Guest Blog: Future of Ageing 2015 series

By: Dr Claire Sexton, University of Oxford

The number of people aged over 65 in the UK is predicted to rise by 12% (1.1 million) between 2015 and 2020.

In light of the challenges an ageing population will bring to health care, social care, and the economy, the briefing paper Political challenges relating to an aging population: Key issues for the 2015 Parliamenthighlighted the importance of policies that “improve preventative healthcare, and help people to remain active and healthy in later life”.

Magnetic resonance imaging (MRI) allows neuroscientists to non-invasively examine the brain throughout the ageing process; with different types of MRI scans enabling the assessment of the size of grey matter structures and the integrity of white matter pathways that serve to connect different grey matter regions. While, to date, MRI studies have played a key role in informing our scientific understanding of the ageing brain, MRI studies are also uniquely placed to help inform public policy through characterising the ageing process in the brain and identifying and assessing factors can help promote healthy brain ageing.

Characterising the Ageing Process

In order to promote healthy brain ageing, it’s first necessary to understand the ageing process. MRI studies have repeatedly demonstrated that ageing is associated with striking changes in brain structure; with older adults typically displaying smaller volumes of grey matter structures, and reduced integrity of white matter pathways, compared with younger adults. A review of longitudinal MRI studies examining whole brain volume concluded that a steady volume loss of 0.2% per year begins after the age of 35 years, which accelerates gradually to a loss of 0.5% at age 60. Pinpointing the age at which structural decline begins has implications for public health interventions, and will indicate the importance of government guidelines and community initiatives targeting the cognitive ageing process early in life.

Identifying and Assessing Factors That Promote Healthy Ageing

MRI studies have documented a host of modifiable factors that are associated with increased rates of structural decline in ageing, including physical inactivity, raised cholesterol levels, high body mass indexand poor sleep quality (Figure). Encouragingly, some interventional studies have indicated that targeting such factors can have beneficial effects on brain structure. For example, a year long programme of physical activity in sedentary adults was shown to lead to increases in the volume of the hippocampus, a structure associated with memory that typically declines in volume with ageing. Further large-scale randomised-controlled trials, in community-based settings, will be required to better assess the timescale associated with structural brain changes, and the optimal duration and nature of interventions.

Figure: Spatial maps displaying, in red-yellow, the regions in which poor sleep quality is associated with increased rates of decline in brain volumes in 147 community-dwelling adults (Sexton et al 2014)