Most studies studying dampness as a risk factor for asthma are of a cross-sectional design. The aim of this study was to investigate if the association between moisture-related problems indoor and asthma found in cross-sectional questionnaire data can be confirmed in longitudinal analyses. The Dampness in Building and Health (DBH) study started in 2000 in Värmland, Sweden, with a baseline questionnaire to all children aged 1-5 y (n = 14,077) and five years later a follow-up questionnaire was distributed to children aged 6-8 y (n = 7,509). Moisture-related problems that were associated with asthma in cross-sectional analysis decreased or disappeared in the longitudinal analysis. However, the association between reports of moldy odor in the homes at baseline and incident asthma remained and became stronger. Our results suggest that cross-sectional data showing associations between moisture-related problems in homes and asthma in children partly can be explained by reporting bias.
This study aimed to estimate the association between eczema in early childhood and the onset of asthma and rhinitis later in life in children.
A total of 3,124 children aged 1-2?years were included in the Dampness in Building and Health (DBH) study in the year 2000, and followed up 5?years later by a parental questionnaire based on an International Study of Asthma and Allergies in Childhood protocol. The association between eczema in early childhood and the incidence of asthma and rhinitis later in life was estimated by univariable and multivariable logistic regression modelling.
The prevalence of eczema in children aged 1-2?years was 17.6% at baseline. Children with eczema had a 3-fold increased odds of developing asthma (adjusted odds ratio [aOR], 3.07; 95% confidence interval (CI) 1.79-5.27), and a nearly 3-fold increased odds of developing rhinitis (aOR, 2.63; 1.85-3.73) at follow-up compared with children without eczema, adjusted for age, sex, parental allergic disease, parental smoking, length of breastfeeding, site of living, polyvinylchloride flooring material, and concomitant allergic disease. When eczema was divided into subgroups, moderate to severe eczema (aOR, 3.56; 1.62-7.83 and aOR, 3.87; 2.37-6.33, respectively), early onset of eczema (aOR, 3.44; 1.94-6.09 and aOR, 4.05; 2.82-5.81; respectively), and persistence of eczema (aOR, 5.16; 2.62-10.18 and aOR, 4.00; 2.53-6.22, respectively) further increased the odds of developing asthma and rhinitis. Further independent risk factors increasing the odds of developing asthma were a parental history of allergic disease (aOR, 1.83; 1.29-2.60) and a period of breast feeding shorter than 6?months (aOR, 1.57; 1.03-2.39). The incidence of rhinitis was increased for parental history of allergic disease (aOR, 2.00; 1.59-2.51) and polyvinylchloride flooring (aOR, 1.60; 1.02-2.51).
Eczema in infancy is associated with development of asthma and rhinitis during the following 5-year period, and eczema is one of the strongest risk factors. Early identification is valuable for prediction of the atopic march.
The aim of this study was to analyse factors associated with remission of atopic dermatitis (AD) in childhood. A population-based AD cohort of 894 children aged 1-3 years from a cross-sectional baseline study in 2000 was followed up in 2005. The association between remission, background, health, lifestyle, and environmental variables was estimated with crude and multivariable logistic regression. At follow-up, 52% of the children had remission. Independent factors at baseline predicting remission were: milder eczema (adjusted odds ratio (aOR), 1.43; 95% confidence interval (95% CI) 1.16-1.77); later onset of eczema (aOR 1.40; 95% CI 1.08-1.80); non-flexural eczema (aOR 2.57; 95% CI 1.62-4.09); no food allergy (aOR 1.51; 95% CI 1.11-2.04), and rural living (aOR 1.48; 95% CI 1.07-2.05). Certain aspects of AD and rural living were important for remission, but despite the initial hypotheses to the contrary, the environmental factors examined in this paper were not substantial predictors of remission.
This paper describes the background, aim and study design for the Swedish SELMA study that aimed to investigate the importance of early life exposure during pregnancy and infancy to environmental factors with a major focus on endocrine disrupting chemicals for multiple chronic diseases/disorders in offspring.
The cohort was established by recruiting women in the 10th week of pregnancy. Blood and urine from the pregnant women and the child and air and dust from home environment from pregnancy and infancy period have been collected. Questionnaires were used to collect information on life styles, socio-economic status, living conditions, diet and medical history.
Of the 8394 reported pregnant women, 6658 were invited to participate in the study. Among the invited women, 2582 (39%) agreed to participate. Of the 4076 (61%) non-participants, 2091 women were invited to a non-respondent questionnaire in order to examine possible selection bias. We found a self-selection bias in the established cohort when compared with the non-participant group, e.g. participating families did smoke less (14% vs. 19%), had more frequent asthma and allergy symptoms in the family (58% vs. 38%), as well as higher education among the mothers (51% vs. 36%) and more often lived in single-family houses (67% vs. 60%).
These findings indicate that the participating families do not fully represent the study population and thus, the exposure in this population. However, there is no obvious reason that this selection bias will have an impact on identification of environmental risk factors.