Abstract
In the face of shifting demographics and an increase in human longevity, it is important to examine carefully what is known about cognitive ageing, and to identify and promote possibly malleable lifestyle and health-related factors that might mitigate age-associated cognitive decline. The Lothian Birth Cohorts of 1921 (LBC1921, n = 550) and 1936 (LBC1936, n = 1091) are longitudinal studies of cognitive and brain ageing based in Scotland. Childhood IQ data are available for these participants, who were recruited in later life and then followed up regularly. This overview summarises some of the main LBC findings to date, illustrating the possible genetic and environmental contributions to cognitive function (level and change) and brain imaging biomarkers in later life. Key associations include genetic variation, health and fitness, psychosocial and lifestyle factors, and aspects of the brain's structure. It addresses some key methodological issues such as confounding by early-life intelligence and social factors and emphasises areas requiring further investigation. Overall, the findings that have emerged from the LBC studies highlight that there are multiple correlates of cognitive ability level in later life, many of which have small effects, that there are as yet few reliable predictors of cognitive change, and that not all of the correlates have independent additive associations. The concept of marginal gains, whereby there might be a cumulative effect of small incremental improvements across a wide range of lifestyle and health-related factors, may offer a useful way to think about and promote a multivariate recipe for healthy cognitive and brain ageing.
Highlights
Promoting successful cognitive ageing is a topic of major importance to individuals and the field of public health
The cohorts provide clear evidence that change in a general cognitive factor accounts for ∼50% of the variance in age-related changes across multiple cognitive domains. These results show that individuals who are cognitively more able in youth show a tendency to still show a higher level of cognitive function in older age (Deary et al 2004b; Royle et al 2013)
Allostatic load (AL) at age 73 was associated with IQ scores at age 11 but did not predict cognitive change from age 11 to 73. In this first study to consider AL, cognitive ability and neuroimaging measures of brain volume, the results suggest that the cumulative wear and tear on the body from a lifetime of stress responsivity is associated with both brain structure and cognitive ability in early- and later life but not with cognitive change from childhood to the early 70s
Summary
Promoting successful cognitive ageing is a topic of major importance to individuals and the field of public health. The LBC studies have recently taken a more complex multivariate approach in which important predictors were modelled simultaneously on cognitive level (age 70) and change (between ages 70 and 76 in LBC1936) using latent growth curve models (Ritchie et al 2016) In these analyses, univariate correlates of age 70 cognitive ability level (at the same time measuring lifetime cognitive change from age 11 to age 70) were many; those individuals with better general cognitive function at age 70 were younger when tested, had higher childhood intelligence, were more educated, were from more professional occupational classes, lived in more affluent areas, were fitter (on all three performance indicators), had lower BMI, were less likely to smoke, and were less likely to have cardio-metabolic illness. Multivariate techniques – considering many predictors together – may provide a more realistic consideration of the predictors of cognitive and brain ageing
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
