Objective: To investigate vitamin D levels among primary and middle school students in Xicheng District, Beijing Municipality, and to examine the association of vitamin D levels with hemoglobin (Hb) and serum ferritin (SF) levels, so as to provide insights into the prevention of anemia among primary and middle school students. Methods: The first, third and fifth grade primary school students and the first grade junior high school students were sampled from Xicheng District in 2019, using the multistage stratified cluster sampling method, and students' gender, age, height, weight and Hb levels were collected. The 25-hydroxyvitamin D [25-( OH )D] was measured using electrochemiluminescence assay, and SF was detected using immunoturbidimetry. The vitamin D deficiency was determined according to the American College of Endocrinology guidelines. The associations of 25-( OH) D levels with Hb and SF levels were examined using Pearson correlation analysis and Spearman rank correlation analysis. Results: Totally 403 primary and junior high school students were investigated, including 196 boys ( 48.64% ) and 207 girls ( 51.36% ). There were 179, 114 and 110 students at ages of 6 to 8 years ( 44.41% ), 9 to 11 years ( 28.29% ) and 12 to 13 years ( 27.30% ), respectively. The mean 25-( OH )D level was ( 14.80±5.96 ) ng/mL among the study students, and there were 90 students ( 22.33% ) with severe vitamin D deficiency, 243 students ( 60.30% ) with vitamin D deficiency, 63 students ( 15.63% ) with vitamin D inadequacy and 7 students ( 1.74% ) with vitamin D sufficiency. The mean Hb level was ( 136.28±8.33 ) g/L and the median SF level (interquartile range) was 56.80 (14.36) ng/mL among the study students, respectively. The 25-( OH )D level positively correlated with Hb ( r=0.364, P<0.001 ) and SF levels ( rs=0.374, P<0.001 ), and after adjustment for age and body mass index, the 25-( OH )D still correlated positively with Hb ( r=0.157, P=0.048 ) and SF levels ( rs=0.174, P=0.022 ) . Conclusions Vitamin D deficiency is prevalent among primary and middle school students in Xicheng District, and the 25-(OH)-D levels correlate positively with Hb and SF levels. 25-( OH )-D deficiency may contribute to the development of anemia.
vitamin D ; hemoglobin ; serum ferritin ; primary and middle school student