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Abstract: Thyroid dysfunction increases the prevalence of metabolic syndrome. However, the link between thyroid hormones and metabolic syndrome remains debatable, and the effect of sex on their relationship is not completely understood. To elucidate the relationship of thyroid hormones with metabolic syndrome and its components according to sex in euthyroid individuals in South Korea. Adult participants who underwent thyroid tests at our institution between January 2015 and December 2018 and had thyroid-stimulating hormone (TSH; 0.270-4.200 μIU/mL) and free thyroxine (FT4; 0.93-1.70 ng/dL) levels in the normal range were included. After correcting for age and body mass index, multiple linear regression was performed to assess the association of TSH and FT4 with metabolic syndrome and its components, and logistic regression was performed to estimate the risk of developing metabolic syndrome and its components according to different thyroid hormone quartiles. We included 12,478 men and 7,575 women in this study. The prevalence of metabolic syndrome was 9.68%. In men, TSH was positively associated with blood pressure and triglycerides, and the odds ratio for high blood pressure and hypertriglyceridemia was approximately 1.3 times higher in the fourth quartile than in the first quartile. FT4 associated positively with waist circumference, and a high odds ratio for abdominal obesity in the fourth quartile was observed in both men (odds ratio [OR], 1.239; 95% confidence interval [CI], 1.045-1.470) and women (OR, 1.302; 95% CI, 1.029-1.649). A negative association was found between FT4 and triglycerides, and concurrently, the odds ratios for hypertriglyceridemia were lower in the fourth quartile in both men (OR, 0.692; 95% CI, 0.619-0.774) and women (OR: 0.641; 95% CI: 0.512-0.803). In addition, a higher odds ratio for high blood pressure was observed in the fourth quartiles of FT4 and TSH in women. However, there was no association between TSH and FT4 levels and the onset of metabolic syndrome in either of the sexes. Serum TSH and FT4 levels were associated with different metabolic syndrome components in men and women, but there was no association with the onset of metabolic syndrome., Competing Interests: The authors have no conflict of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Ji-Eun Oh,1 Sung Ryul Yu,2 Jung-Yoon Yoo,3,&ast; Kyung-A Shin4,&ast; 1Department of Biomedical Laboratory Science, Far East University, Eumseong, Republic of Korea; 2Department of Clinical Laboratory Science, Semyung University, Jecheon, Republic of Korea; 3Department of Biomedical Laboratory Science, Yonsei University MIRAE Campus, Wonju-si, Republic of Korea; 4Department of Clinical Laboratory Science, Shinsung University, Dangjin, Republic of Korea&ast;These authors contributed equally to this workCorrespondence: Kyung-A Shin, Department of Clinical Laboratory Science, Shinsung University, Daehak-ro 1, Jeongmi-myeon, Dangjin, Chungnam, 31801, Republic of Korea, Tel +82-41-350-1408, Fax +82-41-350-1045, Email mobitz2@hanmail.net Jung-Yoon Yoo, Department of Biomedical Laboratory Science, Yonsei University MIRAE Campus, 1 Yonseidae-gil, Wonju-si, Gangwon-do, 26493, Republic of Korea, Tel +82-33-760-2861, Fax +82-33-760-2561, Email jy_yoo@yonsei.ac.krPurpose: Visceral fat accumulation can negatively affect uric acid metabolism in healthy adults. The hypertriglyceridemic-waist (HTGW) phenotype is a predictor of diabetes and cardiometabolic risk. This study aimed to investigate the association between the HTGW phenotype and asymptomatic hyperuricemia in Korean adults.Patients and Methods: The study included 23,240 adults, aged 20– 80 years who underwent comprehensive health examinations at a general hospital in Gyeonggi Province, Korea, from January 2020 to December 2022. The HTGW phenotype was defined as the simultaneous presence of elevated serum triglyceride (TG) levels and increased waist circumference (WC). The diagnostic capability of the HTGW phenotype for hyperuricemia and its association with the condition were assessed using the receiver operating characteristic (ROC) curve and logistic regression analysis.Results: The prevalence of hyperuricemia in the HTGW phenotype was 3.44 times higher than that in the normal TG normal waist (NTNW) phenotype. Compared with those in the NTNW group, the hazard ratios for developing hyperuricemia in the HTGW group were 2.887 (2.566– 3.249, P < 0.001) for men and 7.341 (5.139– 10.487, P < 0.001) for women, and these values remained significant after adjusting for potential confounders. The stratified analysis revealed that the HTGW phenotype, coupled with diabetes, had the highest probability of developing asymptomatic hyperuricemia (2.55 times). ROC curve analysis revealed that the area under the curve values of the WC&ast;TG index for hyperuricemia diagnosis were 0.702, 0.627, and 0.685 for all participants, men, and women, respectively.Conclusion: Among Korean adults, the HTGW phenotype was closely related to hyperuricemia in both men and women and showed a particularly strong association in patients with diabetes. It may be used in combination with an indicator that can complement its accuracy for identifying individuals at high risk of hyperuricemia.Keywords: triglyceride, abdominal obesity, uric acid, metabolic syndrome

Sung Ryul Yu,1 Kyung-A Shin2 1Department of Clinical Laboratory Science, Semyung University, Jaecheon, Republic of Korea; 2Department of Clinical Laboratory Science, Shinsung University, Dangjin, Republic of KoreaCorrespondence: Kyung-A Shin, Department of Clinical Laboratory Science, Shinsung University, Daehak-ro 1, Jeongmi-myeon, Dangjin, Chungnam, 31801, Republic of Korea, Tel +82-41-350-1408, Fax +82-41-350-1045, Email mobitz2@hanmail.netPurpose: The visceral adiposity index (VAI) and lipid accumulation product (LAP) are useful for assessing visceral obesity. However, these indices were developed for Caucasians, and it is necessary to confirm whether the VAI and LAP are appropriate indicators for identifying obesity phenotypes in Asians. This study investigated whether the VAI and LAP are effective indicators for diagnosing four obesity phenotypes in South Korean adults.Patients and Methods: This cross-sectional study enrolled 23,310 adult participants (age ≥ 20 years) who had undergone a health checkup at a general hospital in Gyeonggi-do, South Korea from January 2017 to December 2020. VAI and LAP were calculated based on the presented mathematical model according to sex. According to the metabolic health status and presence or absence of obesity, the obesity phenotypes were classified into 4 groups: metabolically healthy non-obese (N=14,240, 61.1%), metabolically unhealthy non-obese (N=477, 2.0%), metabolically healthy obese (MHO; N=6796, 29.2%), and metabolically unhealthy obesity (MUO; N=1797, 7.7%).Results: The receiver operating characteristics curve analysis showed VAI best predicted MUO among the four obesity phenotypes, whereas the LAP showed excellent discriminating ability for the MUO group (area under the curve 0.877, 0.849, and 0.921 and 0.923, 0.907, and 0.954 for all participants, men, and women, respectively). The optimal VAI cutoff values for identifying the MUO group were 1.83 in men and 1.58 in women, and the optimal cutoff values for the LAP were 41.45 in men and 23.83 in women, with a higher value for men. After adjusting for potential confounding factors, the VAI and LAP were associated with an increased risk in the MHO and MUO groups among the obesity phenotypes in both sexes.Conclusion: In South Korean adults, the VAI and LAP are closely related to the MUO phenotype in both sexes and are effective indices for predicting the MUO phenotype.Keywords: lipid accumulation product, visceral adiposity index, metabolic syndrome, obesity phenotype

Kyung-A Shin,1 Young-Joo Kim2 1Department of Clinical Laboratory Science, Shinsung University, Chungnam, Republic of Korea; 2Department of Exercise Rehabilitation Welfare Soojung Campus, Sungshin University, Seoul, Republic of KoreaCorrespondence: Young-Joo KimDepartment of Exercise Rehabilitation Welfare Soojung Campus, Sungshin University, 2, Bomun-ro 34da-gil, Seoungbuk-gu, Seoul 02844, South KoreaTel/Fax + 822-920-7942Email kyj87@sungshin.ac.krBackground: Obesity markers, the lipid accumulation product (LAP), visceral adiposity index (VAI), triglyceride and glucose (TyG) index, and waist-to-height ratio (WHtR) are useful for assessing the risk of obesity-related cardiovascular disease. However, no previous study has assessed the usefulness of these four indices as predictors of metabolic syndrome among middle-aged and older Korean populations.Purpose: To investigate the usefulness of LAP, VAI, TyG index, and WHtR as predictors of metabolic syndrome in middle-aged and older Korean populations.Methods: This study included 15,490 male and female adults aged 40 years or older who underwent a medical check-up in a general hospital located in a Korean metropolitan area between January 2015 and December 2016. The diagnostic criteria for metabolic syndrome suggested by the American Heart Association/National Heart Lung and Blood Institute were used. LAP, VAI, and TyG index were computed based on the suggested mathematical models. WHtR was computed by dividing waist circumference by height. The independent sample t-test, one-way analysis of variance, Scheffe test, chi-square test, Pearson’s correlation analysis, and logistic regression were used to analyze the data.Results: LAP, VAI, TyG index, and WHtR were significantly related to metabolic syndrome in both sexes. Receiver operating characteristic curve analysis showed the following optimal cutoffs for LAP, VAI, TyG index, and WHtR: 33.97, 1.84, 8.81, and 0.51, respectively. After adjusting for latent confounding variables (age, systolic blood pressure, diastolic blood pressure, and waist circumference), LAP, VAI, TyG index, and WHtR were significantly correlated with metabolic syndrome. Area under the curve (AUC) values based on ROC curves showed that LAP, VAI, TyG index, and WHtR were reliable predictors of metabolic syndrome. LAP had the greatest AUC, suggesting that it was a more useful predictor than the other markers (AUC=0.917, 95% confidence interval: 0.913–0.922).Conclusion: LAP, VAI, TyG index, and WHtR are useful predictors of metabolic syndrome in middle-aged and older Koreans, but LAP had the greatest diagnostic accuracy.Keywords: metabolic syndrome, LAP, VAI, TyG index, WHtR