The Lothian Birth Cohort 1936 Waves 6 and 7

As older people form an increasingly large proportion of human populations across the planet, greater resources will be needed for their management and care. Cognitive ageing, the process by which some cognitive abilities decline in older age, is of particular concern because it can lead to reduced quality of life, problems with daily tasks, a loss of independence, and, in its later stages, increased risk of dementia. Characterising the biological causes of cognitive ageing, and other related aspects of ageing, is therefore important if we are to reduce the burden of ageing at both the individual and societal level. By the time individuals are 85 years old, they are more likely to require assistance to live independently, and have threefold higher risk of dementia than in their 70s. However, we understand little about the brain and cognitive changes that come about at this age and beyond, and which factors might be most important to ameliorate this in future.
In the proposal, we request funds to continue the COVID-delayed collection of a 6th Wave and add to it a 7th Wave of data collection from participants of the Lothian Birth Cohort 1936 (LBC1936), and to support core staff to enable this collection, and conduct the subsequent analyses from which many novel insights about ageing differences can be learned. The LBC1936 are a large group of relatively healthy community-dwelling older adults who are unique in having cognitive data from youth alongside other important early life data, ongoing linkage to health, administrative and mortality records, and repeat cognitive testing, brain ageing, genetic, epigenetic, lifestyle, psychological, social and other important information obtains from ages 70, 73, 76, 79, and 82 years old. Age UK had provided funds to complete collection of Wave6 (mean age 85 years), but COVID-delays mean that this funding period will now end mid-Wave 6. This is an important chance - for which we request minority core support - to continue this highly informative and productive interdisciplinary study which will extend the exceptionally detailed characterisation of participants for almost the entire 8th and 9th decades of life. A purely cross-sectional study with data at age 88 years (their mean age at Wave 7) with this level of data collection and expertise would be world-leading - it is extremely rare to have rich longitudinal data over a preceding 2 decades, plus critical information from much earlier in the lifespan. This longer period of follow up and the work proposed here will enable more precise detection of different aspects of ageing, more detailed ascertainment of those participants who do not return, and new insights into the unique contributions of multiple candidate factors that may determine healthy ageing.

Importantly, alongside new data and hypotheses, this grant would also support stuff crucial for conducting these investigations. The study has a strong and diverse investigator team, and a strong track record in attracting scientists from a many disciplines, which brings with it additional funding, vital complementary expertise and new scientific discoveries. The hub-and-spoke model is reflected in the minority funding request - the School of Philosophy, Psychology and Language Sciences will also contribute 4 staff, with numerous collaborators and resources representing substantial added value.

This is a vanishing window of opportunity to collect extensive data on adults aged 85 and 88 years old, who have also been deeply phenotyped across the 8th decade of life, and for whom rare early life and lifecourse data are also collected. The opportunity to collect such data again in future may not arise for many years.

Cognitive decline is one of the most feared aspects of growing old; a strong evidence base is required for identifying the (malleable and non-malleable) factors that drive cognitive ageing differences and especially those which may be most amenable to intervention. We seek funds to collect a 6th (COVID-delayed) and 7th waves of data from the Lothian Birth Cohort 1936, a large group of relatively healthy community-dwelling older adults, all of whom were born in 1936 (N =1,091 at recruitment). The cohort hasa wide range of phynotypic data from older age (at 70, 73, 76, 79, 82) including cognitive, genetic, epigenetic, lifestyle, physical and medical, with structural and diffusion MRI data at ages 73, 76, 79 and 82. They also have a measure of childhood intelligence from age 11 alongside other early life sociodemographic data. Supporting a 6th and 7th wave - and scientists to collect analyse these data - confer important benefits: multi-wave, multimodal information of this breadth is lacking for people in their 9th decade. The longer duration, extra sampling points, and data linkage (e.g. GP and hospital records to continue to collect data on outcomes for all 1,091 participants) all substantially mitigate any statistical power decrements from attrition (which is low at c.20% every three years). These additional waves will offer a valuable opportunity to characterise patterns of cognitive, brain and other aspects of ageing more precisely at this important and understudied time of life. It will also provide important contemporaneous and retrospective data over nearly two decades to be linked with NHS data-linked outcomes, accruing post-mortem, stem cell and other data types. The current hub-and-spoke model reflects that the interdisciplinary and highly productive investigator team are exceptionally well placed to realise the potential of these data through cultivating extensive collaborative links and the opportunities to obtain funding for future analyses.