Sleepless in inequality: findings from the 2018 behavioral risk factor surveillance system, a cross-sectional study

Despite the large body of research on the adverse effects of income inequality, to date, few studies have examined its impact on sleep. The objective of this investigation is to examine the association between US state income inequality and the odds for regularly obtaining inadequate (< 7 h) and very inadequate (< 5 h) of sleep in the last 24 h.

We analysed data from 350,929 adults participating in the US 2018 Behavioral Risk Factor Surveillance System (BRFSS). Multilevel modeling was used to determine the association between state-level income inequality, as measured by the Gini coefficient, and the odds for obtaining inadequate and very inadequate sleep. We also determined if associations were heterogeneous across gender.

A standard deviation increase in the Gini coefficient was associated with increased odds for inadequate (OR = 1.06, 95% CI: 1.00, 1.13) and very inadequate sleep (OR = 1.11, 95% CI: 1.03,1.20). Also, a cross-level Gini Coefficient X Gender interaction term was significant (OR = 1.07, 95% CI:1.01,1.13), indicating that increasing income inequality was more detrimental to women's sleep behavior.

Future work should be conducted to determine whether decreasing the wide gap between incomes can alleviate the burden of income inequality on inadequate sleep in the United States.