Influence of individual and neighbourhood socioeconomic status on mortality among black, Mexican-American, and white women and men in the United States.

STUDY OBJECTIVE: s: This study examines the influence of individual and neighbourhood socioeconomic status (SES) on mortality among black, Mexican-American, and white women and men in the US. The authors had three study objectives. Firstly, they examined mortality rates by both individual level SES (measured by income, education, and occupational/employment status) and neighbourhood level SES (index of neighbourhood income/wealth, educational attainment, occupational status, and employment status). Secondly, they examined whether neighbourhood SES was associated with mortality after controlling for individual SES. Thirdly, they calculated the population attributable risk to estimate the reduction in mortality rates if all women and men lived in the highest SES neighbourhoods.

DESIGN: National Health Interview Survey (1987-1994), linked with 1990 census tract (neighbourhood proxy) and mortality data through 1997.

SETTING/PARTICIPANTS: Nationally representative sample of 59 935 black, 19 201 Mexican-American, and 344 432 white men and women (six gender and racial/ethnic groups), aged 25-64 at interview.

MAIN RESULTS: Mortality rates for all six gender and racial/ethnic groups were two to four times higher for those with the lowest incomes (lowest quartile) who lived in the lowest SES neighbourhoods (lowest tertile) compared with those with the highest incomes who lived in the highest SES neighbourhoods. For the six groups, the age adjusted mortality risk associated with living in the lowest SES neighbourhoods ranged from 1.43 to 1.61. The mortality risk decreased but remained significant (p values <.05) after adjusting for each of the three individual measures of SES, with the exception of Mexican-American women. Furthermore, the mortality risk associated with living in the lowest SES neighbourhoods remained significant after simultaneously adjusting for all three individual measures of SES for white men (p<0.001) and white women (p<0.05). Deaths would hypothetically be reduced by about 20% for each subgroup if everyone had the same death rates as those living in the highest SES neighbourhoods (highest tertile).

CONCLUSIONS: Living in a low SES neighbourhood confers additional mortality risk beyond individual SES.