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Keywords:

  • health literacy;
  • quality of life;
  • education;
  • race;
  • localized prostate cancer;
  • PCaP

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

BACKGROUND:

Health literacy deficits affect half of the US overall patient population, especially the elderly, and are linked to poor health outcomes among noncancer patients. Yet little is known about how health literacy affects cancer populations. The authors examined the relation between health-related quality of life (HRQOL) and health literacy among men with prostate cancer.

METHODS:

Data analysis included 1581 men with newly diagnosed clinically localized prostate cancer from a population-based study, the North Carolina-Louisiana Prostate Cancer Project (PCaP). Participants completed assessment of health literacy using Rapid Estimate of Adult Literacy in Medicine (REALM) and HRQOL using the Short Form-12 General Health Survey (SF12). Bivariate and multivariate regression was used to determine the potential association between REALM and HRQOL, while controlling for sociodemographic and illness-related variables.

RESULTS:

Higher health literacy level was significantly associated with better mental well-being (SF12-Mental Component Summary [MCS]; P < .001) and physical well-being (SF12-Physical Component Summary [PCS]; P < .001) in bivariate analyses. After controlling for sociodemographic (age, marital status, race, income, and education) and illness-related factors (types of cancer treatment, tumor aggressiveness, and comorbidities), health literacy remained significantly associated with SF12-MCS scores (P < .05) but not with SF12-PCS scores.

CONCLUSIONS:

Among patients with newly diagnosed localized prostate cancer, those with low health literacy levels were more vulnerable to mental distress than those with higher health literacy levels, but physical well-being was no different. These findings suggest that health literacy may be important in patients managing prostate cancer and the effects of treatment, and provide the hypothesis that supportive interventions targeting patients with lower health literacy may improve their HRQOL. Cancer 2012. © 2011 American Cancer Society.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

Prostate cancer is the most common type of cancer among men in the United States,1 with >80% of men diagnosed with clinically localized prostate cancer.2 Each treatment for localized prostate cancer has potentially negative effects: active treatments such as prostatectomy or radiation therapy often cause urinary, bowel, and sexual side effects, which in turn contribute to reduced health-related quality-of-life (HRQOL) and increased psychosocial distress;3, 4 active surveillance, conversely, is associated with significant uncertainty about cancer progression that also affects HRQOL, especially mental well-being.5, 6

Health literacy deficits present a salient challenge for patients with localized prostate cancer when weighing the risks of treatment versus disease progression. Health literacy is defined as the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.7 Health literacy deficits affect half of the overall American patient population, especially the elderly.8 Prostate cancer is most prevalent among men 65 years of age or older;9 there is no consensus among health care providers about the best treatment for localized prostate cancer. Patients who are newly diagnosed are provided with an overwhelming amount of medical terminology and information regarding multiple treatment options and potential HRQOL effects of each. Therefore, health literacy can potentially have an important impact on a patient's ability to fully understand and adapt to the probable effects of prostate cancer treatment, which may in turn have an impact on HRQOL.

However, whether health literacy significantly influences HRQOL in prostate cancer patients has not been previously studied. Most studies to date have focused on how health literacy affects community residents' understanding of and knowledge about cancer, and ultimately, their cancer screening behaviors10 or treatment decision making.11 Among noncancer populations managing different types of chronic illness, health literacy deficits negatively affect health outcomes,12 including poorer health status, lack of knowledge about medical conditions and related care, decreased comprehension of medical information, lack of understanding and use of preventive health services, poorer self-reported health, and increased hospitalizations and health care costs.13 However, the effects of health literacy on HRQOL for patients managing noncancer chronic illness for an extended period of time may be quite different from that for men with newly diagnosed localized prostate cancer when the demands are overwhelming and imminent.

By using a population-based survey, this study aims to examine whether health literacy is related to HRQOL among men with newly diagnosed clinically localized prostate cancer. We hypothesize that higher health literacy levels would be associated with better physical and mental well-being. Establishing a clear relation between health literacy and HRQOL is important because health care providers may be able to provide men with clearer information about and resources for prostate cancer, which helps mitigate the conflicts between the complexity of cancer care and health literacy deficits, and ultimately improve patients' HRQOL.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

Research Sample

The North Carolina-Louisiana Prostate Cancer Project (PCaP) is a multidisciplinary study of individual, social, and tumor-level causes of racial differences in prostate cancer aggressiveness.14 Eligible North Carolina patients were identified by the Rapid Case Ascertainment Core Facility, a collaborative effort of the University of North Carolina-Lineberger Comprehensive Cancer Center and the North Carolina Central Cancer Registry. In Louisiana, eligible patients were identified in collaboration with the Louisiana Tumor Registry in the School of Public Health at Louisiana State University Health Sciences Center. Case ascertainment field representatives abstracted pathology reports, reviewed information used to screen eligibility, and ensured that ascertainment in hospitals and local urology clinics was as complete and rapid as possible.14

Eligible men must: 1) be residents of the North Carolina or Louisiana study areas with a first diagnosis of histologically confirmed adenocarcinoma of the prostate; 2) be 40 to 79 years old at diagnosis; 3) complete the study interview in English; 4) not live in an institution (nursing home); 5) be cognitively intact or not in a severely debilitated physical state; 6) not be under the influence of alcohol, severely medicated, or apparently psychotic at the time of the interview; and 7) self-identify as African American/black or Caucasian American/white.

After institutional review board approval at all sites, approximately 1000 African American and 1000 Caucasian American research subjects were recruited from Louisiana and North Carolina into the parent PCaP study from October 2004 to August 2009. After obtaining informed consent, study nurses conducted an in-person survey (home visits) using structured questionnaires.14 The data for this research were restricted to patients who were within 1 year of diagnosis of clinically localized prostate cancer. The total sample size is 1581, including 756 African Americans and 825 Caucasian Americans.

Measures

HRQOL was measured using the Short Form-12 General Health Survey (SF12; version 2.0), a validated shortened version of the SF-36.15 SF-12 includes 8 domains: physical functioning, role limitations because of physical health problems, bodily pain, general health, vitality, social functioning, role limitations because of emotional health problems, and mental health. Standard norm-based scoring algorithms16 were used to summarize these domains into physical (SF12-Physical Component Summary [PCS]) and mental (SF12-Mental Component Summary [MCS]) component scores,17 which range from 0 to 100. A higher score denotes better HRQOL. The population means of the SF12-PCS and SF12-MCS scores are set at 50.

Health literacy was measured using the Rapid Estimate of Adult Literacy in Medicine (REALM), a validated reading recognition test that comprises 66 health-related words to screen adult reading ability in medical settings.17 The total health literacy scores were skewed, and thus, categorized as: low, ≤sixth grade (REALM ≤44); intermediate, seventh-eighth grade (45 < REALM ≤ 60); and high, ≥ninth grade (REALM >60).

Sociodemographics (ie, age, education, race, income, and education), cancer stage, and types of treatment were obtained from patient self-report. Because of the small numbers of patients receiving treatments other than surgery and radiation (eg, hormonal therapy, chemotherapy, watchful waiting), types of treatment were categorized into 3 groups: surgery, radiation therapy, and other treatments. Cancer aggressiveness was derived based on clinical grade, clinical stage, and prostate-specific antigen (PSA) at diagnosis and categorized into 3 levels: high aggressiveness (ie, Gleason score ≥8; or PSA >20 ng/mL; or Gleason score = 7 with stage cT3-cT4); low aggressiveness (ie, Gleason score <7 and stage cT1-cT2 and PSA <10 ng/mL); or intermediate aggressiveness (all other cases; Gleason score = 7 and clinical stage T1-T2 and PSA ≤20 ng/mL; or Gleason score <7 and stage T3-T4 and PSA <10 ng/mL; or any Gleason score <7 and PSA = 10-20 ng/mL).14 Comorbidities were patient-reported and scored using the Charlson Comorbidity Index.18

Data Analysis

Analyses were conducted using the SAS statistical software package (SAS Institute, Cary, NC; version 9.2).19 Descriptive analyses were conducted for sociodemographic and illness-related characteristics. The differences in sociodemographics among research subjects with different REALM levels were examined using a chi-square test.

To estimate the effects of health literacy on HRQOL, a series of bivariate and multivariate regression models were specified to regress SF12-PCS or SF12-MCS scores on REALM singularly or while controlling for the following potential classes of covariates: sociodemographic (ie, age, marital status, race, family income, and education) and illness-related factors (comorbidities, types of cancer treatment, and cancer aggressiveness). First, the crude models were obtained by introducing REALM or each of the covariates to the regression model to determine whether they were significantly related to SF12-PCS or SF12-MCS scores. Next, the adjusted models were fitted by regressing SF12-PCS or SF12-MCS on REALM and 1) sociodemographics; or 2) illness-related factors that were significant in the crude models. Lastly, the final models were fitted by regressing SF12-PCS or SF12-MCS on REALM, while simultaneously controlling for the sociodemographic and illness-related covariates that were significant in the crude models.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

Characteristics of Research Subjects

In Table 1, the median age of participants was 63 years; the majority were married and had at least a high school education. All had clinical stage T1 or T2 prostate cancer; most had low to intermediate cancer aggressiveness and received surgery or radiation as the primary treatment. About 63% of the research subjects had a high health literacy level (≥ninth grade). The mean number of comorbidities reported was 3. Table 2 indicates that, compared with those with a high literacy level, research subjects who had low to intermediate health literacy levels were more likely to be older (P < .0001), of African American race (P < .0001), have less than $30,000 annual family income (P < .0001), have less than a high school education (P < .0001), and have more comorbidities (P < .0001).

Table 1. Demographic and Background Characteristics of Research Subjects (N=1581)
VariableNo.%
Race  
 African American75648
 Caucasian American82552
Education  
 <High school30219
 High school47930
 >High school79851
Marital status  
 Married123078
 Not married35122
Family Annual income  
 ≤$30,00045932
 $30,001-$60,00041329
 ≥$60,00156239
Cancer stage  
 T188956
 T269244
Cancer aggressiveness  
 Low76950
 Intermediate50733
 High27417
Treatment type  
 Prostatectomy97262
 External radiation33021
 Other treatment26317
Health literacy  
 ≤6th grade35222
 7th-8th grade23315
 ≥9th grade99463
CharacteristicNo.MedianMeanSDRange (Minimum − Maximum)
  1. For physical well-being and mental well-being, greater scores indicate better quality of life.

Age, year158163.0637.838.0 (41-79)
Comorbidity, types15762.032.012.0 (0-12)
Physical well-being156645.543.511.354.4 (9.94-64.34)
Mental well-being156654.852.110.968.7 (8.42-77.09)
Table 2. Characteristics of Research Subjects With Different Health Literacy Levels
VariablesCategoriesHealth Literacy LevelsChi-Square (df)P
Low, ≤6th gradeIntermediate, 7th-8th GradeHigh, ≥9th Grade
No.%No.%No.%
  1. Abbreviation: SD, standard deviation.

RaceAfrican American29238.6814919.7431441.59303.37 (2)<.0001
Caucasian American607.288410.1968082.52
Family annual income≤$30,00020244.019620.9216135.08336.74 (4)<.0001
$30,001-$60,0006916.717618.4026864.89
≥$60,001346.07315.5449588.39
Education<High school20266.895518.214514.90622.95 (4)<.0001
High school11423.8011022.9625553.24
>High school354.40678.4269487.19
CharacteristicMeanSDMeanSDMeanSDFP
Age63.467.8763.758.0061.947.758.21<.0001
Comorbidities32322211.04<.0001

The Relations Between Physical Well-Being (SF12-PCS) and Health Literacy (REALM)

SF12-PCS scores were significantly related to REALM in the crude model (Table 3). SF12-PCS scores of research subjects with a ≥ninth grade health literacy level were on average 2.87 points higher than those who had a ≤sixth grade health literacy level (P < .0001). SF12-PCS scores were similar between those with ≤sixth grade and those with seventh-eighth grade health literacy levels. Bivariate analyses also showed that SF12-PCS was significantly related to sociodemographic (ie, marital status [P = .0142], race [P < .0001], income [≤$30,000 vs >$60,000: P < .0001; $30,001 ∼ $60,000 vs >$60,000: P < .0001], and education [<high school vs >high school: P≤.0001; high school vs >high school: P ≤ .0002]) and illness-related factors (ie, comorbidities [P < .0001], types of treatment [surgery vs other treatment: P = .0008], and cancer aggressiveness [intermediate vs low: P = .0831; high vs low: P < .0001]).

Table 3. Crude and Adjusted Regression Models: Relations Between Physical Well-Being (Short Form-12 General Health Survey Physical Component Summary) and Health Literacy
ParameterCrude ModelsaAdjusted Modelsb
REALMc and SociodemographicsREALMc and Illness-Related FactorsREALM,c Sociodemographics, and Illness-Related Factors
βSEPβSEPβSEPβSEP
  • Abbreviations: REALM, Rapid Estimate of Adult Literacy in Medicine; SE, standard error.

  • a

    Each crude model included 1 of the parameters listed. The intercept for each model was omitted.

  • b

    Each adjusted model included the sociodemographic and/or illness-related factors that were significant in the crude models.

  • c

    REALM refers to health literacy.

Intercept47.101.09<.000148.530.94<.000152.191.27<.0001
Health literacy (referent: ≤6th grade)            
 7th-8th grade−0.350.95.7127−1.631.04.1174−0.670.91.4523−1.691.00.0920
 ≥9th grade2.870.70<.0001−0.450.96.63781.730.68.0109−0.700.92.4529
Age−0.010.04.7062         
Marital status (referent: married)            
 Not married−1.680.68.01420.650.73.3745   0.560.70.4219
Race (referent: Caucasian)            
 African American−2.780.57<.0001−1.210.65.0658   −1.340.63.0336
Family annual income (referent: >$60,000)            
 ≤$30,000−6.810.69<.0001−6.650.88<.0001   −4.910.87<.0001
 $30,001∼ $60,000−3.160.71<.0001−2.850.77.0002   −1.350.74.0701
Education (referent: >high school)            
  <High school−3.770.76<.00010.391.05.7112   0.411.01.6824
 High school−2.410.65.00020.170.75.8173   −0.110.72.8762
Comorbidities−2.050.14<.0001   −1.970.15<.0001−1.860.16<.0001
Treatment (referent: other treatment)            
 Surgery2.170.65.0008   −0.530.64.4087−1.040.67.1206
 Radiation0.691.00.4943   0.910.95.33501.090.99.2709
Cancer aggressiveness (referent: low)            
 Intermediate−1.110.64.0831   −0.680.61.2653−0.160.63.8010
 High−3.840.79<.0001   −2.890.77.0002−2.110.81.0091

The relation between health literacy and SF12-PCS became nonsignificant in the adjusted model that controlled for the effects of sociodemographic covariates (ie, marital status, race, income, and education). Family income was the only variable that was significantly associated with SF12-PCS scores (≤$30,000 vs >$60,000: P < .0001; $30,001 ∼ 60,000 vs $60,000: P = .0002).

Health literacy was significantly related to SF12-PCS scores (P = .0109 for ≥ninth grade) in the adjusted model controlling for illness-related factors (ie, comorbidities, types of treatment, and cancer aggressiveness). SF12-PCS scores of the research subjects whose REALM levels were at ≥ninth grade were 1.73 points higher than those men whose REALM was at ≤sixth grade when holding all illness-related factors constant. Comorbidities (P < .0001) and cancer aggressiveness (high vs low: P = .0002) remained significant.

In the adjusted model that simultaneously controlled for the sociodemographic and illness-related covariates that were significant in the crude models, the relations between REALM and SF12-PCS became nonsignificant. Better SF12-PCS was related to Caucasian American race (P = .0336), higher family income (≤$30,000 vs >$60,000: P < .0001; $30,001 ∼ $60,000 vs >$60,000: P = .0701), and fewer comorbidities (P < .0001). Compared with patients with low cancer aggressiveness, those with high aggressiveness reported lower SF12-PCS scores (P = .0091).

The Relations Between Mental Well-Being (SF12-MCS) and Health Literacy (REALM)

SF12-MCS was significantly associated with REALM in the crude model (Table 4). The mental well-being scores were on average 3 points higher in men with health literacy levels at seventh-eighth (P = .0009) or ≥ninth grade (P < .0001) than in those who had health literacy levels at ≤sixth grade. SF12-MCS also was significantly related to sociodemographic factors (age [P < .0001], marital status [P < .0001], race [P = .0268], income [≤$30,000 vs >$60,000: P < .0001], and education [<high school vs >high school: P = .0008; high school vs >high school: P = .0556]) and comorbidities (P < .0001).

Table 4. Crude and Adjusted Regression Models: Relations Between Mental Well-Being (Short Form-12 General Health Survey Mental Component Summary) and Health Literacy
ParameterCrude ModelaAdjusted Modelb
REALMc and SociodemographicsREALMc and Illness-Related FactorsREALM,c Sociodemographics, and Illness-Related Factors
βSEPβSEPβSEPβSEP
  • Abbreviations: REALM, Rapid Estimate of Adult Literacy in Medicine; SE, standard error.

  • a

    Each crude model included 1 of the parameters listed. The intercept for each model was omitted.

  • b

    Each adjusted model included the sociodemographic and/or illness-related factors that were significant in the crude models.

  • c

    REALM refers to health literacy.

Intercept38.402.57<.000152.290.71<.000137.442.53<.0001
Health literacy (referent: ≤6th grade)            
 7th-8th grade3.030.91.00092.371.00.01782.930.90.00122.280.98.0206
 ≥9th grade2.980.67<.00011.990.92.03052.550.67.00011.860.90.0394
Age0.180.03<.00010.220.04<.0001   0.270.04<.0001
Marital status (referent: married)            
 Not married−2.670.66<.0001−1.590.70.0234   −1.650.69.0167
Race (referent: Caucasian)            
 African American−1.210.55.02681.100.64.0861   1.240.63.0508
Family annual income (referent: >$60,000)            
 ≤$30,000−3.110.67<.0001−3.250.86.0002   −2.340.86.0065
 $30,001∼$60,000−0.770.70.2668−1.480.75.0476   −0.780.74.2953
Education (referent: >high school)            
 <High school−2.480.74.00080.031.02.9718   −0.241.00.8111
 High School−1.200.63.0556−0.360.72.6164   −0.480.71.4988
Comorbidities−0.910.15<.0001   −0.860.15<.0001−1.080.15<.0001
Treatment (referent: other treatment)            
 Surgery−0.480.63.4456         
 Radiation−0.740.97.4422         
Cancer aggressiveness (referent: low)            
 Intermediate−0.600.62.3343         
 High−0.470.77.5408         

The relations between SF12-MCS and REALM remained significant (seventh-eighth vs ≤sixth grade: P = .0178; ≥ninth grade vs ≤sixth grade: P = .0305) in the adjusted model that controlled for the effects of the sociodemographic covariates that were significant in the bivariate analyses (ie, age, marital status, race, income, and education). Better SF12-MCS scores were also significantly associated with older age (P < .0001), being married (P = .0234), and having higher family income (≤$30,000 vs >$60,000: P = .0002; $30,001 ∼ $60,000 vs >$60,000: P = .0476). In the adjusted model controlling for the significant illness-related covariate (ie, comorbidities), SF12-MCS scores were significantly associated with health literacy (seventh-eighth grade vs ≤sixth grade: P = .0012; ≤ninth grade vs ≤sixth grade: P = .0001) and comorbidities (P < .0001).

In the adjusted model that simultaneously controlled for all the covariates that were significant in the crude models, the relation between SF12-MCS and REALM remained significant. When holding all covariates constant, men with health literacy levels at seventh-eighth (P = .0206) or ≥ninth grade (P = .0394) reported SF12-MCS scores about 2 points higher than their counterparts whose REALM scored at ≤sixth grade. Meanwhile, better SF12-MCS scores also were related to older age (P < .0001), being married (P = .0167), higher family income (≤$30,000 vs >$60,000: P = .0065), and fewer comorbidities (P < .0001). Race was marginally significant (P = .0508), which suggests that, when holding other factors constant, African Americans reported better SF12-MCS scores than Caucasian Americans.

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

Health literacy is of significant importance for men with newly diagnosed localized prostate cancer because the majority of patients are 65 years of age or older (where health literacy deficits are more common)20 and because of the complexity and sheer volume of information they receive during the treatment decision-making process. In this study, the percentage of participants with a high school or higher education is slightly lower than that of the overall US population;21 the median age at diagnosis for these participants (ie, 63 years of age) is younger than that of the overall prostate cancer population in the United States.9 Yet health literacy deficits were common among these participants; about 37% had low (≤sixth grade) or intermediate (seventh-eighth grade) health literacy levels. This rate, similar to that reported in a prior study using the Medicare population,22 indicates that a major proportion of the patients with newly diagnosed localized prostate cancer are challenged by health literacy deficits while managing the complex information for treatment decision making and illness management.

The results of this analysis partially support the research hypotheses. Health literacy levels were positively associated with mental well-being on bivariate or multivariate analyses; compared with patients with lower health literacy levels, patients with higher health literacy had better mental well-being (SF12-MCS). However, the relation between health literacy levels and physical well-being (SF12-PCS) was significant only in the bivariate model and became nonsignificant after controlling for sociodemographic and/or illness-related covariates. The significant positive relations between health literacy and mental well-being are similar to previous findings among noncancer populations.23 These results suggest that men with newly diagnosed localized prostate cancer who have different levels of health literacy may have similar physical HRQOL, yet their emotional well-being differs significantly. Previous studies have indicated that the presentation of higher PSA levels24 and advanced stage of prostate cancer25 at diagnosis is associated with patients' low health literacy, especially among African American men. Our findings, adding to previous evidence, suggest that the negative impact of low health literacy extends from before diagnosis of prostate cancer to the early phase of survivorship, when men have to manage complex information and make treatment decisions.

A potential explanation of the relations between health literacy and physical and mental domains of HRQOL may be that low health literacy can limit patient understanding of the complex information about cancer treatments and prognosis, and thus, become a barrier to patient participation in the medical process. People with health literacy deficits tend to have a complex array of difficulties with communication,26 which adds an extra barrier for patients to identify questions to ask, to express their concerns and emotions, to make their needs clear to providers, and to seek additional services such as support for mental health. Health care providers often underestimate cancer patients' needs for psychosocial services27; inadequate health literacy may further limit patients' ability to talk with their families and health care providers about the difficult emotional issues or the abstract psychosocial implications of prostate cancer. Patients with low health literacy thus can be disadvantaged in seeking mental health services, because these services are usually self-initiated or based on physician judgment. Nonetheless, the above results may suggest the need to provide additional support to patients with prostate cancer, especially those with low health literacy. In addition to providing interpretation of complex information, more clear and comprehensible education materials, and decision support tools, health care providers also need to attend to patients' emotional needs, help them express concerns, and provide mental health services when needed.

In this study, the negative effects of health literacy on HRQOL are explained to some extent by additional covariates (eg, family income). Health literacy was significantly related to SF12-PCS and SF12-MCS in bivariate analysis, but its effect on SF12-PCS was fully explained by family income when adjusting for sociodemographic characteristics; its effect on SF12-MCS was explained partially by family income and marital status. Consistent with the results of previous studies,28-31 higher family income in this study is associated with better physical and emotional well-being. Financial concerns are prevalent among cancer patients;29 more income may allow patients to afford materials and human resources to better manage cancer and related symptoms, which helps to improve HRQOL. Regarding marital status, the findings of this study indicate that being married seems to protect the patient, at least in part, from the negative effect of low health literacy on mental well-being. The partners often act as the primary caregiver for cancer patients by providing major emotional and tangible support on a daily basis.32 Married patients may combine their personal resources with those of their partners and thus better manage prostate cancer and related impact.

Another important finding of this study is that African American race is associated with worse physical well-being but better mental well-being after controlling for covariates. Similar differences have been reported in other research that compared African and Caucasian men with prostate cancer.33-35 In this current study, compared with their Caucasian counterparts, significantly greater percentages of African American research subjects have more aggressive cancer, lower family income (<$60,000), and less education (≤high school; data not shown); African American men also seemed to experience decreased physical well-being but yet reported better mental well-being. African Americans may experience more adverse life events (eg, poverty, discrimination) that force them to develop social support network and coping strategies.36 Such experiences could help African Americans effectively mitigate the negative emotional effects of prostate cancer. Their physical well-being, however, may often be challenged by lack of resources because of their lower socioeconomic status and more aggressive cancer at diagnosis.

Finally, the results of this population-based study also suggest that educational level may be a proxy for health literacy. In Table 2, education is positively associated with health literacy; higher levels of education are associated with higher levels of health literacy. Among those who have some high school or higher education, about 60% also report a health literacy level at ninth grade or higher (data not shown); among those who have less than a high school education, about 85% report a health literacy level at seventh-eighth grade or lower. Thus, clinicians may use education level as a proxy for health literacy, as it is a less formal, less threatening assessment to individuals who may be embarrassed by their low literacy skills.37, 38 However, for research purposes, health literacy may need to be measured in addition to the variable of education whenever possible and relevant. In this study, both factors were significantly related to HRQOL in bivariate models (Tables 3 and 4). In the adjusted models including sociodemographics and health literacy, the effect of education on physical well-being was completely explained by income alone, which also completely explained the effect of health literacy; the effect of education on mental well-being was completely explained by inclusion of health literacy along with age, marital status, and income. These results may suggest that education can serve as a proxy for health literacy, but that income may actually be a better proxy, especially for predicting physical well-being.

This study has limitations that merit discussion. Because of the constraints of secondary analysis of cross-sectional data, we lacked the data to establish a causal relation between health literacy and physical and mental well-being. Second, prostate cancer-specific symptoms, important factors influencing HRQOL, were not collected in the PCaP study, and thus were not included in the analyses. However, type of treatment and cancer aggressiveness were used as proxies because of the high correlations between these factors and cancer-related symptoms among clinically localized prostate cancer patients.34 Finally, because of the small number of patients receiving watchful waiting (n = 9), it was not possible to meaningfully assess the separate effects of that type of treatment. Future research is needed to compare patients who receive active treatment with those who receive no treatment, using sufficient sample sizes of subgroup patients receiving different types of treatment.

In summary, this report fills an important literature gap about the relations between health literacy and HRQOL among men with newly diagnosed clinically localized prostate cancer. Health literacy is increasingly recognized as an important factor affecting health outcomes and an important component of improving health care quality and eliminating health disparities.12 This population-based study shows that low health literacy, prevalent among these patients with newly diagnosed clinically localized prostate cancer, is associated with worse mental well-being. This result suggests the need for increased awareness of health literacy issues in prostate cancer among professionals and the public. In addition to providing sufficient information about cancer diagnosis and treatment regardless of patients' health literacy levels, health professionals also need to pay attention to patients' mental well-being, especially among those with health literacy deficits. These practices will in turn promote patients' HRQOL. Future research needs to explore how health literacy relates to patient-health care provider communication and identify optimal methods for effective communication strategies for cancer patients with different health literacy levels.

FUNDING SOURCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

The North Carolina—Louisiana Prostate Cancer Project (PCaP) is carried out as a collaborative study supported by Department of Defense contract DAMD 17-03-2-0052.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES

We thank the staff, advisory committees, and research subjects participating in the PCaP study for their important contributions.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. FUNDING SOURCES
  8. Acknowledgements
  9. CONFLICT OF INTEREST DISCLOSURES
  10. REFERENCES
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