title: Income disparity and risk of death: the importance of health behaviors and other mediating factors.
abstract: BACKGROUND
  Income disparities in mortality are profound in the United States, but reasons for this remain largely unexplained. The objective of this study was to assess the effects of health behaviors, and other mediating pathways, separately and simultaneously, including health insurance, health status, and inflammation, in the association between income and mortality.
  
  
  METHODS
  This study used data from 9925 individuals aged 20 years or older who participated in the 1999-2004 National Health and Nutrition Examination Survey (NHANES) and were followed up through December 31, 2006 for mortality. The outcome measures were all-cause and CVD/diabetes mortality. During follow-up 505 persons died, including 196 deaths due to CVD or diabetes.
  
  
  RESULTS
  After adjusting for age, sex, education, and race/ethnicity, risk of death was higher in low-income than high-income group for both all-cause mortality (Hazard ratio [HR], 1.98; 95% confidence interval [CI]: 1.37, 2.85) and cardiovascular disease (CVD)/diabetes mortality (HR, 3.68; 95% CI: 1.64, 8.27). The combination of the four pathways attenuated 58% of the association between income and all-cause mortality and 35% of that of CVD/diabetes mortality. Health behaviors attenuated the risk of all-cause and CVD/diabetes mortality by 30% and 21%, respectively, in the low-income group. Health status attenuated 39% of all-cause mortality and 18% of CVD/diabetes mortality, whereas, health insurance and inflammation accounted for only a small portion of the income-associated mortality (≤6%).
  
  
  CONCLUSIONS
  Excess mortality associated with lower income can be largely accounted for by poor health status and unhealthy behaviors. Future studies should address behavioral modification, as well as possible strategies to improve health status in low-income people.
authors.affiliation: Division of Health Behavior Research, Washington University School of Medicine, Saint Louis, MO, USA. sjarvand@dom.wustl.edu
authors.forename: Soghra
authors.initials: S
authors.lastname: Jarvandi
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Mario
authors.initials: M
authors.lastname: Schootman
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000191:economics / Q000401:mortality; D003920:Diabetes Mellitus / Q000191:economics / Q000401:mortality; D005260:Female; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012307:Risk Factors; D014481:United States