Urinary iodine excretion in a geographically stratified Danish population sample not affected by iodination programmes. A change towards higher values.

The excretion of urinary iodine was studied in a representative population sample from the county of Funen, Denmark, comprising 505 persons between 25-44 years of age, stratified according to geography, age, and sex. Urine samples were collected for 5 h during late afternoon and early evening. The 24-h iodine excretion was estimated on the basis of iodine and creatinine determinations using correlation equations determined in a pilot study of 50 men and women. The iodine excretion was significantly higher in men: 89 micrograms/24 h (median) than in women: 76 micrograms/24 h; the whole population: 85 micrograms/24 h. No significant differences were observed among the age groups studied. The iodine excretion was significantly higher in people living on small islands: 98 micrograms/24 h (median) compared with 84 micrograms/24 h in urban regions and 78 micrograms/24 h in rural districts. Median iodine excretion per gram of creatinine was 58.8 micrograms for the whole sample. The iodine excretion for men was 77% higher than reported in an earlier investigation performed in Funen, 1969, but still lower than internationally recommended (WHO).