Analysis of selenium intake score and its affecting factors in young adults

Autoimmune thyroid disease (ATD) is the most common organ-specific autoimmune disease clinically manifested as thyroid dysfunction. The two most common ATDs are Graves' Disease and Hashimoto Thyroiditis. It is estimated that 70-80% of the development of ATDs is determined by genetic factors and 20-30% by environmental factors. Selenium is a trace mineral found naturally in foods, and most of human selenium pool is stored in the thyroid gland (0.2–2 μg Selenium per 1 tissue gram). Dietary selenium deficiency is thought to contribute to the development of ATDs. We aimed to evaluate selenium intake affecting factors. All 89 subjects filled a food frequency questionnaire (FFQ) and gave samples for biochemical tests. We analyzed selenium intake and calculated Selenium Intake Score (SIS). Results are shown as median (Interquartile range). Median age 30.5 years (26.0-46.0). There was a trend of higher age associated with higher SIS: rho=0.18, p=0.098. Subjects aged 30 and above had significantly higher SIS as compared to younger subjects from pork (p=0.003), fish (p=0.021), rye bread (p=0.023) and caffeine drinks (p=0.033). The total number of smokers was 31 (35%), and this group had a significantly lower SIS than non-smokers (p=0.007). Higher number of cigarette pack-years correlated with lower SIS: rho=-0.285, p=0.007. Non-smokers had showed significantly higher SIS as compared to current smokers from these food groups: curd (p=0.009), cheese (p=0.012), fish/shrimp (p<0.005), rye bread (p=0.001), vegetables (p=0.043), fruit (p=0.022) and Brazil nuts (p=0.004). Food frequency questionnaire revealed higher selenium intake in non-smokers in comparison to smokers, particularly, with lower SIS seen in participants with higher numbers of pack-years. In addition, an increase in SIS with age (above 30 years) was observed- pork, fish, and rye bread were the main contributing products for higher SIS.This study was supported by the Latvian Council of Science (Grant No: lzp-2018/2-0059).