Understanding the impact of colorectal cancer education: a randomized trial of health fairs

The United States (US) Preventive Services Task Force, the American Cancer Society and the American College of Physicians have established national guidelines that recommend colorectal cancer (CRC) screening for average-risk adults starting at age 50 [1]. Although there have been general increases in CRC screening in the last two decades [2], there are disparities in CRC screening, as well as in CRC incidence and mortality [3]. Research indicates that CRC screening is especially low in minority and low socio-economic status (SES) groups; some research suggests that these populations have both low awareness of CRC and low knowledge about CRC screening [4–7].

Health fairs are a common health promotion strategy used in community settings to disseminate information about public health topics to a large segment of a population. Health professionals, or trained organizational representatives and volunteers sit at a table and offer educational materials, interactive activities, and are available to answer questions. When resources are available, health screening tests such as oral exams, blood pressure checks, cholesterol tests, diabetes tests, HIV tests, and mammography may also offered at these health fair events [8]. There is inconclusive evidence regarding the effectiveness of health screenings done at health fairs. One study in 1985 found that screenings may generate false positives in healthy people, and false negative results may provide a false sense of security for people at risk for disease [9]. Interestingly, a study published in 1991 found that among 303 adult health fair participants, 47 % reported that obtaining screening tests was the sole reason for attending the event [10]. Another study published in 2006 found that screenings may offer financial value for people with little or no insurance [11]. Nevertheless, most recently, community health fairs that offer screenings have been found to be a culturally appropriate way to reach underserved Hispanics [12].

Studies looking at the impact of health fairs have been few. In 2001, one published study did a formative evaluation of the planning and implementation of a health fair and found the event to be a success. Unfortunately, outcome evaluation was beyond the scope of that project [13]. In 2005, a study found lifestyle changes made among participants in rural farm health fairs [14]. Most recently, in 2015, senior wellness fairs were found to be an effective tool to help students obtain skills and knowledge in providing health promotion information to older adults [15].

The Center for Community Health Promotion (CCHP) of the Fred Hutchinson Cancer Research Center (FHCRC) participates in many health fairs throughout three counties in Eastern Washington. CCHP promotores offer instruction about CRC and CRC screening at these events using an inflatable colon. When the inflatable colon cannot be accommodated at an event, the promotores use more conventional materials, such as flip charts, tabletop displays, brochures, and videos. The inflatable colon has been demonstrated to be efficacious in increasing knowledge and intention to be screened, as well as actual screening behavior using a one group pre-test/post-test design in different geographic areas of the US [16–18]. Based on findings from a local prior study where we learned that the inflatable colon was an innovative way to learn about CRC [16], the project team was interested in learning about the success of the inflatable colon relative to the more conventional materials in increasing CRC awareness and knowledge as well as intention to be screened. The overall purpose of this project was to assess two different methods for increasing knowledge about CRC in a health fair context: one, by using a health educator to provide CRC information at a table, or two, to provide a tour through a giant, inflatable, walk-through colon model with physical depictions of healthy tissue, polyps, and CRC.

In the analysis of change in knowledge of risk factors for CRC, participants who received information using the inflatable colon showed an increase in the percentage correct of 7 % compared to participants who received information through tabling, where the increase in the percentage correct on knowledge of risk factors for CRC questions was 2 %. Again, however, the difference between the two groups in the change in knowledge of 5 % was not statistically significant (p value = 0.09) based on robust standard errors from GEE estimates.

In this randomized study, we demonstrated that the use of an inflatable colon increases knowledge about CRC and CRC screening; and is more effective at increasing knowledge than conventional materials, such as flip charts, tabletop displays, brochures, and videos. However, these observed differences were not statistically significant, possibly due to sample size. We also learned that awareness of CRC screening methods increased by a difference of 18 %, but this also was not statistically significant. While there are trends towards the benefit of the inflatable colon our sample size may not have been sufficient to detect significant differences. Intra-site correlation may have reduced our power to detect significant differences between the two groups. Future studies with more participants per study site (e.g. health fair) or more sites would improve power to detect differences in the use of the inflatable colon to educate individuals about CRC.

This study adds to the body of knowledge that educational interventions which vary in the type of learning methods (visual, text and audio) are no more effective at increasing comprehension and recall than interventions that only include written/text materials [21]. In this small study of two clusters, both methods had similar outcomes in terms of awareness of CRC screening methods and in CRC knowledge overall [22–24]. We hypothesized that the inflatable colon, a visual and interactive display, would be more likely to increase CRC knowledge and awareness than an information table with conventional materials. However, even when combined with a walk-through tour, the inflatable colon was not significantly more effective compared to conventional materials.

Data from the one month follow-up questionnaires indicated that it was irrelevant how participants learned about CRC, neither arm (inflatable colon or tabletop information and materials) seemed to retain the knowledge one month after the health fair event. When examining the significance in knowledge after one month from pre- to follow-up, none of the questions had significant improvement except one, “A diet that doesn’t have many fruits and vegetables increases the risk of CRC” (p < 0.01). This was somewhat discouraging. One reason that may contribute to this is the use of a brief telephone call for the follow-up questionnaire, compared to promotor(a)-led personal questionnaires at the pre- and post-test stages. Another reason may be that the one-time, short interaction with promotores, either through the inflatable colon tour, or at an information table, is not long enough to enable participants to retain long-term understanding about CRC. It may be that more exposure to CRC information increases knowledge retention and likelihood to be screened [25]. It may also be that an intervention after participation in the health fair may be needed to have an impact on knowledge and behavior [26, 27]. Another explanation may be that not only health literacy, but also participants’ cognitive abilities, such as working memory and long-term memory, affect their ability to recall information [28]. Given that this population is of low socioeconomic status, it may be that there cognitive abilities are affected by the stressors in their daily lives.

In the US, racial differences in practices, knowledge, and barriers related to CRC screening exist [29]. There is evidence to show that literacy and knowledge regarding cancer may affect participation in prevention [30–32]. When compared to non-Hispanic whites, minorities are more likely to have inaccurate knowledge and beliefs regarding CRC, as well as increased perceived barriers regarding CRC screening [33]. More research is needed regarding interventions that address barriers to CRC screening among Hispanics, the fastest growing population in the US. It is imperative to reinforce the importance of CRC screening and encourage age-eligible participants to obtain CRC screening, but equally important to address barriers to screening [34, 35]. Barriers to colorectal cancer among Hispanics include factors such as fatalism about cancer survival, fear of the test, cost, low literacy and low level education, lack of awareness about screening, and lack of provider recommendation [36, 37]. With the advent of healthcare reform in the US, cost may become less of an issue for documented Hispanics.

The use of an inflatable colon or tabling to instruct participants at health fairs are both effective in changing participants awareness of CRC screening and in knowledge about CRC. There were more significant changes in CRC knowledge among participants who participated in an inflatable colon tour, compared to participants who did not; however, overall, the differences were not significant. Further research is needed to associate intention to obtain CRC screening after learning about CRC with actual CRC screening. Future research could explore ways to better retain CRC knowledge at long-term follow-up.