OBJECTIVES: The finding that migrants to high-income countries have lower rates of morbidity and mortality than non-migrants, controlling for socioeconomic position, is often attributed to the “healthy migrant” hypothesis, which suggests that only the healthiest individuals choose to migrate. This prospective study investigates the healthy migrant hypothesis in a cohort of British emigrants using pre-migration health indicators. We also investigate how early-life health characteristics relate to age at emigration and whether or not the emigrant returned home. METHODS: Data are from the Medical Research Council National Survey of Health and Development, a nationally representative cohort study of people born in England, Scotland or Wales in March 1946. Childhood socio-economic position, health and cognitive ability were compared between 4,378 non-emigrants and 984 emigrants. Of the emigrants, 427 emigrated before age 20 and 557 after that age; 602 emigrants remained abroad and 382 returned home. RESULTS: Emigrants had better childhood health (especially greater height), higher childhood socio-economic position and better childhood cognitive ability at age 8 than non-emigrants. Return emigrants were very similar to emigrants who remained abroad. CONCLUSIONS: We found support for the healthy migrant hypothesis in a cohort of British emigrants. Our findings improve an understanding of how health is distributed within and across nations. © 2015 Canadian Public Health Association or its licensor.

Birth cohort Healthy migrants Healthy immigrants The MRC national survey of health and development Life course

sociological theory prospective study emigrant health survey Prospective Studies human Cohort Studies statistics and numerical data medical research controlled study health status Health Surveys Great Britain childhood Young Adult Humans migrant social theory male female height cognition health status indicator Health Status Indicators major clinical study adult migration United Kingdom cohort analysis Emigration and Immigration Transients and Migrants Child