Economic Inequality in Adult Mortality in Canada: Analyses of the Longitudinal Administrative Databank

This dissertation contains two empirical papers on income and premature mortality, and one methodological paper that concerns the summary measurement of the extent of social inequalities in health. Income dynamics and adult mortality: Canada and the USAChapter 4 examines the effects of income level and income drops on all-cause mortality in Canada and the United States. The Canadian data are from the Longitudinal Administrative Databank (LAD), and the US data are from the Panel Study of Income Dynamics (PSID). The LAD consists of personal income tax records for 20% of Canadian filers from 1982 through 2005. The PSID is a survey sampled in 1968 and followed annually through 1997. Analyses of the PSID confirmed previously published findings that used alternative statistical methods. The effect of income level on hazard of death is twice as large in the United States. The effects of income drops differed in Canada and the United States.Income dynamics and adult mortality in Canada: Chapter 5 re-analyses the LAD data to refine causal inference regarding the effects of income level and income drops on all-cause mortality. Exposure at ages 40-55 is analyzed for induction times ranging from 1-18 years. Income level was defined as the mean of the previous five year period, and income drops was measured both as annual change, and as the difference between projected and observed income. The effect of income level attenuated very little over induction time, and was not confounded by work disability. The effect of income drops also attenuated very little over induction time. Men in couple families showed a monotonic dose-reponse effect of income drops, and exclusion of families with potentially confounding characteristics did not affect the estimated risks. The hypothesized dependency of the effect of income drops on income level was not observed. No differences were observed between the two measures of income drops. Overall, there is strong evidence that the effect of income level on risk of death is primarily causal, while evidence for the effect of income drops is mixed.