Our study had three major findings. First, in California, where mammography rates are high,40
we found no significant disparities by race/ethnicity and income in both family history risk groups. Although our study may not be generalizable nationally, this finding is consistent with Wu et al.'s study using the National Health Interview Survey.41
Second, racial/ethnic disparities were more evident in CRC screening, and we found evidence of a Latino-white gap among the group with a family history. As this is the new contribution of the study, these results should be further explored and confirmed in national population-based data and in medical claims data that contain information on family history. Third and most importantly, personal knowledge of family history did not close the Latino-white gap in CRC screening. This finding is relevant and new, not found in previous diverse population-based studies that have included Latinos with a family history.5, 41
Our estimate that Latinos with a family history risk had 0.28 times the odds of being screened for CRC compared to non-Latino whites points to a considerable disparity, greater than most of the detected disparities from other factors in our model, and of greater magnitude than the Latino-white difference among individuals with no family history (OR 0.74; 95%CI: 0.59 -0.92).
There are several explanations why Latinos are not getting screened for CRC as much as non-Latino whites, even if they know that they have a family member with CRC. On the patient side, the most relevant study to put our results in context is the recent national population-based study conducted by Orom et al. 2010 using the national 2007 Health Information Trends Survey (HINTS). In that study of a multiethnic sample, Orom and her colleagues found 1) that Latinos had lower perceived cancer risk than non-Latino whites, 2) that the lower rates of perceived cancer risk was associated with lower rates of reported family history of cancer among Latinos compared to non-Latino whites, and most importantly, 3) that reporting a family history of cancer was positively associated with higher perceived cancer risk among non-Latino whites, but not among Latinos. Their last finding supports our study results of the widening Latino-white disparity in CRC screening among the group with a family history of CRC. The authors further posit that Latinos with a family history may be less aware of their cancer risk “due to language and other barriers that can make the dissemination of health information difficult.” 14
Even among Latinos who do perceive their family history of colorectal cancer to be associated with increased risk of colorectal cancer, some studies have suggested that compared to non-Latino Whites, on average, Latinos may harbor greater fear or denial of this risk that they delay or fail to seek colorectal cancer screening.16, 17, 32
However, in a study with a diverse sample of women recruited from primary care clinics in San Francisco (42% reported having a family history of cancer), among Latinas who had the highest perceived risk of three cancers, including colon cancer, their perceived risk was associated with obtaining cancer screening tests.42
The study's participants, women associated with a primary care clinic, may be a select sample of women who may tend to value preventive care and who may have a regular provider. Thus, they may be more motivated to be screened for CRC than the average Latino with a family history of CRC. Nevertheless, interventions are needed that address the spectrum of reactions to knowledge of a family history of CRC–i.e. fear, denial, anxiety, and indifference- among affected Latinos to mobilize their CRC screening behavior
On the provider side, studies suggest that rates of family history inquiries are low in routine clinical encounters,13, 43
, We found no studies that determined whether there is a differential rate of obtaining family histories by race/ethnicity. We therefore posit that since obtaining family history and explaining increased risks and recommended screening intervals may require more time in the patient-physician encounter, language and cultural barriers may, on average, differentially deter this knowledge transfer of CRC risk to Latinos but not to whites. In Guerra et al.'s qualitative study on barriers and facilitators to physician recommendation of CRC screening, physicians caring for non-English speaking patients reported that they “had a particularly difficult time recommending CRC screening because translation of the recommendation takes up much of the time allotted for the visit.”44
Similarly, Wee et al.'s study found that Latino adults are less likely to receive counseling from their physicians about CRC tests than non-Latino whites.21
Wee et al.'s study implies that the Latino-white disparity could be more pronounced among those with a family history, since family history counseling requires an even greater time investment.
The differential knowledge transfer of CRC risk may also result when the patient-provider interaction is racially/ethnically discordant. For example, Ge et al. 2009 found that “physicians did not solicit or address cultural barriers to CRC screening and patients did not volunteer culture-related concerns regarding CRC screening” in ethnically discordant physician-patient interactions.45
Drawing on Guerra et al.'s study previously discussed,44
since counseling for family history risk is more complex than average-risk screening recommendations and would require more time, the Latino disadvantages in linguistically and culturally discordant physician relationships may be greater in individuals with a family history of CRC. Discordant ethnic patient-physician relationships are certainly prevalent in California as Latinos are more than a third of California's population, but make up only 5 percent of the state's physician population.46
Thus, racial/ethnic variations in the provider-patient interaction could be a source of the CRC screening disparity, and has a potentially greater penalizing effect on Latinos with a family history of CRC. Finally, our results in California are likely to be present for Latinos across the US, and could be more pronounced in areas with fewer cultural and linguistic services for Latinos.
A key limitation of our study is that it is based on self-reported survey data. Family history reports appear to be generally accurate: validation studies on self-reports of cancer family history suggest reports of first degree relatives are highly accurate 2, 47-49
and reports of second degree relatives to be moderately accurate. One study suggests that the validity of self-reported family history is better for breast and colorectal cancers, than ovarian and endometrial cancers. While self-reported family history is generally valid, recent meta-analysis on the accuracy of self-reported cancer screening suggests screening use in population-based surveys tend to be over-reported50
especially among ethnic minority respondents; thus, the racial/ethnic disparities we report here may be underestimated. The sample size of minority racial/ethnic groups in the CHIS strong family history population may also have limited our capability to detect any disparities in screening by population subgroups. However, we detected a significant effect for Latinos, whose sample size was comparable to that of Asians and Pacific Islanders and African Americans. Finally, our study approach evaluated screening beginning at the age recommended for average-risk adults to compare across all risk categories. Due to smaller samples, we could not ascertain whether disparities may be narrower or wider in evaluating adults with a family history who received mammograms below age 40 years and CRC screening below age 50 years.
Despite these limitations, our study provides a compelling picture on how a family history analysis could direct where efforts are most needed in reducing cancer disparities by race and ethnicity.51, 52
Among California adults, our troubling finding was that knowledge of their family history of colorectal cancer (CRC) did not close the Latino-white gap in CRC screening, but actually widened the disparity. More aggressive interventions that enhance the communication between Latinos and their doctors about family history and cancer risk are needed and could reduce the substantial Latino-white screening disparity in Latinos most susceptible to CRC…51, 52