RESUMO
BACKGROUND: The relation between lower respiratory tract illnesses in early life caused by the respiratory syncytial virus (RSV) and the subsequent development of wheezing and atopy in childhood is not well understood. We studied this relation in children who had lower respiratory tract illnesses that occurred before 3 years of age. METHODS: Children were enrolled at birth and cases of lower respiratory tract illness were ascertained by a physician. Viral tests were done for specimens collected at the time of the illness. Children were classified into five groups according to type and cause of lower respiratory tract illness. Children were then followed prospectively up to age 13, and we measured frequency of wheezing, pulmonary function, and atopic status (allergy skin-prick tests, serum IgE concentrations). FINDINGS: RSV lower respiratory tract illnesses were associated with an increased risk of infrequent wheeze (odds ratio 3.2 [95% CI 2.0-5.0], p < 0.001), and an increased risk of frequent wheeze (4.3 [2.2-8.7], p < or = 0.001) by age 6. Risk decreased markedly with age and was not significant by age 13. There was no association between RSV lower respiratory tract illnesses and subsequent atopic status. RSV lower respiratory tract illnesses were associated with significantly lower measurements of forced expiratory volume (2.11 [2.05-2.15], p < or = 0.001) when compared with those of children with no lower respiratory tract illnesses, but there was no difference in forced expiratory volume after inhalation of salbutamol. INTERPRETATION: RSV lower respiratory tract illnesses in early childhood are an independent risk factor for the subsequent development of wheezing up to age 11 years but not at age 13. This association is not caused by an increased risk of allergic sensitisation.
Assuntos
Asma/etiologia , Hipersensibilidade Imediata/etiologia , Infecções por Vírus Respiratório Sincicial/complicações , Adolescente , Fatores Etários , Análise de Variância , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Imunoglobulina E/sangue , Lactente , Masculino , Razão de Chances , Estudos Prospectivos , Testes de Função Respiratória , Sons Respiratórios , Fatores de Risco , Testes Cutâneos , Inquéritos e QuestionáriosRESUMO
Compelling evidence suggests a causal relation between exposure to parental cigarette smoking and respiratory symptoms during childhood. Still, the roles of prenatal versus postnatal parental smoking need clarification. In this study, the authors assessed the effects of passive smoking on respiratory symptoms in a cohort of over 1,000 children born during 1980-1984. The children were enrolled in the Tucson Children's Respiratory Study in Tucson, Arizona, and were followed from birth to age 11 years. The population was generally middle class and consisted of two main ethnic groups, non-Hispanic Whites (75%) and Hispanics (20%), reflecting Tucson's population. Information on parental smoking and on wheeze and cough in their children was elicited from parents by using questionnaires at five different surveys. Data were analyzed both cross-sectionally and by using the generalized estimation equation approach, a longitudinal mixed-effects model. The best-fitting model indicated that maternal prenatal but not postnatal smoking was associated with current wheeze (odds ratio = 2.3, 95% confidence interval 1.4-3.8) independently of a family history of asthma, socioeconomic factors, and birth weight. This effect was time dependent and significant only below age 3 years; although independent of gender, the association was stronger for girls (odds ratio = 3.6, 95% confidence interval 1.6-8.0). Cough was not associated with parental smoking during the first decade of life. This transitory effect of maternal prenatal smoking on wheezing could be due to changes that affect the early stages of lung development.
Assuntos
Poluição do Ar em Ambientes Fechados/efeitos adversos , Mães , Transtornos Respiratórios/etiologia , Poluição por Fumaça de Tabaco/efeitos adversos , Adulto , Arizona , Criança , Desenvolvimento Infantil/efeitos dos fármacos , Pré-Escolar , Tosse/etiologia , Estudos Transversais , Interpretação Estatística de Dados , Feminino , Humanos , Lactente , Estudos Longitudinais , Masculino , Razão de Chances , Pais , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Sons Respiratórios/etiologia , Inquéritos e QuestionáriosRESUMO
The relationship between parental smoking and lower respiratory tract illness (LRI) was studied in a large cohort of infants followed prospectively from birth. Illnesses were diagnosed by physicians using agreed-on criteria, and parental smoking histories were obtained by questionnaire. The LRIs were differentiated into wheezing and nonwheezing episodes, and the age at first illness of either type was evaluated in relation to smoking by parents. The odds of having an LRI were significantly higher in children whose mothers smoked (odds ratio 1.52; confidence interval 1.07 to 2.15). The odds were higher if the mother smoked a pack of cigarettes or more per day and if the child stayed home rather than attending day care (odds ratio 2.8; confidence interval 1.43 to 5.5). Logistic regression indicated that the LRI rate was significantly elevated both in children exposed to heavy maternal smoke in the absence of day care, and in those who use day care but were not exposed to maternal smoking of a pack or more per day. These findings could not be attributed to other confounding variables. Neither paternal smoking nor smoking by other household members was consistently related to the LRI rate. The relationship of maternal smoking to LRI rate was evident for both wheezing and nonwheezing illnesses. Maternal smoking of a pack or more per day was also related to an early age at first LRI, for both wheezing (p less than 0.05) and nonwheezing (p less than 0.002) illnesses. In sum, maternal smoking is associated with a higher rate of LRIs in the first year, particularly when mothers smoked a pack or more per day and when the child did not use day care.
Assuntos
Broncopatias/etiologia , Pneumopatias/etiologia , Pais , Sons Respiratórios/etiologia , Poluição por Fumaça de Tabaco/efeitos adversos , Broncopatias/complicações , Humanos , Lactente , Modelos Logísticos , Pneumopatias/complicações , Fatores de RiscoRESUMO
Nails are a protective cover for the ends of the fingers and toes which also help to increase tactile sensitivity by exerting counterpressure over the distal pulp.The nail consists of a nail plate resting on the nail bed, which grows out from a nail matrix.Fingernails grow about 1cm three months and toenails at about a third of this rate. Growth is slower in the non-dominant hand and in old age.