Determining the relationship between dietary iodine intake, urinary iodine excretion and thyroid functions in people with TYPE 2 diabetes mellitus

This study was conducted to determine the relationship between dietary iodine intake, urinary iodine excretion and thyroid functions in people with type 2 diabetes mellitus (T2DM). The study was planned on 49 people with T2DM and 49 heathy people aged 18-64 years at Ankara Atatürk Eğitim ve Araştırma Hospital Balgat Endotem District Polyclinic on between March-June 2017. A questionnaire was applied to patients including demografic characteristics, information about disease, nutritional behaviour and physical activity status. The nutritional status of the patients was determined by a one day 24-h dietary recall and food-frequency questionnaire rich in iodine. Anthropometric measurements, body composition and some biochemical parameters of the patients were also determined. The median age of the T2DM patients was 56.0 [53.0-61.0] years and median age of people in control group was 50.0 [49.0-55.0] years. It was determined that 21 people (%42.9) from T2DM patients were male and 28 people (%57.1) were female and from control group 18 people (%36.7) were male, 31 people (%63.3) were female. According to findings %95.9 of diabetes patients, %98.0 of people in control group used iodised salt. There was no significant difference in terms of plasma TSH, T3, T4, TgAb, and TPOAb values between groups (p>0.05). Iodine intake according to one day 24-h dietary recall in T2DM patients (94.8 [76.0-112.0] µg) was significantly lower than people in control group (137.1 [123.1-165.4] µg) (p<0.05). Similarly, it was determined that iodine intake according to food-frequency questionnaire rich in iodine in T2DM patients (93.1 [84.4-113.9] µg) was significantly lower than people in control group (140.2 [125.1-166.1] µg) (p<0.05). It was stated that iodised salt consumption in T2DM patients (5.75±2.12 g) was significantly lower than people in control group (8.02±2.76 g) (p<0.05). When the urinary iodine excretion was examined urinary iodine excretion in people with T2DM was 49.6 [36.3-57.0] µg/L and in control group it was 91.5 [76.1-121.2] µg/L, a significant difference was determined between groups (p<0.05). According to these results, in people with diabetes %49.0 of them had moderate iodine deficiency while in control group there was no one with moderate iodine deficiency. In people with diabetes %38.8 of them and in control group %55.1 of them had mild iodine deficiency and there was a significant difference bewteen groups (p<0.05). There wasn't a significant relationship in terms of urinary iodine excretion and thyroid function tests such as plasma T3, T4, TSH, TgAb, TPOAb between groups (p>0.05). A positive relationship was observed in diabetes (r=0.505, p=0.000) and control group (r=0.466, p=0.001) between urinary iodine excretion and iodine intake according to one day 24-h dietary recall. Similarly a positive relationship was determined in diabetes (r=0.458, p=0.001) and control group (r=0.522, p=0.000) between urinary iodine excretion and iodine intake according to food-frequency questionnaire rich in iodine. There was a positive relationship between urinary iodine excretion in T2DM patients and daily water consumption amount (r=0.336, p=0.018). A positive relationship was observed urinary iodine excretion and iodised salt consumption amount according to 24-h dietary recall in diabetes group (r=0.758, p=0.000) and control group (r=0.374, p=0.008). Iodine deficiency was observed in both groups and yet urinary iodine excretion in diabetes group was significantly lower than control group. It is for this reason, while planning T2DM patients' diet, considering iodine deficiency risk for T2DM patients is thought to be essential in order to improve patients' life quality.