The Relationship between Social Ties and Survival among Black … · Vol. 3, 253-259, April/May...

Vol. 3, 253-259, April/May 1994 Cancer Epidemiology, Biomarkers & Prevention 253

The Relationship between Social Ties and Survival amongBlack and White Breast Cancer Patients1

Peggy Reynolds,2 Peggy T. Boyd, Robert S. Blacklow,James S. Jackson, Raymond S. Greenberg,Donald F. Austin, Vivien W. Chen, Brenda K. Edwards,and the National Cancer Institute Black/White CancerSurvival Study Group3California Department of Health Services, Emeryville, California 94608[P. R.J; California Public Health Foundation, Berkeley, California 94704

[P. T. B.[; Northeastern Ohio Universities College of Medicine,

Rootstown, Ohio 44272 [R. S. B.l; Horace H. Rackham Graduate School,University of Michigan, Ann Arbor, Michigan 48109 U. S. J.[; Emory

University School of Public Health, Atlanta, Georgia 30329 ER. S. C.];Center for Disease Prevention and Control, Portland, Oregon 97232

ID. F. A.]; Department of Pathology, Louisiana State University MedicalCenter, New Orleans, Louisiana 70112 IV. W. C.]; and National CancerInstitute, Rockville, Maryland 20852 [B. K. E.l

Abstract

The relationship between social ties, stage of disease,and survival was analyzed in a population-based sampleof 525 black and 486 white women with newlydiagnosed breast cancer. There were significantdifferences between the two race groups in reported

Received 3/31/93; revised 12/21/93; accepted 12/21/93.

1 This work was supported in part by National Cancer Institute Contracts

NOl -CN-25501 , NOl -CN-35043, NOl -CN-451 74, NOl -CN-451 75, NO1 -

CN-45176, and NO1-CN-75041.2 To whom requests for reprints should be addressed, at EnvironmentalEpidemiology Section, Department of Health Services, 5900 Hollis Street,

Suite E, Emeryville, CA 94608.3 The NCI Black,’White Cancer Survival Study Croup Collaboration

Study Coordinator: Brenda K. Edwards, Ph.D., National Cancer Institute.Investigators: Donald F. Austin, M.D., MPH., Center for Disease Control

and Prevention, Portland, OR; Pelayo Cornea, M.D., Louisiana State Univer-

sity Medical Center; and Raymond S. Greenberg, M.D., Ph.D., Emory Uni-versity School of Public Health; Peggy Boyd, RN., Dr.P.H., California Public

Health Foundation; Vivien W. Chen, Ph.D., Louisiana State University Medi-

cab Center; Ralph J. Coates, Ph.D., Emory University School of Public Health;J. William Eley, M.D., MPH., Emory University School ofPublic Health; andPeggy Reynolds, Ph.D., California State Department of Health Services.

Steering Committee: Sam Shapiro (Chain), The Johns Hopkins School ofHygiene and Public Health; John W. Berg, M.D., AMC Cancer Research Cen-

ten; Robert S. Blacklow, M.D., Northeastern Ohio Universities College ofMedicine; William A. Danity, Ph.D., University of Massachusetts; M. Alfred

Haynes, M.D., MPH., Rancho Palos Vendes, CA; Allen A. Herman, MB.,Ch.B., Ph.D., National Institute of Child Health and Human Development;James S. Jackson, Ph.D., Institute for Social Research, University of Michigan;Hyman B. Muss, M.D., Comprehensive Cancer Center, Wake Forest Uni-versity; and Carol K. Redmond, Sc.D., University of Pittsburgh.

Consultants and Former NCI Participants: George Alexander, M.D., SpecialPopulations Studies Branch, NCI; Roland J. Barrett II, M.D., Bowman Cray

School of Medicine, Wake Forest University; John C. Boyce, M.D., SUNY

Downstate Medical Center; Diana D. Bransfield, Ph.D., Vanderbilt Univer-

sity; Linda A. Clayton, M.D., Harvard School of Public Health; Steve Durako,WESTAT, Inc.; Cecelia M. Fenoglio-Preiser, M.D., University of Cincinnati

Medical Center; Michele Forman, Ph.D., Division of Cancer Prevention and

Control, NCI; Holly Hill, M.D., Emory University, School of Public Health;Steven B. Heymsfield, M.D., Saint Luke’s/Roosevelt Hospital Center; Jan M.Howard, Ph.D., National Institute on Alcohol Abuse and Alcoholism; Carrie

social ties. Using logistic regression to adjust for theeffects of age, race, study area, education, and thepresence of symptoms, there was little or no evidencefor an association between individual network measuresof social ties and stage of disease. However, a summarymeasure of social networks was found to be associatedmodestly with late stage disease, attributable in partto significantly more advanced disease among black, butnot white, women reporting few friends and relatives[relative risk (RR) = 1 .8; 95% confidence interval (Cl) =

1 .1-3.0]. With adjustments for differences in stage ofdisease and other covariates, and with the use ofCox proportional hazards modeling to estimate hazardratios, the absence of close ties and perceived sources ofemotional support were associated significantly with anincreased breast cancer death rate. White women in thelowest quartile of reported close friends and relativeshad twice the breast cancer death rate of white womenin the highest quartile (RR = 2.1; 95% CI = 1.1-4.4).

Notably, both black and white women reportingfew sources of emotional support had a higher deathrate from their disease during the 5-year period offollow-up (RR = 1 .8; 95% Cl = 1 3-2.5). This associationwas stronger for black women (RR = 1 .9; 95% Cl =

1 .3-3.0) and for women presenting with late stagedisease (RR = 1.9; 95% CI = 1.3-2.7). Although theabsence of close ties was associated with late diagnosisamong black women, and was associated with poorersurvival among white women, the absence of sources ofemotional support had a consistent effect on bothgroups of women. These data suggest that functional(“perceived emotional support”) rather than structural(“social network”) measures of social relationships maybe important in influencing disease prognosis.

P. Hunter, M.D., Office of Research on women’s Health; Herbert L. Kotz,

M.D., Bethesda, M.D.; Robert J. Kurman, M.D., The Johns Hopkins Hospital;Robert H. Mayberry, M.D., Emory University School of Public Health; Risa

J. Lavizzo-Mourey, M.D., M.B.A., Agency for Health Care Policy and Re-search; Arnold W. Malcolm, M.D., Saint Joseph Medical Center; Ceorge R.Prout, Jr., M.D., Duck Key, FL; Stanley J. Robboy, M.D., Duke UniversityMedical Center; Mahboob Sobhan, Ph.D., Louisiana State University Medi-cal Center; Ronald S. Weinstein, M.D., University of Arizona Medical Cen-

ten; D. Lawrence Wickenham, M.D., University of Pittsburgh; and xiao-

Cheng Wu, M.D., Louisiana State University Medical Center.National Cancer Institute Participants: Otis Brawley, M.D.; Charles Brown,

Ph.D.; Elizabeth Dean-Cbowen, M.D.; Claudia S. Clover, M.H.S.; Benjamin F.

Hankey, Sc.D.; Linda C. Harlan, Ph.D.; Lance A. Liotta, M.D., Ph.D.;Maunine T. Nelson, MA., M.T.S.; Edward I. Sondik, Ph.D.; and Jacqueline

Whiled, Ph.D.Technical Support Contractor: Margaret N. Wesley, Ph.D.; Margaret

Kildee; Mary Lamb; Shennill Long; Timothy Mann; Lauren Rich; Mary Schanz;

and Jennifer Stevens.

on August 28, 2021. © 1994 American Association for Cancer Research. cebp.aacrjournals.org Downloaded from

http://cebp.aacrjournals.org/

254 Social Ties and Breast Cancer Survival

IntroductionA growing body of literature suggests that the presence onabsence ofsocial ties may be an importantfactor influencingdisease vulnerability. The dramatic overall protective effectof social networks on all cause mortality observed by Berk-man and Syme (1 ) in the Alameda County Study has beenreplicated in community studies in Techumseh, Michigan(2), Evans County, Georgia (3), and in a longer follow-up ofelderly respondents in Alameda County, California (4).Using somewhat different measures of social ties, the sameprotective effects were demonstrated in a short-termfollow-up of an elderly cohort in Durham, North Carolina(5), and in a long-term follow-up among membersofa healthmaintenance organization (6). Similar observations havebeen made for diverse international population-based co-horts, including two from Sweden (7-9), one from Canada(1 0), and one each ofJapanese-Amenican men in Hawaii (1 1)

and the San Francisco Bay area (12).

Despite the general consistency offmndings across studypopulations, the evidence is limited and weakest for women,nonwhites, and noncardiovasculan causes of death. In oneof the few studies to examine this relationship for cancer, afollow-up of the Alameda County Study cohort for cancermorbidity, mortality, and survival, there was a strongly el-evated risk for incidence and mortality from hormone-related cancers (breast, uterine corpus, and ovarian) amongwomen who were socially isolated. However, the risk me-lationships for cancer were, fan less clear for men (1 3).

Social connection measures were derived from the Al-ameda County Study and included in the NCI4 Study ofBlack/White Cancer Survival. The purpose of the analysesreported in this paper was to examine the relationship be-tween social networks/social support and disease prognosisin a population-based series of newly diagnosed breast can-cer cases among black and white women from three geo-graphic areas in the United States.

Materials and Methods

The NCI Black/White Survival Study. The NCI Black/WhiteSurvival Study is a multicenten collaborative case-comparison effort designed to elucidate the factors influ-encing differences in survival between black and white pa-tients with selected sites of cancer. A population-basedsample of black and white women with newly diagnosedbreast cancers was drawn from the metropolitan areas ofAtlanta, Georgia; New Orleans, Louisiana; and SanFrancisco/Oakland, California between January 1 , 1 985 andDecember 31 , 1 986. Study-eligible patients were those withno previous history of cancer (except nonmelanoma skincancer) who were age 20-79 atthe time ofdiagnosis. On thebasis of NCI-specified sample size criteria, approximately70% of eligible black patients were selected for inclusion; asample of white patients frequency matched by age-strata(20-49, 50-64, 65-79) and metropolitan area was selectedfor comparison. Cases were identified via a rapid case as-certainment procedure in each study location. The majorityof cases (65%) were interviewed within 3 months of diag-nosis, and 87% within 6 months of diagnosis. A detaileddescription of the study objectives and design is availableelsewhere (14).

4 The abbreviations used are: NCI, National Cancer Institute; SNI, Social Net-work Index.

Three major data collection efforts were undertaken forthe study: personal interviews; medical record abstracting;and a pathology review. Detailed staging information was

developed from the special study abstracts and pathologyreview using the international tumor-lymph node-metastases system for breast cancer based on evaluation cmi-tenia of the American Joint Committee on Cancer and is de-scnibed in detail elsewhere (1 5). “Early” stage of disease isdefined for this analysis to include in situ, stage I, and stageIINO (patients without node involvement on other evidenceof metastatic spread). “Late” stage is defined to includestages IIN1 , III, and IV. Information on social networks andsocial support was obtained during the personal interview.

Follow-up information on vital status was collected

through two mechanisms. The Atlanta and San Francisco-

Oakland study centers are both participants in the NCI’sSurveillance, Epidemiology, and End Results program androutinely collect active follow-up information on all newlydiagnosed cancer patients in their respective catchment am-

eas. Vital status and cause of death information for the sub-jects from these areas were ascertained via linkage to the(August 1992) Surveillance, Epidemiology, and End Resultssubmission tape from these two areas. In New Orleans,follow-up information for the cases was ascertained througha special contract with the NCI. Active follow-up for all threestudy locations was considered complete through 1990;only 1 50 patients who were lost to follow-up and censoredin our analyses with follow-up dates before 1991 were notknown to have died. All patients with follow-up dates sub-sequent to 1 990 were censored as of December 30, 1990 inthe analyses reported here.

Measures of Social Ties. This study collected informationon two dimensions of social ties, structural (network) andfunctional (emotional and instrumental help) measures. Forstructural measures, questions that were the basis for Berk-man’s SNI (1 ) were drawn from the Alameda County Studyquestionnaire and adapted for administration in a personalinterview. For functional measures, questions were drawnfrom Seeman’s study of angiognaphy patients (1 6) and, inconsultation with Dr. Seeman, adapted for the personalinterview.

The SNI developed by Bemkman is a summary measureofstructunal social relationships. It is composed offive com-ponent parts which are integrated into the index in a non-additive way. The component parts include marital status(currently married versus not), church group participation(yes versus no), other group participation (yes versus no),number of close friends and relatives (by category of me-ported number), and frequency of contacts with friends andrelatives (by categorical response). All of these measureswere collected and scored in a comparable way in thepresent study except for the measure of frequency of con-tacts. Because the questions regarding frequency of contactswere asked differently in the present study, a frequency dis-tnibution was developed for person-time (an average of thefrequency of contacts by person identified) and divided intoquartiles to be used in a comparable manner to the four-levelmeasure from the Alameda County Study. Otherwise, theSNI was constructed for this study exactly as in the Berkmanstudy (17).

The emotional and instrumental support measures de-veloped by Seeman (1 6) also were used in this analysis. Thesources of emotional support measure is derived from a se-nies of four questions: (a) “Do you currently have a familymember on friend you can talk to about your illness?”;



Characteristic

Social ties

sample

No. %“

Excludedcases

No. 0/,,.�

406 40.2 81 38.4

350 34.6 66 31.2

255 25.2 64 30.3

525 51.9 124 58.8

486 48.1 87 41.2

388 38.4

253 25.0

370 36.6

440 43.5

378 37.4

193 19.1

78 37.0

60 30.3

73 34.6

107 50.7

64 30.3

40 19.0

108

903

0

10.7 16 7.6

89.3 192 91.0

3 1.4

Cancer Epidemiology, Biomarkers & Prevention 255

(b) “Do you currently have anyone else to whom you can talkabout your illness?”; (c) “Do you currently have a familymember on friend to whom you can talk about other personalproblems?”; and (d) “Do you currently have anyone else towhom you can talk about other personal problems?”

The emotional support measure was collected andscored dichotomously as described by Seeman; “lowsources of emotional support” is defined as responding posi-tively to at most one of the four questions about sources ofemotional support. The instrumental support measure is de-nived from a longer series of questions about sources of helpfor everyday tasks of living, including preparing meals, get-ting to the doctor, taking came of personal needs, house-keeping, and paying bills. The instrumental support measurealso was collected and scored as described by Seeman, with

a separate score for help from family and/or friends. Indi-viduals with low instrumental support are those reporting nohelp from family onfniends on any ofthose items. Unlike theitems contributing to the SNI, the emotional and instrumen-tal support items were asked specifically in the context of thepatient’s recent illness, rather than as a reflection of pre-illness support, and are analyzed here with respect to prog-nosis only.

Analysis Procedures. Pearson’s x2 statistic was used in com-pamisons ofchanactenistics ofthe social ties study sample andnonmespondents, and between black and white patients.Each measure of social ties and early versus late stage dis-ease, along with covaniates selected as independent predic-tons of stage or design parameters, was entered into an un-conditional logistic regression model using the SASLOGISTIC (SAS Institute, Inc.; Cary, NC; Ven. 6.04) proce-dune. Covamiates included in the models for stage were agegroup (20-49, 50-64, 65-79), mace (in the model for the total

sample, black versus white), study area (Atlanta, New On-leans, San Francisco-Oakland), educational level (less thanhigh school graduate, high school graduate, some college),and reported breast-related symptoms before diagnosis (yesversus no). Models also were run to evaluate the associationwith detailed staging outcomes using the SAS CATMOD pro-cedune. Estimates of the mate ratios (hazard ratios) for dyingof breast cancer were computed via Cox proportional haz-ands modeling using the SAS PHREG procedure, with cen-soning at the time of death for causes other than breast can-cem, and also adjusting for design variables (age group, studyarea, and race) and other covaniates (stage of disease at di-agnosis and the presence of other major chronic comombidconditions). Tests for trend were conducted using a varianton the Cochnan-Ammitage trend test, using a logit link ratherthan a linear probability model (18).

Results

The analysis includes all interviewed black and white breastcancer patients who responded to social connection ques-tions used for either constructing the SNI or measuringsources of emotional and instrumental support. Of the 1222cases eligible for interview, 1 01 1 (82.7%) are included. Thesocial ties analytic sample is compared in Table 1 with casesidentified for study but not interviewed on cases not respond-ing to the social support questions. The social ties sampledoes not differ significantly from excluded patients by agegroup, race, study area, comombidity, on the presence ofsymptoms. However, the study sample does ovemnepresent

earlier staged patients.Theme were significant differences between blacks and

whites for most measures of social ties (Table 2). Black pa-

Table 1 Characteristics of cases in the social ties sample compared with

cases with missing social ties data

Age group

20-49

50-64

65-79

Race

Black

White

Study area

Atlanta

New Orleans

San Francisco/Oakland

Co-Morbidity

Present

Absent

Unknown

Symptoms

None

Some

Unknown

Stage

Early (in situ, I, IlNO)

Late (IIN1, Ill, IV)

Unknown

Total

531 52.5 89 42.4”

458 45.3 113 53.6

22 2.2 9 4.3

1011 211

a Not all totals add to 1 00Yo due to rounding.

1, Distribution for stage of disease is significantly different than the social

support sample (x2; P < 0.05).

tients in this sample were less likely to be married, reportedfewer close friends and relatives, and were less likely to par-ticipate in community groups. However, they were morelikely to participate in church groups and reported a higherfrequency of contacts with friends and relatives. Theme wasno difference in reported sources of emotional support, butblack women reported higher instrumental support.

The relationship between each component part of theSNI and the SNI itself to early versus late stage of disease issummarized in Table 3. Each of these risk relationships isadjusted for age at diagnosis, study area, education, and thepresence of symptoms, as well as for mace in the full sample.Models also were run for detailed staging outcomes, butbecause these results were essentially the same as those forthe dichotomous measure, only results for the simpler mod-els are reported here. The evidence for a relationship be-tween social ties and stage of disease is weak and showssuggestively different profiles for black and white women inthis sample. In general, marital status was associated weaklywith stage, as were moderately fewer social connections assummarized by the SNI. Unmarried women had an approxi-mate relative risk of 1 .3 (95% CI 1 .0-1 .8) for late stagedisease. Although the most isolated women (level I of theSNI) were not significantly more likely to present with latestage disease than women with the most connections (levelIV of the SNI), women ranked overall with relatively fewsocial connections (level II of the SNI) had an approximaterelative risk of 1 .7 (95% Cl = 1 .2-2.5) for late stage disease(Pfontmend = 0.03).

Although the point estimates for most of the measuresof social ties are modest, theme is evidence that these factorsmay be associated with stage differently among blackwomen and white women. White, but not black, women



Table 2 Distribution of social ties variables among blacks and whites

Social Measure

age, study area, race, stage of disease, and the presence ofother chronic health conditions is shown in Table 4. The

Blacks (n = 525) Whites (n=486) relationship between these factors and all cause mortality isNo.” % � % essentially the same, as are these relationships adjusting for

- detailed versus dichotomous measures of stage at diagnosis.Furthermore, point estimates for the social ties measures in

212 40.3 308 63.5” models without adjustment for stage are also essentially the314 59.7 177 36.5 same.

Theme was no evidence that the SNI was itself associated182 35.3 85 17.7” with disease prognosis, nor were the components of this1� � � � measure. White women reporting the fewest number of

115 22.3 175 36.4 close friends and relatives had significantly higher deathratesfmom breastcancer(RR = 2.1 ; 95% CI = 1 .1 -4.4). There

344 65.8 194 40.1 a was no evidencefor trend by level ofthis measure (P = 0.86).1 79 34.2 290 59.9 However, there was a significant interaction effect for white

compared with black patients (P = 0.02). There was also no233 44.7 257 53.2a evidence for trend for any of the other categorical measures288 55.3 226 46.8

presented in Table 4.88 17.6 114 23.9” Most notably, women reporting few sources of emo-98 19.6 125 26.2 tional support had nearly double the rate of dying (RR =

140 28.0 147 30.8 1.8; 95% Cl = 1.3-2.5). This relationship was associated174 34.8 91 19.1 primarily with late stage (RR = 1.9; 95% Cl = 1.3-2.7)

rather than early stage patients (RR = 1 .3; 95% CI = 0.6-89 17.9 89 18.7a 3.0), although theme was little difference in other measures

229 46.2 105 22.1 .

84 1 6.9 1 51 31 .8 of socIal tIes between these two groups (not shown). The94 19.0 130 27.4 modestly elevated mate associated wIth structural measures

of social isolation (elements of the SNI) appeared to be246 47.5 203 42.3 limited primarily to white women in this study, but the272 52.5 277 57.7 higher death mate among women reporting few sources of

emotional support was shared by both black and white164 31.8 229 48.Oa women. As in the analyses for stage the survival disadvan-351 68.2 248 52.0 .

tage among black women remained virtually unchangedin models with and without adjustment for social ties(RR = 1 .7; 95% Cl = 1 .2-2.4).

IV (high)

Emotional support

Low

High

Instrumental support

Low

High

a Distributions among blacks and whites are significantly different (x2; P <

0.01).b Not all totals add to 525 blacks and 486 whites due to different numbers

of missing values by measure.


Social network components

Married

Yes

No

Friends and relatives

I (fewest)

III

IV (most)

Church group

Yes

No

Other group

Yes

No

Contacts

I (fewest)

IV most)

Social Network Index

I (low)

who did not belong to a church group before diagnosis hada modestly higher risk for late stage disease (mace, churchgroup interaction; P = 0.06). Black, but not white, womenreporting fewer close friends and relatives presented withlater stage disease (Pfor trend = 0.06), although a formal testfor a race interaction was not significant. White, but notblack, women reporting less frequent contact with friendsand relatives were more likely to present with early stagedisease (Pfom trend = 0.05). Theme is also a significant in-teraction effect between mace and the lowest frequency ofcontacts in relationship to stage (P = 0.02). Black womenpresented with later stage disease in this study, but the oddsratios for race with adjustment for social ties remained es-sentially unchanged from odds ratios without such adjust-ment (OR = 1.6; 95% CI = 1.2-2.1).

The overall profile of risk relationships for each of themeasures of social ties was consistent between the threestudy locations (not shown). These relationships also werecompared between younger (under 50) and olden (50 orolder) women in the sample (also not shown). Although in-dividual components of the SNI did not demonstrate anystrong association with stage in either age group, the sum-many measure of the SNI suggested that among youngerwomen those with fewer social connections were signifi-cantly more likely to be late stage patients. There was nosuch association found for older women.

The degree to which each measure of social ties is as-sociated with short-term (5-6-year) survival adjusting for

Discussion

This study builds on the literature examining the associationbetween social networks and disease outcomes. It primarilyaddresses the structural features of social ties. It is importantto differentiate between the influence of quantitative (struc-

tural) qualities of social relationships, such as network sizeand composition, and more qualitative features of perceivedsources of social support. This latter feature was assessed inthe Black/White Study by using the instrument introduced bySeeman (1 6) to measure “emotional” and “instrumental”sources of support.

Black and white breast cancer patients in this study dif-fened substantially on a variety of measures of social ties;however, most ofthese differences were not associated withobserved black/white differences in stage at diagnosis. Thereis evidence thatthe SNI may be associated with late stage forblack but not white, and younger (under age 50) but notolden, women. With adjustments for stage of disease, age,mace, and other covamiates, structural measures of social ties(network measures) were not associated consistently withprognosis, but reported sources of emotional support werestrong positive predictors of survival for the total sample andwithin subgroups.

In their study of the influence of social networks on allcause mortality, Berkman and Syme (1) argued that one ofthe more compelling features of the SNI was its consistentcumulative effect on host resistance, even in the presence ofvarious mixes in the component parts. In the present studyof breast cancer patients, who were on average olden thanthe respondents in the community studies, a similar asso-




Table 3 Association betwee n social ties and stage of disease

Social measure

Relative niska (95% confidence interval) for late stage

Totalsample

Blacksonly

Whites

only

Social network componentsMarital status (unmarried) 1 .3 (1 .0-1 .8) 1 .3 (1 .0-1 .9) 1 .3 (0.9-1 .9)

Church group (no) 1 .0 (0.8-i .4) 0.8 (0.5-1 .2) 1 .4 (0.9-2.1)

Other group (nol 1 .2 (0.9-1 .61 1 .0 (0.7-1 .4) 1 .4 (1.0-2.1)

Friends/relatives

I (fewest) 1 .2 (0.8-1 .7) 1 .8 (1 .1-3.0) 0.8 (0.5-1.4)

II 1.2 (0.9-1.8) 1.9 (1.1-3.3) 0.9 (0.5-1.5)

Ill 1.1 (0.8-1.6) 2.2 (1.2-3.9) 0.7 (0.4-il)

IV (most) ref. ref. ref.Contacts

I (fewest) 0.8 (0.5-1 .2) 1 .3 (0.7-2.2) 0.5 (0.3-0.9)

II 0.8 (0.5-1 .2) 0.7 (0.4-1 .2) 0.8 (0.4-1 .3)

III 0.8 (0.5-1 .1) 0.9 (0.6-i .4) 0.6 (0.4-1.1)

IV (most) ref. ref. ref.

Social Network Index

Level I (few connections) 1 .4 (0.9-2.1 ) 1 .3 (0.7-2.4) 1 .3 (0.7-2.4)

Level II 1 .7 (1 .2-2.5) 1 .7 (1 .0-2.9) 1 .4 (0.7-2.4)

Level Ill 1 .1 (0.7-1 .6) 0.6 (0.3-1 .2) 1 .4 (0.8-2.3)Level IV (many connections) ref. ref. ref.

a Approximate relative risk (odds ratio) for late stage disease, estimated via logistic regression and adjusted for race (for total sample only), age at diagnosis, study

area, education, and presence of symptoms.

Table 4 Association between social ties and survival

Hazard ratioa (95% confidence interval)

Social measurefor death from breast cancer

Total Blacks Whitessample only only

Social network components

Marital status (unmarried) 1 .3 (0.9-1 .9) 1 .2 (0.8-1 .9) 1 .6 (0.9-3.0)

Church group (no) 1 .0 (0.7-1 .4) 1 .3 (0.8-2.1 ) 0.5 (0.3-1.0)

Other group (no) 1 .0 (0.7-1 .4) 1 .0 (0.6-1 .6) 1 .1 (0.6-1 .9)

Friends/relatives

I(fewest) 1.4(0.9-2.3) 1.3(0.7-2.3) 2.1 (1.1-4.4)II 0.8 (0.5-1 .3) 0.9 (0.5-1 .8) 0.4 (0.2-1.2)

Ill 1 .1 (0.7-1 .7) 1 .1 (0.6-1 .8) 1 .1 (0.5-2.3)


ContactsI (fewest) 0.8 (0.5-1 .4) 1 .0 (0.5-1 .8) 0.5 (0.2-1.2)

II 0.9 (0.6-1 .5) 0.9 (0.5-1 .7) 0.8 (0.4-1 .7)

Ill 1 .0 (0.6-i .5) 1 .0 (0.6-1 .7) 0.8 (0.4-1 .8)


Social Network IndexLevel I (few connections) 1 .1 (0.7-2.0) 1 .0 (0.5-2.0) 1 .4 (0.6-3.4)Level II 1 .0 (0.6-1 .6) 0.8 (0.5-1 .5) 1 .4 (0.6-3.3)

Level Ill 0.8 (0.5-1 .4) 0.8 (0.4-1 .6) 0.9 (0.4-1.9)Level IV (many connections) ref. ref. ref.

Emotional support (low) 1 .8 (1 .3-2.5) 1 .9 (1 .3-3.0) 1 .5 (0.8-2.6)

Instrumental support (low) 1 .2 (0.8-1 .8) 1 .1 (0.7-1 .7) 1 .5 (0.8-2.8)

a Hazard ratio for dying of breast cancer during the follow-up period (through

1 990), estimated via Cox proportional hazards modeling and adjusted for race(for total sample only), age at diagnosis, study area, stage of disease, andpresence of other comorbid conditions.

ciation for stage of disease was evident only among youngerwomen. In companingyoungemwith olden respondents in theAlameda County Study, Seeman eta!. (4) noted that not onlywas the SNI a stronger predictor of mortality among mespon-dents under age 50 at base line, but also that different com-ponents of the SNI contributed to the risk association formortality in those groups. Marital status was a more impom-tant predictor for respondents younger at base line, while

contacts with friends and relatives was more important forolder respondents. In a study with long-term follow-upamong members of an health maintenance organization,Vogt et a!. (6) reported no association between variousmeasures ofsocial connections and overall cancer mortality.However, they did report a strong and consistent protective

association for two social measures and cancer survivalamong incident cases. Unfortunately, neither of these stud-ies, nor the study by Blazer (5), evaluated this risk relation-

ship separately for men and women. In a hospital-based

study of 283 white women who had died of breast cancer,Marshall and Funch (19) reported longer survival among

young women (under age 45) who indicated greater socialinvolvement in the 5-year period before diagnosis; no suchpattern was evident for older women. The findings fromthe present study are quite consistent with these other

investigations.The most striking finding from this study was the im-

portance of more qualitative rather than structural featuresof social ties for disease outcome. Of all of the social

measures examined, the absence of perceived sources ofemotional support was the single most consistent predictor

of prognosis. It is possible that the best indirect measuresof functional social support are structural measures of inti-mate ties, for which marital status and close friends andrelatives serve as important proxy indicators. These are themeasures which showed notable associations with earlyversus late stage at diagnosis and with prognosis in this

study. These findings are consistent with the very strongrisk for hormone-related cancer mortality in the AlamedaCounty Study among women who felt socially isolated,compared with the more modest risk associated with anetwork measure of isolation (13). Blazer (5) found amuch stronger risk for mortality among respondents me-porting impaired perceived social support than from net-work measures of resources. This is consistent with recentbiological evidence from a series of Stage I breast cancerpatients for whom higher natural killer cell activity was




present among those women reporting high quality emo-tional support from either a spouse or other source of inti-mate ties (20).

Our fmndingthat perceived sources ofemotional supportwere more strongly associated with disease prognosis

among women initially presenting with later stage (meta-static) disease in this study also is consistent with a varietyof other findings. An intriguing 1 0-year follow-up study ofwomen with metastatic breast cancer by Spiegel et a!. (21)

found that women enrolled in a breast cancer support grouphad an average survival time twice that of women in a con-tmol group. Although Cassileth eta!. (22), in a well publicizedstudy of short-term cancer patient survival, found no asso-ciation with various psychosocial measures, a longer(8-year) follow-up ofthese patients found a measure of socialties (modeled after the Bemkman-Syme SNI) to be associatedsignificantly with longer survival time (23). The patients inthe survival analyses were all patients with advanced disease(various cancer types) at diagnosis, and in a second group ofpatients with early stage disease (breast cancer and mela-noma) the investigators noted no significant psychosocialinfluences on time to recurrence. Of all the psychosocialmeasures examined in this latter study, only social ties wereassociated with outcome in the predicted direction.

The present study offers a number of important meth-odological advantages over much of the earlier research inthis area. The Black/White study is population based forthree diverse geographic locations in the United States, casestatus is uniformly determined and histologically confirmed,active follow-up methods optimize available survival infom-mation, and a wealth of information is available on impor-tant prognostic covamiates. Although response mates for thisstudywere quite high and did not differ by age, mace, or

geographic area, the fact that there were proportionatelyfewer late stage patients available for interview does raisesome concern for inferences associated with staging out-comes. Marital status, which is also available for cases notincluded in the interview, does not differ by stage and isassociated comparably with stage and survival outcomes inthe full data set. Although it is difficult to assess the bias thatmight be introduced for the other measures of social ties,stratification by stage produces no different profile for dis-ease prognosis except for the relationship with perceivedsources of emotional support. Because that relationship isstronger among interviewed late stage patients, it may be thatits effect is underestimated in the total sample.

A significant departure from the literature in social ties,which primarily is based on selected white middle-class in-dividuals, is the ability of this study to evaluate the effect ofsocial ties in a population-based sample of both black andwhite women. The observed black/white differences in therelationship between network measures and stage may un-denscore fundamental differences in the family constella-tions, cultural context, and meaning of social ties in thesegroups. Structural measures of social ties are designed asproxy measures for social support, which is addressed moredirectly in this study by questions which ask about perceivedsources of instrumental and emotional support. The generalinconsistency and failure ofthe network measures to predictoutcome in this study may be a function ofthe fact that theyare less well tied to actual sources of emotional support inthis sample, which is more ethnically and economically het-erogenous than those included in earlier studies.

There has been considerable interest in the degree towhich, and mechanism by which, social ties may mitigate

against the stressful consequences of medical interventionfor major chronic diseases and help to explain differentialmortality for subgroups with otherwise comparable dis-

ease status (24-30). An approach using both social net-works and social support has been advocated specifically

for evaluating postmastectomy outcomes in breast cancerpatients (31 ). The analyses in this paper, while showingsome suggestive associations between intimate ties andstage of disease, suggest that although these measures ofintimate ties are strikingly different for black and whitebreast cancer patients, they do not differentiate stronglybetween early and late stage disease in these women.However, the very strong and consistent relationship be-tween sources of emotional support and disease prognosissuggests that qualitative rather than quantitative character-istics of social support systems may be those which mostinfluence physical health outcomes.

AcknowledgmentsThe authors wish to gratefully acknowledge David 0. Nelson and Terry

Camacho-Dickey for their assistance and review in constructing the SocialNetwork Index to be as comparable as possible to the Alameda County StudyMeasure.

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1994;3:253-259. Cancer Epidemiol Biomarkers Prev P Reynolds, P T Boyd, R S Blacklow, et al. Black/White Cancer Survival Study Group.and white breast cancer patients. National Cancer Institute The relationship between social ties and survival among black

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