CEBP CTRC-AACR San Antonio Breast Cancer Symposium Translational Cancer Medicine 2008: Cancer Clinical Trials and Personalized Medicine
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Cell Growth & Differentiation
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kinney, A. Y.
Right arrow Articles by Sandler, R. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kinney, A. Y.
Right arrow Articles by Sandler, R. S.
Cancer Epidemiology Biomarkers & Prevention Vol. 14, 182-189, January 2005
© 2005 American Association for Cancer Research

Social Ties and Colorectal Cancer Screening among Blacks and Whites in North Carolina

Anita Yeomans Kinney1,2, Lindsey E. Bloor2,3, Christopher Martin4,5 and Robert S. Sandler4,5,6

1 College of Nursing, 2 Huntsman Cancer Institute, and 3 Department of Psychology, University of Utah, Salt Lake City, Utah and 4 Division of Digestive Diseases and Nutrition, Center for Gastrointestinal Biology, 5 Department of Epidemiology, School of Public Health, and 6 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

Requests for reprints: Anita Yeomans Kinney, Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112. Phone: 801-585-1151; Fax: 801-581-4642. E-mail: anita.Kinney{at}hci.utah.edu


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Few studies have examined the relationship between social networks and colorectal cancer screening in diverse populations. Prior research suggests that the type of social support as well as the amount or frequency of support available from one's social network may be associated with health outcomes. Therefore, the current study examined relationships between both structural (i.e., quantitative aspects of the social network, such as number of ties and frequency of contact with ties) and functional (i.e., functions provided by social network ties, such as offering emotional or instrumental support) aspects of social ties and utilization of colorectal cancer screening tests. Analyses included 697 randomly selected Blacks and Whites ages 51 to 80 years enrolled as controls in the North Carolina Colon Cancer Study. Social tie and screening information was obtained from face-to-face interviews. Forty-seven percent of participants (40% Blacks and 51% Whites) reported use of one of the options for colorectal cancer screening according to the guidelines at that time. Compared with those with the fewest social connections, those who were most socially connected were more likely to report recent use of colorectal cancer screening [odds ratio (OR), 3.2; 95% confidence interval (95% CI), 1.7-6.2]. This association was stronger among Blacks (OR, 3.8; 95% CI, 1.3-10.7) than Whites (OR, 2.9; 95% CI, 1.2-6.9; P for interaction = 0.006). There were also positive associations between being a church group (OR, 1.9; 95% CI, 1.4-2.7) and other group member (OR, 1.6; 95% CI, 1.1-2.2) and screening. Neither emotional (e.g., offering reassurance that one is cared for) nor instrumental (e.g., giving material assistance) support was associated with screening behavior. These data suggest that structural rather than functional aspects of social ties may be important in influencing colorectal cancer screening behavior.

Key Words: colorectal cancer • screening • social networks • social support • social ties • Blacks


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Colorectal cancer is one of the most common cancers and the second leading cause of cancer death in the United States. When detected in the early stages, colorectal cancer is usually curable. In addition, when precancerous polyps are detected, their removal prevents colorectal cancer from developing. The lifetime risk of developing colorectal cancer is ~6%, and the risk of colorectal cancer increases markedly after age 50 years (1). Among racial/ethnic groups in the United States, Blacks have a higher risk of incident colorectal cancer and death than Whites and are more likely to have their disease detected at a later stage (2).

Many organizations have published recommendations for regular colorectal cancer screening beginning at age 50 years (3). The American Cancer Society guidelines recommend a fecal occult blood test (FOBT) within the previous 12 months, a sigmoidoscopy within the past 5 years, a FOBT within the previous 12 months and a sigmoidoscopy within the past 5 years, a colonoscopy within the past 10 years, or a barium enema within the previous 10 years (4, 5). Despite the well-established benefit of colorectal cancer screening on incidence and early detection (6), utilization rates are low among the U.S. population. Furthermore, the screening rates for Blacks are lower than that for Whites (2).

These racial/ethnic disparities and screening patterns underscore the need to examine psychosocial factors related to colorectal cancer screening generally and among Blacks and Whites specifically. In doing so, we can identify psychosocial factors that are associated with screening behaviors and strive to develop interventions that enhance such factors, thereby increasing colorectal cancer screening. Moreover, a better understanding of the associations between psychosocial resources and colorectal cancer screening among Blacks and Whites specifically may suggest that particular psychosocial factors and interventions are distinctively influential for modifying screening behavior for these racial/ethnic groups. Relatively few studies have assessed psychosocial factors among specific racial/ethnic groups in association with colorectal cancer screening. Therefore, the current study aims to assess select psychosocial resources among Blacks and Whites in association with colorectal cancer screening behavior, which can extend our understanding of these relationships and ultimately contribute to efforts to increase screening rates, improve colorectal cancer outcomes, and decrease racial/ethnic disparities in colorectal cancer prevalence.

Both research and theory suggest that social networks play a critical role in the determination of diverse health-related outcomes (7-9). These structural measures of support traditionally evaluate the concept of social integration or a combined index of marital status, the number and frequency of social contacts, and church and other group memberships (10-12). For health behaviors in particular, people with larger social networks and more frequent contact may practice more preventive health care behaviors (e.g., use of cancer screening tests) and engage more in health promotion activities (e.g., eating a healthy diet and abstaining from tobacco; refs. 13-15). For example, social integration was positively associated with mammography and occult blood stool screening tests in a study among Blacks ages ≥55 years (16). Social network intervention studies to promote communication and screening behaviors have also been conducted (17, 18) and may increase cancer prevention behaviors, such as breast self-exams (18).

Although many researchers focus on the overall construct of social integration, there is also interest in select components of the index, such as marital status or involvement in religious activities. For instance, marital status has been associated with physical health outcomes possibly through the influence of marital interactions on mental health as well as health habits (19). Moreover, there is increasing attention paid to the particular role of religious involvement in health-related outcomes. Low frequency of religious service attendance, for example, has been associated in previous studies with cervical cancer risk (20) and unhealthy lifestyle practices (e.g., smoking and low levels of physical activity; ref. 21). These findings suggest the merit in exploring associations between particular aspects of social integration and health behaviors.

Although most of the literature on the association between social relationships and health has focused on structural aspects of support, such as social integration, some investigators posit that it is the type or function of support provided by network members that may influence health outcomes. This view focuses on functional aspects of support, such as emotional (e.g., offering reassurance that one is loved and cared for), tangible (e.g., giving material or financial assistance), or informational (e.g., someone who has experienced something similar providing information) support. These functional aspects of support have also shown direct and buffering effects on health-related outcomes (22, 23). For instance, perceiving adequate tangible support was associated with lower mortality and improved physical functioning among a cohort of patients with coronary artery disease (23). Such findings suggest that structural and functional aspects of support may influence health in similar or unique ways. Moreover, these aspects of support may operate similarly or differentially among racial/ethnic groups. Thus, it is valuable to evaluate these different aspects of social ties separately (10).

Importantly, race has been shown to modify relationships among social support, social networks, and health outcomes (8, 24, 25). For example, in a study of screening adherence behavior among women of color receiving an abnormal Papanicolaou smear result, emotional support was most strongly related to adherence among Black women; however, tangible support, such as providing childcare or transportation to the clinic, was most strongly related to adherence for Latinas (24). Another study found that a social network summary measure was associated with late-stage disease among Black but not White women with breast cancer (26). Similarities and differences between ethnic/racial groups often are not revealed in investigations. This may be because research on the social support-health link often focuses on particular groups and/or controls for potential racial/ethnic confounders and thus does not allow for intergroup comparisons. In addition, minorities have been underrepresented in most health-related research, further limiting the ability to make racial/ethnic group comparisons. More investigations are needed to generate specific hypotheses regarding the health-related similarities and differences among racial/ethnic groups.

Overall, we find that relatively few studies have examined the relationship between social ties and colorectal cancer screening in diverse populations (16). Previous studies examining the effect of social ties on cancer screening behavior in general have generated mixed results. That is, whereas some studies have identified a positive effect (16, 27-29), others have not observed any effect (30). Across these studies, social ties have been conceptualized in different ways; therefore, equivocal findings may in part be due to how the construct is conceived and operationalized. By assessing both structural and functional aspects of social ties, the current study can evaluate whether neither, one, or both aspects of support are associated with colorectal cancer screening.

Given the evidence and theory reviewed here, the current investigation seeks to determine (a) if there is a positive association between a well-established measure of social networks and the particular practice of colorectal cancer screening, (b) if there is an association between well-established measures of emotional and instrumental support and the practice of colorectal cancer screening, and (c) if there are associations between structural and/or functional aspects of support and colorectal cancer screening and to evaluate whether the associations differ among Blacks and Whites.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Participants
These data were collected as part of the North Carolina Colon Cancer Study, a population-based, case-control study of Blacks and Whites conducted in 33 contiguous counties in central and eastern North Carolina that included rural, suburban, and urban areas (31). The information in this report is based exclusively on information obtained from noncancer controls from the larger study. Informed consent was obtained from all participants.

Potential participants were selected from two sources: records of the North Carolina Division of Motor Vehicles for persons ages <65 years and records of the Health Care Financing Administration for persons age ≥65 years. At the time of this study, 98% of the North Carolina population under age 65 years were registered with the Division of Motor Vehicles and >95% of those ages ≥65 years were registered with Health Care Financing Administration. Using a randomized recruitment strategy, controls were sampled so that the distribution of race, age, and gender matched that of the randomly selected cases in the larger study. Blacks were oversampled in an attempt to approximate a White-to-Black ratio of 1:1 (32, 33). The cooperation rate [interviewed / (interviewed + refused)] was modest (62%; 65% for Whites and 59% for Blacks); however, this rate is comparable with other population-based studies (34).

Data Collection
Trained nurse interviewers used a standardized questionnaire to conduct face-to-face interviews with participants between April 1997 and December 2000. Following a brief description, participants were asked to report when they had a FOBT or colon examination in the 10 years before the interview. They were asked to report the date that the last test was done and to indicate if the last examination was done for screening purposes (e.g., with no symptoms present) or for a problem. If the examination was done because a symptom or problem was present, they were asked to report what it was. The reliability of self-reports for screening behaviors has been shown. The outcome of interest was the self-reported recent use of the options for colorectal cancer tests for screening purposes for people age ≥50 years according to American Cancer Society guidelines when data were collected: (a) FOBT within the previous 12 months, (b) sigmoidoscopy within the past 5 years, (c) FOBT within the previous 12 months and sigmoidoscopy within the past 5 years, (d) colonoscopy within the past 10 years, or (e) barium enema within the previous 10 years (4, 5).

Information was collected on two dimensions of social support, encompassing structural (network) and functional (emotional and instrumental) aspects. The Social Network Index (SNI) was used to measure structural aspects of social support (11). It is composed of five parts: marital status (married or living as married, not married), church group membership (yes, no), other group membership (yes, no), number of close friends and relatives (by category of reported number), and frequency of contacts with friends and relatives (by categorical response). Using this standardized measure, which has shown predictive validity concerning preventive health behaviors, a weighted index of intimate contacts is combined with membership in churches and other groups to yield a four-level index: I,low; II, medium; III, medium-high; and IV, high social integration. Information on religious involvement was also elicited by asking participants how often they attend church or another place of worship.

Quantitative and qualitative aspects of functional support were measured with well-established questions drawn from prior studies conducted by Seeman and others (11, 12, 35, 36). A composite index of perceived availability of emotional support was constructed from binary responses (yes or no) to the following items: (a) "Do you currently have a family member or friend to whom you can talk about your health?" (b) "Do you have anyone else to whom you can talk to about your health?" (c) "Do you have a family member or friend to whom you can talk about your personal problems?" and (d) "Do you have anyone else to whom you can talk about your personal problems?" We computed a total emotional support score by summing these items. The availability of instrumental support (i.e., help, aid, or assistance with tangible needs) was measured by responses to the following item: "When you need some extra help, could you count on anyone to help with daily tasks like grocery shopping, house cleaning, cooking, telephoning, and/or giving you a ride?"(with response options of "yes," "no," or "I did not need help"). Drawing from the same well-established functional support measure, adequacy of emotional support was measured with the following item: "Can you use more emotional support than you receive?" [with response options of "a lot," "some," "a little," or "no, or none" (received sufficient help)]. In addition, adequacy of instrumental support was measured with the following item: "Can you use more help with daily tasks than you received?" [with response options of "a lot," "some," "a little," or "no, or none" (received sufficient help)]. These measures were treated as ordinal level variables in the analyses.

To consider potential covariates that have been associated with social ties and cancer-related outcomes, data on nutritional intake and physical activity were assessed with standardized measures. The Block food frequency questionnaire (37, 38) was used to assess alcohol, fat, vegetable, fruit, and fiber intake. The Stanford 7-day recall method (39, 40) was used to assess physical activity in metabolic equivalents per week divided into quartiles. In addition, information on sociodemographic factors was obtained, including individual's age, educational level, and health insurance status as well as household income level.

Analysis
Unconditional logistic regression analyses were used to obtain odds ratios (OR) and 95% confidence intervals (95% CI) using the PROC LOGISTIC procedure of the SAS statistical software package, version 8 (SAS Institute, Cary, NC). To assess the magnitude of association for each social tie variable on recent use of colorectal cancer screening options, multivariate logistic regression models were used and adjusted for potential confounding factors and factors that have been associated with health care utilization in general, or colon cancer screening in particular, and/or social ties. A backward elimination procedure was used with each social tie variable predicting recent use of colorectal cancer screening options to determine the individual adjusted models. The covariates in the fully adjusted models are noted in the footnote of Table 3. The potential confounding and associated factors considered were age (six-level ordinal variables that reflected 5-year age categories), sex (male, female), race (White, Black), educational level (less than high school, high school, some college, college degree), household income (<$20,000, $20,000-34,999, $35,000-49,999, $50,000-74,999, >$75,000, not reported), health insurance status (none, Medicare, Medicaid, private, health maintenance organization), regular source of health care (yes, no), colorectal cancer in a first-degree relative (yes, no), fat intake (grams per week divided into quartiles), vegetable and fruit intake (servings per week divided into quartiles), fiber intake (grams per week divided into quartiles), self-reported health status (poor, fair, good, very good, excellent), physical activity (metabolic equivalents per week divided into quartiles), alcohol use (none, lower half, upper half of alcohol consumed per week), and cigarette smoking status (never, current, former). Linear trend tests were conducted by calculating P values with the social tie variable coded as an ordinal variable. All P values are two sided. Multiplicative interaction was assessed using first-order cross-product terms for social ties and race/ethnicity, and the log-likelihood ratio test was conducted to determine if race modified the relationship between social tie variables and colorectal cancer screening outcomes (i.e., whether the cross-product term differed statistically from the null).


View this table:
[in this window]
[in a new window]
  		Table 3. Associations between each social network measure and recent use of colorectal cancer screening tests among Blacks and Whites

 
Information was collected on 952 controls between ages 51 and 80 years of both races. The logistic analyses were restricted to individuals age 50 years because colorectal cancer screening guidelines for the general population do not apply to individuals age <50 years. Also excluded from the analyses were individuals who reported having a colorectal cancer test for diagnostic purposes (including those who had one as follow-up for an abnormal examination), leaving 697 available for the analyses.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Sociodemographic factors, health-related characteristics, and distributions of social tie variables of participants are presented in Tables 1 and 2. Unweighed percentages are reported, representing the sample rather than the underlying population. Women comprised 49% of participants and 42% were Black. The average age was 68 years (SD = 8.0) for Blacks and 68 years (SD = 7.9) for Whites.


View this table:
[in this window]
[in a new window]
  		Table 1. Distribution of selected characteristics among overall sample and Blacks and Whites

 

View this table:
[in this window]
[in a new window]
  		Table 2. Distribution of social tie variables overall and among Blacks and Whites

 
A comparison of the data between Blacks and Whites reveals a different distribution for covariates (see Table 1) and social ties (see Table 2). Specifically, Blacks were more likely than Whites to be female (58% versus 43%), to belong to a church group (76% versus 65%), and to attend religious services more frequently. In addition, a larger proportion of Blacks compared with Whites reported that their health was fair or poor. In comparison, Whites were significantly more likely than Blacks to be married (76% versus 52%), to have higher incomes, to have higher educational levels, to belong to a group other than a church, and to have higher SNI scores.

Overall, 47% of participants (40% Blacks and 51% Whites) reported recent use of one of the options for colorectal cancer screening according to the guidelines at that time. When age, educational level, household income, and insurance status were controlled, no significant racial differences in use of colorectal cancer screening tests were observed. Across all years of the study, 15% of participants (13% of Blacks and 17% of Whites) reported having had a sigmoidoscopy without a FOBT within the previous 5 years. Thirty-four percent of participants (28% of Blacks and 39% of Whites) reported having a FOBT without a sigmoidoscopy within the past year. Nine percent of participants (7% of Blacks and 11% of Whites) reported both having had a FOBT within the past year and having had a sigmoidoscopy within the past 5 years. Eight percent (8% of Blacks and 7% of Whites) reported a barium enema within the past 10 years and 18% (16% of Blacks and 19% of Whites) reported having had a colonoscopy within the past 10 years (data not shown).

The relationships between component parts of the SNI and functional social support measures and recent use of colorectal cancer screening options were examined in separate logistic models (see Table 3). Compared with those with the fewest social connections as measured by the SNI, those who were most socially connected were more likely to report recent use of one of the options for colorectal cancer screening (OR, 3.2; 95% CI, 1.7-6.2). This association was stronger among Blacks (OR, 3.8; 95% CI, 1.3-10.7) compared with Whites (OR, 2.9; 95% CI, 1.2-6.9; P for interaction = 0.006). In contrast to this finding, Whites who were married or living as married were less likely to report recent use of colorectal cancer screening than Whites who reported that they were not married or living as married (OR, 0.5; 95% CI, 0.3-0.9). This association was not observed in Blacks (OR, 1.0; 95%CI, 0.6-1.7; P for interaction = 0.08). We followed up this unexpected finding to determine if there was a gender interaction among Whites. Results suggested that married White males were less likely to report recent use of the screening options (OR, 0.5; 95% CI, 0.3-0.9) compared with nonmarried White males. In comparison, the OR was not significant among White females (OR, 0.5; 95% CI, 0.2-1.3; P for interaction = 0.59).

Furthermore, there was a significant positive association between being a member of a church group (OR, 1.9; 95% CI, 1.4-2.7) and recent use of the options for colorectal cancer screening; this association was somewhat stronger among Whites (OR, 2.0; 95% CI, 1.3-3.1) than among Blacks (OR, 1.9; 95% CI, 1.0-3.5; P for interaction = 0.07). Membership in a nonreligious group was also associated with colorectal cancer screening (OR,1.6; 95% CI, 1.1-2.2). This association was significant for Blacks (OR, 2.0; 95% CI,1.2-3.4) but not Whites (OR, 1.4; 95% CI, 0.9-2.2; P for interaction = 0.18). A marginally significant positive association between frequency of church attendance and adherence to colorectal cancer screening guidelines was observed (OR, 1.5; 95% CI, 1.0-2.2). Finally, there was no evidence of associations between functional support measures (i.e., availability or adequacy of emotional support and instrumental support) and colorectal cancer screening in the total sample nor were racial/ethnic differences observed.

There are potential concerns that the dissemination of colorectal cancer screening guidelines increased substantially during the 4-year period of the study, which may have affected screening behaviors. To address this historical threat to internal validity, we ran logistic regression models, including year of interview as a confounding variable for all logistic models. The ORs associated with the social tie variables were not materially altered (data not shown).


   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
The current study investigated associations between both structural and functional aspects of social ties and cancer screening in a diverse population. The results extend our understanding of the observed relationship between social ties and colorectal cancer screening behavior in Blacks and Whites. A noteworthy finding was the importance of structural (i.e., size and frequency of contact of network members) but not qualitative features (i.e., emotional and instrumental support) of social ties for recent use of colorectal cancer screening tests. Our results provide evidence that moderate to high levels of social connectedness are associated with use of colorectal cancer screening. Moreover, participation in community groups was associated with screening behavior. These results are consistent with prior research demonstrating positive associations between structural aspects of social ties and cancer screening (27, 28).

In contrast, Allen et al. used a subset of items from the SNI measuring network size and did not observe an association between the adapted SNI and participation in regular breast cancer screening (14). This null finding was observed among the more narrow population of the study, which included predominantly White women, the majority of whom were ages <65 years, with relatively high income and education levels. Our study consisted of a diverse population in terms of sociodemographics, and a positive association between social connectedness was observed among both Blacks and Whites. Furthermore, the relationship between the SNI and screening was stronger for Blacks than Whites. The reason for this finding is unclear. There is some suggestion that social networks and support may function differently in relation to health outcomes for certain subgroups; however, the current study did not include other psychosocial measures that might illuminate these findings. We can note however that another study observed that Blacks with fewer close social connections, but not Whites, were more likely to be diagnosed with late-stage breast cancer (26). This is consistent with our findings that Blacks with fewer social ties were less likely to practice colorectal cancer screening, as inadequate screening often results in later stage of cancer at diagnosis.

One component of the SNI, religious involvement, was positively associated with recent colorectal cancer screening in Blacks and Whites as well. This finding is consistent with considerable data from numerous studies showing that religious involvement, often measured in terms of affiliation or frequent attendance at religious services, is associated with healthy behaviors, including screening for cancer (20, 41, 42). Type of religion also seems to influence cancer screening behaviors (43). The current study did not elicit information on religious affiliation or beliefs; thus, we were not able to directly assess the effects of these factors on colorectal cancer screening behavior. In addition, religious activity may be associated with health behaviors and other health-related outcomes through various mechanisms, such as having a potential influence on health-related coping strategies, beliefs, and attitudes (44, 45). Future studies are needed that assess religiosity in more detail, including beliefs (e.g., fatalism), attitudes, and other cultural factors to better evaluate the mechanisms by which religiosity or spirituality influences health-promoting behaviors (44). It is also interesting to note that we observed associations between nonreligious group involvement in Blacks but not in Whites. The reasons for this are unclear but may relate to the type of groups belonged to, and their potential for influencing health-related behaviors, among the subgroups studied.

We also observed an unexpected association between marital status and recent colorectal cancer screening among Whites. This finding is not consistent with the marital literature (19) or with the association observed for the SNI in the present sample for which marital status is a heavily weighed component. This may be a spurious finding; alternatively, additional measures of marital quality or other aspects of social support or psychosocial characteristics might be explored to interpret better this finding. For example, information on occupation was not available for the present analyses. The occupational environment and occupationally based support may function differently than the social network and potentially influence individual's health-related behaviors in unique ways.

There are several possible reasons for inconsistent findings across studies concerning social ties as an index or its components and use of cancer screening tests. Differences in study populations may be a part of the reason for discrepant findings. As mentioned earlier, other studies have focused solely on either women (14), younger populations, or underserved populations in terms of race/ethnicity (28). Our study included Blacks and Whites, men and women, and older individuals from a broader range of socioeconomic strata and geographic areas. There is also evidence that other factors of the social environment, such as social norms regarding the efficacy of screening practices as well as aspects of communication and social support from health care providers, may be important psychosocial factors to investigate in relation to colorectal cancer screening behaviors. Future studies may draw on models, such as the Theory of Reasoned Action and Social Learning Theory (46, 47), which incorporate environmental factors to hypothesize how social norms may influence health practices and how these might differ across sociodemographic groups.

In our data, perceived availability of emotional support as measured by a four-item index was not associated with recent use of the options for colorectal cancer screening. This finding is consistent with another study that observed a null association between availability of emotional social support and use of breast cancer screening (14). We also did not observe associations with perceived adequacy of emotional support or measures of instrumental support. One explanation is that functional aspects of support may be more strongly associated with psychological adjustment or physical functioning than with health-related behaviors. That is, emotional or instrumental support may protect against the detrimental effects of stressful circumstances and thus be associated with better adjustment (48). However, our data did not include assessments of stress in the population-based controls and therefore could not test this buffering hypothesis. Alternatively, social desirability may have led participants to report higher levels of emotional and instrumental support, resulting in a downward bias of the risk estimates.

The findings from this study should be interpreted within the limits imposed by the design of the study. Because of the cross-sectional nature of this analysis, causal mechanisms cannot be inferred. Colorectal cancer screening rates in our study are higher than other studies (49); the rates may be higher for several reasons. We used 10 years as the cut point for recent use of double-contrast barium enema and colonoscopy, whereas many other studies collected information on test use within the previous 5 years or ever versus never use. The information about use of colorectal cancer tests was based on self-reports, and the information was not independently validated; therefore, some participants may have incorrectly reported their use of the various tests (i.e., sigmoidoscopy versus colonoscopy or screening versus diagnostic test). There is evidence that the sensitivity of self-reported screening for FOBT, sigmoidoscopy, and colonoscopy is reliable (50), although validity for colonoscopy self-reports may be more reliable than for other colorectal cancer screening tests (51). In addition, one study did find higher frequencies of ever having colorectal cancer screening tests among a sample of African Americans (52).

The format of face-to-face interviews could also raise the possibility of misclassification bias, as social desirability in responding becomes a factor (53, 54). In addition, although participants were specifically asked whether the tests were done for screening or for symptoms, it is possible that some of the reported screening tests were done to evaluate symptoms or abnormal laboratory results. Another related limitation of the present study is that we did not collect information on whether individuals received general or specific recommendations for colorectal cancer screening from a health care provider. It has been shown that recommendations from providers can influence positively screening behaviors (55). Moreover, we do not know if the occurrence of such recommendations differed among racial/ethnic groups in the sample. Finally, because we studied an elderly population, Medicare covered most of the study participants, making screening more available relative to other study samples. The small numbers for individual types of health insurance compromise our ability to compare screening behavior and reports by insurance status.

Another potential limitation of the current study is the possibility of response bias. The response rates for the current study are consistent with rates observed in similar types of studies; however, biased OR estimates are a possibility. To guard against a response bias, we took extensive steps to improve the response rate. Despite this, 38% of the invited controls were classified as nonresponders. Responders and nonresponders did not differ by race or age group (Ps > 0.50), although a greater proportion of nonresponders were female. We do not have more detailed information on the nonresponder group. Finally, among the responders, sample sizes for some of the social tie subgroup analyses were quite small, which may have precluded detection of significant associations.

Despite these limitations, the study has several important strengths. It is a population-based study, and the sampling strategy permitted evaluation and comparison of the effect of social network characteristics on colorectal cancer screening behavior in Blacks and Whites. Two aspects of social networks were evaluated, and we also distinguished between use of colorectal cancer tests for screening and diagnostic purposes. The study included urban, suburban, small town, and rural areas. Another strength was that trained nurse interviewers obtained the information.

Although our study was not designed to test a conceptual model or theory, our data support the hypothesis that social relations are associated with colorectal cancer screening behavior. There is a convincing body of evidence demonstrating the importance of social norms in motivating people to engage in health behaviors (14, 56). Future investigations can explore more comprehensively social norms and other biopsychosocial factors to learn more precisely the pathways by which social networks exert their influence on screening related behaviors. Our results also support the hypothesis that racial similarities and differences in the associations between social ties and screening behavior exist. Therefore, it will also be important to evaluate whether similar or different biopsychosocial pathways explain how social ties influence these behaviors among Blacks and Whites. Future longitudinal studies on the effects of social ties throughout the life span would also enhance our understanding of the causal mechanisms through which the many facets of social ties operate concerning cancer prevention and control. As attitudes, beliefs, and health habits vary between individuals and social and cultural groups, it will be important for future studies to consider and measure specific aspects of the social and cultural context as well as individual differences in personality, emotions, and cognition (57). Ultimately, a better understanding of the causal mechanisms may guide the development of theories that can be used to design and test interventions using social network linkages to improve colorectal cancer screening rates as well as disease-related morbidity and mortality in diverse populations.


   Acknowledgments
 
We thank Joseph Galanko, Elizabeth Marshall, and William Dudley for their assistance with statistical programming and the nurse interviewers and all of the individuals for participation in this study.


   Footnotes
 
Grant support: National Cancer Institute grant R01 CA 66635 (R.S. Sandler), postdoctoral fellowship grant R25 CA57726, and Preventive Oncology Award KO7 CA82121(A.Y. Kinney).

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 3/22/04; revised 7/15/04; accepted 8/ 4/04.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Feuer EJ, Wun M. Probability of developing or dying of cancer, version 4 [software]. Bethesda (MD): National Cancer Institute; 1999.
  2. American Cancer Society. Cancer facts and figures 2003. Atlanta (GA): American Cancer Society; 2003.
  3. Ransohoff DF, Sandler RS. Clinical practice. Screening for colorectal cancer. N Engl J Med 2002;346:40–4.[Free Full Text]
  4. American Cancer Society. Cancer facts and figures 2000. Atlanta (GA): American Cancer Society; 2000.
  5. Burt RW. Colon cancer screening. Gastroenterology 2000;119:837–53.[CrossRef][Medline]
  6. Pignone M, Rich M, Teutsch SM, Berg AO, Lohr KN. Screening for colorectal cancer in adults at average risk: summary of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med 2002;137:132–41.[Abstract/Free Full Text]
  7. Berkman LF. The role of social relations in health promotion. Psychosom Med 1995;57:245–54.[Abstract/Free Full Text]
  8. House JS, Landis KR, Umberson D. Social relationships and health. Science 1988;241:540–5.[Abstract/Free Full Text]
  9. Stansfeld SA. Social support and social cohesion. In: Marmotand M, Wilkinson RG, editors. Social determinants of health. New York: Oxford University Press; 1999. p. 155–78.
  10. Berkman L, Glass T. Social integration, social networks, social support, and health. In: Berkman L, Kawachi I, editors. Social epidemiology. New York: Oxford University Press; 2000. p. 137–73.
  11. Berkman LF, Syme SL. Social networks, host resistance, and mortality: a nine-year follow-up study of Alameda County residents. Am J Epidemiol 1979;109:186–204.[Abstract/Free Full Text]
  12. Seeman TE, Syme, SL. Social networks and coronary artery disease: a comparison of the structure and function of social relations as predictors of disease. Psychosom Med 1987;49:341–54.[Abstract/Free Full Text]
  13. Adami H-O, Lund E, Bergstrom R, Meirik O. Cigarette smoking, alcohol consumption and risk of breast cancer in young women. Br J Cancer 1988;58:832–7.[Medline]
  14. Allen JD, Sorensen G, Stoddard AM, Peterson KE, Colditz G. The relationship between social network characteristics and breast cancer screening practices among employed women. Ann Behav Med 1999;21:193–200.[Medline]
  15. Suarez L, Ramirez AG, Villarreal R, et al. Social networks and cancer screening in four U.S. Hispanic groups. Am J Prev Med 2000;19:47–52.
  16. Kang SH, Bloom JR. Social support and cancer screening among older Black Americans. J Natl Cancer Inst 1993;85:737–42.[Abstract/Free Full Text]
  17. Zhu K, Hunter S, Bernard LJ, et al. An intervention study on screening for breast cancer among single African American women aged 65 and older. Prev Med 2002;34:536–45.[CrossRef][Medline]
  18. Gravell J, Zapka JG, Mamon JA. Impact of breast self-examination planned educational messages on social network communications: an exploratory study. Health Educ Q 1985;12:51–64.[Medline]
  19. Kiecolt-Glaser JK, Newman TL. Marriage and health: his and hers. Psychol Bull 2001;127:472–503.[CrossRef][Medline]
  20. Koenig HG, McCullogugh ME, Larson DB. Handbook of religion and health. New York: Oxford University Press; 2001.
  21. Strawbridge WJ, Shema SJ, Cohen RD, Kaplan GA. Religious attendance increases survival by improving and maintaining good health behaviors, mental health, and social relationships. Ann Behav Med 2001;23:68–74.[CrossRef][Medline]
  22. Ren XS, Skinner K, Lee A, Kazis L. Social support, social selection and self-assessed health status: results from the Veterans Health Study in the United States. Soc Sci Med 1999;48:1721–34.
  23. Woloshin S, Schwartz LM, Tosteson AN, et al. Perceived adequacy of tangible support and health outcomes in patients with coronary artery disease. J Gen Intern Med 1997;12:613–8.[CrossRef][Medline]
  24. Crane LA. Social support and adherence behavior among women with abnormal Pap smears. J Cancer Educ 1996;11:164–73.[Medline]
  25. Gallant MP, Dorn GP. Gender and race differences in the predictors of daily health practices among older adults. Health Educ Res 2001;16:21–31.[Abstract/Free Full Text]
  26. Reynolds P, Boyd PT, Blacklow RS, et al. The relationship between social ties and survival among Black and Whites breast cancer patients. National Cancer Institute Black/Whites Cancer Survival Study Group. Cancer Epidemiol Biomarkers Prev 1994;3:253–9.[Abstract]
  27. Kang SH, Bloom JR, Romano PS. Cancer screening among African-American women: their use of tests and social support. Am J Public Health 1994;84:101–3.[Abstract/Free Full Text]
  28. Suarez L, Lloyd L, Weiss N, Rainbolt T, Pulley L. Effect of social networks on cancer-screening behavior of older Mexican-American women. J Natl Cancer Inst 1994;86:775–9.[Abstract/Free Full Text]
  29. Sutton S, Bickler G, Sancho-Aldridge J, Saidi G. Prospective study of predictors of attendance for breast screening in inner London. J Epidemiol Commun Health 1994;48:65–73.[Abstract]
  30. Glanz K, Resch N, Lerman C, Blake A, Gorchov PM, Rimer BK. Factors associated with adherence to breast cancer screening among working women. J Occup Med 1992;34:1071–8.[CrossRef][Medline]
  31. Keku T, Millikan R, Worley K, et al. 5,10-Methylenetetrahydrofolate reductase codon 677 and 1298 polymorphisms and colon cancer in African Americans and Whites. Cancer Epidemiol Biomarkers Prev 2002;11:1611–21.[Abstract/Free Full Text]
  32. Weinberg CR, Sandler DP. Randomized recruitment in case-control studies. Am J Epidemiol 1991;134:421–32.[Abstract/Free Full Text]
  33. Weinberg CR, Wacholder S. The design and analysis of case-control studies with biased sampling. Biometrics 1990;46:963–75.[CrossRef][Medline]
  34. Hartge P. Raising response rates: getting to yes. Epidemiology 1999;10:105–7.[Medline]
  35. Seeman TE, Berkman LF. Structural characteristics of social networks and their relationship with social support in the elderly: who provides support. Soc Sci Med 1988;26:737–49.
  36. Schoenbach VJ, Kaplan BH, Fredman L, et al. Social ties and mortality in Evans County, Georgia. Am J Epidemiol 1986;123:577–91.[Abstract/Free Full Text]
  37. Block G, Subar AF. Estimates of nutrient intake from a food frequency questionnaire: the 1987 National Health Interview Survey. J Am Diet Assoc 1992;92:969–77.[Medline]
  38. Block G, Thompson FE, Hartman AM, Larkin FA, Guire KE. Comparison of two dietary questionnaires validated against multiple dietary records collected during a 1-year period. J Am Diet Assoc 1992;92:686–93.[Medline]
  39. Blair SN, Haskell WL, Ho P, et al. Assessment of habitual physical activity by a seven-day recall in a community survey and controlled experiments. Am J Epidemiol 1985;122:794–804.[Abstract/Free Full Text]
  40. Richardson MT, Ainsworth BE, Jacobs DR, Leon AS. Validation of the Stanford 7-day recall to assess habitual physical activity. Ann Epidemiol 2001;11:145–53.[CrossRef][Medline]
  41. Fox SA, Pitkin K, Paul C, Carson S, Duan N. Breast cancer screening adherence: does church attendance matter? Health Educ Behav 1998;25:742–58.
  42. Lannin DR, Mathews HF, Mitchell J, Swanson MS, Swanson FH, Edward MS. Influence of socioeconomic and cultural factors on racial differences in late-stage presentation of breast cancer. JAMA 1998;279:1801–7.[Abstract/Free Full Text]
  43. Miller AM, Champion VL. Mammography in women > or = 50 years of age. Predisposing and enabling characteristics. Cancer Nurs 1993;16:260–9.[Medline]
  44. Ellison CG, Levin JS. The religion-health connection: evidence, theory, and future directions. Health Educ Behav 1998;25:700–20.[Abstract]
  45. Kinney AY, Bloor LE, Dudley WN, et al. The role of religious involvement and social support on the risk of colon cancer in Blacks and Whites. Am J Epidemiol 2003;158:1097–107.[Abstract/Free Full Text]
  46. Glanz K, Lewis FM, Rimer BK. Health behavior and health education: theory, research and practice. San Francisco: Jossey-Bass Publishers; 1997.
  47. Taylor SE. Health psychology. 5th ed. New York: McGraw Hill; 2003.
  48. Peterson JL, Folkman S, Bakeman R. Stress, coping, HIV status, psychosocial resources, and depressive mood in African American gay, bisexual, and heterosexual men. Am J Community Psychol 1996;24:461–87.[CrossRef][Medline]
  49. MMWR. Screening for colorectal cancer—United States, 1997. MMWR Morb Mortal Wkly Rep 1999;48:116–21.[Medline]
  50. Baier M, Calonge N, Cutter G, et al. Validity of self-reported colorectal cancer screening behavior. Cancer Epidemiol Biomarkers Prev 2000;9:229–32.[Abstract/Free Full Text]
  51. Madlensky L, McLaughlin J, Goel V. A comparison of self-reported colorectal cancer screening with medical records. Cancer Epidemiol Biomarkers Prev 2003;12:656–9.[Abstract/Free Full Text]
  52. Lipkus IM, Rimer BK, Lyna PR, Pradhan AA, Conaway M, Woods-Powell CT. Colorectal screening patterns and perceptions of risk among African-American users of a community health center. JCommun Health 1996;21:409–27.
  53. Dillman DA. Mail and telephone surveys: the total design method. New York: John Wiley and Sons; 1978.
  54. Sjostrom O, Holst D. Validity of a questionnaire survey: response patterns in different subgroups and the effect of social desirability. Acta Odontol Scand 2002;60:136–40.[Medline]
  55. Zapka JG, Puleo E, Vickers-Lahti M, Luckmann R. Healthcare system factors and colorectal cancer screening. Am J Prev Med 2002;23:28–35.[CrossRef][Medline]
  56. Heaney CA, Israel BA. Social networks and support. 2nd ed. In: Glanz K, Lewisand FM, Rimer BK, editors. Health behavior and health education: theory, research, and practice. San Francisco (CA): Jossey-Bass; 1997. p.179–205.
  57. Vernon SW. Risk perception and risk communication for cancer screening behaviors: a review. J Natl Cancer Inst Monogr 1999:101–19.



This article has been cited by other articles:


Home page
 Cancer Epidemiol. Biomarkers Prev.Home page
A. McQueen, S. W. Vernon, R. E. Myers, B. G. Watts, E. S. Lee, and B. C. Tilley
Correlates and Predictors of Colorectal Cancer Screening among Male Automotive Workers
Cancer Epidemiol. Biomarkers Prev., March 1, 2007; 16(3): 500 - 509.
[Abstract] [Full Text] [PDF]

Home page
 Postgrad. Med. J.Home page
J O'Loughlin, E Dugas, K Maximova, and N Kishchuk
Reporting of ethnicity in research on chronic disease: update
Postgrad. Med. J., November 1, 2006; 82(973): 737 - 742.
[Abstract] [Full Text] [PDF]

Home page
 American Behavioral ScientistHome page
G. L. Kreps
Communication and Racial Inequities in Health Care
American Behavioral Scientist, February 1, 2006; 49(6): 760 - 774.
[Abstract] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kinney, A. Y.
Right arrow Articles by Sandler, R. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kinney, A. Y.
Right arrow Articles by Sandler, R. S.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Cell Growth & Differentiation