Exposure to environmental tobacco smoke and sensitisation in children.

BACKGROUND: Exposure to environmental tobacco smoke (ETS) increases the risk of respiratory illness in children but data are inconclusive regarding the risk of IgE sensitisation. OBJECTIVE: To elucidate whether exposure to smoking prenatally and/or postnatally is related to IgE sensitisation in children at 4 years of age. METHODS: As part of a prospective birth cohort study (BAMSE), a total of 4089 families with children answered questionnaires when the child was 2 months, 1, 2 and 4 years old on environmental factors and symptoms of allergic disease. Blood collected at age 4 years from 2614 children was analysed for IgE antibodies to common inhalant and food allergens. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression with adjustments for potential confounders. RESULTS: There was no evident association between maternal smoking during pregnancy and risk of IgE sensitisation. In contrast, a dose-response effect was found for exposure to ETS from parental smoking during the first few months of life and IgE sensitisation. There was an increased risk of sensitisation to inhalant and/or food allergens (OR(adj) 1.28 (95% CI 1.01 to 1.62)) among children exposed to ETS at 2 months of age. The risk appeared particularly elevated for indoor inhalant allergens, such as cat (OR(adj) 1.96 (95% CI 1.28 to 2.99)) and for food allergens (OR(adj) 1.46 (95% CI 1.11 to 1.93)). The IgE sensitising effect of ETS seemed to be confined to infants of parents without allergic diseases and to ETS exposure during early infancy. CONCLUSIONS: Our data indicate that exposure in early infancy to ETS increases the risk of IgE sensitisation to indoor inhalant and food allergens.

Environmental risk factors for allergy and socioeconomic status in a birth cohort (BAMSE).

Associations between parental educational level and possible risk factors for atopic disease during the first months of life were explored in a cohort of 4089 neonate children born 1994-96 in Stockholm, Sweden. Reports concerning a number of life style factors during pregnancy and after the baby was born were obtained by questionnaire. There was a strong negative association between duration of education and maternal smoking during pregnancy, parental smoking after the baby was born and keeping of cat and dog (p-trend < 0.001), respectively. For example, smoking during pregnancy was reported by 6.7% (95% CI 5.5-7.9) of mothers with college or university degree and by 22.2% (95% CI 20.1-24.5) of those with the shortest education. Indicators of dampness and poor ventilation were also more common in homes of those with the shortest education. The results show that the educational level has an influence on risk factors for development of atopic disease in childhood and indicates a need of deeper understanding of life style in different socioeconomic groups. The data also indicate that various possible confounding factors need to be thoroughly investigated when analysing studies of risk factors for allergic disease in childhood.

A pilot study of lead and cadmium exposure in young children in Stockholm, Sweden: methodological considerations using capillary blood microsampling.

A capillary blood microsampling technique was tested among urban young children in Stockholm. Blood lead (BPb) and hemoglobin (Hb) concentrations were determined in capillary blood obtained by fingerstick from 41 children, 13-20 months old, and the accompanying parent. The quality control included control for lead (Pb) and cadmium (Cd) contamination of material and equipment used for blood sampling, washing procedures for the hands and fingers to be punctured, comparisons of Pb and Cd concentrations in blood obtained by fingerstick and by brachial vein puncture from the same individuals, analysis of external quality control samples for Pb and Cd in blood together with the collected samples, and evaluation of the analytical performance using linear regression analysis. The results showed that blood sampling material may contaminate the blood samples with amounts of Pb and Cd that would seriously influence the monitoring results in the low concentration range (< 100 micrograms Pb/L and < 1 microgram Cd/L). However, it is possible to obtain reliable BPb concentrations (> 10 micrograms Pb/L), but not BCd concentrations (< 1 microgram Cd/L), with the capillary blood microsampling technique tested provided that a strict quality control is applied. The sampling procedure tested was well accepted by the children and their parents. The children's median BPb concentration (27 micrograms/L; range 9-73 micrograms/L) was similar to the median BPb concentration of their parents (27 micrograms/L; range 7-74 micrograms/L). However, the correlation between child and parent BPb concentrations was poor (R2 = 0.20), which may indicate different sources to Pb exposure in children and parents.