We hypothesised that differences in frailty , and change in frailty over time , between first generation migrants and non - migrants in Europe would be modified by migrants ' economic origins , host region and , for the first time , country - level migrant integration policies ( the magnitude of any migrant health inequality being reduced by more inclusive migrant health policies ) . We aimed to quantify the extent to which post - migration socio - economic status and , for the first time , citizenship may explain these expected differences in frailty and hypothesised that acquisition of citizenship may attenuate effect modification by host country migrant integration policies . This work builds upon existing cross - sectional studies of European migrant health in SHARE ( Aichberger et al . , 2010;Brothers et al . , 2014;Ladin and Reinhold , 2013;Solé - Auró and Crimmins , 2008 ) by incorporating further waves of data collection . This increases the number of subjects ' initial interviews available for cross - sectional analyses and permits longitudinal modelling of frailty trajectories ( i.e. frailty over time ) at ages over 50 years . It aims to enrich our understanding of the health issues facing an aging and expanding European migrant population to support policymakers in the strategic planning of health and social care delivery .