title: Interactive effects of diabetes and impaired kidney function on cognitive performance in old age: a population-based study.
abstract: BACKGROUND
  The interactive effect between diabetes and impaired kidney function on cognitive impairment in older adults has not yet been reported. The aim of this study was to investigate the association of diabetes and impaired kidney function with cognitive impairment among Chinese older people living in a rural area.
  
  
  METHODS
  This cross-sectional study included 1,358 participants (age ≥60 years; 60.5% women) in the population-based Confucius Hometown Aging Project in Shandong, China. Data on demographics, lifestyle factors, health history, use of medications, global cognitive function, and kidney function were collected through structured interviews, clinical examinations, and blood tests. We defined diabetes as a fasting plasma glucose level ≥7.0 mmol/l or use of hypoglycemic agents, impaired kidney function as glomerular filtration rate estimated from cystatin C (eGFRcys) <60 ml/min/1.73 m(2). Cognitive impairment was defined using the education-based cut-off scores of Mini-Mental State Examination (MMSE). Data were analyzed using multiple general linear and logistic regression models.
  
  
  RESULTS
  Cognitive impairment was defined in 197 (14.5%) persons. The multi-adjusted β coefficient of MMSE score associated with diabetes was -0.06 (95% confidence interval [CI], -0.16, 0.03); the corresponding figures associated with eGFRcys <60, 60-89.9, and ≥90 ml/min/1.73 m(2) were -0.15 (-0.28, -0.02), -0.01 (-0.10, 0.08), and 0 (reference) (Ptrend = 0.046), respectively. Diabetes and impaired kidney function showed an interactive effect on cognitive impairment ( interaction = 0.02). Compared with individuals having neither diabetes nor impaired kidney function, those with both conditions had a multi-adjusted odds ratio of 4.23 (95% CI, 2.10-8.49) for cognitive impairment. The relative excess risk due to interaction was 2.74.
  
  
  CONCLUSIONS
  This study suggests that concurrent presence of diabetes and impaired kidney function is associated with a substantial likelihood for cognitive impairment in older adults.
authors.affiliation: Division of Non-communicable Diseases Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing, China. zhaoxue_y@163.com.
authors.forename: Zhaoxue
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Department of Neurology, Jining No. 1 People's Hospital, Shandong, China. zhongruiy@hotmail.com.
authors.forename: Zhongrui
authors.initials: Z
authors.lastname: Yan
authors.affiliation: School of Public Health, Jining Medical University, Shandong, China. yajun.liang@ki.se.|Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Stockholm University, Stockholm, Sweden. yajun.liang@ki.se.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Xing Long Zhuang Hospital, Yankuang Group, Shandong, China. jianghui72@126.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Xing Long Zhuang Hospital, Yankuang Group, Shandong, China. ccz927555@163.com.
authors.forename: Chuanzhu
authors.initials: C
authors.lastname: Cai
authors.affiliation: School of Public Health, Jining Medical University, Shandong, China. songaiqin6556@sina.com.
authors.forename: Aiqin
authors.initials: A
authors.lastname: Song
authors.affiliation: Department of Psychological Medicine, National University of Singapore, NUHS Tower Block, 1E Kent Ridge Road, Singapore, Singapore. lei_feng@nuhs.edu.sg.
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.affiliation: Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Stockholm University, Stockholm, Sweden. chengxuan.qiu@ki.se.
authors.forename: Chengxuan
authors.initials: C
authors.lastname: Qiu
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology / Q000523:psychology; D002681:China / Q000453:epidemiology; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood; D048909:Diabetes Complications / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007361:Intelligence Tests; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D016017:Odds Ratio; D051437:Renal Insufficiency / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology
chemical_list: D055316:Cystatin C