Telephone-based adiposity prevention for families with overweight children (T.A.F.F.-Study): one year outcome of a randomized, controlled trial

Abstract

The one-year outcome of the randomized controlled T.A.F.F. (Telephone based Adiposity prevention For Families) study is presented. Screening of overweight (BMI-SDS > 90th centile) children 3.5-17.4 years was performed via the German CrescNet database, and candidates were randomized to an intervention group (IG) and control group (CG). The intervention consisted of computer-aided telephone counselling for one year, supported by mailed newsletters. The primary endpoint was change in BMI-SDS; secondary endpoints were eating behavior, physical activity, media consumption, quality of life. Data from 289 families (145 IG (51% females); 144 CG (50% females)) were analyzed (Full Analysis Set: FAS; Per Protocol Set: PPS). Successful intervention was defined as decrease in BMI-SDS ≥ 0.2. In the FAS, 21% of the IG was successful as compared to 16% from the CG (95% CI for this difference: (-4, 14), p = 0.3, mean change in BMI-SDS: -0.02 for IG vs. 0.02 for CG; p = 0.4). According to the PPS, however, the success rate was 35% in the IG compared to 19% in the CG (mean change in BMI-SDS: -0.09 for IG vs. 0.02 for CG; p = 0.03). Scores for eating patterns (p = 0.01), media consumption (p = 0.007), physical activity (p = 9 × 10-9), quality of life (p = 5 × 10-8) decreased with age, independent of group or change in BMI-SDS. We conclude that a telephone-based obesity prevention program suffers from well-known high attrition rates so that its effectiveness could only be shown in those who adhered to completion. The connection between lifestyle and weight status is not simple and requires further research to better understand.

Figure 1

Flow chart of the study design according to the recommendations of the Consolidated Standards of Reporting Trials (CONSORT). Additional information is provided in a previous publication [11].

Figure 2

The primary endpoint (change in BMI-SDS) for the intervention group, presented as full protocol set (intention-to-treat, ITT / FAS; estimated change in BMI-SDS: −0.015 (95% CI (−0.09, 0.06)) and per protocol set (PPS; estimated change in BMI-SDS: −0.086 (95% CI (−0.18, 0.01)) compared to the control group (estimated change in BMI-SDS: 0.018 (95% CI (−0.03, 0.07)). ANCOVA analysis for the PPS revealed that the coefficient for the control group is 0.11 (95% CI (0.01, 0.20), p = 0.03), demonstrating that the therapy is effective for those who follow it to completion.

Figure 3

(a) Media scores at t0 as they depend on age. Please note that questionnaires were completed by parents for children ≤10 years and by children/adolescents themselves for participants older than 10 years (linear correlation coefficient 0.2 (95% CI (0.07, 0.4), p = 0.007). Differences in media consumption are also evident depending on gender: mean media score for boys (black circles, black line) is 176 as compared to 129 for girls (white circles, dashed line) (95% CI for the difference in means is (24, 70), p = 9 × 10⁻⁵). (b) Correlation between KINDL-R scores and age at baseline (t0). Please note that this age dependence can be found independent on who filled out the questionnaire (parents or participants themselves) (correlation coefficient: −0.32, 95% CI (−0.42, −0.21), p = 5 × 10⁻⁸).