Urinary sodium and iodine concentrations among Belgian adults: results from the first national Health Examination Survey

Background/objectives Iodine deficiency and excessive salt intakes have adverse health consequences. The objective was to measure sodium and iodine concentrations in urine spot samples among a representative sample of Belgian adults and compare those to World Health Organization (WHO) recommendations. Subjects/methods Spot urine samples were collected in 2018 from participants of the Belgian Health Examination Survey. Iodine and sodium concentrations were measured by inductively coupled plasma mass spectrometry and ion selective electrodes respectively. Tanaka and INTERSALT equations were used to predict 24-h urinary sodium excretion using sodium and creatinine concentration in spot samples, sex, and measured height and weight. Results Median urinary iodine concentration (UIC) among adults ( n = 1092) was 93.6 µg/L, indicating mild iodine deficiency according to WHO thresholds. Median UIC among participants who reported thyroid problems over the last year was significantly higher than among those who did not report thyroid problems (104.1 µg/L versus UIC = 92.2 µg/L, p