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

Methods

We developed an educational intervention (Cultivando la Salud) in 2004 to increase breast and cervical cancer screening among low-income, low-literacy, Hispanic female farmworkers aged 50 years and older. Even though Pap test screening is recommended for younger women, we chose to include only women 50 years and older because evidence suggests that rates of invasive cervical cancer are higher, rates of screening are lower, and barriers to screening differ among older Hispanic women than among younger women.[13,18,53,54,55,56,57] We developed the intervention by using principles of community-based participatory research[58] and intervention mapping, a systematic approach for intervention planning and implementation.[14,59] We chose lay health workers to deliver the intervention program because of their unique ability to reach, through personal contact in the community, women who rarely or never access medical care. Lay health workers were expected not only to educate women and motivate them to obtain screening but also to offer practical assistance that would facilitate the women's access to screening services.

The program materials consisted of a program manual, a training curriculum, and a set of teaching tools for the lay health workers ("tool box"). The program manual was designed to increase adoption of the program and to provide guidelines for program implementation and sustainability. It included a description of the program, evidence of its effectiveness, and information about how to develop and manage a lay health worker program. The training curriculum consisted of lesson plans, learning activities, and visual aids for lay health worker training by clinic staff. The "tool box" contained bilingual breast and cervical cancer educational materials including a video, flipchart, breast models, pamphlets, and a teaching guide. The lay health workers used these materials to deliver screening information to women in the community.[60] A pilot study conducted in 2 farmworker communities in south Texas (Brownsville and Pharr) provided information on the appropriateness and acceptability of the educational materials and the feasibility of implementing the program.[14,61]

Study Design

The intervention trial had a pre-post comparison group design with matched pairs of communities in 2 geographic areas, and communities within pairs were randomly assigned to either the intervention or control group. We selected 2 communities along the US-Mexico border (Anthony, NM, and Eagle Pass, TX) and 2 in the Central Valley of California (Merced and Watsonville). We selected colonias (neighborhoods) based on 4 criteria: the existence of a Community and Migrant Health Center with a lay health worker program, a high proportion of farmworker women who were 50 years and older living in the catchment area of the Community/Migrant Health Center, no active breast or cervical cancer educational program currently in operation, and the availability of a screening site supported by the National Breast and Cervical Cancer Early Detection Program within 20 miles of the health center. We selected farmworker "home-based" communities (where farmworker families return following migration for work), because farmworker families typically live in these communities for several months of the year, easing participant follow-up and tracking. Each health center agreed to not engage in any other breast or cervical cancer outreach and education activities in the targeted communities during the term of the study. The 2 communities in each area (US-Mexico border and California Central Valley) were randomly assigned to either the intervention group (Merced and Eagle Pass) or the control group (Watsonville and Anthony).[60]

Participant Recruitment

To be eligible to participate in the baseline survey, women had to be 50 years or older, have no prior or current cancer diagnosis, and have farmworker status (defined as personal or family participation in farm work for at least 5 years during their lifetime). Participants were identified by using the EPI Sampling Quadrants Scheme.[62] Each colonia was divided into 4 quadrants, and after selecting a starting point in each quadrant, data collectors systematically walked the neighborhood door-to-door. Data collectors screened households for eligible women and continued to the next house until all households in the quadrant had been visited. Eligible women were invited to participate in the study, and those who agreed completed the baseline interview. If more than 1 woman in a household was eligible, the woman with the most recent birth date was selected. Participants received a $20 incentive upon completion of the interview.

Baseline data were collected during a 2-month period. All interviewers were recruited from the community and were female, bilingual, and had attended a 2-day training session before data collection. All interviews were conducted in Spanish and lasted approximately 2 hours.

During the recruitment period, 805 eligible women were asked to complete the baseline survey; of these, 713 (88.6%) agreed. Response rates were high in Watsonville (96%), Anthony (92%), and Eagle Pass (88%), but lower in Merced (70%). Among those who agreed to be surveyed, only women not adherent to breast or cervical cancer screening recommendations (i.e., no mammogram in the past year or no Pap test in the past 3 years) were invited to participate in the intervention trial. Of the 713 women who completed the baseline survey, 497 were nonadherent to mammography (n=464) or Pap test (n=243) screening recommendations. Some women (n=211) were nonadherent for both mammography and Pap test screening and therefore were included in both cohorts. All nonadherent women agreed to participate in the trial.

Measurements

The baseline interview consisted of 276 brief, closed-ended questions with discrete response categories. The instrument was refined after pilot testing with 200 low-income Hispanic women and is described elsewhere.[63] The sociodemographic characteristics assessed included age, education, place of birth, income, insurance, marital status, farmworker-related information (e.g., migration, crops), and acculturation level. Screening behavior was assessed by asking participants the exact month and year of their last mammogram and Pap test. Those unable to remember the date were asked to estimate the number of years elapsed since being screened.

Acculturation was measured with the Bidimensional Acculturation Scale, which included 60 items.[64] Psychosocial constructs were assessed with 5-point Likert-type scales. The measure to assess processes of change in decision making was adapted from an existing scale and included 7 items for processes of change for Pap test screening and 9 items for mammography screening.[65] Other scales, including those assessing the perceived pros and cons (benefits and barriers) of mammography (20 items) and Pap test screening (16 items),[66,67,68] subjective norms (6 items),[69] perceived survivability of cancer (2 items),[70] perceived susceptibility to cancer (4 items),[71,72] and mammography and Pap test self-efficacy (a measure of how confident the woman feels in her ability to obtain the screening; 11 and 8 items, respectively),[73] included items from existing scales and new items generated from our focus groups and other findings, as described elsewhere.[74] The internal consistency of scales with more than 3 items for the baseline data was as follows: perceived susceptibility to breast and cervical cancer (0.93 and 0.93, respectively), perceived pros and cons of mammography (0.84 and 0.82, respectively), perceived pros and cons of Pap test screening (0.87 and 0.75, respectively), processes of change for mammography (0.57) and Pap test (0.90) screening, self-efficacy for mammography (0.92) and Pap test (0.95) screening, subjective norms for mammography (0.80) and Pap test (0.82) screening, and acculturation (0.90).

Intervention Implementation

Lay health workers contacted all women in the intervention communities who had completed the baseline survey to set up an appointment for a 1-on-1 session in the women's homes within 2 months of the initial contact. The sessions, lasting 1 to 2 hours each, consisted of a presentation and discussion using the Cultivando la Salud materials. At the end of each session, the lay health workers gave the women information about local providers of breast and cervical cancer screening. Two weeks after the intervention was delivered, the lay health workers contacted the participants in person or by phone to provide any further assistance that might be needed.

We used process evaluation measures, including lay health worker encounter forms and randomly selected instances of direct observation (by a supervisor), to provide information about program delivery.

Women in the intervention and control communities were followed up 6 months after the completion of the educational intervention. During the follow-up visit, the women completed a second face-to-face interview and received an incentive of $20.

Analyses

To assess the overall effectiveness of the intervention on the primary outcomes, we calculated the percentage of women who reported having completed screening for each behavioral outcome (mammography and Pap test) among those reached for follow-up in the mammography (n=307) and Pap test (n=170) cohorts. We also calculated the percentage of women who reported having completed screening among all women regardless of whether they were reached for follow-up (intent-to-treat analysis, n=497).

We first tested differences in screening completion between the intervention and control groups stratified by geographic region (US-Mexico border and California Central Valley) using the Mantel-Haenszel test. We then used generalized linear mixed models to perform the analysis of the effect of the intervention on mammography and Pap test screening. In these analyses, demographic variables that were significantly associated with the outcomes or were significantly different between groups (i.e., education for the Pap test model, and income and insurance for the mammography model) were included in the fixed effect for adjustment of the model that had logit as its link function. Site location (US-Mexico border or California) was used as a random effect to adjust for possible correlation of the outcome within the geographic area.

The validity of self-reported screening behavior was evaluated by reviewing the medical records of all women who reported having completed screening and a random sample of 25% of participants who reported having no screening in each site. Screening records for 58.3% of women in the mammography cohort and 57.3% of women in the Pap test cohort were located. We calculated validity with concordance, sensitivity, and specificity estimates.[75] Overall, concordance, sensitivity, and specificity estimates for both cohorts met Tisnado's[76] criteria for good agreement (concordance estimate>0.80). The concordance estimate for the mammography cohort was 0.81, with sensitivity and specificity estimates of 0.83 and 0.81, respectively. For the Pap test cohort, the concordance estimate was 0.83, with sensitivity and specificity estimates of 0.83 and 0.82, respectively.

To assess the efficacy of the intervention on intermediate variables, we first calculated scale scores for each construct. We then assessed differences at follow-up (posttest) between the intervention and control groups on intermediate variables by using a generalized linear mixed model with site as the random effect and the pretest score serving as a covariate. We also adjusted for demographic variables.

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