Objectives: To estimate the incidence and risk of childhood overweight and obesity according to socioeconomic status in Peruvian and Vietnamese school-aged children.

Methods: Longitudinal data from the Young Lives study were analyzed. Exposure was wealth index in tertiles. Outcome was overweight and obesity. Cumulative incidence per 100 children-years, relative risks (RR), and 95 % confidence intervals (95 % CI) were calculated. A hierarchical approach, including child- and family-related variables, was followed to construct multivariable models.

Results: The cumulative incidence of overweight and obesity was 4.8 (95 % CI 4.1-5.5) and 1.7 (95 % CI 1.3-2.2) in the younger and older Peruvian cohort, respectively; and in Vietnam 1.5 (95 % CI 1.2-1.8) and 0.3 (95 % CI 0.2-0.5), respectively. The incidence of overweight and obesity was higher at the top wealth index tertile in all samples. In the older cohorts, comparing highest versus bottom wealth index tertile, RR of overweight and obesity was four to nine times higher: 4.25 in Peru (95 % CI 2.21-8.18) and 9.11 in Vietnam (95 % CI 1.07-77.42).

Conclusions: The results provide important information for childhood obesity prevention in countries moving ahead with economic, epidemiological and nutritional transitions.

Keywords: Developing countries; Pediatric obesity; Peru; Prospective studies; Social class; Vietnam

Article written using Young Lives data from the UK Data Archive by researchers from the CRONICAS Center of Excellence in Chronic Diseases, Universidad Peruana Cayetano Heredia, Peru; School of Medicine, Universidad Peruana Cayetano Heredia, Peru; and the School of Medicine, Peruvian University of Applied Sciences (UPC), Peru.

Rodrigo M. Carrillo-Larco,  J. Jaime Miranda, Antonio Bernabe-Ortiz (2015) 'Wealth Index and Risk of Childhood Overweight and Obesity: Evidence from Four Prospective Cohorts in Peru and Vietnam', Int J Public Health. 2015 Nov 24. [Epub ahead of print]. Download full version from the publisher's website.