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Centre for Policy on Ageing | |
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Cross-sectional versus longitudinal estimates of cognitive change in nondemented older people
— a CERAD study | | Author(s) | Joseph M Unger, Gerald van Belle, Albert Heyman |
| Journal title | Journal of the American Geriatrics Society, vol 47, no 5, May 1999 |
| Pages | pp 559-563 |
| Keywords | Mental ageing ; Dementia ; Age groups [elderly] ; Evaluation ; Cross sectional surveys ; Longitudinal surveys ; United States of America. |
| Annotation | Cross-sectional data are a collection of independent observations. Longitudinal data are characterised by repeated observations within subjects that are typically correlated. Both types of data are used to derive estimates of change of a response over time (age). The authors analysed the effect of increasing age on cognitive function in 425 control subjects from those recruited by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), using the Mini Mental State Examination (MMSE). Cross-sectional analyses were derived by generalised linear models and longitudinal estimates by generalised estimating equations. The cross-sectional model indicated a small but significant decline in MMSE of -.4 points per 10 years. The longitudinal model indicated a small but significant increase in MMSE of about +.6 points per 10 years. Evidence of an early learning effect and non-random dropout exists. The authors conclude that there is a small but significant decline in scores on the MMSE with increasing population age. The effect can be masked in longitudinal cohorts by a learning effect (especially early in follow-up) and other factors associated with repeated testing. (RH). |
| Accession Number | CPA-990825305 A |
| Classmark | D6: EA: BB: 4C: 3KB: 3J: 7T |
Data © Centre for Policy on Ageing |
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| ...from the Ageinfo database published by Centre for Policy on Ageing. |
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