Association of Iodine-Related Knowledge, Attitudes, and Behaviours with Urinary Iodine Excretion in Pregnant Women with Mild Iodine Deficiency

Abstract

Background: China’s universal salt-iodization program has all but eliminated iodine deficiency disorders. Concern has shifted to mild iodine deficiency. Our study examined factors with the potential to predict mild iodine deficiency in pregnant women. Methods: A total of 2 400 pregnant women were enrolled using a multistage, stratified, random-sampling method. Data were collected through face-to-face interviews, a standardized questionnaire, an iodine-related knowledge questionnaire, urine samples, and household cooking salt samples. Results: The median urinary iodine concentration (MUIC) was 148.0 μg/L for all participants, and 155.0 μg/L, 151.0 μg/L, and 139.6 μg/L in the first, second, and third trimesters, respectively. The third trimester’s MUIC was significantly lower than that of the first trimester, and the usage rates of iodized salt and qualified-iodized salt were 71.5% and 59.4%, respectively. Iodine-related knowledge was significantly different between the high and low UIC groups. Participants’ MUIC increased significantly with increases in iodine-related knowledge. The third trimester was a significant risk factor for high UIC, whereas abundant iodine-related knowledge, study the dietary knowledge urgently, and consumption of iodine-rich food within 48 hours of a urine iodine test were significant protective factors for high UIC (P<0.05). Conclusions: Iodine levels are adequate among pregnant women in Shanghai during the first and second trimesters, but insufficient in the third trimester. The use of iodized cooking salt does not determine the iodine status of pregnant women. Abundant iodine-related knowledge is important for pregnant women in the third trimester to maintain adequate urinary iodine.

Relationship between iodine knowledge and dietary iodine intake in pregnant and lactating women: a cross-sectional study

“…According to the lower limit of appropriate iodine nutritional status for pregnant and lactating women (MUIC < 150 µg /L and 100 µg /L, respectively), as recommended by the WHO, women in our study were in an appropriate iodine nutritional status and the results about pregnant women were similar to those reported in a previous surveillance study conducted in Xinjiang (18,25) . There were differences in the MUICs among pregnant women in different trimesters, with significantly higher MUICs in early than late pregnancy, which is consistent with the results of the Shanghai (26) , Chongqing (27) , and Australian studies (28) . This finding may be related to the increased demand for THs by the fetus.…”

“…During the first 20 weeks of pregnancy, the fetus is completely dependent on the maternal supply of THs. When the fetal thyroid gland matures, maternal iodine is transferred to the fetus, increasing the maternal demand for iodine (3,26) . Pregnant women in late pregnancy are advised to increase the intake of iodine-rich foods.…”

“…Contrary to expectations, UIC was not shown to be associated with iodine knowledge scores in pregnant and lactating women, which is consistent with the results of a Norwegian study (13) . In a study of pregnant women in Shanghai (26) and a study of 2642 pregnant women in Zhejiang Province, China (17) , the MUIC was shown to increase significantly with increasing iodine knowledge scores. There was no variability in iodine knowledge scores among other personal characteristics among pregnant and lactating women.…”