How will the obesity epidemic influence healthy ageing? The potential for health behaviours to alleviate the obesity burden across generations

AE1: Obesity and Healthy ageing AE2: Key determinants of health including genetic variants AE3: Life course epidemiology AE4: Statistical analysis

Aim: Global population trends in obesity and ageing raise challenges for health and society. To address the potential of health behaviours to alleviate the obesity-related health burden, I aim to determine influences on health behaviours and adiposity, their interrelations and relationship to components of healthy ageing (physical and cognitive capability) across generations.
Objectives: To establish (within and across generations) associations between: (1) early life factors and health behaviours, (2) time-varying behaviour and adiposity trajectories, (3) time-varying behaviours and components of healthy ageing; and to establish whether: (4) relationships between obesity trajectories and healthy ageing components are modified by time-varying behaviours, and (5) the influence of genetic variants on weight gain is modified by time-varying behaviours.
Methods: The 1946, 1958 and 1970 British birth cohorts will be used. Prospective data include adiposity measures from early life onwards, health behaviours during adulthood and measures of healthy ageing. For each objective, within cohort analyses will be conducted; in cross-cohort analyses, comparability of measures will be considered. Relevant statistical methods (e.g. structural equation modelling, multilevel models, marginal structural models, g-estimation of structural nested models) will be used. Causal inference methods and sensitivity analysis will be applied to explore conclusion robustness to assumption violations.
Scientific opportunities: The project will shed light on the influence of obesity trends on healthy ageing across generations, quantify the likely impact of intervening on behaviours at different life stages and contribute to the design of trials to reduce consequences of obesity and that promote uptake and maintenance of healthy behaviours. It will advance knowledge of healthy ageing by deepening our aetiological understanding of ageing processes and how these processes have changed over time.

Findings from this project have the potential to contribute to the nation's health with relevance for both younger and older generations who will benefit from improved interventions to lessen the detrimental effects of obesity as generation's age. In addition to scientists working in closely-related fields, I anticipate that the following groups will benefit from my research:
- Academics and health care practitioners who design, evaluate or implement interventions designed to promote the uptake and maintenance of healthy behaviours. My findings will identify potential early life intervention targets and quantify the potential effects of interventions targeted at different behaviours and at different ages. Findings will therefore feed in to intervention design in the medium term.
- Research staff employed on the project and PhD students will benefit in the short to medium term. The work will build capacity for data analysis, critical examination, evidence synthesis and communication skills, all of which are highly relevant in both academic and non-academic settings. The project will facilitate the transmission of experience on longitudinal research and contribute to early career development.
- Organisers and funders of cohort studies would benefit in the medium term (i.e. during the duration of the award). By producing topical and policy relevant research, I will be highlighting the importance of investing in national birth cohorts and demonstrating the value of comparisons across them.
- Charities (e.g. Age UK and HOOP (Helping Overcome Obesity Problems)) and other non-government agencies with interests in ageing or obesity who work to raise awareness and alleviate the impact of ageing or obesity. Such organisations can use my research evidence on the impact that obesity will have in current and future generations on different components of healthy ageing to lobby for policy change.
- Policy makers involved in development and implementation of national and local policies, rely on evidence accumulation to inform policy and debate aiming to improve the health of the nation. The project will contribute to the UK evidence base on how obesity influences components of health ageing across generations and what behaviours one might adopt to alleviate the burden.
(Timings for benefits are difficult to predict for charities and policy makers given fluctuations in national and local agendas, with uptake of evidence possibly extending over a long period. However, given that both ageing populations and obesity are of current public health importance and given population trends, likely to remain a focus of importance, I envisage that the research findings will be both timely and necessary.)
- The general public, including study participants. In the short term, awareness raising activities, by myself (e.g. via press releases and participation in MRC open days) and in particular of non-governmental agencies, impacts on the general public. I anticipate that there will also be benefits to cohort members who will see their ongoing commitment to study participation as worthwhile.
- National and international bodies responsible for health care guideline development. In the longer term, the results of intervention trials, to which my results have contributed to the design, will form part of guidelines for the reduction of the health consequences of obesity and promotion of the uptake and maintenance of healthy behaviours.