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 ＜ 0.01);the TPO levels were 23.8 (16.4-31.0) and 23.8 (15.9-37.6) U/ml,respectively,the difference was not statistically significant (Z =-1.084,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),and no correlation with ethnic group (r =0.003,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.

Objective To investigate the iodine nutritional and thyroid stimulating hormone level of patients with thyroid nodules in different regions of Qinghai Province and analyze the characteristics of changes in different regions.Methods In 2014-2016,thyroid nodules in 9 regions of Qinghai Province (Tibetan areas:Xiewu,Nangqian,Jiegu,Guoluo;non-Tibetan areas:Xining,Huzhu,Menyuan,Minhe,and Ledu) were selected and serum thyroid stimulating hormone (TSH) and urine iodine were measured.Results A total of 553 thyroid nodules,the median urinary iodine (MUIC) was 160.8 μg/L and the median TSH was 2.97 mU/L.The iodine nutritional status was at an appropriate level.Among them,MUIC (206.8 μg/L) in thyroid nodules in the Menyuan area was slightly higher than the appropriate amount,there was a significant difference in MUIC among different region (x2 =47.747,P ＜ 0.05);of TSH in thyroid nudules in the 9 regions,the differences were statistically significant (x2 =34.832,P ＜ 0.05).Non-Tibetan areas were compared with Tibetan areas,there was a significant difference in MUIC (155.6,185.6 μg/L),TSH (2.68,3.45 mU/L,Z =-3.677,-5.410,P ＜ 0.05);Among them,the differences was statistically significant between MUIC (152.8,187.7 μg/L) of women with thyroid nodules (Z =-3.504,P ＜ 0.05);there was a statistically significant difference in TSH levels among men (2.58,3.46 mU/L) and women (2.80,3.44 mU/L) with thyroid nodules (Z =-3.613,-4.040,P ＜ 0.05);there were no significant differences in MUIC levels among thyroid nodules of each age groups (P ＞ 0.05);of the TSH level in 30-and 50-＜ 65 years groups (2.63,3.17;2.25,3.58 mU/L),the differences were statistically significant (Z =-2.892,-3.233,P ＜ 0.05),and other groups were no significant differences (P ＞ 0.05).Conclusion The iodine nutrition of patients with thyroid nodules in these regions of Qinghai Province is generally at an appropriate level,the MUIC and TSH levels in Tibetan areas were lower than those in non-Tibetan areas,and iodine nutrition status and TSH levels should be monitored for key populations.