title: Modifiable risk factors for Alzheimer disease and subjective memory impairment across age groups.
abstract: BACKGROUND
  Previous research has identified modifiable risk factors for Alzheimer's disease (AD) in older adults. Research is limited on the potential link between these risk factors and subjective memory impairment (SMI), which may precede AD and other dementias. Examination of these potential relationships may help identify those at risk for AD at a stage when interventions may delay or prevent further memory problems. The objective of this study was to determine whether risk factors for AD are associated with SMI among different age groups.
  
  
  METHODS
  Trained interviewers conducted daily telephone surveys (Gallup-Healthways) of a representative community sample of 18,614 U.S. respondents, including 4,425 younger (age 18 to 39 years), 6,365 middle-aged (40 to 59 years), and 7,824 older (60 to 99 years) adults. The surveyors collected data on demographics, lifestyles, and medical information. Less education, smoking, hypertension, diabetes, less exercise, obesity and depression, and interactions among them, were examined for associations with SMI. Weighted logistic regressions and chi-square tests were used to calculate odds ratios and confidence intervals for SMI with each risk factor and pairwise interactions across age groups.
  
  
  RESULTS
  Depression, less education, less exercise, and hypertension were significantly associated with SMI in all three age groups. Several interactions between risk factors were significant in younger and middle-aged adults and influenced their associations with SMI. Frequency of SMI increased with age and number of risk factors. Odds of having SMI increased significantly with just having one risk factor.
  
  
  CONCLUSIONS
  These results indicate that modifiable risk factors for AD are also associated with SMI, suggesting that these relationships occur in a broad range of ages and may be targeted to mitigate further memory problems. Whether modifying these risk factors reduces SMI and the eventual incidence of AD and other dementias later in life remains to be determined.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chen
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Prabha
authors.initials: P
authors.lastname: Siddarth
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, United States of America; UCLA Longevity Center on Aging, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Ercoli
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Merrill
authors.affiliation: David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America; Department of Public Policy, UCLA School of Public Affairs, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Fernando
authors.initials: F
authors.lastname: Torres-Gil
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, United States of America; UCLA Longevity Center on Aging, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Small
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology* / Q000209:etiology*; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult