Impact of pregnancy on prevalence of goitre and nodular thyroid disease in women living in a region of borderline sufficient iodine supply.

An interplay of genetic, epigenetic, and environmental factors contributes to thyroid disease. In a cross-sectional study, we aimed to determine the influence of parity in combination with other risk factors on the prevalence of goitre and nodular thyroid disease (NTD) in women living in a region of previous overt iodine deficiency, which experienced a continuous improvement in alimentary iodine supply in the last two decades. Thyroid ultrasonography (7.5 MHz; Merck Thyromobil) was performed by the same investigator in 736 women living in Thuringia and Saxony. Age and BMI were documented and a comprehensive history on pregnancies, family history of thyroid disease, and past or present smoking was obtained. Goitre prevalence was 19.1%. Solitary thyroid nodules were detected in 21.5%, and multiple nodules in 23.8% of women. In a multivariate analysis, neither age nor parity was positively correlated with goitre prevalence and NTD. A significant correlation was detected between BMI and goitre and multinodular disease. Goitre was found in 25.3% of women with a positive family history for thyroid disease, as opposed to 16.1% goitre in women with a negative family history. Neither goitre nor NTD were associated with a history of smoking in the whole study population. Thyroid nodules and/or goitre are present in up to 45% of women in an area of previous overt iodine deficiency. Whereas BMI and family history are positively correlated with the presence of NTD and goitre, no such correlation could be detected for pregnancy and smoking after processing our data with multivariate analyses. Georg Thieme Verlag KG Stuttgart * New York.