Association between urinary sodium levels and iodine status in Korea
- Author:
Jonghwa AHN
1
;
Jang Ho LEE
;
Jiwoo LEE
;
Ji Yeon BAEK
;
Eyun SONG
;
Hye-Seon OH
;
Mijin KIM
;
Suyeon PARK
;
Min Ji JEON
;
Tae Yong KIM
;
Won Bae KIM
;
Young Kee SHONG
;
Won Gu KIM
Author Information
- Publication Type:2
- From:The Korean Journal of Internal Medicine 2020;35(2):392-399
- CountryRepublic of Korea
- Language:English
-
Abstract:
Background/Aims:To evaluate the association between the urinary sodium concentration and iodine status in different age groups in Korea.
Methods:This nationwide, population-based, cross-sectional study used data from the Korean National Health and Nutrition Examination Survey (VI 2-3, 2014 to 2015). We included 3,645 subjects aged 10 to 75 years with normal kidney function and without a history of thyroid disease. Adequate iodine intake was defined as a urinary iodine/creatinine (I/Cr) ratio of 85 to 220 µg/g. The urinary sodium/ creatinine (Na/Cr) ratios were classified as low (< 47 mmol/g), intermediate (47 to 114 mmol/g), or high (> 114 mmol/g).
Results:The median urinary iodine concentration (UIC) was 292 µg/L (interquartile range [IQR], 157 to 672), and the median urinary I/Cr ratio was 195 µg/g (IQR, 104 to 478). Iodine deficiency (< 100 µg/L) and iodine excess (> 300 µg/L) were observed in 11.3% and 49.0% of subjects, respectively. The UIC was significantly associated with the urinary sodium concentration, and the urinary I/Cr ratio was significantly correlated with the urinary Na/Cr ratio (both p < 0.001). The distributions of UIC, urinary I/Cr ratio, and Na/Cr ratio varied among age groups. Low urinary I/Cr and Na/Cr ratios were most common in young adults (age, 19 to 29 years), while high urinary I/Cr and Na/Cr ratios were most common in elderly people (age, 60 to 75 years).
Conclusions:Iodine intake was significantly associated with sodium intake in the Korean population. Our study suggested that an adequately low salt intake might be helpful for preventing iodine excess in Korea.
