Table 4 Summary of experimental studies including TV limiting devices

French (2011); USA [79]

n=75 adolescents randomised, n=87 HHs; 12–17 yrs; Sex not reported; HH TV ≥ 10 hrs per person per wk.

Cluster RCT; 12 mths; Intervention - TV limiting devices, guidelines about food availability, 6 x group sessions, behavioural strategies, phone calls, 12 x home-based activities; Control - no intervention.

SB - TV (SR); PA - MVPA (SR); Other - zBMI, dietary intake, eating behaviours, PA encouragement, PA with others in HH, TV is on.

Significant decrease in reporting TV is on, and significant increase in consumption of fruit and veg in intervention compared to control. At HH level there was a significant decrease in TV watching, and a significant increase in PA encouragement, PA with others in HH compared to control.

Gender, smoking, age, HH income, configuration, race, education; baseline values of outcomes; HH clustering.

Goldfield (2006); Canada [89]

n=30; 8–12 yrs; 43% M; overweight or obese, TV/video games ≥15 hrs per wk, <30 mins MVPA per day.

RCT; 8 wks; Intervention - wore PA monitor (open-loop feedback) and rewarded for PA (reinforcement) with TV access via token controlled TV limiting device; Control - wore a PA monitor (open-loop feedback only).

SB - TV based, other (SR); PA - activity counts, MVPA, VPA (Acc); Other - height, weight, BMI, dietary intake.

Significantly greater changes in total activity counts and MVPA, and reduction in TV based SB, fat intake, calories from snacks and snack intake in front of TV, and improvement in weight and BMI, compared to control. Reductions in weight, fat intake, calories from snacks, calories consumed in front of TV significantly correlated with reduction in TV based SB.

Not noted.

Ni Mhurchu (2009); New Zealand [85]

n=29; 9–12 yrs; 62% M; TV > 20 hrs per wk.

RCT (Pilot); 6 wks; Intervention - electronic TV monitors, encouraged to restrict TV to 60 mins per day, ideas to reduce TV; Control - ideas to reduce TV.

SB - TV, total screen time (SR); PA - steps (pedometer); Other - BMI, energy intake from snacks; Interviews.

No significant differences. Decrease in weekly TV of 254 mins in intervention and 3 mins in control (NS). Total screen time decreased and steps increased slightly in both groups (NS). Mixed views on family acceptability of TV time monitors.

Baseline values of outcomes.

Robinson (2006); USA [80]

n=181; mean 8.9 yrs; 54% M.

Cluster RCT; 6 mths; Intervention - SMARTschool curriculum (18 lessons with TV Turn Off Challenge and goal to reduce to 7 hrs per wk), TV allowance device, parent newsletters; Control - no intervention.

SB - TV, video, video game play (SR); Other - family member TV viewing; Interviews.

Significant reduction in weekday TV, and weekday and weekend video game play compared to control. Significant reduction in mother, father and sibling TV viewing compared to control. Age, supervision, and prior TV and video game use moderated intervention effects.

Baseline values of outcomes.

Todd (2008); USA [81]

n=21; 8–11 yrs; M only; TV > 3.5 hrs or EM > 5.8 hrs per day.

RCT; 20 wks; Intervention - seminar including goal setting, newsletters, TV allowance device, software to limit computer use, phone calls, recommendation to reduce EM to 90 mins per day; Control - no intervention.

SB – EM use (SR); PA - steps (pedometer); Other - height, weight, BMI, % body fat, snacks and meals consumed with EM, dietary intake, bone mineral density.

Significant treatment by time interaction for EM use and % body fat. Intervention decreased EM use from 153mins per day to 81 (10 wks) and 82 (20 wks) and control from 157 to 119 and 95 (adjusted difference of 73 mins at 20 weeks); Intervention decreased % body fat from 26.1 to 24.6 (20 wks) and control increased from 27.7 to 28.0. Significant reduction in snacks and meals consumed with EM, compared to control.

Organised activity, electronic media access.