title: Serum folate, vitamin B12 and cognitive impairment in Chilean older adults.
abstract: OBJECTIVE
  To analyse the relationship between serum folate (SF), vitamin B12 and impaired cognitive function in the Chilean elderly.
  
  
  METHODS
  We analysed the relationships between impaired cognitive function and age, SF (µg/l) and vitamin B12 (pg/ml) with Student's t test, as well as between impaired cognitive function and gender, educational level, residence area, diabetes and hypertension with the χ 2 test. Multiple logistic regressions with interactions were estimated to assess the impact of SF on impaired cognitive function according to these methods.
  
  
  METHODS
  Chile.
  
  
  METHODS
  Older adults (>65 years, n 1051), drawn from representative households of a national prevalence study, assessed using the Modified Mini Mental Status Examination (MMMSE). Individuals with altered MMMSE scores (≤13 points) were sequentially assessed using the Pfeffer Functional Activities Questionnaire (PFAQ).
  
  
  RESULTS
  Multivariate models using the MMMSE demonstrated an increased risk of impaired cognitive function for seniors who had hypertension, diabetes and higher vitamin B12 levels. SF and its square (SF2) were statistically significant, indicating that this predictor of impaired cognitive function displays a U-shaped distribution. The interaction between SF and vitamin B12 was not statistically significant. Models using the MMMSE plus PFAQ suggested that urban residence decreased the risk of impaired cognitive function, whereas male gender, older age, vitamin B12 levels and hypertension increased this risk. The variables SF and SF2 and the SF × vitamin B12 interaction were statistically significant (P<0.05). The risk of impaired cognitive function depended on different combinations of SF and vitamin B12 levels. When SF was low, a one-unit increase in SF (1 µg/l) diminished the risk. When SF was elevated, a further increase in SF raised the risk, especially at low vitamin B12 levels.
  
  
  CONCLUSIONS
  The relationship between folate, vitamin B12 and impaired cognitive function warrants further study.
authors.affiliation: 1Research Group on Community Nutrition and Oxidative Stress,Universitat de les Illes Balears,07122 Palma de Mallorca,Spain.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Castillo-Lancellotti
authors.affiliation: 2Department of Public Health, Faculty of Medicine,Pontifical Catholic University of Chile,Santiago,Chile.
authors.forename: Paula
authors.initials: P
authors.lastname: Margozzini
authors.affiliation: 2Department of Public Health, Faculty of Medicine,Pontifical Catholic University of Chile,Santiago,Chile.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Valdivia
authors.affiliation: 2Department of Public Health, Faculty of Medicine,Pontifical Catholic University of Chile,Santiago,Chile.
authors.forename: Oslando
authors.initials: O
authors.lastname: Padilla
authors.affiliation: 3Public Health and Nutrition Unit,Laboratory of Molecular Epidemiology,Institute of Nutrition and Food Technology,University of Chile,Santiago,Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Uauy
authors.affiliation: 5Department of Nutrition,Diabetes and Metabolism, Faculty of Medicine,Pontifical Catholic University of Chile,Santiago,Chile.
authors.forename: Jaime
authors.initials: J
authors.lastname: Rozowski
authors.affiliation: 1Research Group on Community Nutrition and Oxidative Stress,Universitat de les Illes Balears,07122 Palma de Mallorca,Spain.
authors.forename: Josep A
authors.initials: JA
authors.lastname: Tur
mesh_terms: D000203:Activities of Daily Living; D000367:Age Factors; D000368:Aged; D002677:Chile; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000097:blood* / Q000150:complications; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005494:Folic Acid Deficiency / Q000097:blood* / Q000150:complications; D015577:Geriatric Assessment; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D015596:Nutrition Assessment; D009752:Nutritional Status; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014505:Urban Population; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000150:complications; D014803:Vitamin B Complex / Q000097:blood*
chemical_list: D014803:Vitamin B Complex; D005492:Folic Acid; D014805:Vitamin B 12
keywords: Chile; Elderly; Executive function; Folic acid