RESUMO
Objective@#To estimate the detection rate of low hemoglobin among primary and middle school students in Ningxia, and to explore association between physical growth indicators with level of hemoglobin in different economic zones from both the student and school levels, and to provide an effective basis for anemia prevention of primary and secondary school students.@*Methods@#The stratified random cluster sampling method was used to measure 5 447 primary and middle school students physical growth indicators and hemoglobin values. Prevalence of low hemoglobin was described and its association with physical growth indicators were analyzed through HLM models.@*Results@#The detection rate of low hemoglobin among primary and middle school students was 12.7%, of which 13.0% were boys and 12.4% were girls, without significant gender differences(χ2=0.43, P>0.05). Low hemoglobin in rural areas was higher than urban areas, as well as in the lowage group which was 18.5%, 12.6%, 8.3%, 11.5% in the 7, 9, 12, and 14-year-old groups, respectively, and the differences between the groups were statistically significant(χ2=43.49, 68.13, P<0.05). The wasting group had the highest detection rate of low hemoglobin, and low hemoglobin in obesity and overweight was lower than that of the normal group, with significant differences between groups(Z=2.08, P<0.05). Positive association between height and weight with hemoglobin was observed(γ 30 =0.13, γ 40=0.06), and the association of hip circumference with hemoglobin was negative(γ 50=-0.02). Body weight had a significant associated with the hemoglobin value in different economic film intervals(P<0.05).@*Conclusion@#The detection rate of low hemoglobin is relatively high among primary and middle school students in rural areas, low-age groups, and wasting groups in Ningxia. The differences between school groups are significant, and it is necessary to mine school-level variables.
RESUMO
Objective@#To understand the vitamin D nutritional status and associated factors of children and adolescents aged 6-18 in Yinchuan, so as to provide theoretical basis for improving the vitamin D malnutrition status of children and adolescents.@*Methods@#Using stratified cluster sampling method, 1 615 children and adolescents from 36 classes in 2 primary schools, junior high schools and high schools were randomly selected from Yinchuan, Ningxia. Venous blood sampling,physical examinations and questionnaires were conducted.@*Results@#The vitamin D deficiency rate and appropriate rate for students were 66.9% and 33.1%, respectively. There was a statistically significant difference in vitamin D deficiency among different age groups(χ2=25.65, P<0.05). The 6-year-old group had the highest(79.2%), followed by the 13-year-old group (76.6%), and the 12-year-old group (75.3%). The results of binary Logistic regression showed that the factors influencing the vitamin D nutritional status of children and adolescents included age(OR=0.95), daily outdoor exercise time(OR=0.49), exclusive breastfeeding (OR=0.63) and mother’s education(OR=0.73, 0.43). The decision tree QUEST and Logistic regression combination model results show that the key factors affecting vitamin D nutrition status include daily outdoor exercise time, age, mother’s education, BMI, and interaction between outdoor exercise time and age, interaction between outdoor exercise time and mother’s education, interaction between age and mother’s education, interaction between exclusive breastfeeding and BMI.@*Conclusion@#The detection rate of vitamin D deficiency in children and adolescents aged 6-18 in Yinchuan is high, factors associated with vitamin D nutritional status includes daily outdoor exercise time, age, mother’s education, BMI, and interaction between outdoor exercise time and age, interaction between outdoor exercise time and mother’s education, interaction between age and mother’s education, interaction between exclusive breastfeeding and BMI.