Background/Aims: Iodine plays a key role in thyroid functioning. Poor thyroid functioning has been linked to cognitive decline. This study aims to investigate whether iodine status is associated with cognitive functioning and mood state in a sample of healthy older Australians.
Methods:Eighty-four men and women aged 60-95 years with normal cognitive function participated in this cross-sectional study. Three repeated fasting urine samples were collected a week apart to assess median urinary iodine concentration for the group. Usual dietary iodine intake was measured using an iodine-specific food frequency questionnaire and three repeated 24-hour dietary recalls while nutritional status was assessed using the Mini Nutritional Assessment (MNA). Cognitive function was assessed by the CogState battery of tests and the Rey Auditory Verbal Learning Task (RAVLT) and mood state determined by the Geriatric Depression Scale (GDS). Associations between iodine status and cognitive tests were assessed by Wilcoxon signed-rank, Pearson, and Spearman rank correlation tests.
Results: Median urinary iodine concentration (MUIC) indicated mild iodine deficiency (71μg/L; IQR = 55 – 102 μg/L).Iodine status was not significantly associated with any domains of cognitive function. Memory was negatively correlated with mood state (r = -0.375; P<0.05) and positively associated with nutritional status (r = 0.235; P<0.05).
Conclusions:Iodine status is not associated with cognitive functioning in a sample of older people with mild iodine deficiency. It remains to be seen whether more severe iodine deficiency in this age group would have a beneficial impact on domains of attention, visuospatial processing, and executive processing.
Funding source(s): N/A