Evaluation of Three New Strategies to Fight Obesity in Families
Context: Endeavours to reduce overweight by calorie-restriction diets are often neither sufficient nor sustained. The growing obesity epidemic demands additional measures to enhance and sustain weight loss.
Objective: To evaluate three alternative weight-loss measures on top of a calorie-restriction diet.
Design, Setting, and Participants: Six-month randomized and controlled trial using a three-factorial design. The participants were 110 families with 142 obese parents and their 119 obese children.
|Study Design:||Observational Model: Family-Based
Time Perspective: Prospective
|Official Title:||Evaluation of Three New Strategies to Fight Obesity in Families|
- In the parents the outcome variable at 6 months was the relative weight loss. In children, because of their body growth, the outcome variable was the age-adjusted BMI standard deviation score (BMI-SDS). [ Time Frame: six and twelve month ] [ Designated as safety issue: No ]
- effects of the different combinations of the additional strategies to reduce weight [ Time Frame: 12 months ] [ Designated as safety issue: No ]
Biospecimen Retention: Samples Without DNA
|Study Start Date:||April 2006|
|Study Completion Date:||December 2007|
|Primary Completion Date:||April 2007 (Final data collection date for primary outcome measure)|
For the parents the financial incentive was 5 euros for every kilogram of weight-loss. For children the weight loss was calculated differently, taking into account the individual need of each child to lose weight. Children with a body mass index between the 90th and 97th age-adjusted BMI-percentile were asked to maintain their weight, and were paid in dependence on how well they managed to achieve this goal. Children with age-adjusted BMI-percentiles between 97 and 99, or above the 99th age-adjusted BMI-percentile received 5 euros per weight losses of respectively 500 g or 1 kg.
The telemedical equipment consisted of a weighing scale for each family, an accelerometer for each participant, and a Homebox for each family which received the data from the scale and the accelerometers via bluetooth and transfered them via a telephone link to a server in Munich.
The basic diet for all participants was supported by a list giving the calorie contents of a large variety of food-stuffs. The dual diet group received a second list giving the glycemic index (GI) for a large variety of carbohy-drates. Emphasis was placed on a preference for low-GI carbohydrates but not on avoidance of carbohydrates as required by the Atkins diet.
Intervention: All families kept to a calorie-restriction diet and were assigned at random to one or more of three additional weight-loss strategies: (1) a diet on top of calorie-restriction with preference for carbohydrates having a low glycemic index (dual diet), (2) financial incentive, and (3) continuous telemetric control of weight and physical activity (telemonitoring). The design made it possible to determine the effect of each single measure: financial incentive vs. no financial incentive (54 vs.56 families), calorie-restriction vs. dual diet (53 vs. 57 fami-lies) and telemonitoring vs. no telemonitoring (19 vs. 91 families). The design also allowed an assessment of the effects of combinations of the additional measures, each adapted for possible effects of the other factors.
Main Outcome In the parents the outcome variable at 6 months was the relative weight loss. In children, be-cause of their body growth, the outcome variable was the age-adjusted BMI standard deviation score (BMI-SDS). Analysis was done by three-factorial ANOVA and by a one-factorial ANOVA with the included Dunnett test as a post-hoc comparison, to distinguish between the effects of the different combinations of the additional strategies.