1. Migration, methodologies and health inequality SEED Group 14.5.09

2. Less mobility over time? Rogerson et al (2002)

3. Mobility and health inequalties between areas - Types of migration Selective migration –The impact of selective migration upon area health inequalities varies with scale and location but there is some evidence that in the UK, at a small scale, it contributes to inequalities. Population loss –Selective migration in combination with population loss may encourage the ‘residualisation’ of the poorest and most unhealthy populations in deprived areas Population turnover –Population instability may improve health in deprived areas while in other areas it is associated with worse health outcomes.

4. Mobility and health inequalties between areas - role in understanding… The exceptionality of the most deprived places –Population loss is one of the key characteristics that make most deprived places different from more advantaged areas Variations between deprived areas –Migration may be significant to understanding differences in health between deprived areas. –In the USA “out-migration/population loss” has been assessed as a indicator for use by the Economic Development Administration to target development assistance for economic distress as it appears to identify regions experiencing different demographic processes than other distress indicators Area based social policy –Migration may provide clues about the long-term persistence of spatial inequalities in health and the apparent failure of many area-based social policies to reduce poverty and improve health in the most deprived areas

5. Migration as a methodological solution Genetic v environmental health risk factors –Comparisons of the health status of international migrant groups to host populations and non–migrant counterparts in their country of origin Life course and environmental exposures in childhood and adult life to health risks –Comparison of the characteristics of place of birth or childhood residence and adult areas of residence

6. Migration as a methodological problem Population denominators –Errors in population denominators in ecological and epidemiological analysis The ‘exposure fallacy’ –How long have people been exposed to the envionment they live in? Increasing social bias in longitidinal studies –Due to the increasing social stratification of patterns of migration (?) Multilevel models attempts to separate area context and composition affects –Ignore the “individual-contextual interactions” exemplified by migration

7. How many residents of England and Wales? When 2001 population figures for England and Wales from the Office for National Statistics (ONS) 2001 Census were published there was a discrepancy between the ONS 2001 Census figures and the ONS 2001 Mid-Year population estimates of… 1,140,000 people There were over a million fewer residents of England and Wales in the 2001 Census than had previously been suggested were present by the Mid-Year population estimates.

8. What accounted for the discrepancy between 2001 Census and Mid-Year population estimates? ONS Improving Migration and Population Statistics Project has researched this question Source: http://www.statistics.gov.uk/about/methodology_by_theme/revisions_to_population_estimates/introduction.asp

9. Population change and SMRs in UK districts Davey Smith et al, 1998, Lancet, 352: 1439 Change in population 1971-1991 Correlation between population change and SMRs: - 0.62 Correlation between population change and SMRs after controlling for proportion of population in social classes IV, V and unclassified in 1991: - 0.49

10. Health selective migration In the UK people that report good health are on average more likely to move –Percentage of residents that changed address within the UK, in year prior to 2001 Census: ‘Good’ health – 12.5% ‘Not good’ health – 8.6% However the health status of migrants varies with: –Age of migrant –Socio-economic status of migrant –Reason for migration – education, employment, family relationships etc. –Distance of migration

11. Percentage of residents that changed address within the UK in year prior to 2001 Census, by age and sex, [Champion, 2005, Focus on People and Migration, London: ONS] 11% total population changed address within the UK in the year prior to 2001 Census

12. Health selective migration by age group Young adults –In early adulthood migrants report better health than non-migrants of their age, with the exception of migrants moving short distances –A moderate ‘healthy migrant effect’ persists separate from individual socio-demographic characteristics –Few moves in this age group are directly related to health events Midlife –… In mid-life, around age 40 years, the pattern reverses and migrants report worse health than non-migrants Elderly –Among the elderly disability-related moves, to increase proximity to kin, and institutional moves, resulting from chronic ill health, have been identified as two of the main causes of migration. Infants and children –There has been very little research that has compared broad measures of health among infant and child migrants and non-migrants [Bentham, 1988, Soc Sci Med, 26: 49-54; ; Findlay, 1988, International Migration Review, 22,:4-29; ; Verheij et al., 1998, JECH, 52: 487-493; Larson et al., 2004, Soc Sci Med, 59: 2149-2160; Norman et al., 2005, Soc Sci Med, 60: 2755-2771]

13. Have patterns of mobility been social stratifying over time? No chart! Life course trajectories through education, employment and family formation have become more diverse in recent decades – and also more socially stratified? So e.g. teenage mothers have become a ‘social problem’

14. Is social status increasingly mantained though sucessful spatial mobility? The ‘spatialisation of class’, –i.e. The concept that spatial inequalities are of growing importance as an expression of social inequality and that individual socio-economic status is increasingly reproduced though patterns of spatial inequality (Dorling, 2006; Burrows & Gane, 2006; Savage, Bagnall & Longhurst, 2005). –E.g. access to schools? Gentrification and studentification of disadvantaged areas by advantaged young adults? Implications for health?

15. Area deprivation and age groups Romeri et al (2006)

16. Area ethnicity and mobility CCSR website