Overview of Arterial Hypertension in Quilombos in Brazil: A Narrative Review

Resumo: Hypertension is a chronic medical condition characterized by pathological elevation of blood pressure, affecting 1.13 billion individuals globally and presenting a significant public health concern. Its etiology is multifactorial, influenced by genetic/epigenetic, environmental, and social factors. In Brazil, nearly a quarter of the general population experiences hypertension; however, the literature underscores its disproportionate impact on Afro-descendant communities, often marginalized from basic healthcare services. This study aims to gather prevalence data and establish a nationwide overview of hypertension within 21st-century quilombola communities through a comprehensive literature review. Fifteen studies published between 2001 and 2021, meeting the specified methodological criteria, were selected. These studies collectively encompass 140 quilombola communities spanning 11 Brazilian states. The aggregate prevalence of hypertension across these communities averages at 32.1% (ranging from 13.8% to 52.5%). This panorama unequivocally highlights the recurring and paramount health challenge posed by hypertension within these populations, underscoring the need for tailored management strategies.


Introduction
Arterial hypertension (AH), or simply hypertension, is a clinical condition characterized by the chronic elevation of blood pressure, and is strongly correlated with an elevated risk of cardiovascular, cerebral, and renal diseases.As per the World Health Organization, hypertension stands as a leading cause of premature mortality globally.The condition impacts approximately 1.13 billion individuals, with two-thirds of those affected residing in countries with limited socioeconomic development, thereby presenting a grave public health concern (WHO, 2021).
AH falls within the category of multifactorial clinical conditions, where its emergence is influenced by a blend of predisposing genetic elements, along with epigenetic, environmental, and social factors.In the context of Brazil, AH is identified by a consistent elevation of systolic blood pressure (SBP) equal to or exceeding 140 mmHg and/or diastolic blood pressure (DBP) equal to or exceeding 90 mmHg (BARROSO et al., 2021).
As far back as the late 1980s, evidence was already emerging indicating a higher frequency of hypertensive cases among individuals of African descent (LIU et al., 1989).Subsequent studies have consistently highlighted a greater prevalence of hypertension within these population groups (CAULFIELD et al., 1995;COOPER;ROTIMI, 1997;CHOBANIAN et al., 2003;AGYEMANG;BHOPAL, 2003;SWIFT;MACGREGOR, 2004;YOUNG et al., 2005;CAMPBELL;TISHKOFF, 2008;FRANCESCHINI, 2014).This variance in prevalence has spurred comprehensive investigations into the underlying factors contributing to these susceptibility disparities, exemplified by the extensive academic studies aimed at identifying the genes and variants associated with this phenotype.

Formation of the Brazilian population and the remnants of quilombos
The historical composition of the Brazilian population centers around three primary demographic groups: Native-American, European, and African.The course of colonization, commencing in the 15th century, ushered in millions of Europeans (predominantly Iberians) and sub-Saharan Africans to Brazil, sparking a profound intermingling among these three communities.This intricate backdrop gave rise to quilombos, traditionally described as sanctuaries for enslaved individuals who valiantly resisted the oppressive system of slavery (CARVALHO et al., 1996).
| Página 3 de 21 However, this characterization fails to capture the diverse range of processes through which black communities organized themselves and established claims to their territories.Consequently, contemporary quilombo remnants cannot be solely seen as direct continuations of their historical counterparts.The definition of quilombo remnants is outlined in Article 2 of Decree 4. 887, dated November 20, 2003: Quilombo community remnants, as per the terms of this Decree, are identified as ethnic--racial groups, determined by self-attribution criteria, possessing their distinct historical trajectories, marked by specific territorial relationships, and presumed black heritage rooted in resistance against historical oppression endured (BRASIL, 2003).
Broadly interpreted, these quilombo remnants represent dynamic social entities that have evolved from various formative histories, not always hinging on escape and isolation as the sole backdrop (O'DWYER, 2002).
Documentation reveals the existence of quilombo communities not only in remote rural regions but also in urban and peri-urban locales across nearly the entire country, with exception of Acre and Roraima states, and the Federal District (Figure 1).While more than 2,800 communities have received official certifications (PALMARES, 2021), the exact number of quilombo remnants communities remains elusive.A second map of Brazil illustrates the 11 states with certified quilombola communities recognized by the Palmares Foundation, which were selected and investigated within this study (indicated in blue).Additionally, there are 13 states boasting certified quilombola communities; however, they lack eligible scientific productions (represented in green).

Remnants of quilombos and hypertension
Historically, populations with African ancestry have been marginalized in almost every socioeconomic aspect of individual rights.Macedo et al. (2021) described the communities of quilombo remnants in Rio Grande do Norte in a way that can be applied to many other quilombola communities spread across Brazil.In this context of stark impoverishment and limited education and employment opportunities, a staggering 87.3% of families are registered with CADÚnico to access Social Assistance policies, with only 54% benefiting from the Bolsa Família Program.Such disparities stem from unequal access to services, benefits, and prospects, further accentuating inequalities and laying bare the presence of institutional racism.The repercussions of this policy implementation extend to eroding the collective identity of these communities as black populations (GROSSI et al., 2019).
The advent of the National Policy for the Comprehensive Health of the Black Population (BRASIL, 2009) underscored the imperative to promote and safeguard health equity for black communities, including quilombolas.In this vein, epidemiological studies serve as vital tools to pinpoint prevalent diseases within these groups, enabling the precise tailoring of public policies to address their specific needs.
However, epidemiological studies pertaining to arterial hypertension among Afro-descendant populations, particularly quilombolas, remain notably scant.In the 1990s, when indications were already emerging about the heightened frequency of hypertension among African descendants -as previously mentioned -a specific study on the topic reported a 6.3% prevalence of hypertension within the Kalunga quilombola population in Goiás (JARDIM et al., 1992).At that time, it was deduced that lifestyle, dietary habits, and community isolation collectively contributed to the relatively low prevalence of identified cases of hypertension.
Yet, the quilombola populations have undergone substantial epidemiological transition over the past decades, evidenced by the transformations witnessed in communities like Vale do Ribeira-SP, where traditional ways of life have experienced shifts (ANGELI et al., 2011).This transition, characterized by an escalated prominence of non-communicable chronic diseases, such as hypertension, juxtaposed against conditions stemming from inadequate access to fundamental sanitation and healthcare services, such as parasitic infections, is intrinsically tied to these transformations.Thus, it stands to reason that the situation observed for the Kalunga quilombola population in the 1990s no longer echoes the contemporary reality for most quilombola communities.
Given the context here discussed, the current study strives to evaluate the prevalence of hypertension within quilombola communities through an in-depth literature review.The motivation for this research arises from the deficiency of a comprehensive national outlook on this ailment within these populations, particularly within the scope of the 21st century.

Methods
This narrative review delves into the existing literature, with a focus on national production, encompassing both domestic and international journals found within the following databases LILACS, MEDLINE, PUBMED, Scielo, Capes' Portal de Periódicos, and Google Scholar.The search process, conducted autonomously by two reviewers throughout March 2021, was driven by keywords including "quilombo(s)", "quilombola(s)", "quilombola population(s)", "quilombola community(ies)", "hypertension", "essential hypertension", and their variations.
The investigation was delimited to works published between January 2001 and March 2021, purposefully reflecting the initial two decades of the 21st century to capture the latest insights into hypertension within Brazil's quilombola populations.Eligibility criteria encompassed original studies -scientific articles, thesis, dissertations, and course completion works -furnished with complete electronic text availability.These works exclusively addressed essential hypertension within Afro-descendant communities, specifically the quilombola communities, leading to the preliminary selection of 46 studies.Thematic content analysis, as outlined by Bardin (2009), was employed in a three-step process: pre-analysis, material exploration, and interpretation of results.The pre-analysis phase involved abstract and record perusal to discern primary exclusion criteria, including duplicates, studies involving disparate health indicators, gender-specific studies, literature reviews, and studies that did not exclusively address quilombola populations or offered secondary hypertension prevalence data.This process led to the exclusion of seven duplicates, three gender-specific studies, two secondary data studies on hypertension prevalence, one literature review, and one study that did not exclusively address quilombola communities.
Material exploration consisted of a comprehensive reading of the remaining 32 studies, categorizing shared information.Data organization involved constructing a | Página 6 de 21 variable table encompassing title, authors, publication type, year, community names, Brazilian state locations, sample size, participant age groups, average participant age, gender-segregated and overall hypertension prevalence rates, hypertension classification references, blood pressure measurement methods, and other relevant data.Further exclusions took place at this juncture, including seven studies delving into various health indicators without presenting hypertension prevalence data, five studies lacking comprehensive hypertension data, and five studies indicating redundancy with more comprehensive evaluations of quilombola communities.
Hence, the ultimate stage of thematic content analysis centered on 15 studies meeting strict inclusion criteria.These studies, characterized by originality, fulltext availability, and data detailing global hypertension prevalence in quilombola populations, are detailed in Table 1.Additionally, as a supplementary analysis, the prevalence of hypertension within individual quilombola communities and the cumulative prevalence were juxtaposed against the respective Brazilian states' data, sourced from the National Health Survey (BRASIL, 2020).
The predominant approach in the analyzed studies (86.7%) involved the utilization of blood pressure measurements for the classification of hypertensive | Página 10 de 21 individuals, albeit with variations concerning the number of readings and the temporal intervals between them.Despite these variances in assessment criteria, individuals with recorded systolic and/or diastolic blood pressure readings (averaged across multiple measurements or the highest recorded measurement) reaching or surpassing 140/90mmHg, and/or those under antihypertensive medication were classified as hypertensive.Meanwhile, two studies opted for a self-reported classification of hypertension, wherein research participants themselves affirmed being hypertensive based on prior diagnoses (Chart 1).More detailed information concerning the investigated communities, their geographical placements, the respective sample sizes, age parameters of research participants (including minimum age or designated age groups, as well as average age), and the prevalence of hypertension can be found in Table 1.
Considering the aggregate of 140 communities addressed in the scrutinized studies, the mean overall prevalence of hypertension amounted to 32.1%.Of note, the community of Santo Antônio, situated in the Concórdia do Pará municipality within the state of Pará, exhibited the lowest recorded prevalence at 13.8% (BORGES, 2011).In contrast, the highest prevalence (52.5%) emerged in Mata Cavalo, located within the Nossa Senhora do Livramento municipality in Mato Grosso (SANTOS et al., 2015).

Comparative analysis
Upon consideration of the 15 studies' evaluation encompassing 11 states (as depicted in Figure 1), and drawing from the latest data furnished by the National Health Survey (PNS) (BRASIL, 2020), notable disparities emerge.Among these states, Pará exhibited the lowest hypertension prevalence at 15.3%, while Minas Gerais stood at the other end of the spectrum with the highest prevalence at 27.7%.In terms of regional distribution, the North registered the least prevalence at 16.8%, while the Southeast recorded the highest at 25.9%.
Comparatively, a noteworthy trend surfaces: the vast majority of communities demonstrated hypertension prevalence equal to or surpassing the figures recorded for the respective states and regions where they are situated.However, an exception presents itself in the case of Santo Antônio in Pará, boasting a prevalence of 13.8% (Table 2).
The most pronounced divergences in prevalence materialized between the Mata Cavalo community (52.5%) and the state of Mato Grosso (21.6%), as well as the Pé do Morro community (50.2%) and the state of Tocantins (22.5%).Both of these communities boasted the highest global hypertension prevalence rates, with over half of the surveyed individuals classified as hypertensive.

Discussion
The current study has underscored the substantial prevalence of hypertension within quilombola populations across all Brazilian macro-regions.A comparison of prevalence averages between the scrutinized communities and official state and regional data reveals consistently elevated values within the communities.
The overall average hypertension prevalence across the communities assessed within the studies encapsulated in this work stood at 32.8±10.66%,markedly surpassing the prevalence rate of 23.9% reported for the entire Brazilian population in the latest PNS survey of 2019 (BRASIL, 2020).While acknowledging the multifaceted risk factors encompassing genetics, environment, and social dimensions (BARROSO et al., 2021), it is the genetic ancestry that has garnered significant attention in discussions concerning hypertension, particularly within Africandescendant populations.This study's findings substantiate the prevailing notion in literature that hypertension is more prevalent among Afro-descendant populations.Globally, individuals of African descent manifest elevated blood pressure from a younger age and exhibit greater incidence and lifetime prevalence of hypertension compared to other global populations (MURTHY et al., 2013;LACKLAND, 2014;CHOR et al., 2015;LARIFLA et al., 2015;MARDEN et al., 2016;JONES et al., 2017;MILLS;STEFANESCU;HE, 2020).
Consequently, the substantial African ancestral component in shaping the Brazilian population can be discerned as a pivotal contributor to the high hypertension prevalence observed within Brazil.In this context, it's important to recall that ancestry proportions for the Brazilian populace stand at 68.1%, 19.6%, and 11.6% for European, African, and Native American contributions, respectively (SOUZA et al., 2019).
This landscape unequivocally underscores hypertension as a matter of great health concern.Noteworthy is the study by Jardim et al. (1992), which evaluated a segment of the Kalunga-GO community in 1992 and uncovered a low prevalence of 6.3%.Conversely, in 2017, the work by Paiva (PAIVA, 2017) portrayed a contrasting reality, observing a prevalence of 30.2% within the same community.This dynamic mirrors an illustrative instance of the epidemiological transition that quilombola populations have been navigating.
However, it is imperative to stress that there exists a notable dearth of epidemiological studies on hypertension within quilombola populations.Even though the precise number of quilombo remnants remains undisclosed, the evaluations have been conducted on slightly over a hundred, despite records indicating thousands of communities across the nation.The certified remnants alone, endorsed by the Palmares Cultural Foundation, exceed 2,800.
Epidemiological studies serve as instrumental components in health planning, facilitating the delineation of health profiles within populations and steering resource allocation and investments, fostering equitable access to benefits (ABRASCO, 1997).Consequently, these studies are indispensable in shaping the hypertension prevalence profile within quilombola populations, informing strategies that encompass lifestyle adjustments, community education, and meticulous monitoring for both affected individuals and those at risk of developing the condition.

Conclusion
This study serves to underscore the inherent vulnerability of quilombola communities, illuminating a stark reality: hypertension prevails significantly higher within these communities (32.8%) when juxtaposed with the broader Brazilian population (23.9%).This elevated prevalence predominantly emanates from the distinctive attributes characterizing quilombola populations, necessitating tailored and efficacious healthcare interventions.
While recent years have witnessed the development or adjustment of public policies such as the Brasil Quilombola Program, the National Program for Integral Health of the Black Population, and the Family Health Strategy to ostensibly address the healthcare needs of quilombola populations, the practical implementation of these initiatives has yet to yield the necessary transformations.In practice, communities remain underserved on the peripheries of a wellintentioned yet ineffective healthcare system.

Figure 1 .
Figure 1.(a) Map of Brazil highlights the 24 states with certified quilombola communities acknowledged by the Palmares Foundation (shown in green).Notably, Roraima, Acre, and the Federal District are the sole entities within the federation without certified quilombola communities (depicted in grey).(b)A second map of Brazil illustrates the 11 states with certified quilombola communities recognized by the Palmares Foundation, which were selected and investigated within this study (indicated in blue).Additionally, there are 13 states boasting certified quilombola communities; however, they lack eligible scientific productions (represented in green).

Table 1 .
Data on the prevalence of arterial hypertension extracted from the studies analyzed.
continua... Physis: Revista de Saúde Coletiva, Rio de Janeiro, v. 33, e33050, 2023 | Página 7 de 21 continua... Physis: Revista de Saúde Coletiva, Rio de Janeiro, v. 33, e33050, 2023 | Página 9 de 21 N = sample number.A = Mean age calculated considering all the communities collectively.B = There is no duplication of communities examined in other research involving populations from Maranhão state since they are situated in distinct municipalities.C = Prevalence value calculated from the sum of individuals classified as hypertensive in the three stages (I, II and III).Source: Own elaboration.

Chart 1 .
Criteria employed for classifying hypertensive individuals in the examined quilombola population studies.