Psychosocial determinants and perceived environmental barriers as mediators of the effectiveness of a web-based tailored intervention promoting physical activity in adolescents: the HELENA Activ-O-Meter.

BACKGROUND: The aim was to examine if psychosocial determinants (attitudes, self-efficacy, social support from a sports partner) and perceived environmental barriers (PEB) of physical activity (PA) mediated the effect of a 3-month Internet-based intervention on PA in European adolescents. METHODS: A sample of 536 adolescents (51% boys) aged 12-17 years were randomly assigned to intervention or control condition. Questionnaires were used to assess different PA behaviors, psychosocial determinants and PEB at baseline and at 3-month follow-up. Mediating effects were assessed with the bootstrapping method. RESULTS: PEB regarding neighborhood safety mediated the effect of the intervention on all PA indices. PEB regarding sports facilities availability at neighborhood and PEB regarding sport-related facilities availability at school mediated the effect of the intervention on moderate to vigorous PA (MVPA) and moderate PA (in leisure time and at school, respectively). Social support from a sports partner suppressed the effect of the intervention on vigorous PA and MVPA. No other factor had a mediation effect. CONCLUSIONS: All PEB measures appear to mediate PA behaviors of different intensities and in different contexts. Interventions promoting PA in adolescents should also focus on improving the targeted PEB as mediators of engagement in PA to bring the desired effects in actual behaviors.

Pilot evaluation of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Food-O-Meter, a computer-tailored nutrition advice for adolescents: a study in six European cities.

OBJECTIVE: To investigate the feasibility and impact of the Food-O-Meter, an Internet-based computer-tailored nutrition intervention in adolescents. DESIGN: Participants in the intervention condition received the computer-tailored advice at baseline and at 1 month, those in the control condition received standardised advice. Effects were evaluated at 1 month (n 621) and at 3 months (n 558) using multi-level modelling. SETTING: Secondary schools in six European cities. Adolescents accessed the intervention in the school computer room under the supervision of teachers. SUBJECTS: Classes with students aged 12-17 years in the schools participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) cross-sectional study were randomised into intervention and control schools. RESULTS: In most participating centres the intervention was feasible and generally well appreciated, especially by girls. Technical problems and lack of motivation of the teachers hindered implementation in some centres. Overweight adolescents had higher scores for reading and using the advice than normal weight adolescents. After 1 month adolescents receiving the standardised advice reported an increase in fat intake, while fat intake in the intervention condition was stable (F = 4·82, P < 0·05). After 3 months, there was a trend in the total group for an intervention effect of the tailored advice on fat intake (F = 2·80, P < 0·10). In the overweight group there was a clear positive effect (F = 5·76, P < 0·05). CONCLUSIONS: The Food-O-Meter should be developed further. The results were modest but clear for percentage energy from fat, specifically in the overweight group. Adaptations based on new research are needed to enhance the reliability and effectiveness of the intervention.

Prevalence of obesity and body mass index correlates in a representative sample of Cretan school children.

OBJECTIVE: This study aimed to estimate the prevalence of overweight and obesity and investigate associated factors in a representative sample of Cretan school children. METHODS: As part of a cross-sectional study in children aged 10-12 years (n = 481, 48% boys) in 27 (urban and rural) schools in Crete, Greece, the rates of overweight and obesity were estimated and multiple logistic regression was used to explore the relationship between several factors and body mass index (BMI). RESULTS: It was shown that 28% and 13% of children were overweight and obese, respectively. Factors affecting children's BMI classification included: gender (95% CI: 0.21 to 0.56); birth weight (95% CI: 1.33 to 3.46); parental overweight or obesity (95% CI: 1.11 to 6.5 and 95% CI: 4.37 to 30.7 for one and both overweight or obese parents, respectively), paternal educational level (95% CI: 0.89 to 3.48 and 95% CI: 1.49 to 6.13 for low and high educational level, respectively); and cardiovascular fitness levels (95% CI: 0.87 to 0.92). CONCLUSION: The combined prevalence of overweight and obesity was alarmingly high in the current population (41%); several physiological, behavioural and social factors were shown to affect children's BMI status. These findings highlight the extent of the child obesity problem in Crete and support the need for actions to be taken at a national level to tackle the obesity epidemic.