The health impacts of changes in individual or household income: A systematic review

Background: Income is a centrally important determinant of population health, yet the health impacts of changes to income are unknown. This study aimed to systematically review the available literature to clarify the health impact of changes to individual or household income.Methods: We undertook a systematic review, critical appraisal and narrative synthesis. We searched seven databases and the grey literature. The exposure of interest was any change in individual or household income and we included studies with any general health or mortality outcome. We limited the review to longitudinal studies with a non-unexposed comparison group and excluded studies considering only specific health outcomes. There were no restrictions to the time period or populations of interest.Findings: We screened 7,283 citations and identified 19 high quality studies for inclusion. Fourteen examined the impact of secular changes in income and generally found that increased income led to increased self-assessed health. The impact of inheritances or lottery wins was uncertain but generally positive. Changes in income in the context of social security changes had mixed impacts on health.Interpretation: Increased income over time is associated with increased self-assessed health but there is an absence of evidence of the impact on mortality. There is a need for studies of the impacts of changes in individual income on mortality and for evaluations of changes in policy that affect incomes.