Screen time and adiposity in adolescents in Mexico.

Objective: To assess the association of time spent viewing television, videos and video games with measures of fat mass (BMI) and distribution (triceps and subscapular skinfold thicknesses (TSF, SSF)).

Design: Cross-sectional validated survey, self-administered to students to assess screen time (television, videos and video games) and lifestyle variables. Trained personnel obtained anthropometry. The association of screen time with fat mass and distribution, stratified by sex, was modelled with multivariable linear regression analysis, adjusting for potential confounders and correlation of observations within schools.

Setting: State of Morelos, Mexico.

Subjects: Males (n 3519) and females (n 5613) aged 11 to 18 years attending urban and rural schools in Morelos.

Results: In males, screen time of >5 h/d compared with <2 h/d was significantly associated with a 0.13 (95% CI 0.04, 0.23) higher BMI Z-score, 0.73 mm (95% CI 0.24, 1.22) higher SSF and 1.08 mm (95% CI 0.36, 1.81) higher TSF. The positive association of screen time with SSF was strongest in males aged 11-12 years. Sexual maturity appeared to modify the association in females; a positive association between screen time and SSF was observed in those who had not undergone menarche (P for trend = 0.04) but not among sexually mature females (P for trend = 0.75).

Conclusion: Screen time is associated with fat mass and distribution among adolescent males in Mexico. Maturational tempo appears to affect the relationship of screen time with adiposity in boys and girls. Findings suggest that obesity preventive interventions in the Mexican context should explore strategies to reduce screen time among youths in early adolescence.