Smoking during pregnancy and hyperactivity-inattention in the offspring:comparing results from three Nordic cohorts

• Published in: International Journal of Epidemiology
• Main Authors: Obel, Carsten, Linnet, Karen Markussen, Henriksen, Tine Brink, Rodriguez, Alina, Järvelin, Marjo Riita, Kotimaa, Arto, Moilanen, Irma, Ebeling, Hanna, Bilenberg, Niels, Taanila, Anja, Ye, Gan, Olsen, Jørn
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: Northern Finland
• Online Access: https://portal.findresearcher.sdu.dk/da/publications/1b6c2650-53ed-11dd-b1a1-000ea68e967b; https://doi.org/10.1093/ije/dym290

Udgivelsesdato: Feb-2 BACKGROUND: Prenatal exposure to smoking has been associated with Attention Deficit Hyperactivity Disorder (ADHD) in a number of epidemiological studies. However, mothers with the ADHD phenotype may 'treat' their problem by smoking and therefore be more likely to smoke even in a society where smoking is not acceptable. This will cause genetic confounding if ADHD has a heritable component, especially in populations with low prevalence rates of smoking since this reason for smoking is expected to be proportionally more frequent in a population with few 'normal' smokers. We compared the association in cohorts with different smoking frequencies. METHODS: A total of 20 936 women with singleton pregnancies were identified within three population-based pregnancy cohorts in Northern Finland (1985-1986) and in Denmark (1984-1987 and 1989-1991). We collected self-reported data on their pre-pregnancy and pregnancy smoking habits and followed the children to school age where teachers and parents rated hyperactivity and inattention symptoms. RESULTS: Children, whose mothers smoked during pregnancy, had an increased prevalence of a high hyperactivity-inattention score compared with children of nonsmokers in each of the cohorts after adjustment for confounders but we found no statistical significant difference between the associations across the cohorts. CONCLUSION: The estimated association was not strongest in the population with the fewest smokers which does not support the hypothesis that the association is entirely due to genetic confounding