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.