Mortality of migrants from the Indian subcontinent to England and Wales: effect of duration of residence

Background. Few studies have examined mortality of migrants by duration of residence in the country of destination. Methods. I examined mortality of South Asian migrants by duration of residence in England and Wales. The cohort (N = 2,272, age 25-54 years in 1971) was followed from 1971 to 2000. Results. All-cause mortality of South Asian migrants increased with increasing duration of residence in England and Wales. A yearly increase in duration of residence was associated with a hazard ratio of 1.07 (95% confidence interval [CI] = 1.02-1.13) among persons ages 25-34 years in 1971, 1.03 (1.00-1.07) among those ages 35-44 years, and 1.02 (1.00-1.05) among those ages 45-54. Cardiovascular disease mortality was the main component of this trend. Yearly increases in duration of residence were associated with cardiovascular disease mortality hazard ratios of 1.09 (1.03-1.16), 1.04 (1.00-1.09) and 1.02 (1.00-1.05) for the youngest, middle and oldest age groups, respectively. Comparable results were seen for coronary heart disease and for cancer mortality. Age at migration was positively related to mortality independent of duration of residence but the confidence intervals were wide. Adjusting for socioeconomic position did not alter these patterns. Conclusions. Cardiovascular and cancer mortality of South Asian migrants increased with duration of residence in England and Wales