Association of poverty with sudden infant death syndrome in metropolitan counties of the United States in the years 1990 and 2000

BACKGROUND: Sudden infant death syndrome (SIDS) has been associated with poverty indirectly in the United States with the use of vital statistics data by using proxies of socioeconomic status such as maternal education. OBJECTIVES: The objective of this analysis was to examine the relationship of poverty to SIDS at an ecologic level, by examining the association between poverty within metropolitan counties of the United States and the occurrence of SIDS within those metropolitan counties. METHODS: The percentage of each US county's population below established federal poverty guidelines (poverty index) was obtained from US Census data for 1990 and 2000 by race (Hispanic-HISP, non-Hispanic white-NHW, and non-Hispanic black-NHB). These data were merged by year of birth, county, and race with US Vital Statistics Linked Birth and Infant Death Certificate data. RESULTS: Fourth (highest poverty quartile) versus first quartile poverty odds ratios (OR) were significantly increased in 1990 and 2000 for NHB (OR1990 = 1.84, OR2000 = 2.29) and NHW (OR1990 = 1.87, OR2000 = 2.17), but not for HISP (OR1990 = 0.64, OR2000 = 0.59). CONCLUSIONS: There is a significant association between poverty and SIDS at the metropolitan county level for NHB and NHW. Hispanics do not demonstrate this association.