Cumulative Effect of Obesogenic Behaviours on Adiposity in Spanish Children and Adolescents.

OBJECTIVE Little is known about the cumulative effect of obesogenic behaviours on childhood obesity risk. We determined the cumulative effect on BMI z-score, waist-to-height ratio (WHtR), overweight and abdominal obesity of four lifestyle behaviours that have been linked to obesity. METHODS In this cross-sectional analysis, data were obtained from the EnKid sudy, a representative sample of Spanish youth. The study included 1,614 boys and girls aged 5-18 years. Weight, height and waist circumference were measured. Physical activity (PA), screen time, breakfast consumption and meal frequency were self-reported on structured questionnaires. Obesogenic behaviours were defined as <1 h PA/day, ≥2 h/day screen time, skipping breakfast and <3 meals/day. BMI z-score was computed using age- and sex-specific reference values from the World Health Organization (WHO). Overweight including obesity was defined as a BMI > 1 SD from the mean of the WHO reference population. Abdominal obesity was defined as a WHtR ≥ 0.5. RESULTS High screen time was the most prominent obesogenic behaviour (49.7%), followed by low physical activity (22.4%), low meal frequency (14.4%), and skipping breakfast (12.5%). Although 33% of participants were free of all 4 obesogenic behaviours, 1, 2, and 3 or 4 behaviours were reported by 44.5%, 19.3%, and 5.0%, respectively. BMI z-score and WHtR were positively associated (p < 0.001) with increasing numbers of concurrent obesogenic behaviours. The odds of presenting with obesogenic behaviours were significantly higher in children who were overweight (OR 2.68; 95% CI 1.50; 4.80) or had abdominal obesity (OR 2.12; 95% CI 1.28; 3.52); they reported more than 2 obesogenic behaviours. High maternal and parental education was inversely associated (p = 0.004 and p < 0.001, respectively) with increasing presence of obesogenic behaviours. Surrogate markers of adiposity increased with numbers of concurrent presence of obesogenic behaviours. The opposite was true for high maternal and paternal education.