Modifiable environmental obesity risk factors among elementary school children in a Mexico-us border city.

Background: The increasing overweight (OW) and obesity (OB) prevalence in Mexican children warrant the assessment of the environmental risk factors.

Objective: To assess whether there is an association between food availability in children's environments and their food consumption with BMI z-score and waist circumference (WC).

Methods: Six hundred and eighty four children, 264 parents, 22 teachers and cafeteria staff in the schools and street vendors participated in the study. Weight, height, and WC of 5(th) grade children were assessed. Food frequency, physical activity (PA) and eating habits questionnaires were applied to parents, children and teachers. A food inventory questionnaire was applied to parents, cafeteria staff in the schools, street vendors and stores near the schools.

Results: The children's mean age was 10.5. Twenty eight per cent of the children were overweight, 26% obese and 25% had abdominal obesity. A positive correlation was found between energy-dense foods (EDF), fruit and vegetable availability at home and their weekly consumption. Also a correlation between consumption of soft drinks and other EDF was found. The largest contributors to food consumption were the availability at home and at school (R2 = 0.11, p = 0.0001). Children's TV viewing was positively correlated with parents TV viewing time. For each hour of increase (from cero to seven) in daily TV viewing children were more likely to be overweight or obese (OR=1.22 95% CI 1.02-1.45, p=0.026).

Conclusion: EDF, fruit and vegetable availability in and near home and school along with hours of TV viewing were positively associated with obesity.