Global prevalence of overweight and obesity in preschoolers.

Twenty-three studies reporting cross-sectional and longitudinal data were conducted in 14 different countries between 1998 and 2008. The number of preschool age children totaled more than 43,837 with one study not reporting a sample size. Studies used both international (i.e., International Obesity Task Force (IOTF), World Health Organization (WHO)) and national reference standards (i.e., United States - Centers for Disease Control and Prevention (CDC), Spain - SRS, Italy - Luciano) to classify children as overweight or obese. Within the same sample the percentage of children classified in these categories often showed a 1.5- to 2-fold difference in the prevalence of overweight/obesity with greatest differences in the between country-specific standards (CDC vs. Luciano). WHO percentages frequently exceeded the IOTF percentages. The prevalence of overweight/obese children escalated with increasing age from 2-5 years in both boys and girls with girls showing higher frequencies in 2/3rds of the 72 sex-paired comparisons. The results indicate a recent high prevalence of overweight and obesity in middle and high income countries, among both well-off and lower income segments of populations, in both rural and urban areas, and among all ethnic and racial groups represented. Because a high proportion of preschool overweight/ obese children will continue to increase their adiposity and are at risk for the early onset of metabolic syndrome, cardiovascular disease, type 2 diabetes, musculoskeletal disorders and behavioral problems, concerted public health efforts are needed to coordinate culturally-appropriate parental and caregiver education, home lifestyle changes, dietary and exercise modifications that will reverse the current trajectory.