Health Literacy and Perceived Control: Intermediary Factors in the Relationship Between Race and Cardiovascular Disease Risk in Incarcerated Males in the United States

Abstract

Background:

Black race, inadequate health literacy, and poor perceived control are predictors of increased cardiovascular disease (CVD) risk. The purpose of this study was to explore the relationships among race, health literacy, perceived control, and CVD risk while controlling for known risk factors in incarcerated males.

Methods:

We included data from 349 incarcerated males to examine race and CVD risk (Framingham Risk Score) using a serial mediation model with health literacy and perceived control using 95% confidence intervals from 5000 bootstrap samples.

Results:

Of the participants (age = 36 ± 10; education = 12 ± 2; BMI = 28.3 ± 5.0), 64.2% were White and 35.8% Black. Black incarcerated males were younger (p = .047) with lower levels of health literacy (p < .001). All three indirect effects of race on CVD were significant while the direct effect of race was not. Black incarcerated males had higher levels of CVD risk through health literacy (a₁b₁ = .3571, 95% CI [.0948, .7162]) and lower levels of CVD risk through perceived control (a₂b₂ = −.1855, 95% CI [−.4388, −.0077]). Black incarcerated males had higher levels of CVD risk through health literacy influenced by perceived control (a₁b₂d₂₁ = .0627, 95% CI [.0028, .1409]) indicating that despite the protective effect of higher levels of perceived control in Black incarcerated males, CVD risk remained higher compared to their White counterparts.

Conclusion:

Future CVD risk reduction interventions in incarcerated males, specifically Black incarcerated males, should include goals of improving health literacy and perceived control in addition as modifiable risk factors.

Cardiovascular disease (CVD) remains a leading cause of death in incarcerated and formerly incarcerated people in the United States, with heart disease mortality rates increasing annually across the US.¹ Approximately 10% of the 2.2 million incarcerated people in the US report a diagnosis of CVD either as a pre-existing condition or one that is diagnosed during incarceration and in 2016, 28% of all deaths in custody were attributable to CVD. ^1–3 Following release, incarcerated people have a higher risk of death related to CVD compared to the general population.⁴ Binswanger et al.⁴ found that the adjusted risk of death for formerly incarcerated people was 3.5 times that of the general population and that within the two weeks following release, formerly incarcerated people were 12.7 times more likely to die than the general population from CVD, suicide, homicide, and drug overdose. ^{5, 6}

Additionally, the prevalence of CVD and resulting mortality is higher in Black Americans than other racial groups both inside and outside of the prison system.^7–9 Tajeau and colleagues¹⁰ found that CVD disparity is primarily explained by social determinants of health and personal CVD risk factors. Literature on cardiovascular health in incarcerated people is sparse and often reliant upon governmental reports rather than academic writings. Literature that does exist is often out-dated and health information from the general public is often extrapolated to incarcerated peopleimproperly.¹¹

Race is a social construct rather than a biological difference. Racial categorization and the discrimination with which it is associated results in higher risk for CVD. Race as a predictor of CVD is multi-faceted, with effects of systemic racism and socio-economic factors playing a role in CVD risk differences.¹² The social determinants of health are linked to increased risk of CVD ^{9, 10, 13, 14} and are often compounded in incarcerated people which is disparately composed of Black males.¹⁵ Health literacy is one of these determinants and is a modifiable risk factor for CVD.^{16, 17}

Health literacy is the ability to obtain and understand health information to make appropriate decisions regarding treatment options. ¹⁸ Specifically, health literacy is composed of multiple domains including print literacy, numeracy skills, information literacy, and oral literacy.^{19, 20} Health literacy is the critical juncture between health education and decision-making. Without adequate levels of health literacy, individuals may be unable to engage in self-care, make appropriate decisions about their health and well-being, and assess risk inherent in health-related behaviors.²¹ Previous research has identified white race, younger age, and higher education levels as predictors of adequate health literacy.²² A recent scientific statement from the American Heart Association nested health literacy within the social determinants of health within the life course model of risk factors and CVD.²³

Levels of perceived control can affect the relationship between health literacy and health outcomes, either by enhancing or diminishing the relationship.²⁴ Perceived control, or the belief that one is in control of one’s environment and health outcomes via an inner locus of control has a direct relationship with improved physical and psychological health.²⁵ However, this relationship differs substantively in Black and White populations.²⁵ Higher levels of perceived control have been found to be a protective factor against the development of CVD in White populations whereas that is not always the case for Black populations.¹⁰

Self-identified Black race, inadequate levels of health literacy, and low levels of perceived control have been established as predictors of increased CVD risk in the general population.⁹ However, little is known about the relationship among these factors in the overall interplay of CVD risk in incarcerated males. Therefore, the purpose of this paper was to use the Framingham Risk Score to explore the relationships among race, health literacy, perceived control, and CVD risk, while controlling for well-known risk factors (education, partner status, and body mass index) in incarcerated males.

Methods

Design

This analysis was conducted using baseline data of 378 incarcerated males who participated in a longitudinal biobehavioral CVD risk reduction intervention study in all four Kentucky state medium security prisons. We were unable to enroll incarcerated females because of administrative regulations. The current analysis includes 349 incarcerated people for whom we had data on all variables of interest. Twenty-nine participants were excluded from the analysis due to missing data. There were no significant differences between those incarcerated people included in the analysis and those who were not.

Sample and Setting

Participants enrolled met the following criteria: age 18 years or older; current incarceration in 1 of the 4 medium security Kentucky state prisons with a parole date set for nine months or more beyond study enrollment date; and with the ability to read and write in English. Participants were excluded if they were acutely febrile at time of initial assessment; had a history of chronic illness which could increase the risk of future CVD such as an acute cardiac event or cardiovascular intervention within the last 6 months, uncontrolled hypertension, asthma, chronic obstructive pulmonary disease, cystic fibrosis, diabetes mellitus requiring insulin usage, and congestive heart failure. Additionally, due to Kentucky Department of Corrections visitor safety requirements, participants were excluded if they had been admitted to the psychiatric unit or placed in segregation during the month prior to enrollment date.

Procedure

This study was approved by the Institutional Review Board of the University of Kentucky, and the Kentucky Department of Corrections. The study was advertised at each prison using flyers, and announcements on prison radio and television. All enrollment, consent, and data collection were performed by our trained research staff in the prisons. Each participant gave informed consent and signed the consent form. Participants completed questionnaires and all clinical measures were completed by trained members of the research staff. Demographic and clinical characteristics were obtained at the same appointment.

Measures

Cardiovascular Disease Risk.

The Framingham Risk Score (FRS) is a measure used for prediction of ten-year risk of a CVD event (myocardial infarction or death). The FRS was developed based on the Framingham Heart Study, a prospective cohort study which began in 1948 and is currently in the third generation of participants.²⁶ The FRS is a reliable and valid measure of individual CVD event risk in multiple populations and²⁷ has been revised multiple times as more information was gained from the Framingham study. The score is determined based on age, gender, total cholesterol, high-density lipoprotein (HDL) levels, systolic blood pressure, diabetes, and smoking status. Raw scores range from −4 to 30 in men and are then converted to 0 to 30% risk scores with higher percentages indicating an increased 10-year risk of CVD. Because the converted score groups people into risk categories potentially reducing the sensitivity of the results, we used the raw FRS score as a continuous variable in our analysis.²⁷ The FRS has been shown to be both sensitive and specific to the prediction of CVD events. Sensitivity is on average about 70% with specificity nearly 80% and an AUC for prediction ranging from 74–80% in multiple populations.²⁸

Health Literacy.

Health literacy was measured in this study using the Newest Vital Sign (NVS). The NVS is a 6-item questionnaire used to assess the ability to read and apply information from a nutrition label that can be completed in 3–5 minutes.²⁹ The NVS evaluates both reading and numeracy skills. Scores can range from 0 to 6 and represent the number of questions answered correctly, with higher scores indicating higher levels of health literacy. Individuals who score 4 or more correct answers are categorized as having adequate health literacy; those scoring less than 4 are categorized as having inadequate health literacy.²⁹ Prior psychometric testing of the NVS indicated adequate reliability and validity.²⁹ The Cronbach alpha for this measurement in our study was 0.794.

Perceived Control.

Perceived control was measured using the Control Attitudes Scale-Revised (CAS-R). The CAS-R is an eight-item instrument with scores ranging from 8 – 40 with higher scores indicating greater levels of perceived control. Each item is rated on a five-point Likert scale from 1 (totally disagree) to 5 (totally agree). Two of the items are reverse scored before summation of the scale. The instrument has been found to be valid and reliable in multiple populations living with or at risk for cardiovascular disease.³⁰ The Cronbach alpha for this measurement in our study was 0.843.

Clinical and Sociodemographic Indicators.

Self-identified race was initially collected using the categories White, Black, American Indian/Alaskan Native, and other. These categories were truncated to White and Black in the analysis due to small numbers of individuals who self-identified as neither White nor Black or did not report race (n=6). These individuals were not included in the final analysis. Other self-reported sociodemographics included age, education in years, and partner status. Body mass index (BMI) was collected as a covariate as it is known to be a predictor of CVD³¹ and is not contained in the calculation of the FRS. Calculated BMI has been used routinely in clinical and research settings to identify individuals and populations at risk for CVD.⁹

Data Analysis

All analyses were completed using SPSS (version 26) for Windows. Frequencies and proportions were used to describe the sample regarding sociodemographic and clinical information. To compare characteristics between participants who self-identified as Black or White, we used Fischer’s Exact test and the two-tailed student’s t-test. Serial mediation was conducted using PROCESS (model six) for SPSS macro (2020, v.3.5) to determine the total, direct, and indirect effects of race, health literacy, and perceived control on CVD risk. This macro is based on an ordinary least squares regression model; therefore, traditional multiple linear regression results were obtained. We controlled for other well known risk factors not included in the FRS, education, partner status, and BMI, in all analyses.

In this serial mediation model, with two sequential mediators (i.e., health literacy and perceived control), three indirect effects, a direct effect, and a total effect of race on CVD risk were generated and we examined the significance of effects using 95% confidence intervals from 5000 bootstrap samples. In our analyses, race, was a dichotomized variable with white as the reference group; therefore, one-unit changes in predictor variables represent the comparison of Black to White participants. These indirect effects of race on CVD risk were (1) through health literacy, (2) through perceived control, and (3) through perceived control influenced by health literacy. In this serial mediation model, we did not control for age, gender, total cholesterol, high-density lipoprotein levels, systolic blood pressure, treatment for hypertension, diabetes, and smoking status due to their presence in the outcome, the FRS equation that is the CVD risk measure in this study. We did control for education, partner status, and BMI, well-known risk factors of CVD not included in the FRS.

Results

Table 1 provides the participant demographics. All 349 participants were male with a mean age of 36 years (± 10) and a mean education level of 12 years (± 2). Most (85.8%) were not married or partnered. Of the participants, 64.2% were White, 35.8% were Black. Mean BMI was 28.3 ± 5.0, indicating that, on average, members of this sample were overweight. Mean raw scores of the FRS were 6.63 ± 4.90, which corresponds to risk percentages of 2.3 to 13.3% over the next ten years. Those who identified as Black were younger (35 ± 9 versus 37 ± 10, p = .047) and had lower levels of health literacy (3.84 ± 1.90 versus 4.69 ± 1.63, p < .001) than those who identified as white. No statistically significant differences were noted between races in perceived control, education, partner status, BMI, or CVD risk (Table 1).

Table 1.

Characteristics of Incarcerated Males

	All Subjects N = 349 Mean ± SD or N (%)	White Subjects n = 224 (64.2) Mean ± SD or n (%)	Black Subjects n = 125 (35.8) Mean ± SD or n (%)	P Value
Age in Years	36.10 ± 9.78	36.90 ± 9.95	34.65 ± 9.34	.047¥
Perceived Control Score	31.84 ± 5.54	31.45 ± 5.28	32.54 ± 5.92	.076¥
Health Literacy Score	4.38 ± 1.78	4.69 ± 1.63	3.84 ± 1.90	<.001¥
Education Level in Years	12.22 ± 1.95	12.27 ± 2.12	12.13 ± 1.62	.541¥
Partner Status  Partnered  Unpartnered	50 (14.2) 303 (85.8)	32 (14.3) 192 (85.7)	17 (13.6) 108 (86.4)	.990€
Body Mass Index (BMI)	28.31 ± 5.00	28.24 ± 4.83	28.45 ± 5.27	.711¥
Cardiovascular Disease Risk Score	6.63 ± 4.90	6.71 ± 4.64	6.50 ± 5.35	.671¥

Legend: ¥ = groups compared using t-tests; € = groups compared using chi-square

Multiple Linear Regression

The regression model (Table 2) for prediction of CVD risk was significant at an omnibus level [F (11,6) p < .001], and all predictors explained 16% of the variance in CVD while controlling for education, partner status, and body mass index. Health literacy (−.1588, p = .003) and perceived control (−.1171, p = .030) were significant predictors of CVD, while race (−.495, p = .346) did not predict CVD risk.

Table 2.

Linear Regression Results for the Prediction of Cardiovascular Disease Risk in Incarcerated Males

Variable	Unstandardized Coefficient β	Standard Error	Standardized Coefficient β	Confidence Interval	P Value
Race (White reference)	−.4954	.5254	−.1012	−1.5288, .5381	.346
Health Literacy	−.4363	.1469	−.1588	−.7252, −.1474	.003
Perceived Control	−.1035	.0476	−.1171	−.1971, −.0100	.030
Education	.3517	.1275	.1404	.1009, .6025	.002
Partner Status (Partnered reference)	1.2869	.6903	.0915	−.0858, 2.6595	.066
Body Mass Index	.2490	.0514	.2537	.1478, .3501	< .001

Model statistics, R² .16, F (11, 6, 342) p value < .001.

Path Analyses

Among paths (Figure 1), race significantly predicted both mediators, health literacy (a₁= −.8185, p < .001) and perceived control (a₂ = .7915, p = .003). Health literacy predicted perceived control (d₂₁ = .7401, p < .001)), and CVD risk (b₁ = −.43664, p = .030), and perceived control predicted CVD risk (b₂ = −.1035, p = .030). In this sample, incarcerated Black males had lower levels of health literacy and higher levels of perceived control than their White counterparts.

Figure 1.

Path Analyses of the Effect of Race on Cardiovascular Disease through Health Literacy and Perceived Control in Incarcerated Males

Serial Mediation Analysis

The total (c = −.2610, p = .614) and direct effects (c’ = −.4954, p = .346) of race on CVD in this sample were not significant (Table 3) while all three indirect effects were significant. Incarcerated Black males had higher levels of CVD risk through health literacy (a₁b₁ = .3571, 95% CI [.0948, .7162]) with lower levels of CVD risk through perceived control (a₂b₂ = −.1855, 95% CI [−.4388, −.0077]). Incarcerated Black males had higher levels of CVD risk through health literacy influenced by perceived control (a₁b₂d_{21 =} .0627, 95% CI [.0028, .1409]) indicating that despite the protective effect of higher levels off perceived control in incarcerated Black males, CVD risk remained higher compared to their white counterparts.

Table 3.

Indirect, Direct, and Total Effects of Race on Cardiovascular Disease in Incarcerated Males

	Bootstrap Effect	Bootstrap SE	LCI	UCI
Race → health literacy → CVD risk (indirect effect)	.3571	.1614	.0948	.7162
Race → perceived control → CVD risk (indirect effect)	−.1855	.1128	−.4388	−.0077
Race → health literacy→ perceived control → CVD risk (indirect effect)	.0627	.0354	.0028	.1409
	Standardized Coefficient β	SE	LCI	UCI
Race → CVD risk (direct effect)	−.1012	.5254	−1.5288	.5381
Race → CVD risk (total effect)	−.0533	.5165	−.1.2770	.7549

Discussion

We explored whether the relationship among race and CVD risk was mediated by health literacy and perceived control while controlling for additional risk factors (i.e., education, partner status, and body mass index). Race, health literacy, and perceived control are well known predictors of CVD⁹ and with the exception of race, these relationships were seen in our multiple linear regression (Table 2). Further analysis indicated that both health literacy and perceived control influenced the relationship between race and CVD risk both independently and in combination. We found that incarcerated Black males had lower levels of health literacy and higher levels of perceived control, which taken in combination created a competitive mediating effect making the overall relationship between race and CVD risk difficult to see through a standard multiple linear regression.

Race

The United States incarceration rate is the highest in the world with 698 per 100,000 people incarcerated in 2020 ^{15, 32} Incarcerated people in the United States often have lower levels of education and are more likely to have experienced poverty and/or homelessness than the general population^{33, 34} This incarceration rate disproportionately affects Black males with estimates indicating that 1 in 17 Black males compared to 1 in 91 White males were incarcerated in 2015.³⁵ High incarceration rates among Black males are due in large part to systemic racism in American society. Systemic racism with its multiple sequelae such as high incarceration rates, unequal education, and unequal healthcare access has affected multiple generations of Black Americans decreasing familial resources, maintaining poverty, and affecting overall health and well-being.^32–34

Nearly 40% of US incarcerated people are Black, while the percentage of Black Americans overall in the US is 13.4%.³⁶ Disparate incarceration in Kentucky is even more apparent as 35.8% of incarcerated people participating in this study in Kentucky state prisons identified as Black, while according to the census, Black individuals make up 8.5% of the state population³⁷ The cancer of systemic racism is implicit in policing practices and policies like the war on drugs and the school to prison pipeline that fill prisons in the US disproportionately with Black males.^{15, 35, 38} Social factors affect both potential for incarceration and CVD risk in the United States.

Health Literacy

A bivariate analysis of the data for this study indicated that there was a significant difference between health literacy scores between Black and White incarcerated males with Black incarcerated males having lower levels of health literacy overall. Inadequate levels of health literacy have been linked to increased CVD risk due to decreased ability to understand and follow instructions related to medications, treatments, and lifestyle changes. Inadequate levels of health literacy have also been linked to the decreased ability to assess the risk of unhealthy behaviors that can lead to chronic disease such as CVD. ³⁹ Inadequate health literacy is often, but not always associated with lower educational levels and is frequently seen in situations where health disparities exist including older and minority populations as health literacy is often used as a proxy variable for other difficult to measure social determinants of health..^{18, 40, 41} Inadequate health literacy is associated with decreased knowledge of disease, self-care management skills and an inability to appropriately assess risks to health.⁴² As a modifiable risk factor, health literacy is well positioned to be a focus of interventions to decrease CVD risk. Health literacy is actionable and a positive change can dramatically improve one’s ability to self-manage chronic illness and improve overall risk for CVD. In the future, programs in primary and secondary schools to improve the health literacy of the general population could improve overall levels of health literacy and may play a role in the mitigation of health disparities. ^{17, 43}

Perceived Control

There was no statistical difference in levels of perceived control based on bivariate analysis between Black and White incarcerated males, however, in the path analysis Black race was associated with increased perceived control.. Perceived control was higher in Black incarcerated males and the strength of the relationship between health literacy and perceived control was stronger than that of race and health literacy and resulted in a negation of the expectation of increased risk of CVD in Black incarcerated males. Increased perceived control was an enhancer of health in this analysis. This mathematic relationship lends credence to the theoretical basis that both health literacy and perceived control affect CVD risk.^{23, 25}

The disparate incarceration of Black males is so common in our society that it is often seen as a normative experience for young Black men,^44–46 despite the fact that incarceration has effects on all aspects of a person’s life and can have intergenerational effects on families that reinforce poverty and prevent full civic engagement for these men.^{45, 47} We postulate that this normative expectation may have affected the levels of perceived control in incarcerated Black males in this study, with perceived control acting as a protective measure against CVD risk in Black incarcerated males. The social determinants of health and the psychological sequelae of these determinants have an impact on CVD risk. The recognition that these determinants are highly significant in the prediction of disease have prompted many to call for inclusion of the social determinants of health in risk prediction models like the Framingham Risk Score.⁴⁸

This sample was relatively healthy due in large part to the design of the biobehavioral intervention. Additionally, the Black incarcerated people in our study were on average three years younger than their White counterparts. Despite being younger on average, the Black incarcerated males in this sample had lower levels of health literacy than their White counterparts. A recent systematic literature review identified predictors of health literacy as being; older, male, minority, lower educational and socioeconomic levels.⁴⁹ The intersection of these risk factors increases risk of lower levels of health literacy and when considered in context one or more risk factors may be a stronger predictor than others.

Each of the independent variables in this analysis have been linked to increased cardiovascular risk in prior research and within the theoretical framework that was the basis for this study^{9, 22, 50} Advocating for the use of his mediation tool in the analysis of cross-sectional data, Hayes’ perspective is that “statistical methods are just mathematical tools that allow us to discern order in apparent chaos, or signals of processes that may be at work amid random background noise or other processes that we haven’t incorporated into our models. The inferences that we make about cause are not products of the mathematics underneath the modeling process. Rather, the inferences we make are products of our minds-how we interpret the associations we have observed, the signal we believe we have extracted from the noise.” ⁵¹ He continues to say that we must hold ourselves to high standards when we interpret data from analyses such as this and we feel that prior research supporting the cause-and-effect relationships of these variables and the use of a theoretical framework to underpin our data analysis lend credence to our methodology.

Limitations

There are some limitations inherent when working with an incarcerated population. Institutionalization may impact the answers provided by incarcerated people, as they may fear repercussions from prison administrators if questions are answered in a manner deemed socially unacceptable. There is no way to determine if the incarcerated person who chose to participate in the study had differing levels of health literacy or CVD risk than those who did not. This risk was mitigated by continued reassurance of participants that their data was unidentifiable to the prison administration officials unless there were instances that required legal reporting of predetermined issues (e.g. suicidal ideation, and threats of harm to self or others). Additionally, the data used in this analysis was collected from state prisons in one state which may limit generalizability.

This study included only incarcerated males. This was due to restrictions in the state of Kentucky regarding research and prison security levels. Additionally, the participants in this study were young with a mean age of 36 ± 10 years and were healthy enough to participate in the biobehavioral intervention. These factors limit the generalizability of our findings. Studies involving incarcerated people are difficult due to the many legal and ethical quandaries related to such research. When possible, incarcerated people inclusive of all genders and age ranges should be included in research to increase generalizability to the general prison population.

Adverse childhood experiences (ACEs) are risk factors for increased CVD risk.^{52, 53} Many incarcerated people have high levels of adverse childhood experiences which may in part explain the high levels of CVD risk. We did not collect adverse childhood event data in this study. Future research should include an assessment of ACEs, particularly as they relate to CVD risk in incarcerated people.

Conclusions

Mass incarceration of Black men spurred on by systemic racism as well as the policing and social policies of the 1970’s, 1980’s, and 1990’s in the United States have negatively affected both social and health outcomes for Black men. The intersectionality of poverty, incarceration, and high risk for CVD in Black men cannot be ignored as it is a public health crisis.³⁸ Future CVD risk reduction interventions for incarcerated people should include goals of improving health literacy and perceived control in addition to the traditional modifiable risk factors often included in biobehavioral interventions for incarcerated people of all races, but specifically for incarcerated Black males.