Relationship between vitamin D level and thyroid peroxidase level in Qinghai Province

Abstract

Objective To investigate the relationship between vitamin D level and thyroid peroxidase (TPO) level in Qinghai Province. Methods In 2015 and 2016, a stratified cluster sampling method was used to select 1 873 people in 9 regions of Qinghai Province, including 935 males and 938 females, the average age was (52.3 ± 10.9) years old, there were 1 040 Han people and 833 Tibetans. Fasting venous blood samples were collected, and vitamin D and TPO levels were detected by a fully automated chemiluminescence immunoassay system, vitamin D and TPO levels were compared in different gender, ethnic group, and altitude populations. Results The vitamin D level was (16.3 ± 7.5) μg/L, and abnormal rate of vitamin D was 89.2% (1 670/1 873); the TPO level [median (quartile)] was 23.8 (16.0 - 35.0) U/ml, and the positive rate of TPO was 26.8% (502/1 873). The vitamin D levels of males and females were (16.9 ± 7.6) and (15.6 ± 7.6) μg/L, respectively, the difference was statistically significant (t = 3.684, P 0.05). The vitamin D levels of the Han people and the Tibetans were (16.2 ± 7.8) and (16.3 ± 7.3) μg/L, respectively, the difference was not statistically significant (t = - 0.110, P > 0.05); the TPO levels were 23.5 (15.7 - 34.8) and 24.0 (16.5 - 35.1) U/ml, respectively, the difference was not statistically significant (Z = - 0.078, P > 0.05). The vitamin D levels of middle-altitude (1 500 - 3 000 m) and high-altitude (> 3 000 m) populations were (16.6 ± 7.7) and (15.8 ± 7.5) μg/L, respectively, and the difference was not statistically significant (t = 2.126, P > 0.05); the TPO levels were 23.4 (16.0 - 33.0) and 24.0 (16.0 - 36.8) U/ml, respectively, the difference was not statistically significant (Z = - 1.296, P > 0.05). There was negative correlations between vitamin D level and TPO level, altitude (r = - 0.150, - 0.052, P 0.05). Conclusions The vitamin D level is negatively correlated with TPO level in Qinghai population. The abnormal rate of vitamin D is high, and vitamin D level of males is higher than that of females. Key words: Serum; Vitamin D; Thyroid peroxidase