Income distribution, socioeconomic status, and self rated health in the United States: multilevel analysis

OBJECTIVE: To determine the effect of inequalities in income within a state on self rated health status while controlling for individual characteristics such as socioeconomic status. DESIGN: Cross sectional multilevel study. Data were collected on income distribution in each of the 50 states in the United States. The Gini coefficient was used to measure statewide inequalities in income. Random probability samples of individuals in each state were collected by the 1993 and 1994 behavioural risk factor surveillance system, a random digit telephone survey. The survey collects information on an individual's income, education, self rated health and other health risk factors. SETTING: All 50 states. SUBJECTS: Civilian, non-institutionalised (that is, non-incarcerated and non-hospitalised) US residents aged 18 years or older. MAIN OUTCOME MEASURE: Self rated health status. RESULTS: When personal characteristics and household income were controlled for, individuals living in states with the greatest inequalities in income were 30% more likely to report their health as fair or poor than individuals living in states with the smallest inequalities in income. CONCLUSIONS: Inequality in the distribution of income was associated with an adverse impact on health independent of the effect of household income.