Correlation Between Serum 25-hydroxyvitamin D Levels And Hypothyroidism In Women During Early Pregnancy

Purpose:To observe the level of 25(OH)D and thyroid related indicators in early pregnancy(≤12 weeks) women in Qingdao. To explore the relationship between 25(OH)D nutritional status and hypothyroidism.Methods: 129 pregnant women from maternity clinic for regular antenatal examination in Qingdao university hospital during 2014.7 ~ 2014.12 were recuited. The serum 25(OH)D,thyrotropin(TSH),Free thyroxine(FT4),free triiodothyronine(FT3),thyroid peroxidase antibody(TPOAb)levels were determined in all subjects.(1)We obtain 25(OH)D level distribution for the women in early pregnancy and comparison of serum 25(OH) D levels of 8 weeks, 12 weeks of gestation according to the evaluation standard of nutritional status of vitamin D which was made by US endocrine society in 2011;(2) Based on the gestational age-specific reference intervals,we screening prevalences of hypothyroidism;(3)Analying the assosiation between the 25(OH)D and TSH, FT4, FT3,TPOAb,hypothyroidism;(4)The samples were divided into two groups according to the season : sunny season group(July-October) and lack of sunshine season group(November-December).Comparing the differences of serum 25(OH)D in different seasons groups.Results:(1) The 25(OH)D was range between 5.35 to 44.33 ng/m L in early pregnancy women, the lower quartile, the median and quartiles were 9.93ng/m L, 12.96ng/m L, and 15.43ng/m L respectively. The frequency distribution ratio of Vitamin D deficiency, lack of vitamin D, vitamin D sufficient were 89.15%,9.3% and 1.55%.(2) There were no significant difference between different gestation weeks(8 weeks, 12 weeks) of the 25(OH)D level and frequency distribution(all P >0.05).(3) The prevalence of clinical hypothyroidism, subclinical hypothyroidism, low T4 levels, were 0.78%,4.65%,6.20% respectively, the prevalence between different gestational weeks had no significant differences(all P > 0.05).(4) The TPOAb total positive rate was 10.85%.The TPOAb positive rate in subclinical hypothyroidism group is significantly higher than normal thyroid function group in 8 weeks of gestation(P < 0.05), and the prevalence of subclinical hypothyroidism in TPOAb positive group was higher than TPOAb negative group(P<0.05).(5)The TSH, FT4,FT3 and prevalence of hypothyroidism had no significant difference between different nutritional status of 25(OH)D group(all P > 0.05).(6) There were no significant difference between total hypothyroidism group,hypothyroidism between groups and normal thyroid function group of the 25(OH) D level and frequency distribution(all P > 0.05).(7) There was no significant correlation between 25(OH)D and TSH, FT4, TPOAb(all P>0.05).But there was significant correlation between 25(OH)D and FT3 in linear regression analysis(P < 0.05). And There was no significant correlation between 25(OH)D and FT3 in multiple linear regression analysis(P > 0.05).(8)The serum 25(OH) D levels in sunny season group is significantly higher than lack of sunshine season group. The difference was statistically significant.(P < 0.05).Conclusion:(1)The deficiency of 25(OH)D was common in early pregnancy women in Qingdao area;(2)25(OH)D level have no obvious correlation with hypothyroidism;(3) Season have effects on the 25(OH)D concentrations in early pregnancy women;(4) TPOAb positive is a risk factor for subclinical hypothyroidism during early pregnancy.