Atopy risk factors at birth and in adulthood

Abstract

Objective: To study the association between atopy and variables such as weight, length, and socioeconomic level at birth and in young adulthood.Methods: A total of 2,063 subjects were investigated in a prospective birth cohort study of individuals born in Ribeirão Preto, Brazil, in 1978Brazil, in /1979, and examined at the age of 23-25 years. Skin prick tests (SPT) for eight common allergens in Brazil were performed. Subjects with a wheal reaction ≥ 3 mm to one or more of the eight allergens tested were considered to be atopic. We used the log-binomial model (generalized linear model) in order to assess the association between atopy and birth or adult variables. Results:The prevalence of positive SPT was 47.6%. Male gender was associated with an increased risk of atopy (relative risk [RR] = 1.18; 95% confidence interval [95%CI] 1.07-1.30). Low level of schooling was a protective factor against atopy, with a RR = 0.74; 95%CI 0.62-0.89. Living with a smoker in childhood was also associated with lower risk of atopy (RR = 0.87; 95%CI 0.79-0.96). Birth weight, length and order, maternal age, and intrauterine growth restriction were not associated with positive SPT. Conclusions:This study showed that male gender was associated with an increased risk of atopy. Low socioeconomic status, assessed by low level of schooling, was a protective factor against atopy. These data agree with the hygiene hypothesis.J Pediatr (Rio J). 2011;87(4):336-342: Allergens, allergy, risk factors, skin test. ResumoObjetivo: Estudar a associação entre atopia e variáveis como peso, comprimento e nível socioeconômico no nascimento e na idade adulta jovem. Métodos:Foram investigados 2.063 indivíduos em um estudo prospectivo de coorte de nascimento com indivíduos nascidos em Ribeirão Preto (SP), em 1978/1979, e examinados aos 23-25 anos de idade. Realizaram-se testes cutâneos de puntura (TCP) para oito alérgenos comuns no Brasil. Foram considerados atópicos os indivíduos que apresentaram reação papular ≥ 3 mm para um ou mais dos oito alérgenos testados. A fim de avaliar a associação entre atopia e variáveis no nascimento e na idade adulta, utilizamos o modelo log-binomial (modelo linear generalizado).Resultados: A prevalência de TCP positivo foi de 47,6%. O gênero masculino esteve associado a aumento do risco de atopia [risco relativo (RR) = 1,18; intervalo de confiança de 95% (IC95%) 1,07-1,30]. O baixo nível de escolaridade foi um fator de proteção contra atopia, com um RR = 0,74; IC95% 0,62-0,89. A convivência com um fumante na infân-cia também esteve associada a um menor risco de atopia (RR = 0,87; IC95% 0,79-0,96). Peso e comprimento ao nascer, ordem de nascimento, idade materna e restrição de crescimento intrauterino não estiveram associados a TPC positivo. Conclusões:Este estudo demonstrou que o gênero masculino esteve associado a um aumento do risco de atopia. O baixo nível socioeconômico, estabelecido pelo baixo nível de escolaridade, foi um fator de proteção contra a atopia. Esses dados estão de acordo com a teoria da higiene...

Factors Associated with Atopy in Toddlers: A Case-Control Study

“…Male toddlers (63.4%) were found to be about twice as likely (odds ratio of 2.072; p = 0.03) than female toddlers to develop atopic diseases up to the age of three ( Table 1 and Table 4 ). The male gender has previously been identified as a genetic and lifestyle risk factor in the development of atopy [ 53 , 54 ]. Ferraz et al [ 53 ] and Moore et al [ 54 ] investigated the risk of the male gender in relation to atopic dermatitis and sensitization to a number of allergens, respectively.…”

“…The male gender has previously been identified as a genetic and lifestyle risk factor in the development of atopy [ 53 , 54 ]. Ferraz et al [ 53 ] and Moore et al [ 54 ] investigated the risk of the male gender in relation to atopic dermatitis and sensitization to a number of allergens, respectively. Similar studies also found males to be more susceptible to asthma in childhood than females [ 55 , 56 ], possibly because male children have a smaller airway in portion to their lung size than with females, making them more sensitive to infections and airborne triggers [ 57 ], in turn leading to greater sensitivity to aeroallergens [ 58 ].…”

The association of the ‘additional height index’ with atopic diseases, non-atopic asthma, ischaemic heart disease and mortality: a population-based study

“…Similarly, another study indicated that poor fetal growth may reduce the risk of skin prick test reactivity during childhood 17. Considering the childhood period, decreasing risks of asthma, rhinitis and allergic sensitisation in 4-year-old children have been found with increasing socioeconomic position, something that may influence dietary patterns 35.…”

“…Catch-up growth may also be more predictive of childhood asthma than birth weight and length, which have otherwise been associated with such diseases 14 15. One study found an association between restricted growth in late gestation and an increased rate of later development of an atopic phenotype, whereas another found contrasting results 16 17. Similarly, anthropometric measures pointing to growth that is slower than normal in the prepubertal period, such as low adult leg length, leg : trunk ratio and total height, have been linked to higher rates of coronary heart disease, diabetes and mortality, although to lower rates of non-smoking-related cancers 18–23…”

Prevalence of Asthma symptoms and risk factors in adolescents

“…Among these environmental factors are pollution, nutrition, exposure to allergens, socioeconomic level, and family size. However, there is no evidence to associate these factors with atopic phenotypes in epidemiological studies 17 .…”