Background Bullying has been shown to be a serious problem amongst school children, but few studies have been population-based and included pre-school children.
Methods The study is part of a cross-sectional comparative study in 1984 and 1996, focusing on children's and their families’ health and welfare in the Nordic countries. At each point of time parents of 3000 randomly selected children aged 2–17 years in each of five Nordic countries received a postal questionnaire. Altogether approximately 20 000 questionnaires were completed. The prevalence of bullying, risk factors for bullying and possible effect factors were analysed.
Results Parents reported bullying of their child in 15.1% of the cases. Bullying varied from 7.2% in Sweden to about 20% in Denmark and Finland. There was a small increase in bullying from 13.7% in 1984 to 16.4% in 1996. Bullying was most frequent in boys (OR: 1.4) and in children 2–6 and 7–12 years old (OR: 2.0 and 2.2 compared with older children). Children of single parents and of parents with low education had increased risks (OR: 1.4 and 1.4). Children with chronic conditions had higher risks for being bullied (OR: 2.3). In 1996 children with psychiatric/nervous problems and hyperactivity had high risks for being bullied (OR: 8.8 and 10.5) and for bullying others (3.9 and 3.5). Being bullied was associated with poor thriving and psychosomatic and psychological problems. No countries had national interventions before 1984, but Sweden had early focused on the problem and implemented a strong national policy before 1996. After 1996 national anti-bullying policies were strengthened in the Nordic countries, most in Sweden and Norway.
Conclusion Bullying is common among Nordic children, including pre-school children. Bullying is a threat to children's health, and augments problems in children with chronic conditions. The low prevalence of bullying in Sweden may be a result from sustained, strong anti-bullying policies. There is still a need for continuing interventions.