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Accounting for differences in cognitive health between older adults in New Zealand and the USA

Published online by Cambridge University Press:  09 December 2014

Christine Stephens Open the ORCID record for Christine Stephens [Opens in a new window] ,
John Spicer ,
Claire Budge ,
Brendan Stevenson  and
Fiona Alpass
Christine Stephens*
Affiliation:
School of Psychology, Massey University, Palmerston North, New Zealand
John Spicer
Affiliation:
School of Psychology, Massey University, Palmerston North, New Zealand
Claire Budge
Affiliation:
School of Psychology, Massey University, Palmerston North, New Zealand
Brendan Stevenson
Affiliation:
School of Psychology, Massey University, Palmerston North, New Zealand
Fiona Alpass
Affiliation:
School of Psychology, Massey University, Palmerston North, New Zealand
*
Correspondence should be addressed to: Christine Stephens, School of Psychology, Massey University, Private Bag 11 222, Palmerston North, New Zealand. Phone: +64 63505799; Fax: +64 63505679. Email: [email protected].
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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.

Keywords

cognitive functioningcognitive healthcognitionolder adultsagingsuccessful aging
Type
Research Article
Information
International Psychogeriatrics , Volume 27 , Issue 4 , April 2015 , pp. 591 - 600
Copyright
Copyright © International Psychogeriatric Association 2014 

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