Geographic location and ethnicity comprehensively influenced vitamin D status in college students: a cross-section study from China

Abstract

Background Vitamin D plays an important role in the health of adolescents, whereas vitamin D status of Chinese college students was seldom studied in China. To explore the vitamin D status and its relationship with ethnicity and geographic location in Chinese college students. Methods The freshmen were taken a physical examination by trained medical personnel after they reported to university. Demographic information including age, gender, ethnicity, region of original residence was collected using a questionnaire survey. Serum 25(OH)D3 concentrations were measured using a liquid chromatograph mass spectrometer. Multiple regression analyses were used to explore the factors that influence serum 25(OH)D3 levels. Results Totally 3220 freshmen who came from 26 provinces, autonomous districts or municipalities were recruited, with a mean age of 18.75 ± 1.18 years and 70.2% of them were female. The mean serum 25(OH)D3 levels were 18.51 ± 6.54 ng/mL, and the proportion of vitamin D deficiency (< 20 ng/mL) and insufficiency (20 ~ < 30 ng/mL) was 64.4% and 30.2%, respectively. The combined proportion of vitamin D deficiency and insufficiency was increased with the latitude increased. Miao had the highest serum 25(OH)D3 levels, whereas Kazak ethnic had the lowest (22.51 ng/mL vs. 13.94 ng/mL) among different ethnic groups. Female students, students from city, Uighur and Kazak ethnic, residing in high latitude was significantly associated with lower serum 25(OH)D3 levels (P < 0.05). Conclusions Vitamin D deficiency is an important health problem in Chinese college students. Sunlight activities, dietary and life-style intervention for college students according to geographic location and ethnicities should be considered.