Nutritional status and risk factors of overweight and obesity for children aged 9–15 years in Chengdu, Southwest China

BACKGROUND Obesity is widespread in the world including developing countries. However malnutrition in poor areas is still a serious problem. Few investigations, especially in a large sample, have been performed in Western area of China. This study aimed to evaluate the nutritional status of school children aged 9-15 years in large Southwest city of China, and identify the differential impact of aberrant birth categories and family history of obesity related disease on childhood overweight and obesity development. METHODS A multistage random cluster sampling was performed to evaluate the prevalence of thinness, overweight and obesity, which were defined by the new age-, sex-, specific BMI reference developed by World Health Organization (WHO) (2007). And then a frequency matched case-control study was performed to identify the risk factors of overweight and obesity. RESULTS 7,194 children (3,494 boys, 3,700 girls) were recruited, and 1,282 (17.8%) had excess bodyweight (14.5% overweight, 3.3% obesity). The combined prevalence gradually decreased with age, and were more prevalent among boys than girls (P <0.05). Meanwhile 6.3% were found thinness and there were little differences in genders (P >0.05). Preterm large for gestational age (OR = 2.746), maternal history of obesity related disease (OR = 1.713), paternal history of obesity related disease (OR = 1.583), preterm appropriate for gestational age (OR = 1.564), full term small for gestational age (OR = 1.454) and full term large for gestational age (OR = 1.418) were recognized as significant risk factors in the multivariate regression analysis (P <0.05). CONCLUSIONS While overweight and obesity was dramatically spreading, malnutrition still remained a serious problem. This unmatched nutritional status should be emphasized in backward cities of China. Children born of both preterm and LGA, whose parents particularly mothers had a history of obesity related disease, should be emphatically intervened as early as possible.