Subclinical hypothyroidism (SCH) is not associated with metabolic derangement, cognitive impairment, depression or poor quality of life (QoL) in elderly subjects Young Joo Park a,d , Eun Jung Lee a , You Jin Lee c , Sung Hee Choi a,d , Joon Hyuk Park e , Seok Bum Lee g , Soo Lim a,d , Won Woo Lee f , Hak C. Jang a,d , Bo Youn Cho a , Jong Inn Woo b , Ki Woong Kim b,e, * a Department of Internal Medicine, Seoul National University of College of Medicine, 28 Yeongeon-dong Jongno-gu, Seoul 110-744, Republic of Korea b Department of Psychiatry, Seoul National University of College of Medicine, 28 Yeongeon-dong Jongno-gu, Seoul 110-744, Republic of Korea c Thyroid Cancer Clinic, National Cancer Center, 111 Jungbalsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea d Department of Internal Medicine, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Republic of Korea e Department of Neuropsychiatry, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Republic of Korea f Department of Nuclear Medicine, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Republic of Korea g Department of Psychiatry, Dankook University Hospital, Anseo-dong, San 16-5, Cheonan-si, Chungcheongnam-do 330-715, Republic of Korea 1. Introduction The SCH is affecting about 5% of the general population (Tunbridge et al., 1977). However, this condition is much more prevalent among elderly subjects (Hollowell et al., 2002; O’Leary et al., 2006), and its’ prevalence was estimated to be as high as 20% among women aged at least 60 years (Sawin et al., 1985; Parle et al., 1991; Canaris et al., 2000). SCH may be also very prevalent in Korean elderly as it was reported to be more prevalent in iodine- sufficient areas (Szabolcs et al., 1997). Although the impacts of overt hypothyroidism on metabolic and neuropsychiatric functions are relatively well documented (Klein and Ojamaa, 2001; Uzunlulu et al., 2007), the effects of SCH remain controversial. Several previous studies have reported that SCH was associated with increase of metabolic diseases and neuropsychiatric disorders (Staub et al., 1992; Monzani et al., 1997; Kahaly, 2000; Jensovsky et al., 2002; Kanaya et al., 2002; Imaizumi et al., 2004; Sait Gonen et al., 2004; Knudsen et al., 2005; Walsh et al., 2005; Wilson et al., 2006; Wu et al., 2006; Coban et al., 2007; Singh et al., 2008), but these relationships have not been confirmed by other studies (Van den Beld et al., 2005; Cappola et al., 2006; Jorde et al., 2006; Roberts et al., 2006). Several studies in aged people also have reported no significant association between SCH and neuropsychiatric parameters (Van den Beld et al., 2005; Cappola et al., 2006; Roberts et al., 2006). In the population- based prospective (Leiden 85-Plus study), the thyroid stimulating hormone (TSH) and free thyroxine (fT4) levels were also not associated with depression or cognitive impairment (Gussekloo et al., 2004). These conflicting results may be attributed to potential differences in the characteristics of subjects studied, particularly with regards to the comorbid conditions, and assessment tools used. Although neuropsychiatric disorders such as dementia and major depressive disorder are very common in the elderly population and are known to influence cognition and mood, standardized diagnostic assessments of these conditions were not performed in the previous studies (Monzani et al., 1993; Baldini et al., 1997; Del Ser Quijano et al., 2000; Jensovsky et al., 2002; Gussekloo et al., 2004; Jorde et al., 2006; Roberts et al., 2006). Archives of Gerontology and Geriatrics 50 (2010) e68–e73 ARTICLE INFO Article history: Received 16 February 2009 Received in revised form 24 May 2009 Accepted 26 May 2009 Available online 9 July 2009 Keywords: Subclinical hypothyroidism Neuropsychological function Metabolic dysfunction in elderly ABSTRACT The objective of this study was to examine the relationship between SCH and metabolic and neuropsychiatric derangements in Korean elderly subjects. Nine hundred and eighteen euthyroid and SCH subjects aged 65 years and older were enrolled in the present study. We compared anthropometric (age, sex, blood pressure, body mass index = BMI, body fat contents = BF, waist circumference = WC and hip circumference = HC), laboratory (glucose and lipid profile, renal and liver functions, and C-reactive protein = CRP levels), and neuropsychiatric (neuropsychological function, mood, and QoL) parameters of SCH subjects with those of euthyroid subjects. Associated metabolic disorders of the subjects were also compared between the euthyroid and SCH groups. We could not observe any differences between the SCH group and the euthyroid group with regards to metabolic parameters as well as neuropsychiatric parameters. These findings may suggest that SCH does not appear to be associated with metabolic and neuropsychiatric derangement in elderly subjects. ß 2009 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: Department of Neuropsychiatry, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi- do 463-707, Republic of Korea. Tel.: +82 31 787 7432; fax: +82 31 787 4058. E-mail address: kwkimmd@snu.ac.kr (K.W. Kim). Contents lists available at ScienceDirect Archives of Gerontology and Geriatrics journal homepage: www.elsevier.com/locate/archger 0167-4943/$ – see front matter ß 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.archger.2009.05.015