Obesity and socioeconomic status in children of Tijuana

BACKGROUND: Although obesity has been associated with socioeconomic status among Hispanics living in the United States, little is known about whether a similar association exists among Hispanics living in Mexico, particularly among those living along the U.S.-Mexico border. OBJECTIVE: To determine the prevalence of obesity and its association with socioeconomic status in Mexican schoolchildren attending public and private schools in Tijuana, Baja California. METHODS: Anthropometric measurements and socioeconomic status were assessed in a cross-sectional study of 1172 school children, aged 6 to 13 years from 55 schools in Tijuana in 2001-2002. Underweight (body mass index BMI] for age 5th percentile or lower), risk of overweight (BMI at 85th percentile or higher), and overweight (BMI greater than 95th percentile) were assessed using charts published by the Centers for Disease Control and Prevention. RESULTS: Abnormalities in weight were found in 46.3% of 587 boys and 43.7% of 585 girls in the study. Undernutrition was found in 3.7% of the boys and 3.8% of the girls. The general prevalence of overweight was 23.2% for boys and 21.7% for girls. Children living in low-income neighborhoods had the thickest biceps skinfolds (p<0.01), while children living in moderate-income neighborhoods and attending public schools had the thickest triceps skinfolds (p<0.001). Although boys living in high socioeconomic status neighborhoods were at decreased risk for being overweight, boys and girls attending private schools had a 75% increased risk (odds ratio, 1.75; confidence interval, 1.22-2.52) of being overweight than children attending public schools. CONCLUSIONS: Adiposity varies by type of school and neighborhood socioeconomic status. The biphasic curve in risk for being overweight associated with neighborhood socioeconomic status suggests that Mexican children living along the U.S. border may be experiencing a nutrition transition with respect to an increased risk of obesity and related chronic disease.