Variations in cognitive abilities across the life course: Cross-sectional evidence from Understanding Society: The UK Household Longitudinal Study

Abstract

Background: Populations worldwide are aging. Cognitive decline is an important precursor of dementia, illness and death and, even within the normal range, is associated with poorer performance on everyday tasks. However, the impact of age on cognitive function does not always receive the attention it deserves.

Methods: We have explored cross-sectional associations of age with five cognitive tests (word recall, verbal fluency, subtraction, number sequence, and numerical problem solving) in a large representative sample of over 40,000 men and women aged 16 to 100 living in the UK.

Results: Women performed better on word recall tests and men had higher scores for subtraction, number sequence and numerical problem solving. However, age-cognition associations were generally similar in both genders. Mean word recall and number sequence scores decreased from early adulthood with steeper declines from the mid-60s onwards Verbal fluency, subtraction and numerical problem solving scores remained stable or increased from early to mid-adulthood, followed by approximately linear declines from around age 60. Performance on all tests was progressively lower in respondents with increasingly worse self-rated health and memory. Age-related declines in word recall, verbal fluency and number sequence started earlier in those with the worst self-rated health. There was no compelling evidence for age dedifferentiation (that the general factor of cognitive ability changes in strength with age).

Conclusions: We have confirmed previously observed patterns of cognitive aging using a large representative population sample.

Keywords: Age differences; Aging; Cognitive ability; Memory.

Fig. 1

a: Prevalence of self-rated health by age among men and women b: Prevalence of self-rated memory by age among men and women.

Fig. 2

Mean standardised z-scores for all five cognitive measures by age and gender.

Fig. 3

Mean standardised z-scores for all five cognitive measures by age and self-rated health.

Fig. 4

Mean standardised z-scores for all five cognitive measures by age and self-rated memory.

Fig. 5

Mean g scores by age and gender, self-rated health, and self-rated memory.

Fig. 6

g-Factor loadings (left), uniquenesses (middle), and communalities (right) estimated using (a) LOSEM and (b) moderated factor analysis for the five cognitive tests.