Why a peer intervention program for Mexican-American women failed to modify the secular trend in cancer screening.

Abstract

INTRODUCTION: We evaluated an intervention program for Mexican-American women to increase Pap smear and mammography screening. METHODS: The three-year intervention included the presentation of role models in the media and reinforcement by peer volunteers. We used a two-community (intervention and comparison) pre-post test design. Activities were targeted to a mainly Spanish-speaking, poverty-level, immigrant population. Pre- and postintervention screening rates were based on independent random samples of Mexican-American women 40 years and older. RESULTS: Women reported a 6% absolute increase in Pap smear use similar to the 7% increase in the comparison community. Both communities experienced large but similar increases in recent mammography use (17% and 19%). Adjusting for differences in demographic factors, intervention and comparison changes remained identical. CONCLUSIONS: Our peer intervention failed to accelerate the secular trend in cancer screening low-income Mexican-American women. Likely, promotional activities were too diffuse and the comparison community was contaminated with similar interventions. Strong social and market forces make it difficult to measure the effect of a specialized intervention on cancer screening rates.