RESUMO
BACKGROUND AND AIMS: Evidence for the role of the hygiene hypothesis and the development of Ulcerative Colitis (UC) is unclear. We aimed to explore the association between environmental factors in infancy and UC. METHODS: A hospital-based case-control study (52 UC cases, response: 77%, 174 age- , sex and place of living matched controls, response: 62%) was carried out in the Central South of Chile in 2009/2010. Patients or parents underwent a personal interview about early life experiences. RESULTS: High paternal education (adjusted Odds Ratio (aOR): 2.1; 95% CI: 1.0-4.5) as proxy for socioeconomic status was positively associated with case status in the final multivariate logistic regression model. Likewise, having older siblings was a risk factor for UC (aOR: 2.2; 95%CI: 1.1.-4.4). CONCLUSIONS: The importance for some early life environmental factors in the development of UC was established. However, the role of the hygiene hypothesis could not be confirmed for all environmental factors.
Assuntos
Colite Ulcerativa/etiologia , Hipótese da Higiene , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Chile , Colite Ulcerativa/etnologia , Escolaridade , Meio Ambiente , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Fatores de Risco , Irmãos , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Childhood asthma has a high prevalence in South America--a region of the world currently undergoing a thorough modernization and transition process. Asthma in South America is mainly associated with poor urban environment, which actually may challenge the role of the hygiene hypothesis. We systematically assessed the impact of environmental factors in the first year of life on asthma. METHODS: A case-control study including 188 asthmatics and 294 hospital-based controls aged 6-15 years was carried out in the Central South of Chile. Parents of study participants completed a computer-assisted interview on environmental factors (such as birth order, day-care attendance, pneumonia infection, regular animal and furry pet contact, and environmental tobacco smoke exposure) in the first year of life and potential confounders. Atopy was assessed using skin prick tests. Multivariate logistic regression models were calculated to assess the association between exposures and asthma, adjusting for potential confounders. RESULTS: Day-care attendance (OR = 0.31; 95% CI: 0.10, 0.94) and regular farm animal contact (OR = 0.38; 95% CI: 0.17, 0.85) were inversely related to childhood asthma in the logistic regression models. Pneumonia infection (OR = 2.24; 95% CI: 1.21, 4.16) and mold or dampness in the home (OR = 1.87; 95% CI: 1.18, 2.97) in the first year of life were positively associated with asthma. CONCLUSION: Our results suggest that the hygiene hypothesis is also applicable in the Chilean setting, a South American country in epidemiological transition.
Assuntos
Asma/epidemiologia , Exposição Ambiental/efeitos adversos , Adolescente , Idade de Início , Asma/etiologia , Asma/fisiopatologia , Estudos de Casos e Controles , Criança , Chile/epidemiologia , Intervalos de Confiança , Feminino , Seguimentos , Humanos , Incidência , Lactente , Modelos Logísticos , Masculino , Razão de Chances , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/epidemiologia , Fatores de Risco , Índice de Gravidade de Doença , Distribuição por Sexo , Poluição por Fumaça de Tabaco/efeitos adversos , Poluição por Fumaça de Tabaco/estatística & dados numéricosRESUMO
BACKGROUND: Asthma in children is an emerging public health problem in South America. So far, research in this part of the world is limited. This paper presents the methodology and description of the data acquisition of an asthma case-control study conducted in the Central South of Chile. METHODS/DESIGN: A hospital-based case-control study about asthma (188 cases, 294 controls) in children (6-15 years) was carried out in Valdivia, Chile between November 2008 and December 2009. Data on asthma risk factors were collected by computer-assisted personal interview using validated questions from e.g. ISAAC phase II. Data on household dust exposure (endotoxin, allergen analyses), skin prick tests to most common allergens, stool examinations for parasitic infection, and blood samples (total IgE, genetics) were collected. Additionally, 492 randomly chosen blood donors were recruited in order to assess allele frequencies in the population of Valdivia. DISCUSSION: Overall 1,173 participants were contacted. Response was 82% among cases and 65% among controls. Atopic sensitization was high (78% among cases, 47% among controls). Cases had a statistically significantly (p < .0001) increased self-reported 12-month prevalence of symptoms of rhinitis (82% vs. 51%) and wheeze (68% vs. 16%). The study is well placed to address current hypotheses about asthma and its correlates in the South American context. Results of this study might help develop novel, innovative and individualized prevention strategies in countries in transition with respect to the South American context.
Assuntos
Asma/epidemiologia , Doadores de Sangue/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Hipersensibilidade/epidemiologia , Adolescente , Adulto , Alérgenos , Asma/genética , Asma/imunologia , Estudos de Casos e Controles , Criança , Chile/epidemiologia , Poeira , Endotoxinas , Meio Ambiente , Feminino , Frequência do Gene , Variação Genética , Haplótipos , Humanos , Hipersensibilidade/imunologia , Imunoglobulina E/sangue , Masculino , Pessoa de Meia-Idade , Rinite/epidemiologia , Rinite/imunologia , Fatores de Risco , Testes Cutâneos , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Asthma is a complex disease characterized by striking ethnic disparities not explained entirely by environmental, social, cultural, or economic factors. Of the limited genetic studies performed on populations of African descent, notable differences in susceptibility allele frequencies have been observed. OBJECTIVES: We sought to test the hypothesis that some genes might contribute to the profound disparities in asthma. METHODS: We performed a genome-wide association study in 2 independent populations of African ancestry (935 African American asthmatic cases and control subjects from the Baltimore-Washington, DC, area and 929 African Caribbean asthmatic subjects and their family members from Barbados) to identify single-nucleotide polymorphisms (SNPs) associated with asthma. RESULTS: A meta-analysis combining these 2 African-ancestry populations yielded 3 SNPs with a combined P value of less than 10(-5) in genes of potential biologic relevance to asthma and allergic disease: rs10515807, mapping to the alpha-1B-adrenergic receptor (ADRA1B) gene on chromosome 5q33 (3.57 x 10(-6)); rs6052761, mapping to the prion-related protein (PRNP) gene on chromosome 20pter-p12 (2.27 x 10(-6)); and rs1435879, mapping to the dipeptidyl peptidase 10 (DPP10) gene on chromosome 2q12.3-q14.2. The generalizability of these findings was tested in family and case-control panels of United Kingdom and German origin, respectively, but none of the associations observed in the African groups were replicated in these European studies. Evidence for association was also examined in 4 additional case-control studies of African Americans; however, none of the SNPs implicated in the discovery population were replicated. CONCLUSIONS: This study illustrates the complexity of identifying true associations for a complex and heterogeneous disease, such as asthma, in admixed populations, especially populations of African descent.
Assuntos
Asma/genética , População Negra/genética , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla , Adulto , Negro ou Afro-Americano/genética , Barbados , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo ÚnicoRESUMO
OBJECTIVE: To present the most important and recent results of studies on asthma genetics. These data may help general physicians understand the impact of genetics on this complex disorder and how genes and polymorphisms influence asthma and atopy. SOURCES: Data were collected from MEDLINE. Genetic association studies were selected from the Genetic Association Database, which is an archive of human genetic association studies of complex diseases and disorders organized by the National Institutes of Health. SUMMARY OF THE FINDINGS: Considering the data from several important twin studies on asthma genetics, heritability, which measures the contribution of genetic factors to the variance of asthma, may be estimated in 0.48-0.79. A huge number of genetic association studies have been trying to identify asthma susceptibility genes. The most replicated results in the genetic association studies involve the following five regions of the human genome: 5q31-32, 6p21, 11q12-13, 16p11-12, and 20p13. Only recently a new asthma susceptibility gene (ORMDL3) has been identified by a whole genome association study, considered to be a major determinant for childhood asthma. CONCLUSIONS: Genetic contribution to asthma may be estimated ranging from 48 to 79%. Several loci seem to influence asthma susceptibility. Genes located on chromosome 5q (ADRB2, IL13 and IL4) and the recently identified ORMDL3, on chromosome 17, seem to be determinants of childhood asthma. Diagnostics and pharmacogenetics may be the first clinical implication of extensive studies on asthma genetics.
Assuntos
Asma/genética , Predisposição Genética para Doença , Criança , Cromossomos Humanos , Doenças em Gêmeos/genética , Genoma Humano , Estudo de Associação Genômica Ampla , Humanos , Farmacogenética , Estudos em Gêmeos como Assunto , Estados UnidosRESUMO
OBJETIVO: Apresentar os resultados dos estudos mais importantes e recentes sobre a genética da asma. Estes dados devem auxiliar os clínicos gerais a compreender o impacto da genética sobre este distúrbio complexo e como os genes e polimorfismos influenciam a asma e a atopia. FONTES DOS DADOS: Os dados foram coletados do banco de dados MEDLINE. Os estudos de associação genética foram selecionados do Genetic Association Database, um repositório de estudos de associação genética de doenças e distúrbios complexos organizado pelo National Institutes of Health. SÍNTESE DOS DADOS: Considerando os dados de diversos importantes estudos de gêmeos sobre a genética da asma, a heritabilidade, que mensura a contribuição dos fatores genéticos para a variância da asma, pode ser estimada entre 0,48 e 0,79. Uma grande quantidade de estudos de associação genética tentou identificar genes de susceptibilidade à asma. Os resultados mais replicados nos estudos de associação genética envolvem as cinco regiões do genoma humano a seguir: 5q31-32, 6p21, 11q12-13, 16p11-12, e 20p13. Recentemente, outro gene de susceptibilidade à asma (ORMDL3), considerado determinante crítico para a asma infantil, foi identificado por um estudo genômico de associação. CONCLUSÕES: É possível estimar que a contribuição genética à asma varia entre 48 e 79 por cento. Diversos loci parecem influenciar a susceptibilidade à asma. Os genes localizados no cromossomo 5q (ADRB2, IL13 e IL4) e o gene ORMDL3, no cromossomo 17, identificado recentemente, parecem ser determinantes para a asma infantil. O diagnóstico e a farmacogenética podem ser as primeiras implicações clínicas de estudos extensivos sobre a genética da asma.
OBJECTIVE: To present the most important and recent results of studies on asthma genetics. These data may help general physicians understand the impact of genetics on this complex disorder and how genes and polymorphisms influence asthma and atopy. SOURCES: Data were collected from MEDLINE. Genetic association studies were selected from the Genetic Association Database, which is an archive of human genetic association studies of complex diseases and disorders organized by the National Institutes of Health. SUMMARY OF THE FINDINGS: Considering the data from several important twin studies on asthma genetics, heritability, which measures the contribution of genetic factors to the variance of asthma, may be estimated in 0.48-0.79. A huge number of genetic association studies have been trying to identify asthma susceptibility genes. The most replicated results in the genetic association studies involve the following five regions of the human genome: 5q31-32, 6p21, 11q12-13, 16p11-12, and 20p13. Only recently a new asthma susceptibility gene (ORMDL3) has been identified by a whole genome association study, considered to be a major determinant for childhood asthma. CONCLUSIONS: Genetic contribution to asthma may be estimated ranging from 48 to 79 percent. Several different loci seem to influence asthma susceptibility. Genes located on chromosome 5q (ADRB2, IL13 and IL4) and the recently identified ORMDL3, on chromosome 17, seem to be determinants of childhood asthma. Diagnostics and pharmacogenetics may be the first clinical implication of extensive studies on asthma genetics.