Cognitive function and associated factors among older people in Taiwan: Age and sex differences Cheng-Lun Li a , Hui-Chuan Hsu a,b, * a Department of Health Care Administration, Research Center on Health Policy and Management, Asia University, No. 500, Lioufeng Road, Wufeng, Taichung 41354, Taiwan b Department of Medical Research, China Medical University Hospital, China Medical University 1. Introduction Cognitive impairment has significant negative impacts for older people. Dementia or severe cognitive impairment not only affects the quality of life for older people but also causes a heavy burden for their families and increases medical costs for society. Only when the cognitive impairment is mild is it possible to prevent worsening of the progression (Weimer & Sager, 2009). Previous studies have explored the risk factors for cognitive function impairment and the incidence of dementia (Burton, Campbell, Jordan, Strauss, & Mallen, 2013; Loef & Walach, 2013; Teixeira et al., 2012; Wang et al., 2010; Yen et al., 2010), and some studies have tried to explored the changes in the cognitive function of older people (Eisele et al., 2012; Matthews, Marioni, & Brayne, 2012; Piccinin et al., 2012; Yen et al., 2010). Furthermore, age and sex have been demonstrated to be significant risk factors for cognitive function (Fernandez Martinez et al., 2008; Matthews et al., 2012; Piccinin et al., 2012; Proust-Lima et al., 2008; Yen et al., 2010). The patterns and factors related to the cognitive function over time in different age and sex groups have not been compared thoroughly in the existing literature. Previous studies have found factors related to cognitive impairment among older people. The incidence of cognitive impairment is related to being older, being female, and having a lower education level (Kawas, Gray, Brookmeyer, Fozard, & Zonderman, 2000; Miech et al., 2002; Sabia et al., 2009; Shadlen et al., 2006; Yen et al., 2010). Certain chronic diseases are associated with cognitive impairment, including diabetes, chronic kidney disease, vascular diseases, and stroke (Duron & Hanon, 2008; Etgen, Chonchol, Forstl, & Sander, 2012; Gorelick, 2005; Kilander, Nyman, Boberg, Hansson, & Lithell, 1998; Mok et al., 2004; Muller, Grobbee, Aleman, Bots, & Van Der Schouw, 2007; Okereke et al., 2008; Tzourio, 2007). Cognitive impairment is associated with frailty (Auyeung, Lee, Kwok, & Woo, 2011; Boyle, Buchman, Wilson, Leurgans, & Bennett, 2010; Curcio, Henao, & Gomez, 2014; Faria Cde, Lourenco, Ribeiro, & Lopes, 2013; Han, Lee, & Kim, 2014; Kilgour, Todd, & Starr, 2014; Shimada et al., 2013; Samper-Ternent, Al Snih, Raji, Markides, & Ottenbacher, 2008). In Archives of Gerontology and Geriatrics 60 (2015) 196–200 A R T I C L E I N F O Article history: Received 31 October 2013 Received in revised form 6 October 2014 Accepted 7 October 2014 Available online 17 October 2014 Keywords: Cognitive function Longitudinal study Older adults Age difference Gender difference A B S T R A C T Purpose: The aim of this study was to examine cognitive function and the risk and the protective factors by age and sex among Taiwanese older people. Methods: The data were from a nation-representative panel of older people in Taiwan. The participants completing both the 2003 and 2007 waves were included for analysis in this study (n = 3228). Descriptive analysis and generalized linear model were applied, and the samples were stratified by age groups and by sex. Results: The factors related to higher cognitive function at the intercept included being younger, male, higher education, and doing unpaid work. At the time slope, the age effect and physical function difficulties would reduce the cognitive function across time, while education and providing informational support would increase the cognitive function across time. There were age- and sex- differences in the factors related to cognitive function, particularly on the working status and social participation. Conclusion: Different health promotion strategies to target these populations should be accordingly developed. ß 2014 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: Department of Health Care Administration, Asia University, No. 500, Lioufeng Road, Wufeng, Taichung 41354, Taiwan. Tel.: +886 4 23323456x1827; fax: +886 4 23332970. E-mail address: gingerhsu@seed.net.tw (H.-C. Hsu). Contents lists available at ScienceDirect Archives of Gerontology and Geriatrics jo ur n al ho mep ag e: www .elsevier .c om /lo cate/ar c hg er http://dx.doi.org/10.1016/j.archger.2014.10.007 0167-4943/ß 2014 Elsevier Ireland Ltd. All rights reserved.