Racial differences in colorectal cancer screening practices and knowledge within a low-income population†
All participants provided written informed consent, and the study was approved by the institutional review boards at Wake Forest University Medical Center and Ohio State University.
Although colorectal cancer (CRC) is the third leading cause of cancer death among US women and is particularly deadly among African Americans, CRC screening rates remain low. Within a low-income population of women, the authors examined racial differences in practices, knowledge, and barriers related to CRC screening.
Face-to-face interviews were conducted with 941 women (white, n = 186; African American, n = 755) older than age 50 years who were living in subsidized housing communities in 11 cities in North and South Carolina. Women were asked questions about their CRC screening history and their knowledge and beliefs concerning CRC screening.
Half (49%) of the women interviewed were within CRC screening guidelines, and this did not vary by race (P = .17). However, African American women were half as likely as white women to report having had a screening colonoscopy within the past 10 years (odds ratio [OR], 0.46; P < .001). Awareness of tests for CRC was low overall (39%) and was lower among African Americans than whites (OR, 0.44; P < .001). Compared with white women, African American women were less likely to report embarrassment as a barrier (OR, 0.59; P = .008) and more likely to report lack of insurance coverage (OR, 1.75; P = .098).
Efforts must continue to increase women's knowledge of both CRC screening tests and colon cancer risk factors. Among these low-income women, routine encounters with the healthcare system may present opportunities to reduce deficits in CRC knowledge and to improve overall CRC screening rates. Cancer 2008. © 2007 American Cancer Society.
Colorectal cancer (CRC) is the third most common cause of cancer death among women in the United States, and its morbidity and mortality are preventable. The American Cancer Society estimated that in 2007, 26,180 women would die and that 74,630 new cases of CRC would be diagnosed among women.1 Colorectal cancer is particularly burdensome among African American women who experience a higher incidence rate (56.1 vs 46.8 per 100,000) and a higher mortality rate (24.5 vs 17.1 per 100,000) than white women.2
CRC screening rates remain low, despite evidence that screening reduces CRC incidence and can help reduce CRC mortality by early detection of cancers at more treatable stages.1, 3–6 Several CRC screening options are recommended for average-risk adults ages 50 years and older. These include an annual fecal occult blood test (FOBT), a flexible sigmoidoscopy (FSIG) every 5 years, a colonoscopy every 10 years, or a double-contrast barium enema (DCBE) every 5 years.1, 3 DCBE has less data supporting its effectiveness in light of its level of invasiveness.6 Data from the 2002 Behavioral Risk Factor Surveillance System Survey (BRFSS) show that only 29% of women ages 50 years and older had received a FOBT in the past 2 years and that only 48% had ever had a FSIG or colonoscopy.7 Compared with white women, African American women had lower rates of CRC screening. Women with very low incomes (<$15,000) also had much lower rates of CRC screening within guidelines.7 In addition, socioeconomic factors, such as younger age, the absence of health insurance, and low level of education, are consistently associated with decreased CRC screening rates.7–10
Because race and socioeconomic status (SES) are highly intertwined in the US, it is unclear whether CRC screening rate differences are true racial disparities or reflect differences in SES instead.11–13 Race and SES both appear to play roles in CRC incidence and survival.14–16 Although, beyond race, SES appears to be a predictor of cancer survival,17, 18 studies report that race also may be an important and independent predictor of stage at cancer diagnosis.18, 19 Thus, the examination of factors, such as those that may influence CRC screening and that may explain the differential impact of race on CRC morbidity and mortality, is critical.
Little is known about what influences individuals to seek CRC screening and whether such factors vary by race or SES. Prior studies have reported that lack of knowledge about screening tests and barriers at the patient, provider, and system levels contribute to low CRC screening rates.8–10, 20–23 For instance, insurance barriers affect CRC screening, including factors such as whether an individual has insurance, whether benefits cover CRC screening, and whether a person is designated to be at average risk or high risk of CRC.8, 24 However, few studies have been conducted in mainly low-SES populations. Thus, although we recognize various barriers that contribute to low screening rates, we still lack information about knowledge, beliefs, and screening practices of low-income individuals. Such information could be used to increase CRC screening participation among this population subgroup. Furthermore, although we know that tailoring intervention materials25 or culturally targeting interventions26 provides promise, we lack specific information about how awareness, knowledge, beliefs, and CRC screening practices of low-income persons may vary by race.
We interviewed female residents of low-income housing communities in North and South Carolina to explore their knowledge and beliefs about CRC screening and to determine whether these perceptions, or reported CRC screening practices, varied by race.
MATERIALS AND METHODS
Data for this study are from baseline interviews performed from June 2000-August 2001 as part of the Carolinas Cancer Education and Screening (CARES) Project, a trial of a community-based intervention designed to improve CRC screening rates among poor and minority women in North and South Carolina. Participants were residents of subsidized housing communities and included both African American and white women. All women provided written informed consent, and the study was approved by the institutional review boards at Wake Forest University Medical Center and The Ohio State University.
Participant Selection and Interview Process
Cross-sectional samples from lists of women residents of subsidized housing communities were randomly selected for the study. These lists were provided by the housing authorities of cities in the Southeast Division of the American Cancer Society at 5 time points (cycles) in the study. This Southeast Division included the cities of Greensboro, High Point, Winston-Salem, Rocky Mount, Wilson, Greenville, and Charlotte, North Carolina and Rock Hill, Anderson, Spartanburg, and Greenville, South Carolina.
Independent samples were taken at each cycle, and women were interviewed only once. Approximately 800 women were sampled in each cycle to obtain at least 400 interviews, 100 from each of the 4 regions within the Southeast Division. These natural regions were geographically separate and formed distinct media markets, which reduced cross-contamination within the study. A letter that introduced the project was sent to each woman selected, and an interviewer contacted each woman to determine eligibility (>50 years of age, resident of housing community), willingness to participate, and appointment time for the interview. Five attempts were made to contact each selected woman.
Data used in these analyses were collected during Cycles 1 and 2 of the study, before the introduction of any intervention. Interview response rates were 67% for Cycle 1 (n = 512) and 80% for Cycle 2 (n = 457) for a combined response rate of 73.5% (N = 969 including 28 women who listed a race other than African American or white) for these 2 survey cycles. Our analyses included a total of 941 surveys completed by white (n = 186) or African American (n = 755) women balanced across the 2 baseline study cycles.
Face-to-face interviews were conducted in participants' homes. Surveys asked questions on demographics, medical history, social support, sources of information about health, and about intentions and behaviors concerning CRC screening. Surveys also included questions to assess women's knowledge and beliefs about CRC and CRC screening, about the particular screening tests, and about barriers to screening. During interviews, women were first asked to name CRC tests, and then the women were given descriptions of each test before they were questioned about individual tests. In addition, during the 2 baseline study cycles, detailed questions were asked concerning beliefs about and barriers to the FSIG test specifically. These questions provided more information about this particular CRC screening test for our analyses.
Basic descriptive statistics were computed to describe the demographics of the study population. Women in the 2 racial groups were compared with respect to demographics, knowledge about CRC screening tests and risk factors, beliefs about colon cancer and CRC screening tests, and CRC screening experience. Frequencies and percentages were calculated for each demographic factor, and chi-square tests were used to test the differences in factors between African American and white women in the sample. The Fisher exact test was used where any expected cell count was ≤5.
Racial groups were also compared by frequency of recent CRC screening as follows: FSIG within the last 5 years, FOBT within the last year, colonoscopy within the last 10 years, or barium enema (DCBE) within the last 5 years. Having “any CRC test within guidelines” was also compared, which was defined as FSIG, FOBT, or colonoscopy within their respective timeframe guidelines. Although respondents were asked about receipt of DCBE, this test was not included as part of “any CRC test within guidelines,” as the test was a somewhat controversial option at the time15 and was not routinely recommended by physicians in the geographic regions under study. To model the effect of race on screening, a random effects model was used to account for the natural correlation of persons within a community across cycles. The model fit was a generalized linear mixed model with a logit link and binomial error function. Cycles 1 and 2 and age group (51–64 years, 65–74 years, 75–84 years, and ≥85 years) were included as fixed effects, and city was included as a random effect.
Specifically, both cycle and city were included in our models to adjust for any confounding by cycle or city. However, the major factors upon which this article is based—race, income, and education—did not differ between cycles. Age group was included in the model to reduce confounding after descriptive statistics revealed differences in age between races in this sample. Insurance status was not included in the model because its inclusion was not found to impact the effect of race on screening. The SAS macro GLIMMIX (SAS Institute, Cary, NC) was used for calculations. Odds ratios with 95% confidence intervals were calculated for the odds of each CRC screening test for African American compared with white women.
Frequencies and percentages were also calculated by racial group for each of the knowledge, belief, and barrier questions. The same generalized linear mixed model was used to identify and test odds ratios between racial groups for agreement with each knowledge, belief, and barrier item. The SAS System for Windows (SAS version 9.1; SAS Institute, Cary, NC; Windows operating system; Microsoft, Redmond, Wash) was used for all analyses.
Characteristics of Study Population
Demographic data for the study population are summarized in Table 1. Very few participants had graduated from high school (23%) or gone to college (7%), and most were either retired (41%) or unable to work (44%). The majority (86%) of women had some form of health insurance, and approximately two-thirds (64%) of the participants had a medical condition that required regular physician visits. Nearly two-thirds (63%) of the women had been encouraged to get an FSIG or FOBT test by their physician.
Table 1. Demographic Characteristics and Health History of Study Participants, by Race (N = 941)
|Total||80 (755)||20 (186)||100 (941)|| |
| Age, y|
| 51–64||43 (321)||16 (29)||37 (350)|| |
| 65–74||28 (211)||38 (71)||30 (282)|| |
| 75–84||22 (164)||30 (56)||23 (220)|| |
| 85+||8 (59)||16 (30)||9 (89)||<.001|
| 8th grade or less||39 (293)||32 (59)||37 (352)|| |
| 9th to 10th grade||33 (249)||31 (58)||33 (307)|| |
| HS grad, GED, tech||21 (160)||28 (52)||23 (212)|| |
| Some college||7 (51)||9 (17)||7 (68)||.096|
| Work status|
| Full/Part Time||10 (78)||3 (6)||9 (84)|| |
| Retired||37 (278)||57 (106)||41 (384)|| |
| Unable to work||46 (344)||35 (65)||44 (409)|| |
| Unemployed||4 (33)||2 (3)||4 (36)|| |
| Volunteer/Other||3 (22)||3 (5)||3 (27)||<.001|
| Marital status|
| Married/Living Together||5 (41)||1 (2)||5 (43)|| |
| Never married||16 (119)||8 (15)||14 (134)|| |
| Separated/Divorced||28 (212)||29 (54)||28 (266)|| |
| Widowed||50 (379)||62 (115)||53 (494)||<.001|
|Any Insurance (Yes)||84 (635)||91 (170)||86 (805)||.01|
| Current smoking status|
| Current||19 (140)||24 (44)||20 (184)|| |
| Former||25 (192)||24 (45)||25 (237)|| |
| Never||56 (422)||52 (97)||55 (519)||.29|
| Medical condition requiring regular doctor visits (Yes)||65 (488)||63 (118)||64 (606)||.74|
| Doctor told you that you had colon cancer (Yes)||1 (10)||2 (3)||1 (13)||.73|
| Doctor told you that you had other cancer (Yes)||8 (57)||19 (35)||10 (92)||<.001|
| Doctor ever encouraged you to get FSIG or FOBT (Yes)||62 (464)||67 (123)||63 (587)||.21|
The vast majority (80%) of study participants were African American. Comparing study participants by race, African American participants were younger and less likely to be retired than white participants, and African Americans were more likely to be married and/or living together (all P < .001). White participants were more likely to have health insurance (P = .01) and to report a history of cancer other than CRC compared with African American participants (P < .001).
CRC screening behaviors
Approximately half (49%) of the women had any CRC screening test within guidelines (Table 2). For the individual tests, screening practices within guidelines were all lower than 30%. There was no difference by race in receipt of “any CRC screening within guidelines” (P = .17), or of individual FOBT (P = .41), FSIG (P = .58), or DCBE (P = .35) tests within recommended time frequency guidelines. There was a significant difference by race for colonoscopy, with fewer African American women completing a colonoscopy within guidelines compared with white women (OR, 0.46; P < .001).
Table 2. CRC Screening Tests Received, by Race
|Any CRC screening in guidelines§||863||48 (337)||54 (90)||49 (427)||0.77 (0.54–1.11)||.17|
|FOBT within last year||907||19 (137)||15 (27)||18 (164)||1.22 (0.76–1.95)||.41|
|FSIG within last 5 y||915||28 (208)||31 (55)||29 (263)||0.90 (0.62–1.31)||.58|
|Colonoscopy within last 10 y||871||19 (132)||31 (50)||21 (182)||0.46 (0.31–0.69)||<.001|
|Barium enema within last 5 y||897||15 (105)||16 (29)||15 (134)||0.80 (0.50–1.28)||.35|
CRC screening awareness and knowledge
Across participants, 39% reported awareness of a test that checks to see if a person has CRC (Table 3), with African Americans having lower odds of knowing that there are tests to detect colon cancer versus whites (36% vs 52%; OR, 0.44; P < .001). When asked to name a specific test to check for colon cancer, only 9% could specifically name FSIG or FOBT, and 15% could name colonoscopy. African Americans again had significantly lower odds than whites of naming FSIG (OR, 0.59; P = .04), FOBT (OR, 0.39; P < .001) and colonoscopy (OR, 0.24; P < .001). African Americans were also less likely to report knowing the description of flexible sigmoidoscopy (OR, 0.55; P = .049).
Table 3. Knowledge, Beliefs, and Barriers about CRC Screening Tests and Colon Cancer, by Race (N = 941)
|Knowledge of CRC screening tests|
| Knowledge of screening tests for CRC||941||36 (274)||52 (97)||39 (371)||0.44 (0.31–0.62)||<.001|
| Name a test to check for colon cancer (FSIG)||941||8 (57)||13 (25)||9 (82)||0.59 (0.35–0.98)||.04|
| Name a test to check for colon cancer (FOBT)||941||7 (56)||14 (26)||9 (82)||0.39 (0.23–0.64)||<.001|
| Name a test to check for colon cancer (colonoscopy)||941||12 (90)||27 (51)||15 (141)||0.24 (0.16–0.38)||<.001|
| Knowledge of FSIG||941||13 (53)||22 (21)||15 (74)||0.55 (0.30–1.00)||.049|
| Knowledge of FOBT||941||37 (146)||44 (42)||38 (188)||0.66 (0.40–1.09)||.11|
|Accuracy of knowledge about screening tests|
| How often should woman > 50 y get FSIG (5 y)||941||5 (18)||9 (9)||5 (27)||0.34 (0.14–0.82)||.02|
| How often should woman > 50 y have FOBT (1/y)||941||34 (136)||35 (33)||34 (169)||0.91 (0.55–1.51)||.72|
| After a couple tests okay, no longer necessary (false)||941||64 (479)||65 (120)||64 (599)||0.78 (0.55–1.12)||.18|
|Knowledge about colon cancer (strongly agree/agree that…)|
| Person can tell if has CC without going to the doctor||941||26 (194)||25 (47)||26 (241)||1.35 (0.90–2.00)||.15|
| In general, people have no control over whether CC will be detected early||941||57 (434)||58 (108)||58 (542)||1.14 (0.80–1.61)||.47|
| If you have CC, it can't be cured, so why bother with tests||941||27 (207)||29 (54)||28 (261)||1.15 (0.78–1.67)||.49|
|Beliefs about FSIG screening tests for CC (strongly agree/agree that…)|
| Feel OK so why bother getting FSIG; it won't find anything||776‡||38 (237)||46 (71)||40 (308)||0.79 (0.54–1.16)||.24|
| FSIG is a safe procedure||622‡||91 (450)||92 (117)||91 (567)||0.93 (0.44–1.96)||.85|
| Think FSIG is useful in testing for CC||700‡||94 (523)||93 (136)||94 (659)||1.39 (0.65–2.95)||.39|
| Enemas too much bother for FSIG||706‡||23 (126)||36 (54)||25 (180)||0.51 (0.34–0.78)||.002|
| Getting a FSIG test is uncomfortable||594‡||71 (332)||74 (95)||72 (427)||0.87 (0.55–1.37)||.54|
| A FSIG test hurts||587‡||68 (318)||71 (86)||69 (404)||0.77 (0.48–1.23)||.27|
|Barriers to CRC screening tests (strongly agree/agree that…)|
| Not presently covered by any health insurance||940||16 (119)||9 (16)||14 (135)||1.75 (0.90–3.39)||.098|
| Afraid if test found something, they might have to remove part of colon||702‡||60 (340)||68 (94)||62 (434)||0.72 (0.47–1.10)||.13|
|Barriers to FSIG tests (strongly agree/agree that…)|
| It takes too much time to get a FSIG test||613‡||21 (104)||20 (26)||21 (130)||1.24 (0.75–2.03)||.40|
| I don't know where to get a FSIG test||758‡||25 (152)||21 (31)||24 (183)||1.32 (0.83–2.08)||.24|
| It's embarrassing to get a FSIG test||725‡||42 (242)||58 (85)||45 (327)||0.59 (0.40–0.87)||.008|
| Discomfort of FSIG test would keep me from getting another||645‡||29 (147)||31 (42)||29 (189)||0.82 (0.53–1.27)||.37|
| It costs too much to have a FSIG test||473‡||32 (123)||29 (27)||32 (150)||1.27 (0.75–2.15)||.38|
Respondents' overall knowledge about colon cancer and screening tests was often inaccurate (Table 3). Few women knew the recommended screening frequency for FSIG (5%) or FOBT (34%), although most (64%) women recognized that continuous screening was necessary. Accuracy of knowledge was similar by race, except that African Americans were less likely to know the recommended screening interval for FSIG (OR, 0.34; P = .017). Although few agreed that one could recognize CRC without consulting a physician (26%) or that CRC is incurable (28%), most agreed that individuals had no control over early detection of the disease (58%). Knowledge about these items did not differ by race.
Combining responses about knowledge of CRC screening tests with screening behaviors (data not shown), women who could name an FSIG test compared with women who could not had almost 8 times the odds of having received a CRC screening test within guidelines (OR, 7.82; P < .001). Similarly, women who could name an FOBT compared with women who could not had more than twice the odds of having received a CRC screening test within guidelines (OR, 2.19; P = .003). Women who could name a colonoscopy compared with women who could not had more than 7 times the odds of having received a CRC screening test within guidelines (OR, 7.39; P = .001). There were no significant differences by race in these relationships between knowledge of CRC tests and screening practices.
Beliefs and barriers to CRC screening
The majority of participants believed that FSIG was safe (91%) and useful for detecting CRC (94%), and agreement that FSIG was uncomfortable (72%) or hurt (69%) was frequent as well (Table 3). Beliefs about the FSIG test did not consistently vary by race, but African Americans had half the odds of whites of agreeing that “It is too much bother to use the enemas to prepare for a FSIG test” (OR, 0.51; P = .002).
Nearly two-thirds (62%) of the study population reported concern that a positive finding on a CRC screening test could result in removal of part of the colon (Table 3). Few (14%) women reported lack of health insurance as a barrier to CRC screening. Barriers to CRC screening, in general, did not vary by race (Table 3), but African American women had marginally higher odds of reporting lack of health insurance (OR. 1.75; P = .098). Across races, women with insurance had 1.54× the odds of having any CRC screening within guidelines compared with women without insurance (P = .045) (data not shown).
Few women reported factors such as embarrassment (45%), cost (32%), discomfort (29%), time to do the test (21%), and knowledge of where to get the test (24%) as barriers to FSIG. Barriers to FSIG were generally similar across races. However, African Americans were less likely to agree that “It's embarrassing to get a FSIG test” than white participants (OR, 0.59; P = .008).
Despite evidence that early CRC detection can help reduce both morbidity and mortality, rates of CRC screening among individuals older than age 50 remain low.27 Underuse is particularly problematic among certain population subgroups, including poor, less-educated, and minority women such as those interviewed for this study. Given increasing attention to the issue of health disparities in this country,28 our focus on this underserved population provides important new information.
The population of women studied in the Carolinas Cancer Education and Screening (CARES) project was comprised of very low-income women who lived in public housing complexes. When using the categorization of “any CRC screening within recommended guidelines” to examine reported screening practices, more than half of the women in this study were not within CRC screening guidelines, despite the finding that the majority reported routine encounters with the medical system. Furthermore, although national data show that CRC screening is lower among African Americans than among whites,7 our study found comparable overall CRC screening rates for low-income women from these 2 racial groups. Screening use was similarly low for both African Americans and whites for use of FSIG within the last 5 years, use of FOBT within the last year, and use of DCBE within the last 5years. However, we found a significant racial disparity among these women with respect to having had a colonoscopy within the last 10 years, with African American women having half the odds of having received this test compared with white women.
In addition, among all women studied, knowledge of CRC screening tests was disturbingly low, especially for African American women. Compared with white women, African American women had less than half the odds of knowing there are tests to detect colon cancer, and they also had lower odds of either naming or reporting knowledge of specific CRC screening tests. Across racial groups, fewer than 1 in 10 women were able to name a fecal occult blood test (FOBT) or a flexible sigmoidoscopy (FSIG) as a test for colon cancer.
Notably, women's lack of knowledge of screening tests was also associated with lower rates of overall screening. Given that women who could name the individual FSIG test had almost 8 times the odds of having received the test, and women who could name the colonoscopy test had over 7 times the odds of having received the test within guidelines, this knowledge deficit is particularly troublesome.
Across racial groups, these women noted important barriers to screening, with barriers somewhat divergent between African Americans and whites. Reported barriers, such as fear of screening results, and specific FSIG test barriers, including not knowing where to get a test, lack of time, and high cost, were consistently reported across both groups. However, African American women had higher odds of noting lack of insurance coverage than white women. African American women also had lower odds of reporting embarrassment and bother than white women, similar to previously reported differences associated with mammography screening practices.29
Results from our study show that both knowledge deficits and barriers to screening are consistent with results of prior research.9, 10, 20–22 It is disconcerting that fewer than 1 in 10 women can name a specific test to check for colon cancer and that fewer than 2 in 10 report knowledge of any CRC screening tests. Additionally troubling are the prevalent misconceptions among these women that they cannot control early detection of colon cancer and that colon cancer cannot be cured, thus making tests useless (in their minds). Yet, because nearly two-thirds of these women had a medical condition that required regular physician visits and almost two-thirds of participants reported that a physician had encouraged them to get a FOBT or FSIG test, our results signal a need to do more to improve patient knowledge of colon cancer and to reduce barriers to CRC screening. For example, by promoting medical office visits as actual opportunities to provide CRC screening, healthcare providers can be encouraged to help increase CRC screening rates and to educate patients about the importance of screening to detect colon cancer early so that it can be treated.
Furthermore, when there is a significant knowledge difference between African Americans and whites, this disparity is cause for concern, especially when all women studied were poor and living in public housing. Thus, our results reveal that race, and not just low SES, matters in studies of CRC screening knowledge and practice. Future research may help uncover some of the factors contributing to these differences and perhaps highlight opportunities for health communications to both improve knowledge about CRC and reduce barriers to screening.
Several limitations to this study should be noted. First, this cross-sectional study is limited to a population of largely very low-income women. Whereas these results may be generalized across other low-income populations of women, certain characteristics of this group (eg, living in public housing and living in the South) may distinguish this study population. Furthermore, because individuals of higher socioeconomic status were not included, we are unable to assert that these findings are unique to those of lower socioeconomic status. Other limitations stem from reliance on self-reported data, which may vary when compared with medical-record data.30 It can be concluded, however, that among these poor women, lack of knowledge about tests and perceptions of barriers to screening both likely contribute to low CRC screening rates.
More than half of a population of low-income, African American and white women reported nonadherence to CRC screening guidelines, highlighting the need to discover ways to improve CRC screening rates. Unfortunately, many of these women appeared to be poorly informed about both colon cancer and CRC screening tests, despite encounters with the medical system. Among all women studied, their knowledge of CRC screening tests was disturbingly low, and was most pronounced for African American women. Yet, regardless of differences in knowledge, CRC screening rates were less than optimal across racial groups in this population.
Successful interventions have invested in options to reduce or remove various barriers to screening tests.31, 32 Our results, in turn, suggest opportunities to improve access to colon cancer prevention and treatment by addressing knowledge deficits that may be affecting cancer screening practices. For instance, our findings show that there is considerable room for improvement with respect to educating women about both colon cancer and CRC screening tests. Although one cannot conclude on the basis of these results that providing women with more information about the importance of CRC screening and how to gain access to it will increase compliance with screening guidelines, it does seem likely that more information can help. Efforts to improve knowledge of colon cancer risk factors, access to screening, and what to expect from CRC screening may help providers and policymakers reduce many barriers to CRC screening.