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Seeromanie Harding and Erik Lenguerrand, University of Glasgow and Michael Rosato, University of Ulster
(Project no. 30099)
There is increasing evidence that health is patterned over the life course of several generations and that both social and biological predictors play a part. Migrant studies provide a useful opportunity to investigate the intergenerational transmission of health risks and how rapidly new environments affect changes in disease risk. Migrant groups such as the Caribbeans and South Asians living in the UK experience more chronic disease morbidity in adulthood than whites and the cause of these differences remains a mystery. The conventional wisdom of migration studies is that a shift in disease patterns towards that of the host population is expected in subsequent generations as they adopt local lifestyles. Very few studies have been able to test this empirically and many report divergence rather than convergence towards local rates of disease. US-based research suggests that the health of US-born Blacks is worse than that of foreign-born Blacks, and that this is linked to deprivation and negative health behaviours. International comparisons indicate the influence of different environments on health behaviours and the development of disease risks. For example, in a study of people of West African ancestry in Cameroon, Jamaica and Britain (Manchester), the prevalence of diabetes and hypertension was lowest in rural Cameroon and highest in Manchester. These studies suggest that the environmental factors play an important role in ethnic differences in chronic disease.
The following summarises some of our findings using LS data which has informed the current research questions. Excess mortality persists among second and third generations of Irish people living in England and Wales, in spite of upward intergenerational mobility. Coronary heart disease mortality among migrant South Asians, known to be high relative to the national average, increases with increasing duration of residence suggesting that social factors play a major role. Upward social mobility between 1971 and 1991 was more common among migrant groups than the rest of the population, though this was linked possibly to an initial under-employment following migration. However, persisting disadvantage is also more common and this contributed to the emergence of social gradients in health in the 1990s among the major minority groups. UK-born ethnic minorities have experienced upward intergenerational mobility but they reported more limiting long-term illness (LLTI) than the foreign-born in the same minority groups. Birth-weight (a sensitive indicator of health in infancy and adulthood) of babies of mothers born in the Indian subcontinent, sub-Saharan Africa or the Caribbean is lower than babies of British-born White mothers. We expected an intergenerational increase in birth weights but our findings did not support this.
We are currently using the LS to examine the impact of three major social influences - family structure, socio-economic advantage and area of residence - on LLTI and on mortality among foreign-born and UK-born minority groups (approved LS project). We are using data from the 1971, 1981 and 1991 Censuses and events from 1981-2001. We would want to extend this analysis to incorporate the 2001 Census data.
The LS provides a rare opportunity to track changes in social predictors over the life courses of migrants and their children and to examine how these relate to health outcomes in adulthood. Family life has changed considerably over time and there is some evidence that among migrants changes across generations may be adverse, confounded by economic deprivation and area of residence for some groups. The consequences of these changes on health outcomes are not known. This research will contribute to the scant epidemiological evidence on social mobility and health and will be useful for informing government policies on ethnic inequalities.