title: Association of metabolic syndrome and 25-hydroxyvitamin D with cognitive impairment among elderly Koreans.
abstract: OBJECTIVE
  Metabolic syndrome and vitamin D deficiency are prevalent in older adults, and are considered risk factors for cognitive impairment. We investigated the combined effects of MetS and serum 25-hydroxyvitamin D (25[OH]D) levels on cognitive function in older adults.
  
  
  METHODS
  We studied 2940 participants aged ≥65 years from the Korean Urban Rural Elderly cohort study. Metabolic syndrome was defined according to the updated Adult Treatment Panel III criteria. Serum 25(OH)D levels were categorized into four groups: <25, 25-49, 50-74 and ≥75 nmol/L. Cognitive function was assessed using the Mini-Mental State Examination.
  
  
  RESULTS
  Participants with cognitive impairment had higher metabolic syndrome prevalence and lower serum 25(OH)D levels than those without cognitive impairment. In univariate analysis, both metabolic syndrome and low 25(OH)D levels were associated with cognitive impairment. These associations remained unchanged after adjusting for potential confounders including age, sex, season and education. In addition, participants with metabolic syndrome and low 25(OH)D had significantly increased odds for cognitive impairment (odds ratio 3.06, 95% CI 1.61-5.80) when compared with those with no metabolic syndrome and high 25(OH)D.
  
  
  CONCLUSIONS
  Metabolic syndrome was associated with cognitive impairment, and this risk was synergistically increased when metabolic syndrome was combined with low 25(OH)D. A focus on individuals with metabolic syndrome and low 25(OH)D might be helpful to identify older adults who are at risk of cognitive impairment. Geriatr Gerontol Int 2017; 17: 1069-1075.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Lee
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Korea.|Department of Medicine, Yonsei University Graduate School of Medicine, Seoul, Korea.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyoung Min
authors.identifier: http://orcid.org/0000-0001-7867-1240
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Cardiovascular and Metabolic Disease Etiology Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Yun
authors.affiliation: Cardiovascular and Metabolic Disease Etiology Research Center, Yonsei University College of Medicine, Seoul, Korea.|Department of Public Health, Yonsei University Graduate School, Seoul, Korea.
authors.forename: Bo Mi
authors.initials: BM
authors.lastname: Song
authors.affiliation: Department of Public Health, Yonsei University Graduate School, Seoul, Korea.|Division of Geriatrics Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jong Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: Cardiovascular and Metabolic Disease Etiology Research Center, Yonsei University College of Medicine, Seoul, Korea.|Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyeon Chang
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yumie
authors.initials: Y
authors.lastname: Rhee
authors.affiliation: Department of Sociology, Yonsei University, Seoul, Korea.
authors.forename: Yoosik
authors.initials: Y
authors.lastname: Youm
authors.affiliation: Division of Geriatrics Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Chang Oh
authors.initials: CO
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D057187:Independent Living; D007723:Korea / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D024821:Metabolic Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D016017:Odds Ratio; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012424:Rural Population; D012720:Severity of Illness Index; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000175:diagnosis / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: cognitive impairment; elderly; metabolic syndrome; vitamin D