allergens (common atopy) and atopic symptoms are markedly less prevalent in children living on a farm, compared with non-farm children living in the same rural areas. Living conditions on farms may, however, vary largely between different countries. It is also not yet known whether the "protective" effect of a farm environment can also be found in adults. MATERIALS AND METHODS Common atopy and respiratory health were assessed by skin prick tests (SPT), questionnaire and measurement of bronchial hyper-responsiveness (BHR) in the Sund Stald (SUS) study, a cohort study on respiratory health in Danish farming students and conscripts from the same rural areas as controls. Results of SPT were confirmed by IgE serology in all SPT+ subjects and a subset of SPT- subjects. Prevalences of common atopy, respiratory symptoms and bronchial hyper- responsiveness were compared for farmers and controls, and for those who had or had not lived on a farm in early childhood. RESULTS In multiple logistic regression analyses adjusting for ever smoking and a familial history of allergy, both being a farmer (ORs 0.62-0.75) and having had a farm childhood (ORs 0.55-0.75) appeared to contribute independently to a lower risk of sensitization to common allergens as assessed by SPT and IgE serology. A farm childhood was also inversely associated with high total IgE (OR 0.68), presence of respiratory symptoms (ORs 0.69-0.79) and BHR (OR 0.61) in these analyses. Direction and strength of the association between being a farmer and respiratory symptoms or BHR varied widely (ORs 0.69-1.28). CONCLUSION The "anti-atopy" protective effect of a farm childhood could be confirmed in Danish farming students: prevalences of positive SPT, specific and total IgE, allergic symptoms and BHR were lower in those being born or raised on a farm. Past exposure to the farm environment in early childhood may therefore also contribute to a lower risk of atopic sensitization and disease at a later age.
Collapse
Affiliation(s)
- L Portengen
- Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, The Netherlands
| | | | | | | | | | | |
Collapse
|
15
|
Abstract
The evidence as to whether exposure to environmental airborne endotoxin plays a protective or an inducing role in the development of asthma is reviewed. Studies of endotoxin and atopy, endotoxin and asthma, and farming and asthma are considered and, in each instance, a distinction is made between evidence of primary causation and evidence of secondary causation. It is concluded that, although it is plausible that bacterial endotoxin may protect against the development of asthma, there is considerable reason for caution regarding this hypothesis.
Collapse
Affiliation(s)
- J Douwes
- Institute for Risk Assessment Sciences, Division of Environmental and Occupational Health, Utrecht University, The Netherlands.
| | | | | |
Collapse
|
16
|
Braun-Fahrländer C. The role of the farm environment and animal contact for the development of asthma and allergies. Clin Exp Allergy 2001; 31:1799-803. [PMID: 11737027 DOI: 10.1046/j.1365-2222.2001.01269.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
17
|
Riedler J, Braun-Fahrländer C, Eder W, Schreuer M, Waser M, Maisch S, Carr D, Schierl R, Nowak D, von Mutius E. Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey. Lancet 2001; 358:1129-33. [PMID: 11597666 DOI: 10.1016/s0140-6736(01)06252-3] [Citation(s) in RCA: 940] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND A farming environment protects against development of asthma, hay fever, and atopic sensitisation in children. We aimed to establish whether increased exposure to microbial compounds has to occur early in life to affect maturation of the immune system and thereby reduces risk for development of allergic diseases. METHODS We did a cross-sectional survey in rural areas of Austria, Germany, and Switzerland. 2618 (75%) of 3504 parents of 6-13-year-old children completed a standardised questionnaire on asthma, hay fever, and atopic eczema. Children from farming families, and a random sample of non-farmers' children, who gave consent for blood samples to be obtained for measurements of specific serum IgE antibodies to common allergens were invited to participate (n=901). FINDINGS Exposure of children younger than 1 year, compared with those aged 1-5 years, to stables and consumption of farm milk was associated with lower frequencies of asthma (1% [3/218] vs 11% [15/138]), hay fever (3% [7] vs 13% [18]), and atopic sensitisation (12% [27] vs 29% [40]). Protection against development of asthma was independent from effect on atopic sensitisation. Continual long-term exposure to stables until age 5 years was associated with the lowest frequencies of asthma (0.8% [1/122]), hay fever (0.8% [1]), and atopic sensitisation (8.2% [10]). INTERPRETATION Long-term and early-life exposure to stables and farm milk induces a strong protective effect against development of asthma, hay fever, and atopic sensitisation.
Collapse
Affiliation(s)
- J Riedler
- Paediatric Pulmonology and Allergology, Children's Hospital, Salzburg, Austria.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Remes ST, Castro-Rodriguez JA, Holberg CJ, Martinez FD, Wright AL. Dog exposure in infancy decreases the subsequent risk of frequent wheeze but not of atopy. J Allergy Clin Immunol 2001; 108:509-15. [PMID: 11590373 DOI: 10.1067/mai.2001.117797] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Influence of household pets in the development of childhood asthma or atopy has been controversial. OBJECTIVE The purpose of this study was to investigate whether pet exposure in early life decreases the subsequent risk of frequent wheezing and/or allergic sensitization. METHODS This was a prospective observational birth cohort study. The setting was a large health maintenance organization in Tucson, Ariz; the subjects were a population sample of 1246 newborns enrolled at birth and followed prospectively to age 13 years. The main outcome measures were as follows: time to first report of frequent wheezing (>3 episodes in the past year), skin prick test reactivity at 6 years and 11 years of age, and total serum IgE at 9 months, 6 years, and 11 years of age. RESULTS Children living in households with > or =1 indoor dogs at birth were less likely to develop frequent wheeze than those not having indoor dogs (P =.004). This inverse association was confined to children without parental asthma (hazard ratio = 0.47; P <.001 [Cox regression]) and was not evident for children with parental asthma (hazard ratio = 0.96; P =.87). Adjustment by potential confounders did not change the results. Indoor cat exposure was not significantly associated with the risk of frequent wheezing. Neither cat exposure in early life nor dog exposure in early life was associated with skin prick test reactivity or total serum IgE at any age. CONCLUSION Dog exposure in early life might prevent the development of asthma-like symptoms, at least in low-risk children with no family history of asthma. Nevertheless, early pet exposure does not seem to significantly influence the development of allergic sensitization.
Collapse
Affiliation(s)
- S T Remes
- Respiratory Sciences Center, Arizona Health Sciences Center, University of Arizona, Tucson 85724, USA
| | | | | | | | | |
Collapse
|
19
|
Downs SH, Marks GB, Mitakakis TZ, Lëuppi JD, Car NG, Peat JK. Having lived on a farm and protection against allergic diseases in Australia. Clin Exp Allergy 2001; 31:570-5. [PMID: 11359424 DOI: 10.1046/j.1365-2222.2001.01070.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Farmers' children in northern Europe have a lower prevalence of atopy, hay fever and asthma than other children. Farms in Australia differ in scale and operation from those in Europe and the prevalence of allergic diseases in children is higher. OBJECTIVE To investigate whether having lived on a farm as a child in Australia is associated with a lower risk of allergic diseases. METHODS Cross-sectional study of children (n = 1500) aged 7-12 years from two rural towns: Wagga Wagga in a mixed farming region, and Moree in a crop farming region. Parents answered a questionnaire and children had a skin prick test for atopy. RESULTS Twenty percent of children had lived on a farm for at least 1 year. The effect of having lived on a farm differed between the towns (P < 0.001). It was associated with a lower risk of atopy in Wagga (adjusted odds ratio (aOR) 0.47, 95% confidence interval (CI) 0.32-0.72) but not in Moree (aOR 0.97, 95% CI 0.62-1.53). Children from Wagga were more likely to have lived on a livestock farm than children from Moree (26.1% vs. 9.1%, 95% CI for the difference 8.9-25.4). CONCLUSION Having lived on a farm in Australia can confer protection against atopy in children. Further studies are needed to identify possible protective mechanisms associated with farm animals or to establish whether the protective effect is explained by other related exposures.
Collapse
Affiliation(s)
- S H Downs
- Institute of Respiratory Medicine, University of Sydney, Sydney, Australia.
| | | | | | | | | | | |
Collapse
|
20
|
Abstract
There has been considerable recent broadening of basic concepts of intestinal food allergy, in particular the importance of non-IgE-mediated mechanisms. The traditional emphasis on IgE-mediated allergy now appears inappropriate in light of current studies of the basic mechanisms of oral tolerance to dietary antigen and of increasing recognition of the requirement for early infectious challenge in the prevention of allergic sensitization. This major change in emphasis has been forced both by basic scientific studies and by recognition of novel patterns of food allergic disease within the pediatric population, in which rapid increase in food-allergic sensitization has been noted in the last decade and previously rare phenomena such as multiple food allergies and sensitization of exclusively breast-fed infants to antigens eaten by the mother have become commonplace. It is thus emerging that the possession of exaggerated IgE responses may not be the direct cause of food allergic sensitization but may ensure that such sensitization is clinically obvious. Those without such immediate responses have a complex of symptoms, including diet-responsive eczema and a marked disturbance of intestinal motility. The clear demographic links with socioeconomic privilege and relative protection from gastrointestinal infarctions concord with recent murine data suggesting an obligatory input from innate immune responses to the gut flora in the establishment of oral tolerance.
Collapse
Affiliation(s)
- S H Murch
- Royal Free and University College School of Medicine, London, UK.
| |
Collapse
|
21
|
Affiliation(s)
- D P Strachan
- Department of Public Health Sciences, St George's Hospital Medical School, London, UK
| |
Collapse
|