School-based intervention on healthy behaviour among Ecuadorian adolescents: effect of a cluster-randomized controlled trial on screen-time

Background

Effective interventions on screen-time behaviours (television, video games and computer time) are needed to prevent non-communicable diseases in low- and middle-income countries. The present manuscript investigates the effect of a school-based health promotion intervention on screen-time behaviour among 12- to 15-year-old adolescents. We report the effect of the trial on screen-time after two stages of implementation.

Methods

We performed a cluster-randomised pair matched trial in urban schools in Cuenca-Ecuador. Participants were adolescents of grade eight and nine (mean age 12.8 ± 0.8 years, n = 1370, control group n = 684) from 20 schools (control group n = 10). The intervention included an individual and environmental component tailored to the local context and resources. The first intervention stage focused on diet, physical activity and screen-time behaviour, while the second stage focused only on diet and physical activity. Screen-time behaviours, primary outcome, were assessed at baseline, after the first (18 months) and second stage (28 months). Mixed linear models were used to analyse the data.

Results

After the first stage (data from n = 1224 adolescents; control group n = 608), the intervention group had a lower increase in TV-time on a week day (β = −15.7 min; P = 0.003) and weekend day (β = −18.9 min; P = 0.005), in total screen-time on a weekday (β = −25.9 min; P = 0.03) and in the proportion of adolescents that did not meet the screen-time recommendation (β = −4 percentage point; P = 0.01), compared to the control group. After the second stage (data from n = 1078 adolescents; control group n = 531), the TV-time on a weekday (β = 13.1 min; P = 0.02), and total screen-time on a weekday (β = 21.4 min; P = 0.03) increased more in adolescents from the intervention group. No adverse effects were reported.

Discussion and Conclusion

A multicomponent school-based intervention was only able to mitigate the increase in adolescents’ television time and total screen-time after the first stage of the intervention or in other words, when the intervention included specific components or activities that focused on reducing screen-time. After the second stage of the intervention, which only included components and activities related to improve healthy diet and physical activity and not to decrease the screen-time, the adolescents increased their screen-time again. Our findings might imply that reducing screen-time is only possible when the intervention focuses specifically on reducing screen-time.

Trial registration

Clinicaltrials.gov identifier NCT01004367.

Prevalence and socioeconomic differences of risk factors of cardiovascular disease in Ecuadorian adolescents

PURPOSE

The aim of this paper is to report the prevalence of cardiovascular risk factors and socioeconomic differences in school-going Ecuadorian adolescents.

METHODS

A cross-sectional study was performed from January 2008 until April 2009 in 770 adolescents aged 10 to 16 years old, who attend secondary schools in an urban (Cuenca), and rural area (Nabón) in Ecuador. Data collected for the overall sample included anthropometric variables (weight, height and waist circumference), blood pressure and socio-demographic characteristics. Fasting blood glucose and lipid profile determinations were collected in a subsample of 334 adolescents.

RESULTS

The most prevalent cardiovascular risk factors were dyslipidemia (34.2%), abdominal obesity (19.7%) and overweight (18.0%). The prevalence of the remaining cardiovascular risk factors were high levels of blood pressure (6.2%) and obesity (2.1%). Boys were 3.3 times (P < 0.001) more likely to have risk levels of blood pressure. Compared to their peers from lower socioeconomic groups, children from better off socioeconomic strata were 1.5 times (P = 0.048) more likely to be overweight/obese and 1.5 times (P = 0.046) more likely to have abdominal obesity. Overweight and obese children were 4.4 times more likely to have dyslipidemia (P < 0.001). Children living in the rural area were 2.8 times (P = 0.002) more likely to have dyslipidemia than those from the urban area.

CONCLUSIONS

Our results demonstrate the advanced levels of the nutrition transition in this Ecuadorian adolescent population. Primary health care should monitor and take actions to address this public health problem in adolescents.