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Hygiene Hypothesis (hygiene + hypothesis)
Selected AbstractsToo clean, or not too clean: the Hygiene Hypothesis and home hygieneCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2006S. F. Bloomfield Summary The ,hygiene hypothesis' as originally formulated by Strachan, proposes that a cause of the recent rapid rise in atopic disorders could be a lower incidence of infection in early childhood, transmitted by unhygienic contact with older siblings. Use of the term ,hygiene hypothesis' has led to several interpretations, some of which are not supported by a broader survey of the evidence. The increase in allergic disorders does not correlate with the decrease in infection with pathogenic organisms, nor can it be explained by changes in domestic hygiene. A consensus is beginning to develop round the view that more fundamental changes in lifestyle have led to decreased exposure to certain microbial or other species, such as helminths, that are important for the development of immunoregulatory mechanisms. Although this review concludes that the relationship of the hypothesis to hygiene practice is not proven, it lends strong support to initiatives seeking to improve hygiene practice. It would however be helpful if the hypothesis were renamed, e.g. as the ,microbial exposure' hypothesis, or ,microbial deprivation' hypothesis, as proposed for instance by Bjorksten. Avoiding the term ,hygiene' would help focus attention on determining the true impact of microbes on atopic diseases, while minimizing risks of discouraging good hygiene practice. [source] Hygiene hypothesis, allergy and BCG: a dirty mix?CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2008C. C. Obihara First page of article [source] Asthma in late adolescence , farm childhood is protective and the prevalence increase has levelled offPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 5 2010Göran Wennergren Wennergren G, Ekerljung L, Alm B, Eriksson J, Lötvall J, Lundbäck B. Asthma in late adolescence , farm childhood is protective and the prevalence increase has levelled off. Pediatr Allergy Immunol 2010: 21: 806,813. © 2010 John Wiley & Sons A/S While the prevalence of and risk factors for asthma in childhood have been studied extensively, the data for late adolescence are more sparse. The aim of this study was to provide up-to-date information on the prevalence of and risk factors for asthma in the transitional period between childhood and adulthood. A secondary aim was to analyze whether the increase in asthma prevalence has levelled off. A large-scale, detailed postal questionnaire focusing on asthma and respiratory symptoms, as well as possible risk factors, was mailed to 30 000 randomly selected subjects aged 16,75 in Gothenburg and the surrounding western Sweden region. The present analyses are based on the responses from 1261 subjects aged 16,20 (560 men and 701 women). The prevalence of physician-diagnosed asthma was 9.5%, while 9.6% reported the use of asthma medicine. In the multivariate analysis, the strongest risk factors for physician-diagnosed asthma and other asthma variables were heredity for asthma and heredity for allergy, particularly if they occurred together. Growing up on a farm significantly reduced the prevalence of physician-diagnosed asthma and the likelihood of using asthma medication, OR 0.1 (95% CI 0.02,0.95). Smoking increased the risk of recurrent wheeze, long-standing cough, and sputum production. In conclusion, the prevalence of physician-diagnosed asthma and the use of asthma medication in the 16- to 20-yr age group support the notion that the increase in asthma prevalence seen between the 1950s and the 1990s has now levelled off. In line with the hygiene hypothesis, a farm childhood significantly reduced the likelihood of asthma. The adverse effects of smoking could already be seen at this young age. [source] Probiotics and prebiotics in atopic dermatitis: review of the theoretical background and clinical evidencePEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 2p2 2010Leontien B. Van Der Aa van der Aa LB, Heymans HSA, van Aalderen WMC, Sprikkelman AB. Probiotics and prebiotics in atopic dermatitis: review of the theoretical background and clinical evidence. Pediatr Allergy Immunol 2010: 21: e355,e367. © 2009 John Wiley & Sons A/S The prevalence of atopic dermatitis (AD) has risen over the past decades, especially in western societies. According to the revised hygiene hypothesis this increase is caused by a changed intestinal colonization pattern during infancy, which has an impact on the immune system. Manipulating the intestinal microflora with pro-, pre- or synbiotics is an innovative way to prevent or treat AD. This review provides an overview of the theoretical basis for using probiotics and prebiotics in AD and presents the current evidence from randomized controlled trials (RCTs) regarding prevention and treatment of AD and food allergy in children with pro-, pre- and synbiotics. Seven RCTs on prevention and 12 RCTs on treatment were found by searching the Pubmed, Embase and Cochrane databases. Results of these trials are conflicting. In conclusion, at this moment there is not enough evidence to support the use of pro-, pre- or synbiotics for prevention or treatment of AD in children in clinical practice. [source] Disease patterns of outpatient visits by Japanese expatriate children in ThailandACTA PAEDIATRICA, Issue 3 2009Rie Sakai Abstract Aim: To clarify the health-related conditions of Japanese expatriate children in Thailand. Methods: Records of Japanese children who consulted outpatient clinics at Bangkok Hospital in 2005 and 2006 (n = 2141) were analysed, and then compared with data from the patient survey conducted by the Ministry of Health, Labour and Welfare of Japan in 2005 (n = 575 400). Results: ,diseases of the respiratory system', categorized as chapter X under ICD-10 was the most frequent category in both Thailand and Japan. Although ,certain infectious and parasitic diseases' (chapter I) was the second most frequent category in Thailand, it was infrequent in Japan. In the subcategories of ,diseases of the respiratory system', ,acute upper respiratory infections' was frequent and asthma was infrequent in Thailand. Conversely, ,acute upper respiratory infections' showed a low percentage and asthma was the most frequently observed disease in Japan. Conclusion: This study examined Japanese children having the same genetic background but divided into two groups according to different living environments. Results demonstrate that children living in Japan contract asthma more frequently than infectious diseases, whereas those living in Thailand show the opposite trend, which supports the hygiene hypothesis that infections may protect against the development of allergic diseases, such as asthma. [source] A meta-analysis of the association between Caesarean section and childhood asthmaCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2008S. Thavagnanam Summary Background Children born by Caesarean section have modified intestinal bacterial colonization and consequently may have an increased risk of developing asthma under the hygiene hypothesis. The results of previous studies that have investigated the association between Caesarean section and asthma have been conflicting. Objective To review published literature and perform a meta-analysis summarizing the evidence in support of an association between children born by Caesarean section and asthma. Methods MEDLINE, Web Science, Google Scholar and PubMed were searched to identify relevant studies. Odds ratio (OR) and 95% confidence interval (CI) were calculated for each study from the reported prevalence of asthma in children born by Caesarean section and in control children. Meta-analysis was then used to derive a combined OR and test for heterogeneity in the findings between studies. Results Twenty-three studies were identified. The overall meta-analysis revealed an increase in the risk of asthma in children delivered by Caesarean section (OR=1.22, 95% CI 1.14, 1.29). However, in this analysis, there was evidence of heterogeneity (I2=46%) that was statistically significant (P<0.001). Restricting the analysis to childhood studies, this heterogeneity was markedly decreased (I2=32%) and no longer attained statistical significance (P=0.08). In these studies, there was also evidence of an increase (P<0.001) in the risk of asthma after Caesarean section (OR=1.20, 95% CI 1.14, 12.6). Conclusion In this meta-analysis, we found a 20% increase in the subsequent risk of asthma in children who had been delivered by Caesarean section. [source] The allergy-protective properties of Acinetobacter lwoffii F78 are imparted by its lipopolysaccharideALLERGY, Issue 6 2010J. Debarry To cite this article: Debarry J, Hanuszkiewicz A, Stein K, Holst O, Heine H. The allergy-protective properties of Acinetobacter lwoffii F78 are imparted by its lipopolysaccharide. Allergy 2010; 65: 690,697. Abstract Background:, An increasing number of epidemiological studies show that exposure to farming environment during early childhood strongly influences the development of allergic reactions later in life (,hygiene hypothesis'). Also, it had been shown that certain bacteria from this environment may have allergy-protective properties. In the present study, we further characterized one of these bacteria, namely Acinetobacter lwoffii F78, with regard to the bacteria-induced signaling and possible mechanisms of allergy protection. Methods:, The impact of A. lwoffii F78 on human monocyte-derived dendritic cells especially with respect to their THelper cell polarization capacity was investigated by ELISA and real-time PCR experiments as well as confocal microscopy. The responsible molecule for these effects was further characterized and identified using blocking experiments. Results:, It was shown that A. lwoffii F78 induced a TH1-polarizing program in human dendritic cells which led to TH1 differentiation. In addition, a positive influence on the TBet/GATA3 level could be detected. Blocking experiments revealed that the lipopolysaccharide (LPS) of A. lwoffii F78 was the responsible molecule promoting these effects. Conclusion:, We found evidence that the allergy-protecting effects of A. lwoffii F78 are because of the activation of a TH1-polarizing program in human dendritic cells, and that the LPS of A. lwoffii F78 is responsible for these beneficial effects. [source] Do immune responses to inhaled skin flakes modulate the expression of allergic disease?CLINICAL & EXPERIMENTAL ALLERGY, Issue 8 2007E. R. Tovey Summary We examine the nature of the immune responses to inhaled skin particles and query whether early exposure could play a role in providing protection against the development of allergic disease. Currently, the main hypothesis used to explain environmental modulation of allergic diseases, the ,hygiene hypothesis', is linked exclusively to microbial exposures acting upon the innate immune system. However, many of the exposures sustaining this hypothesis also involve co-exposure to skin flakes from humans or animals. Such skin flakes contain a complex mixture of antigens, glycolipids and small peptides that may induce immune responses. Should these responses prove relevant to the modulation of allergic diseases, it provides new opportunities to better understand the epidemic of allergic disease and to develop new interventions for its prevention. [source] Too clean, or not too clean: the Hygiene Hypothesis and home hygieneCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2006S. F. Bloomfield Summary The ,hygiene hypothesis' as originally formulated by Strachan, proposes that a cause of the recent rapid rise in atopic disorders could be a lower incidence of infection in early childhood, transmitted by unhygienic contact with older siblings. Use of the term ,hygiene hypothesis' has led to several interpretations, some of which are not supported by a broader survey of the evidence. The increase in allergic disorders does not correlate with the decrease in infection with pathogenic organisms, nor can it be explained by changes in domestic hygiene. A consensus is beginning to develop round the view that more fundamental changes in lifestyle have led to decreased exposure to certain microbial or other species, such as helminths, that are important for the development of immunoregulatory mechanisms. Although this review concludes that the relationship of the hypothesis to hygiene practice is not proven, it lends strong support to initiatives seeking to improve hygiene practice. It would however be helpful if the hypothesis were renamed, e.g. as the ,microbial exposure' hypothesis, or ,microbial deprivation' hypothesis, as proposed for instance by Bjorksten. Avoiding the term ,hygiene' would help focus attention on determining the true impact of microbes on atopic diseases, while minimizing risks of discouraging good hygiene practice. [source] | ||||||||||