Quantification of iodine supply: representative data on intake and urinary excretion of iodine from the German population in 1996.

Background/methods: In Germany, iodine deficiency is common. In a representative group of 2,500 Germans (age >13 years), using a specially designed food questionnaire, the iodine intake was calculated. In addition, iodine and creatinine concentrations in spot urine samples were determined in three groups with a possibly increased risk of iodine deficiency (769 conscripts, 886 pairs of mothers and newborns) or future hyperthyroidism (574 adults, age range 50-70 years) from 26 representative regions. In four groups of controls (young and older male and female adults; n = 91), 24-hour urine iodine and creatinine were measured in six diurnal fractions to calculate group- and period-specific factors for the estimation of the 24-hour iodine excretion from data of iodine/creatinine ratio and time of micturition in spot urine samples.

Results: The mean calculated iodine intake (excretion) was 119 microg/day for the group of Germans above 13 years; it was 119 microg/day (125 microg/day) for adults aged 50-70 years, 137 microg/day (125 microg/day) for conscripts, and 162 microg/day for breast-feeding mothers. The median iodine concentration (iodine/creatinine ratio) was 9.4 microg/dl (83 microg/g) in 566 adults aged 50-70 years, 8.3 microg/dl (57 microg/g) in 772 conscripts. and 5.6 microg/dl (156 microg/g) in 739 breast-fed newborns.

Conclusions: Compared to older data, the iodine intake in Germany has increased. In 1996, the meticulously quantified average deficit was about 30% of the recommended iodine intake.