Our project focuses on a previously neglected area of research: how does providing care for grandchildren impact on the health and wellbeing of grandparents? Promoting the health and wellbeing of older people is a critical policy issue as the population ages, while social, economic and demographic changes across Europe point to an increasing role for grandparents in providing childcare support to families. Despite competing pressures on older workers to remain in the workforce for longer and to provide care to frail family members, there are additional pressures on grandparents to provide childcare. This is thought to be due to policies encouraging more mothers into the paid workforce, increases in rates of family breakdown and single motherhood, and financial pressures on families. This vital economic and social role is largely overlooked or taken for granted by policymakers, and the health impacts on older people of taking on these childcare roles are not known. This issue affects millions of people. There are 14 million grandparents in the UK, many of working age: 25% of grandparents over the age of 50 are under 60, and 40 per cent are under 65. In Britain, 17% of grandparents with a grandchild under 16 provide intensive levels of childcare of at least ten hours a week and around one in thirty provides full time care to, or lives with a grandchild. Prior research suggests those grandparents with 'primary care' responsibilities for a grandchild or who undertake intensive grandparenting roles are often among the most disadvantaged and in the poorest health. However, since this is mostly drawn from cross-sectional data, it is not known whether or to what extent this is due to cumulative disadvantages throughout the life course or to the impact of grandchild care per se. A better understanding of the underlying mechanisms and causal pathways between grandchild care and grandparent health and wellbeing is needed. Earlier findings on the relationship between grandchild care and grandparent health are inconclusive and researchers have suggested that this may be because this relationship is likely to vary by socio-economic circumstances with those in the most vulnerable groups being the most adversely affected. Using the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE) we will examine the long-term social, health and economic determinants of grandparents' current health and wellbeing status, focusing on the intervening role of grandchild care. We will focus on understanding how cumulative advantage and disadvantage interacts with grandchild care to affect grandparent health and wellbeing. Using the life history information collected we will be able to explore the relationship between different life experiences and grandparents' current health and wellbeing. For example, we will be able to capture lifetime experiences such as time spent in institutional care as children, with single parents, periods of poor health as children and with ill-health and disability as adults, periods of unemployment, experiences of divorce, widowhood and single parenthood, periods of partner's ill health/disability, and frequent house moves. Such an analysis will provide us with a better understanding of the cumulative impact of life course trajectories on health outcomes among grandparents. We will also explore how variations over time in grandparent childcare and other socio-economic and demographic factors affect grandparents' own health and wellbeing. This is important as understanding the health and wellbeing impact of engagement in childcare on older people will provide important evidence to enable policy makers across Europe to ensure that the role of grandparents in children's lives is better supported and any deleterious effects on health are minimised.