Mediating factors in the relationship between income and mammography use in low-income insured women

Aim: We used secondary data from a prospective randomized mammography recruitment trial to examine whether attitudinal and facilitating characteristics mediate the observed relationship between annual household income and mammogram receipt among women in an integrated health plan. Methods: We compared 1419 women due for a screening mammogram based on the 1995 annual household income poverty definition for a family of four (<$15,000 vs. >$15,000). A telephone survey was used to collect information on household income, demographics, health behavior, attitudinal and facilitating variables. Administrative databases were used to document mammography receipt. We used Cox proportional hazards models to estimate the hazards ratio (HR) and 95% confidence interval (CI) of subsequent mammography use separately for women with and without a prior mammogram. Results: Several variables, including employment, living alone, believing that mammograms are unnecessary, having friends supportive of mammography, and ease of arranging transportation, completely mediated the effect of income on mammography use. In multivariable models, the direct predictive effect of income on mammography was reduced to nonsignificance (HR 1.13, 95% CI 0.82-1.54 in women with previous mammogram and HR 0.91, 95% CI 0.41-2.00 in women without previous mammogram). Conclusions: Providing insurance does not ensure low-income populations will seek screening mammography. Efficacious interventions that address attitudes and facilitating conditions may motivate mammography use among low-income women with insurance.