Association between neighborhood poverty and use of screening colonoscopy, 2000–2007.

*Neighborhood socioeconomic status was measured by the percentage of households in the census-tract level below the 1999 federal poverty levels based on 2000 US census. Quartile 1 corresponds to the lowest socioeconomic (highest household poverty rates) group and Quartile 4 corresponds to the census tracts with the highest socioeconomic status relative to others in the study.†Estimates were adjusted for age at baseline, gender, modified Charlson comorbidity index at baseline, number of years of enrollment and health plan. Likelihood-ratio test p-value for heterogeneity across census tract was