Association between Sleep Duration and Subclinical Thyroid Dysfunction Based on Nationally Representative Data

Abstract

Background: Sleep duration is an identified risk factor for adverse health outcomes. As the endocrine system is closely intertwined with sleep duration and quality, the association between endocrine dysfunction and sleep has been evaluated. Thyroid function, particularly that related to thyrotropin (TSH), is also known to be influenced by the sleep/awake status and circadian rhythm. Additionally, a link between sleep duration and autoimmunity, which is a common cause of thyroid dysfunction, has been suggested; however, depending on the sleep deprivation method used in studies, the effects of sleep on thyroid function vary. The relationship between subclinical thyroid dysfunction and sleep duration is poorly documented. Thus, to elucidate the impact of sleep on thyroid function, we investigated the association of subclinical thyroid dysfunction with sleep duration using representative data from the sixth Korea National Health and Nutrition Examination Survey, conducted from 2013 to 2015. Methods: In all, 4945 participants (2543 male and 2402 female) were included after excluding subjects using the following criteria: <19 years of age, free T4 level outside the normal range, history of thyroid disease, or incomplete data. The population was classified into three groups: short sleeper (<7 h/day), normal sleeper (7–8 h/day), and long sleeper (>8 h/day). The odds ratio (OR) for subclinical hypothyroidism or hyperthyroidism according to sleep duration was evaluated. Results: The short, normal, and long sleeper groups consisted of 2097, 2514, and 334 subjects, respectively. On multiple logistic regression analysis, compared to normal sleepers, short sleepers showed a significantly increased risk of subclinical hyperthyroidism (OR 1.37, 95% confidential interval (CI) 1.02–1.84, p = 0.036), while the risk of subclinical hypothyroidism in short sleepers was not elevated. Comparing long sleepers to normal sleepers, the OR for subclinical hyperthyroidism and hypothyroidism was 1.79 (95% CI 1.12–2.86, p = 0.015) and 1.91 (95% CI 1.03–3.53, p = 0.039), respectively. Conclusions: Both shorter and longer sleep durations were associated with an increase in the risk of subclinical thyroid dysfunction compared to the optimal sleep duration. This analysis of representative population data shows that sleep duration could intertwine with thyroid function resulting in increased risk of subclinical thyroid dysfunction.

Sex Difference in the Association between Sleep Duration and Thyroid Disease among South Korean Adults

“…In previous studies, subclinical thyroid disease was associated with short and long sleep durations [8]. Based on this study, short sleep was increased in hyperthyroidism; however, the same was not observed in hypothyroidism.…”

Novel genetic variants associated with brain functional networks in 18,445 adults from the UK Biobank

“…A previous study has also linked reductions in intrinsic functional connectivity in the somatomotor network to participants with subclinical hypothyroidism compared to controls 27 . Interestingly, studies have also found subclinical thyroid dysfunction to be associated with sleep quality 28,29 . Considering that we also observed phenotypic correlations between sleep duration, insomnia and graph theory measures, it is possible that PAX8 variants may play a role in the regulation of genes associated with functional brain network properties and sleep.…”

Serum 25-hydroxyvitamin D and Metabolic Parameters in Healthy Korean Adults: Korean National Health and Nutrition Examination Survey VI

“…The statistical analysis of KNHANES has been reported in previous studies. 15,[17][18][19][20] https://doi.org/10.2147/IJGM.S329243…”