Effectiveness of Cultivando La Salud: A Breast and Cervical Cancer Screening Promotion Program for Low-Income Hispanic Women

María E. Fernández, PhD; Alicia Gonzales, MSW; Guillermo Tortolero-Luna, MD, PhD; Janet Williams, MPH; Monica Saavedra-Embesi, MPH; Wenyaw Chan, PhD; Sally W. Vernon, PhD

Disclosures

Am J Public Health. 2009;99(5):936-943. 

In This Article

Discussion

Our systematic review of the literature assessing the effectiveness of lay health worker models indicated that although such models represent a promising approach in health promotion, the evidence is insufficient to justify practice or policy recommendations.[50] Although intervention studies with lay health workers targeting Hispanics exist, few included rigorous evaluation methods to test program effectiveness,[50,77] and even fewer evaluated effects on mammography and Pap test screening.[78,79,80] Our study adds to the evidence of the effectiveness of the lay health worker approach among Hispanics and also to the US Preventive Services Task Force recommendation of 1-on-1 education as an effective strategy for increasing both breast and cervical cancer screening.[52] Our study also supports the Task Force recommendations for use of "small media" materials for increasing breast and cervical cancer screening[52] and adds to the small number of studies that target Hispanic women.

Because several studies have shown that less acculturated women are less likely to obtain mammograms and Pap tests,[81,82,83,84] we designed our intervention materials to appeal to these women.[7] Our study findings showed that the program was equally effective among low-acculturated and bicultural women. Future studies designed to identify which components of effective programs are most salient to persons of varying acculturation levels could improve our understanding of how to develop appropriately targeted programs for Hispanics.

We identified key determinants of screening during the pilot phase.[14,61] During program development, we chose methods and strategies that were expected to affect these determinants[59]: role models, persuasive messages, vicarious reinforcement,[85] facilitation,[86] and entertainment education (providing learning through a medium that both educates and entertains).[87] The results showing that the intervention did influence several of these variables ( Table 3 ) provide further evidence that the observed program effectiveness was attributable to the intervention and not to another external factor. These results also provide information about the effect of specific elements of the program. The intervention increased self-efficacy and positive attitudes toward screening and decreased fatalistic beliefs about the survivability of cancer (for breast cancer) but did not influence perceptions about the negative aspects of screening (cons).

We targeted perceived susceptibility in our program because it has been shown to be associated with breast and cervical cancer screening.[88,89] We included in our educational materials staged testimonials of women who had been diagnosed with these cancers; the actors were carefully chosen so that the study participants would identify with the characters and messages. Although these strategies influenced perceived susceptibility for breast cancer, they did not seem to influence perceived susceptibility for cervical cancer. This may indicate that stronger messages or different approaches are needed. Future studies should examine how changes in perceived susceptibility and other determinants interact to influence mammography and Pap test screening.

Although the intervention successfully increased the perception of pros about both mammography and Pap test screening, neither the perception of cons for mammography nor those for Pap test screening were significantly different between the intervention and control groups at the posttest assessment. Nevertheless, the intervention influenced the overall decisional balance scores (decisional balance=pros-cons),[65] which were higher in the intervention group than in the control group (for both mammography and Pap test screening). It is possible that an intervention such as Cultivando la Salud may increase positive attitudes about screening but may not be sufficient to decrease negative (and perhaps accurate) perceptions of the screening tests (e.g., pain, embarrassment, cost, inconvenience). These findings indicate that it may be more important and feasible to shift decisional balance by increasing the perception of pros rather than by decreasing the perception of cons.

In general, the intervention had a similar effect on intermediate variables for both mammography and Pap test screening. One difference was that although the intervention increased perceived susceptibility and survivability of breast cancer among women in the mammography cohort, it did not increase these perceptions related to cervical cancer among women in the Pap test cohort. Because mean scores for cervical cancer survivability were high in both the intervention and the control groups, it is possible that there is a ceiling effect and that the intervention messages were not strong enough to further increase perceived survivability.

Strengths and Limitations

A strength of our study is that we assessed the effectiveness of the Cultivando la Salud program under real-world conditions. The program was implemented in the same manner as it would be in clinic and community settings. Although many intervention trials describe implementation by researchers or program developers, in our study the clinic staff used the program to train lay health workers, who in turn delivered the intervention. This process increased the external validity of our study, and practitioners can be more confident that the intervention will have a similar impact in their communities than if we had conducted the trial under more artificial conditions.

Several factors limit the generalizability of our study findings. First, although the program was designed to be applicable to Hispanics from different subpopulations and used bilingual materials, the study participants were primarily Mexican American. Studies examining program effectiveness with other Hispanic populations are warranted. Also, because most participants preferred the Spanish-language materials, we recommend future studies evaluating the English-language materials. Finally, because this study included only women who were 50 years and older, no information about the potential effectiveness of the Pap test screening component among younger women was produced. Evaluation of the Pap test screening materials among younger women is encouraged.

Two possible limitations are related to the study response rate. First, the reported response rate (88.6%) was based on all women who completed the baseline interview among all women eligible for the interview. However, only a subset of these women (i.e., those nonadherent to breast and cervical cancer screening) was eligible for the intervention trial. Because we do not have screening information for those who refused to participate in the survey, we cannot calculate a response rate specifically for nonadherent women. Another possible limitation is the potential for nonresponse bias introduced by different response rates across sites. We did not have information on women who refused to participate, so we could not analyze differences in demographic characteristics or other factors that might distinguish participants from nonparticipants. However, because the invitation to participate in the intervention trial took place after completion of the survey, and all women across the 4 sites who had completed the survey and were nonadherent to screening agreed to participate in the trial, it is unlikely that group assignment influenced the participation rate.

Another limitation of the study was the rate of loss to follow-up (33.1%). Although we attempted to reach participants for follow-up during seasons when there was less migration for farm work, migration schedules vary depending on the crops that individual farmworker families typically follow. The fact that women in the intervention group had higher rates of loss to follow-up than did those in the control group may partially be explained by the fact that the intervention group on the US-Mexico border (Eagle Pass) had a higher proportion of women who were still doing farm work (15% vs 5%) and migrating for work (65% vs 25%) than did the control group. Another potential explanation of differential follow-up across groups is that the additional time burden for women in the intervention group may have affected willingness to complete final follow-up. At follow-up, women in the intervention group were being asked to spend another 2 hours with a data collector to talk about breast and cervical cancer screening yet again. This may have seemed unnecessary, particularly for those who had already obtained screening or had made a decision not to be screened.

When we addressed the potential bias introduced by our rate of loss to follow-up in an intent-to-treat analysis, screening completion among the intervention group remained higher than in the control group, but these differences were not statistically significant. Analyses that compared women who were lost to follow-up and those who remained in the study, however, revealed no differences on variables related to screening (income, education, insurance). Thus, the intent-to-treat analysis may be overly conservative.

Conclusions

Our study provided further evidence that the lay health worker model can increase breast and cervical cancer screening among low-income Hispanic women. Although several examples of successful lay health worker programs have now been documented, more research that explores the interaction between lay health workers and community members is needed. Such studies will improve our understanding of the active ingredients of the lay health worker model (e.g., information tailoring, trust, modeling, persuasion) and subsequently lead to more effective interventions, lay health worker training, and implementation protocols.

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