title: Accounting for differences in cognitive health between older adults in New Zealand and the USA.
abstract: BACKGROUND
  National differences in cognitive health of older adults provide an opportunity to shed light on etiological factors. We compared the cognitive health of older adults in New Zealand and the USA, and examined differences in known risk factors.
  
  
  METHODS
  Two nationally representative samples were derived from the 2010 waves of the New Zealand Longitudinal Study of Ageing (n = 953) and the US Health and Retirement Study (HRS) (n = 3,746). Data from comparable measures of cognitive function, gender, age, income, education, prevalence of cancer, diabetes, heart disease, hypertension and stroke, exercise, alcohol consumption, smoker status, depression, and self-reported health were subjected to hierarchical regression analysis to examine how national differences in cognitive function might be explained by differences in these risk factors.
  
  
  RESULTS
  The New Zealand sample scored 4.4 points higher on average than the US sample on the 43 point cognitive scale. Regression analyses of the combined samples showed that poorer cognitive health is more likely in those who are male, older, less educated, have suffered a stroke, consume alcohol less frequently, are more depressed, and report worse overall health. Controlling for age and sex reduced the mean difference to 2.6 and controlling for risk factors further reduced it to 2.3.
  
  
  CONCLUSIONS
  Older New Zealand adults displayed better cognitive function than those in a US sample. This advantage can be partially explained by age and sex differences and, to some extent, by differences in known risk factors. However, the national advantage remained even when all measured risk factors are statistically controlled.
authors.affiliation: School of Psychology,Massey University,Palmerston North,New Zealand.
authors.forename: Christine
authors.initials: C
authors.lastname: Stephens
authors.affiliation: School of Psychology,Massey University,Palmerston North,New Zealand.
authors.forename: John
authors.initials: J
authors.lastname: Spicer
authors.affiliation: School of Psychology,Massey University,Palmerston North,New Zealand.
authors.forename: Claire
authors.initials: C
authors.lastname: Budge
authors.affiliation: School of Psychology,Massey University,Palmerston North,New Zealand.
authors.forename: Brendan
authors.initials: B
authors.lastname: Stevenson
authors.affiliation: School of Psychology,Massey University,Palmerston North,New Zealand.
authors.forename: Fiona
authors.initials: F
authors.lastname: Alpass
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology* / Q000209:etiology; D004522:Educational Status; D005260:Female; D006801:Humans; D007182:Income / Q000706:statistics & numerical data; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009520:New Zealand / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D020521:Stroke / Q000150:complications; D014481:United States / Q000453:epidemiology
keywords: successful aging