Coffee consumption during pregnancy and the risk of hyperkinetic disorder and ADHD: a prospective cohort study

Aim: Based on hypotheses from experimental studies, we studied the association between intrauterine exposure to coffee and the risk of clinically verified hyperkinetic disorder and attention-deficit hyperactivity disorder (ADHD). Methods: A cohort study with prospectively collected data from the Aarhus Birth Cohort, Denmark. We included 24 068 singletons delivered between 1990 and 1998. Linkage was performed with three Danish longitudinal registers: The Danish Psychiatric Central Register, The Integrated Database for Labour Market Research and The Danish Civil Registration System. We identified 88 children with hyperkinetic disorder and ADHD. Information about coffee consumption during pregnancy was obtained at 16 weeks of gestation from self-administrated questionnaires. Potential confounding factors were evaluated using Cox regression analyses. Results: We found that intrauterine exposure to 10 or more cups of coffee per day was associated with a threefold increased risk of hyperkinetic disorder and ADHD. After adjustments for a number of confounding factors, the risk decreased and became statistically insignificant (RR 2.3, 95% CI 0.9-5.9). Conclusion: Prenatal exposure to high levels of coffee did not significantly increase the risk of clinically verified hyperkinetic disorder and ADHD in childhood.