Format

Send to:

Choose Destination
See comment in PubMed Commons below
BMJ. 2012 Jan 5;344:d7622. doi: 10.1136/bmj.d7622.

Timing of onset of cognitive decline: results from Whitehall II prospective cohort study.

Author information

  • 1Institut National de la Santé et de la Recherche Médicale, U1018, Centre for Research in Epidemiology and Population Health, Hôpital Paul Brousse, 94807 Villejuif Cedex, France.

Abstract

OBJECTIVES:

To estimate 10 year decline in cognitive function from longitudinal data in a middle aged cohort and to examine whether age cohorts can be compared with cross sectional data to infer the effect of age on cognitive decline.

DESIGN:

Prospective cohort study. At study inception in 1985-8, there were 10,308 participants, representing a recruitment rate of 73%.

SETTING:

Civil service departments in London, United Kingdom.

PARTICIPANTS:

5198 men and 2192 women, aged 45-70 at the beginning of cognitive testing in 1997-9.

MAIN OUTCOME MEASURE:

Tests of memory, reasoning, vocabulary, and phonemic and semantic fluency, assessed three times over 10 years.

RESULTS:

All cognitive scores, except vocabulary, declined in all five age categories (age 45-49, 50-54, 55-59, 60-64, and 65-70 at baseline), with evidence of faster decline in older people. In men, the 10 year decline, shown as change/range of test × 100, in reasoning was -3.6% (95% confidence interval -4.1% to -3.0%) in those aged 45-49 at baseline and -9.6% (-10.6% to -8.6%) in those aged 65-70. In women, the corresponding decline was -3.6% (-4.6% to -2.7%) and -7.4% (-9.1% to -5.7%). Comparisons of longitudinal and cross sectional effects of age suggest that the latter overestimate decline in women because of cohort differences in education. For example, in women aged 45-49 the longitudinal analysis showed reasoning to have declined by -3.6% (-4.5% to -2.8%) but the cross sectional effects suggested a decline of -11.4% (-14.0% to -8.9%).

CONCLUSIONS:

Cognitive decline is already evident in middle age (age 45-49).

PMID:
22223828
[PubMed - indexed for MEDLINE]
PMCID:
PMC3281313
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk