Adequate Animal Protein Intake Maintains Normal Thyroid Antibody Levels in Pregnant Women With Mild Iodine Deficiency
Abstract Background: Both of the iodine and animal protein may affect thyroid function. We explored the association between animal protein intake and thyroid antibody status in pregnant women after universal salt iodization.Method: Pregnant women were enrolled by using a multistage, stratified random sampling method. 4,646 eligible participants were interviewed in person with questionnaires physical examination and thyroid antibody test. Results: Only thyrotropin receptor antibodies (TR-Ab) positive rates were different among different animal protein intake groups. The median of urinary iodine concentration (UIC) in thyroid peroxidase antibodies (TPO-Ab) positive groups was higher than the negative group. The median of total protein intake, animal protein intake and UIC in TR-Ab positive group was higher than the negative group. The medians of total protein intake and UIC in TPO-Ab/TG-Ab/TR-Ab positive group were higher than the negative group. The above differences were statistically significant (P < 0.05). The multivariable logistic regression results showed that insufficient iodine had a negative correlation with TPO-Ab positive and TR-Ab positive (P < 0.05). The middle third and top third animal protein intakes served as protective factors for TR-Ab (coefficient = 0.559, 95% CI = 0.415–0.752; coefficient = 0.0.406, 95% CI = 0.266–0.621) and positive TPO-Ab/TR-Ab/TG-Ab (coefficient = 0.817, 95% CI = 0.687–0.971; coefficient = 0.805, 95% CI= 0.672–0.964). Conclusions: Adequate animal protein intake protects against elevated anti-thyroid antibody levels in pregnant women with mild iodine deficiency.