A randomized trial of the effects of reducing television viewing and computer use on body mass index in young children.

OBJECTIVE: To assess the effects of reducing television viewing and computer use on children's body mass index (BMI) as a risk factor for the development of overweight in young children. DESIGN: Randomized controlled clinical trial. SETTING: University children's hospital. PARTICIPANTS: Seventy children aged 4 to 7 years whose BMI was at or above the 75th BMI percentile for age and sex. INTERVENTIONS: Children were randomized to an intervention to reduce their television viewing and computer use by 50% vs a monitoring control group that did not reduce television viewing or computer use. MAIN OUTCOME MEASURES: Age- and sex-standardized BMI (zBMI), television viewing, energy intake, and physical activity were monitored every 6 months during 2 years. RESULTS: Children randomized to the intervention group showed greater reductions in targeted sedentary behavior (P < .001), zBMI (P < .05), and energy intake (P < .05) compared with the monitoring control group. Socioeconomic status moderated zBMI change (P = .01), with the experimental intervention working better among families of low socioeconomic status. Changes in targeted sedentary behavior mediated changes in zBMI (P < .05). The change in television viewing was related to the change in energy intake (P < .001) but not to the change in physical activity (P =.37). CONCLUSIONS: Reducing television viewing and computer use may have an important role in preventing obesity and in lowering BMI in young children, and these changes may be related more to changes in energy intake than to changes in physical activity.

Cost effectiveness of recruitment methods in an obesity prevention trial for young children.

BACKGROUND: Recruitment of participants for clinical trials requires considerable effort and cost. There is no research on the cost effectiveness of recruitment methods for an obesity prevention trial of young children. METHODS: This study determined the cost effectiveness of recruiting 70 families with a child aged 4 to 7 (5.9+/-1.3) years in Western New York from February 2003 to November 2004, for a 2-year randomized obesity prevention trial to reduce television watching in the home. RESULTS: Of the 70 randomized families, 65.7% (n=46) were obtained through direct mailings, 24.3% (n=17) were acquired through newspaper advertisements, 7.1% (n=5) from other sources (e.g., word of mouth), and 2.9% (n=2) through posters and brochures. Costs of each recruitment method were computed by adding the cost of materials, staff time, and media expenses. Cost effectiveness (money spent per randomized participant) was US $0 for other sources, US $227.76 for direct mailing, US $546.95 for newspaper ads, and US $3,020.84 for posters and brochures. CONCLUSION: Of the methods with associated costs, direct mailing was the most cost effective in recruiting families with young children, which supports the growing literature of the effectiveness of direct mailing.

Relationship between parental estimate and an objective measure of child television watching.

Many young children have televisions in their bedrooms, which may influence the relationship between parental estimate and objective measures of child television usage/week. Parental estimates of child television time of eighty 4-7 year old children (6.0 +/- 1.2 years) at the 75th BMI percentile or greater (90.8 +/- 6.8 BMI percentile) were compared to an objective measure of television time obtained from TV Allowance devices attached to every television in the home over a three week period. Results showed that parents overestimate their child's television time compared to an objective measure when no television is present in the bedroom by 4 hours/week (25.4 +/- 11.5 vs. 21.4 +/- 9.1) in comparison to underestimating television time by over 3 hours/week (26.5 +/- 17.2 vs. 29.8 +/- 14.4) when the child has a television in their bedroom (p = 0.02). Children with a television in their bedroom spend more objectively measured hours in television time than children without a television in their bedroom (29.8 +/- 14.2 versus 21.4 +/- 9.1, p = 0.003). Research on child television watching should take into account television watching in bedrooms, since it may not be adequately assessed by parental estimates.