Television, computer use and body mass index in Australian primary school children.

OBJECTIVE: To investigate relationships between children's body mass index (BMI) and parent reports of children's television and video game/computer habits, controlling for other potential risk factors for paediatric obesity.

METHODS: Child BMI was calculated from measured height and weight collected in 1997 as part of a large, representative, cross-sectional study of children in Victoria, Australia. Parents reported the amount of time children watched television and used video games/computers, children's eating and activity habits, parental BMI and sociodemographic details.

RESULTS: A total of 2862 children aged 5-13 years participated. Child mean BMI z-score was significantly related to television (F = 10.23, P < 0.001) but not video game/computer time (F = 2.23, P = 0.09), but accounted for only 1 and 0.2% of total BMI variance, respectively. When parental BMI, parental education, number of siblings, food intake, organized exercise and general activity level were included, television ceased to be independently significantly related to child BMI. Using adjusted logistic regression, the odds of being overweight and obese generally increased with increasing television viewing. No relationship was found for video game/computer use.

CONCLUSIONS: A small proportion of variance in child BMI was related to television, but not video game/computer time. This was far outweighed by the influence of other variables. Causal pathways are likely to be complex and interrelated.