Background Compared to other Organisation for Economic Co-operation and Development (OECD) nations, US infant mortality rates (IMRs) are particularly high. These differences are partially driven by racial disparities, with non-Hispanic black having IMRs that are twice those of non-Hispanic white. Income inequality (the gap between rich and poor) is associated with infant mortality. One proposed way to decrease income inequality (and possibly to improve birth outcomes) is to increase the minimum wage. We aimed to elucidate the relationship between state-level minimum wage and infant mortality risk using individual-level and state-level data. We also determined whether observed associations were heterogeneous across racial groups.
Methods Data were from US Vital Statistics 2010 Cohort Linked Birth and Infant Death records and the 2010 US Bureau of Labor Statistics. We fit multilevel logistic models to test whether state minimum wage was associated with infant mortality. Minimum wage was standardised using the z-transformation and was dichotomised (high vs low) at the 75th percentile. Analyses were stratified by mother's race (non-Hispanic black vs non-Hispanic white).
Results High minimum wage (adjusted OR (AOR)=0.93, 95% CI 0.83 to 1.03) was associated with decreased odds of infant mortality but was not statistically significant. High minimum wage was significantly associated with reduced infant mortality among non-Hispanic black infants (AOR=0.80, 95% CI 0.68 to 0.94) but not among non-Hispanic white infants (AOR=1.04, 95% CI 0.92 to 1.17).
Conclusions Increasing the minimum wage might be beneficial to infant health, especially among non-Hispanic black infants, and thus might decrease the racial disparity in infant mortality.
- infant mortality
- social epidemiology
- health inequalities
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Contributors NR helped to conceptualise the study and wrote the first draft of the paper. DC, AE and PM helped to interpret the findings and reviewed and revised the manuscript. NR and AO assisted with the literature review for the Introduction and Discussion sections. RP conceptualised and designed the study, conducted the analyses, and reviewed and revised the manuscript. All authors approved the final manuscript as submitted and agreed to be accountable for all aspects of the work.
Funding National Institutes of Health Research, National Institute on Minority Health and Health Disparities 1R15MD010223-01. RP is a Tier II Canada Research Chair in Social and Health Inequities throughout the lifespan.
Disclaimer The authors have no financial relationships relevant to this article to disclose.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethics approval was obtained from the University of Nevada Reno’s institutional review board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data linked to area of birth and death may be obtained from a third party and are not publicly available.
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