The results of the study have been published recently in the Journal of Sleep Research.
Main results:
1. All the families that participated in the study had at least one TV set. In 21% of families, there was a TV set in the children's room. On average, the TV was switched on for 4,2 h a day. Children actively watched TV for a mean of 1,4 h a day and were passively exposed to TV 1,4 h a day.
2. Both active TV viewing and passive TV exposure were related to shorter sleep duration and sleeping difficulties, especially sleep-wake transition disorders and overall sleep disturbances.
3. There was also a clear association between the contents of actively viewed TV programs and the sleep problem scores. Watching adult targeted programs, such as current affairs programs, police series, movies, series, was related to an increased frequency of various sleeping difficulties.
4. Watching TV alone was related to sleep onset problems.
5. Watching TV at bedtime was also associated with various sleeping problems, especially sleep-wake transition disorders and daytime somnolence.
6. Particularly high passive exposure to TV (>2,1 h/day) and viewing adult-targeted TV programs were strongly related to sleep disturbances. The association remained highly significant when socio-economic status, family income, family conflicts, the father's work schedule, and the child's psychiatric symptoms were controlled for statistically. The adjusted odds ratios were 2.91 (95% CI 1.03-8.17) and 3.01 (95% CI 1.13-8.05), respectively. There was also an almost significant interaction between passive TV exposure and active viewing of adult programs (AOR 10.14, 95% CI 0.81-127.04, p=0.07). By contrast, active TV viewing time and the viewing of children's programs were not correlated with sleep problems.
Most of the previous research has concentrated on active TV viewing while passive TV exposure has only rarely been considered. Passive TV exposure can be particularly harmful to young children because it increases the risk of children coming into contact with programs intended for adults.
Quality sleep is essential for children's wellbeing and health. Therefore reducing the quantity of passive TV exposure and limiting children's opportunities to watch adult-targeted programs might help to reduce children's sleeping problems and increase average sleep duration, which could further lead to beneficial changes in children's daytime behavior. Parents should be advised to control the quantity of TV viewing, to monitor the program content viewed, and to limit children's exposure to passive TV. Watching TV at bedtime should be discouraged.