A multilevel analysis of income inequality and cardiovascular disease riskfactors

Recent research has suggested that inequality in the distribution of income is associated with increased mortality, even after accounting for average income levels. Using data from the Behavioral Risk Factor Surveillance Syst em (BRFSS), we investigated whether inequality in the distribution of incom e within US states is related to the prevalence of four cardiovascular dise ase risk factors (body mass index (BMI), history of hypertension, sedentari sm, and smoking). Multilevel models (including both state-level and individ ual-level variables) were used to examine associations of state inequality with risk factor levels before and after adjustment for individual-level in come. For three of the four risk factors investigated (BMI, hypertension, a nd sedentarism), state inequality was associated with increased risk factor levels, particularly at low income levels (annual household incomes <$25,0 00), with associations persisting after adjustment for individual-level inc ome. Inequality was also positively associated with smoking, but associatio ns were either stronger or only present at higher income levels. Associatio ns of inequality with the outcomes were statistically significant in women but not in men. Although not conclusive, findings for three of the four ris k factors are suggestive of a contextual effect of income inequality, parti cularly among persons with lower incomes. (C) 2000 Elsevier Science Ltd. Al l rights reserved.