title: Physical Frailty, Cognitive Impairment, and the Risk of Neurocognitive Disorder in the Singapore Longitudinal Ageing Studies.
abstract: The independent and combined effects of physical and cognitive domains of frailty in predicting the development of mild cognitive impairment (MCI) or dementia are not firmly established.
  
  
  
  This study included cross-sectional and longitudinal analyses of physical frailty (Cardiovascular Health Study criteria), cognitive impairment (Mini-Mental State Examination [MMSE]), and neurocognitive disorder (DSM-5 criteria) among 1,575 community-living Chinese older adults from the Singapore Longitudinal Ageing Studies.
  
  
  
  At baseline, 2% were frail, 32% were prefrail, and 9% had cognitive impairment (MMSE score < 23). Frailty at baseline was significantly associated with prevalent cognitive impairment. Physical frailty categories were not significantly associated with incident NCD, but continuous physical frailty score and MMSE score showed significant individual and joint associations with incident mild NCD and dementia. Compared with those who were robust and cognitively normal, prefrail or frail old adults without cognitive impairment had no increased risk of incident NCD, but elevated odds of association with incident NCD were observed for robust with cognitive impairment (odds ratio [OR] = 4.04, p < .001), prefrail with cognitive impairment (OR = 2.22, p = .044), and especially for frail with cognitive impairment (OR = 6.37, p = .005). The prevalence of co-existing frailty and cognitive impairment (cognitive frailty) was 1% (95% confidence interval [CI]: 0.5-1.4), but was higher among participants aged 75 and older at 5.0% (95% CI: 1.8-8.1).
  
  
  
  Physical frailty is associated with increased prevalence and incidence of cognitive impairment, and co-existing physical frailty and cognitive impairment confers additionally greater risk of incident NCD.
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, National University of Singapore, Singapore.
authors.forename: Liang
authors.initials: L
authors.lastname: Feng
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, National University of Singapore, Singapore.
authors.forename: Ma Shwe Zin
authors.initials: MS
authors.lastname: Nyunt
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, National University of Singapore, Singapore.
authors.forename: Qi
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, National University of Singapore, Singapore.
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.affiliation: Neuroscience and Behavioral Disorders Program, Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Tih Shih
authors.initials: TS
authors.lastname: Lee
authors.affiliation: Department of Psychological Medicine, National University Hospital, Singapore.
authors.forename: Tung
authors.initials: T
authors.lastname: Tsoi
authors.affiliation: Institute of Geriatrics and Active Ageing and.|Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore.
authors.forename: Mei Sian
authors.initials: MS
authors.lastname: Chong
authors.affiliation: Institute of Geriatrics and Active Ageing and.|Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore.
authors.forename: Wee Shiong
authors.initials: WS
authors.lastname: Lim
authors.affiliation: Department of Psychology, National University of Singapore, Singapore.
authors.forename: Simon
authors.initials: S
authors.lastname: Collinson
authors.affiliation: Department of Geriatric Medicine, Khoo Teck Puat Hospital, Singapore.
authors.forename: Philip
authors.initials: P
authors.lastname: Yap
authors.affiliation: Department of Geriatric Medicine, Alexandra Hospital, Singapore.
authors.forename: Keng Bee
authors.initials: KB
authors.lastname: Yap
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, National University of Singapore, Singapore.
authors.forename: Tze Pin
authors.initials: TP
authors.lastname: Ng
mesh_terms: D000368:Aged; D060825:Cognitive Dysfunction / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019965:Neurocognitive Disorders / Q000453:epidemiology*; D010808:Physical Examination; D015995:Prevalence; D018570:Risk Assessment; D012846:Singapore / Q000453:epidemiology
keywords: Cognitive impairment; Frailty; Neurocognitive disorders