Association High-Iodine-Containing Seaweed Soup Consumption after Birth and Subclinical Hypothyroidism in Korean Women: Korea National Health and Nutrition Examination Survey IV (2013–2015)

Abstract

Background and Objectives: This study was to investigate the association between the previous history of seaweed intake after childbirth and subclinical hypothyroidism (SCH) occurrence in Korean women based on the latest nationally representative epidemiological survey data, the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI). Materials and Methods: This study used data from KNHANES VI, a cross-sectional, nationally representative survey that comprises a health interview survey, health examination survey, and nutrition survey. Of the initial 22,948 Korean participants enrolled in KNHANES VI, 2,046 women were selected for this analysis. To examine SCH, the thyroid-stimulating hormone (TSH) reference range was defined using a population-based TSH range. Results: Subclinical hypothyroidism was increased in those who consumed seaweed soup after childbirth, but this was not significant (OR 1.3, CI: 0.80-2.13, p=0.293). However, the odd ratio for SCH differed according to the duration of seaweed soup consumption. When seaweed soup was consumed within 1 week after birth, the OR was increased in the crude model (OR 2.61, CI: 1.39-4.89, p=0.002), but this was no longer significant in the adjusted model (OR 1.89, CI: 0.79-4.50). Conclusion: The notable finding from this study is that the previous history of excessive seaweed consumption during post-partum period may not be a risk factor for SCH in Korean women.