National Trends in Hemoglobin Concentration and Prevalence of Anemia among Chinese School-Aged Children, 1995-2010

Objective: To assess the trend of sex disparity in hemoglobin concentration and prevalence of anemia among Chinese school-aged children from 1995 to 2010. Study design: Data were collected from 360 866 children aged 7, 9, 12, 14, and 17 years during 4 cross-sectional surveys (1995, 2000, 2005, and 2010) of the Chinese National Surveys on Students Constitution and Health. Shifts in hemoglobin concentration distributions were compared by sex. Average shifts and sex differences were calculated with quantile regression models. Logistic regression was used to estimate the prevalence odds ratio of sex for prevalence of anemia in different surveys. Results: The mean hemoglobin concentration increased among Chinese children between 1995 and 2010, from 132.7 to 138.3 g/L in boys, and from 127.7 to 132.3 g/L in girls. The prevalence of anemia decreased from 18.8% in 1995 to 9.9% in 2010. It was higher in rural than urban children among all age groups. The prevalence odds ratios of girls versus boys for anemia increased in both urban and rural areas over time. Conclusion: Hemoglobin concentration and prevalence of anemia improved among Chinese school-aged children over time. Hemoglobin concentration improved faster in boys than girls and as a result the relative prevalence of anemia in girls compared with boys increased. Sex-specific preventive guidelines and public health policies for childhood anemia are needed in China.