Effect of area poverty rate on cancer screening across US communities

Abstract

Study objective: To analyse the contextual effect of area poverty rate on never having been screened for breast, cervical, and colorectal cancer by (1) describing the extent of the variation in screening behaviours among 98 US metropolitan areas; (2) determining if the variation in lack of screening can be explained by differences in the characteristics of the persons who resided in these areas; and (3) determining if living in a metropolitan area with a higher poverty rate increased the likelihood of never having been screened for cancer over and above individual characteristics. Design: Cross sectional survey using data from the 2002 Behavioral Risk Factor Surveillance System. Multilevel logistic regression included both individual level factors as well as area poverty rate. Setting: Ninety eight areas across the USA. Participants: Over 118 000 persons residing in 98 areas; a sample aimed at estimating 48.3% of the US population age 18 or older. Main results: After adjustment for individual level factors, increasing area level poverty rate (per 5%) remained associated with never having had a mammogram (odds ratio (OR) = 1.28, 95% confidence interval (CI): 1.03 to 1.37); clinical breast examination (OR = 1.28, 95% CI: 1.11 to 1.48), colonoscopy/sigmoidoscopy (OR = 1.10, 95% CI: 1.01 to 1.19), and a faecal occult blood test (OR = 1.19, 95% CI: 1.12 to 1.27). Poverty rate was not independently associated with never having had a Pap smear (OR = 1.12; 95% CI: 0.90 to 1.41). The size of the variance among metropolitan or micropolitan statistical areas (MMSAs) varied by type of screening test, with intraclass correlation coefficients ranging from 4.9% (never having had a Pap smear) to 1.2% (never having had a colonoscopy/sigmoidoscopy). Conclusions: Area poverty rate was independently associated with never having been screened for breast and colorectal cancer, but not cervical cancer. The size of the variance among MMSAs was modest at best.