摘要：Objectives. We examined the relationship between state-level income inequality and alcohol outcomes and sought to determine whether associations of inequality with alcohol consumption and problems would be more evident with between-race inequality measures than with the Gini coefficient. We also sought to determine whether inequality would be most detrimental for disadvantaged individuals. Methods. Data from 2 nationally representative samples of adults (n = 13 997) from the 2000 and 2005 National Alcohol Surveys were merged with state-level inequality and neighborhood disadvantage indicators from the 2000 US Census. We measured income inequality using the Gini coefficient and between-race poverty ratios (Black–White and Hispanic–White). Multilevel models accounted for clustering of respondents within states. Results. Inequality measured by poverty ratios was positively associated with light and heavy drinking. Associations between poverty ratios and alcohol problems were strongest for Blacks and Hispanics compared with Whites. Household poverty did not moderate associations with income inequality. Conclusions. Poverty ratios were associated with alcohol use and problems, whereas overall income inequality was not. Higher levels of alcohol problems in high-inequality states may be partly due to social context. A growing literature examines the impact of area-level income inequality on health. Inequality, or the size of the difference in income between rich and poor, is distinct from absolute income or socioeconomic status (SES). 1 Recent systematic reviews have found associations between income inequality and health. 2–6 Theoretical 3,7 and empirical work suggests that income inequality may affect health through psychosocial pathways, whereby people compare themselves with those who are better (or worse) off, 4,8–10 and neomaterial pathways, whereby inequality leads to limited public investment in social goods such as education, health services, and welfare that directly affect health. 3,11,12 (The term “neomaterial” is used to acknowledge the fact that material conditions relevant to present-day health outcomes differ from those material conditions that influenced infectious diseases in the 19th century. 3 ) Most research on income inequality and health has focused broadly on health status and mortality, 2 but a few studies focus on specific health outcomes and health behaviors. 2,13,14 Among these is a small literature on alcohol that suggests that income inequality is associated with increased frequency of alcohol consumption, 13 volume of alcohol consumed, 14,15 drinking to drunkenness, 14 and death from chronic alcohol-attributable illnesses. 16 Results are not unequivocal, however. Findings for alcoholic cirrhosis are mixed, with one study finding a positive association for men but not women 15 and others finding no association. 17,18 Another study documented a curvilinear relationship with alcohol-related hospitalization, suggesting an initial decline in hospitalizations followed by a rapid rise as inequality increases. 16 Finally, one study found that state-level income inequality was negatively associated with women’s alcohol dependence, but not after adjustment for state beer taxes. 19 To date, this literature on income inequality and alcohol has not examined whether income inequality affects alcohol consumption and related problems equally across SES and race/ethnicity. Furthermore, it has primarily measured income inequality using the Gini coefficient, a measure that captures the difference between an observed income distribution and a condition of complete equality. 1 We have expanded on the existing literature by examining SES and race/ethnicity as moderators of associations between income inequality and alcohol outcomes, and by examining race-based measures of income inequality in addition to the Gini coefficient. Income inequality may not affect everyone in the same way. 2,20 Affluent individuals may benefit from 2 or be immune to the negative effects of21 living in unequal areas, whereas poorer people and Black and Hispanic people may suffer a “double jeopardy” in unequal areas. 20,21 This double jeopardy hypothesis, however, may be specific to certain health and social outcomes. 18 For example, compared with more egalitarian areas, areas with more unequal income distribution have stronger inverse associations between individual SES and adolescent literacy 21 as well as mortality from alcoholic liver disease. 18 These studies indicate that there is an interaction of individual SES and income inequality for certain outcomes. By contrast, some evidence suggests largely uniform (rather than differential) effects of income inequality on poor self-rated health 22 ; however, most alcohol studies have not examined possible moderators of effects of income inequality. Income inequality can be measured overall or by comparing the status of 2 groups. Overall measures incorporate the range and distribution of incomes with the extent of inequality. The most commonly used overall measure is the Gini coefficient. 1 By contrast, relative measures emphasize income or poverty differences between groups based on demographic characteristics. For example, between-race income inequality measures summarize differentials in income between various racial/ethnic groups living in the same area and have been used in the criminology literature. 23,24 In the United States, there are stark differences in income and poverty status between Whites, Blacks, and Hispanics. In 2000, the ratio of per capita income of Whites to Blacks was 1.66 and of Whites to Hispanics was 1.97, with 15% of Whites, almost 30% of Blacks, and more than 20% of Hispanics having family incomes below the federal poverty threshold. 25 Use of these relative measures seems especially relevant given our interest in examining whether race/ethnicity moderates the associations between income inequality and alcohol outcomes. We examined whether income inequality, measured by the Gini coefficient and 2 between-race measures, is associated with light to moderate alcohol consumption, heavy alcohol consumption, alcohol-related consequences, and alcohol dependence. Although not tested explicitly here, heavy (but not light) alcohol consumption may be linked to income inequality primarily through the psychosocial pathway (such as drinking to cope with stress), whereas alcohol problems additionally may be influenced by neomaterial effects of inequality (such as increased policing 24 or decreased funding for alcohol treatment services). We also investigated whether associations with inequality were most detrimental for disadvantaged individuals (people in poor neighborhoods, with low household income, or racial/ethnic minority status), which also may suggest neomaterial effects of inequality. 3
