Factors Associated with Thyroid Disorders and Iodine Adequacy in Pregnant Saudi Women

Abstract

Little is known about iodine adequacy and gestational thyroid disorders (GTDs) in Saudi Arabia. This study measured the rates of GTDs and iodine adequacy in 810 healthy Saudi women. Concentrations of serum thyroid hormones and 24-h urine iodine (24-h UIC), and GTDs were diagnosed according to the American Thyroid Association guidelines. Dietary and socioeconomic data to determine factors associated with GTDs and iodine insufficiency were collected. GTDs were detected in 265 women (32.7%) as follows: subclinical (SCH; 20.2%) and overt (OH; 5.8%) hypothyroidism, isolated hypothyroxinemia (ISH; 4.7%) and hyperthyroidism (2%). The SCH (109.2 μg/L; IQR: 77.2–149.7), OH (95.3 μg/L; IQR: 74.3–130.5) and ISH (107.3 μg/L; IQR: 65.5–133.1) groups had median 24-h UIC below the WHO recommended limit, whereas the euthyroid (191.4 μg/L; IQR: 170.03–219.8) and hyperthyroid (159.5 μg/L; IQR: 152.9–238.3) groups were iodine sufficient. Numbers of pregnancies, less education, not consuming iodized salt and not using iodine supplements increased risk of hypothyroidism and ISH. Contrariwise, interval ≥ 3 years from last pregnancy and higher 24-h UIC decreased odds of hypothyroidism and ISH. Moreover, dairy products and egg consumption were markedly lower in all GTD groups. Dairy products and seafood consumption correlated independently with 24-h UIC of the study participants, whereas consuming yogurt, eggs, redfish and shellfish protected against GTDs. In conclusion, GTDs appear to be prevalent in pregnant Saudi women and the hypothyroid and hypothyroxinemia groups had iodine insufficiency. However, consuming iodized salt, iodine supplements, dairy products, seafoods and eggs may protect against GTDs.