[Urinary iodine concentration in adult patients with type 1 diabetes mellitus]

In patients with type 1 and 2 diabetes mellitus only rare data concerning the status of iodine supplementation and impact of possible iodine deficiency is available.

To get basic information about (a) state of supply with iodine in patients with type 1 diabetes mellitus (DM1T), (b) the difference from non-diabetic population, (c) possible association of iodine saturation with some clinical and laboratory features of the diabetic syndrome, including the state of thyroid gland.

We examined 54 men and 51 women treated with DM1T in a cross-sectional study. Age: median 42 years (25th quartil 31, 75th quartil 55), DM1T duration: 18 years (13, 23), BMI: 25.9 (23.3, 29.7), HbA1c: 61 mmol/mol (51, 71), creatinine: 71 μmol/l (61, 83), micro-albuminuria 4.3 μg/min (1.9, 11.8), TSH: 1.77 mIU/l (1.12, 2.80). The iodine saturation was evaluated using iodine concentration in a sample of first morning urine.

Urinary iodine concentration in the whole group: median 152 μg/l, 25th quartile 117 μg/l, 75th quartile 219 μg/l. More than 50 % of the urinary iodine samples fell within range of optimal saturation (100-200 μg/l), 13 % within insufficient saturation (< 100 μg/l), 35 % of the samples showed increased saturation (> 200 μg/l), in which 2/3 were men. Using multiple regression analysis we found significant positive association of urinary iodine concentration and male gender, body weight, stature, and serum creatinine. No relation between urinary iodine and clinical and laboratory features of the diabetic syndrome was found.

Iodine saturation in examined patients with DM1T was in accordance with ICCIDD (WHO) requirements for optimal/good saturation in non-diabetic population. With respect to the chosen normal urinary iodine concentration, eg. 100, resp. 150 μg/l the features of diabetic syndrome were not different. The question whether other factors than general measures taken in the past for solution of the iodine deficiency in the Czech Republic are involved in good level of iodine saturation in patients with DM1T should be addressed in further investigations comprising larger cohorts of patients.Key words: diabetes mellitus - urinary iodine concentration.