Sample attrition and physical health of immigrants in the UK

This thesis contains three papers on immigrants, i.e. foreign-born people, in the UK. The first paper is methodological, the other two papers focus on physical health. All papers use data from the UK Household Longitudinal Study (UKHLS) which started in 2009 and includes an Ethnic Minority Boost sample, providing large enough sample sizes to study the immigrant population in detail. The first paper analyses sample attrition of immigrants at wave 2 of the UKHLS. We find that non-contact of immigrants is mainly determined by characteristics related to high residential mobility. However, it is also predicted by poor cooperation at the first interview. This suggests that for some immigrants non-contact could constitute a hidden refusal. Interview refusal of immigrants is predicted by similar characteristics than for UK-born. The second paper investigates the Healthy Immigrant Effect (HIE) in the UK. The HIE is understood as a health advantage of recent immigrants compared to the native-born population, which gets smaller with increasing length of residence. The cross-sectional analysis finds that immigrants have a health advantage in the first years after immigration, which decreases the longer immigrants have been in the country. The magnitude of the HIE depends on the measure of poor health: poor self-rated health and diagnosed chronic condition yield much larger HIE than poor physical health functioning (Short-Form 12) which is arguably more suitable to this immigrant-native comparison. The last paper considers one possible explanation for the duration effect, i.e. why immigrants lose their initial health advantage: Immigrants tend to have poorer work conditions than native-born employees. We find that physical work conditions explain some of the excess deterioration of immigrants’ health, while psychosocial work conditions only play a minor role. Health deterioration among less educated immigrants is better explained with work conditions than that among degree-educated immigrants.