Re: "Population- and community-based recruitment of African Americans and Latinos: the San Francisco Bay Area Lung Cancer Study"

Rethinking sources of representative controls for the conduct of case-control studies in minority populations

BACKGROUND

Recruitment of controls remains a challenge in case-control studies and particularly in studies involving minority populations.

METHODS

We compared characteristics of controls recruited through random digit dialing (RDD) to those of community controls enrolled through churches, health events and other outreach sources among women of African ancestry (AA) participating in the Women's Circle of Health Study, a case-control study of breast cancer. Odds ratios and 95% confidence intervals were also computed using unconditional logistic regression to evaluate the impact of including the community controls for selected variables relevant to breast cancer and for which there were significant differences in distribution between the two control groups.

RESULTS

Compared to community controls (n=347), RDD controls (n=207) had more years of education and higher income, lower body mass index, were more likely to have private insurance, and less likely to be single. While the percentage of nulliparous women in the two groups was similar, community controls tended to have more children, have their first child at a younger age, and were less likely to breastfeed their children. Dietary intake was similar in the two groups. Compared to census data, the combination of RDD and community controls seems to be more representative of the general population than RDD controls alone. Furthermore, the inclusion of the community group had little impact on the magnitude of risk estimates for most variables, while enhancing statistical power.

CONCLUSIONS

Community-based recruitment was found to be an efficient and feasible method to recruit AA controls.

Studying cancer in minorities: a look at the numbers

BACKGROUND

Inclusion of minorities is an important but challenging aspect of epidemiologic studies in the United States. One aspect of this challenge that has received little attention is the actual number of minorities with specific cancers. The authors aimed to understand how population characteristics affect the numbers of minority cancer cases in Surveillance, Epidemiology, and End Results (SEER) regions.

METHODS

By using SEER data, the authors identified 6 cancers with higher incidence rates in racial and ethnic minorities and reviewed the annual number of cases of those cancers in SEER areas where there are large numbers of blacks, Hispanics, and Asians. The authors examined the age characteristics of the populations in SEER areas using data from the US Census.

RESULTS

Although there are substantial numbers of cases for the most common cancers with higher incidence in blacks, their numbers are quite small for other cancers, <150 cases, and in many areas, <100 per year. Few registries have substantial numbers of Hispanics or Asians. As expected, the proportion of minority populations is lower in older age groups, whereas the proportion of non-Hispanic whites is larger.

CONCLUSIONS

Because of the sharp decline in minority populations associated with age and the high age-specific incidence rates of most cancers, the actual number of minority cases is quite small for several cancers. Thus, the inclusion of minority groups in studies of any but the most common cancers presents a challenge.

Challenges and Approaches to Newcomer Health Research

Newcomers include immigrants, refugees, or asylum seekers. Approaches to research in newcomer populations include consideration of the insider–outsider status of the researcher(s), sample selection and recruitment strategies, and attention to language barriers. Potential research participants need to be identified, approached, and made to feel safe before, during, and after participation in research. Interpersonal relationships need to be negotiated with awareness of potential power imbalances, institutional discrimination, and trauma associated with premigration, migration, and settlement experiences. Embedded within these approaches should be awareness of the need to ensure the cultural safety of research participants through implementation of culturally competent research strategies.