Project – Prevalence and Risk Factors of Hypertension among Adults in Selected Communities in Agege LGA, Lagos State.

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Hypertension is one of the most important non-communicable diseases and a major modifiable risk factor for cardiovascular, cerebrovascular and renal diseases. It occurs when blood pressure remains persistently elevated, placing excessive pressure on the walls of blood vessels and progressively increasing the risk of complications such as stroke, heart disease, heart failure and chronic kidney disease. The World Health Organization (WHO) currently defines hypertension in adults as systolic blood pressure of 140 mmHg or higher and/or diastolic blood pressure of 90 mmHg or higher when measured on two different days, although treatment decisions may also consider an individual’s overall cardiovascular risk and comorbidities (World Health Organization [WHO], 2025; WHO, 2021). The condition is particularly important from a public-health perspective because it is often asymptomatic, meaning that many individuals may live with elevated blood pressure for years without knowing it. Consequently, routine blood-pressure measurement remains essential for early detection and prevention of complications.

The global burden of hypertension has increased substantially over the past several decades, particularly in low- and middle-income countries. The NCD Risk Factor Collaboration reported that approximately 1.28 billion adults aged 30–79 years were living with hypertension globally in 2019, with a large proportion unaware of their condition or not receiving adequate treatment (NCD Risk Factor Collaboration [NCD-RisC], 2021). More recent WHO estimates indicate that approximately 1.4 billion adults aged 30–79 years had hypertension in 2024, representing about one-third of the population in this age range; approximately two-thirds of affected adults live in low- and middle-income countries (WHO, 2025). This distribution is important because many developing countries face simultaneous challenges of infectious diseases, non-communicable diseases, limited health-care resources and socioeconomic inequalities. The growing hypertension burden therefore places additional demands on health systems and increases the need for community-level prevention, screening and treatment programmes.

Nigeria is similarly experiencing a substantial hypertension burden. A systematic analysis by Adeloye et al. (2021), based on 53 studies involving 78,949 participants, estimated the crude prevalence of hypertension in Nigeria at 30.6%, while age-adjusted prevalence was estimated at 32.5% in 2020. The authors also estimated a substantial increase in the absolute number of Nigerians living with hypertension over the period examined. More recently, a 2026 systematic review and meta-analysis involving 32 population-based studies and 49,788 participants estimated a pooled hypertension prevalence of 34.2% among Nigerian adults, although substantial heterogeneity existed between the studies. These findings demonstrate that hypertension is not a marginal health problem in Nigeria but a widespread public-health concern affecting a considerable proportion of the adult population (Adeloye et al., 2021; 2026).

The burden of hypertension in Nigeria is particularly relevant in urban settings where population growth, changing dietary practices, reduced physical activity and other aspects of urbanisation may influence cardiovascular risk. Data from a large population-based survey conducted in urban Lagos included 5,365 participants and used components of the WHO STEPwise approach to assess blood pressure and related risk factors. The study involved several metropolitan Local Government Areas, including Agege, and illustrates the importance of examining hypertension at community level rather than relying exclusively on national estimates (Ejim et al., 2019). The researchers reported that the prevalence and distribution of blood-pressure abnormalities varied across demographic and behavioural characteristics, demonstrating the relevance of locally generated evidence for understanding hypertension in urban Nigerian communities.

Evidence specifically relating to Lagos further demonstrates the public-health significance of hypertension. A recent study involving adults screened across Lagos during a 2023 community-based blood-pressure screening campaign reported hypertension among 52.5% of the 1,547 participants screened. The study identified age, male sex, higher body mass index and lower educational attainment among factors associated with elevated blood pressure, while a substantial proportion of participants with hypertension were either newly detected or were not adequately engaged with treatment. Although the opportunistic nature of the screening means that its prevalence estimate should not automatically be interpreted as representative of all adults in Lagos, the findings demonstrate the continuing importance of screening and risk-factor assessment in the state (2026).

The situation is also demonstrated by evidence from the Lagos Health District that includes Agege Local Government Area. Bankole et al. (2025) conducted a cross-sectional survey among 2,060 residents of Agege, Alimosho and Ifako-Ijaiye Local Government Areas in November 2023. The study reported a hypertension prevalence of 39.5% and a prehypertension prevalence of 34.4%, with hypertension particularly evident among older adult age groups. The inclusion of Agege in this study provides direct evidence that elevated blood pressure constitutes a significant health concern within the geographical area relevant to the present research. However, because the previous study covered three LGAs and was conducted during an outreach programme, there remains a need for more focused investigation of adults within selected communities in Agege LGA, particularly with attention to the specific risk factors operating within those communities (Bankole et al., 2025).

Hypertension is influenced by a combination of modifiable and non-modifiable risk factors. Non-modifiable factors include increasing age, genetic predisposition and family history, while modifiable factors include excessive dietary salt consumption, unhealthy diets, physical inactivity, overweight and obesity, tobacco use and harmful alcohol consumption. The WHO also identifies diabetes and kidney disease as conditions associated with increased hypertension risk (WHO, 2025). Evidence from Nigerian populations similarly indicates relationships between blood pressure and sociodemographic, anthropometric and lifestyle characteristics. For example, a large Lagos-based analysis examined factors such as age, sex, body mass index, education, occupation, physical activity and other sociodemographic and lifestyle characteristics in relation to blood pressure, highlighting the importance of understanding hypertension through a multifactorial rather than single-cause approach (WHO, 2025; Eze et al., 2025).

The consequences of undetected and uncontrolled hypertension extend beyond elevated blood-pressure readings. Persistent hypertension can damage blood vessels and vital organs and substantially increase the risk of cardiovascular disease, stroke and kidney disease. The WHO therefore identifies hypertension as a major cause of premature death and emphasises regular blood-pressure measurement, healthy diet, physical activity, reduction of harmful alcohol consumption and tobacco cessation as important components of prevention and control (WHO, 2025). In Nigeria, where hypertension detection and control remain important challenges, community-based identification of adults at increased risk can support earlier intervention and referral. The WHO hypertension guideline further recommends evidence-based pharmacological treatment for adults with confirmed hypertension alongside appropriate lifestyle interventions, demonstrating that early identification can provide an important entry point for effective disease management (WHO, 2021).

Despite the availability of knowledge concerning hypertension and its risk factors, important gaps remain at the community level. National and state-level prevalence estimates may conceal substantial differences between communities arising from socioeconomic circumstances, dietary patterns, occupation, physical activity, access to health services and health-seeking behaviour. The inclusion of Agege among the LGAs examined in the large Lagos urban survey and the more recent evidence from Lagos Health District demonstrate the relevance of the area, but they do not provide a sufficiently detailed assessment of selected Agege communities as the sole focus of investigation (Ejim et al., 2019; Bankole et al., 2025). A community-focused study can therefore provide information on the proportion of adults affected and examine the demographic, behavioural and lifestyle factors associated with hypertension among residents. Such evidence can contribute to targeted health education, screening, prevention and referral strategies in Agege LGA.

Against this background, the present study focuses on the prevalence and risk factors of hypertension among adults in selected communities in Agege Local Government Area, Lagos State. The study is designed to determine the proportion of adults with hypertension and examine selected factors that may be associated with the condition, including age, sex, family history, body weight, dietary practices, physical activity, alcohol consumption and tobacco use. By generating community-specific evidence, the study seeks to contribute to the understanding of hypertension in an urban Nigerian setting and provide information that may support appropriate public-health interventions, particularly early detection, health education, lifestyle modification and referral for appropriate care. This focus is consistent with the WHO STEPS approach, which emphasises systematic assessment of major behavioural and biological risk factors for non-communicable diseases at population level (WHO, 2025; WHO, 2021).

1.2 Statement of the Problem

Hypertension has become a major public-health challenge because of its high prevalence, often silent presentation and association with serious cardiovascular and renal complications. Globally, approximately 1.4 billion adults aged 30–79 years were estimated to have hypertension in 2024, while a substantial proportion were unaware of their condition. The persistence of undiagnosed hypertension means that individuals may remain exposed to elevated cardiovascular risk without receiving appropriate counselling, monitoring or treatment (WHO, 2025). The problem is particularly important in low- and middle-income countries, where the burden of hypertension has increased while health systems may face limitations in sustained screening, treatment and follow-up.

Nigeria faces a similar challenge, with systematic evidence indicating that approximately one-third of Nigerian adults are affected by hypertension. Adeloye et al. (2021) estimated an age-adjusted prevalence of 32.5% in 2020, while a more recent meta-analysis reported a pooled prevalence of 34.2%. The differences between studies partly reflect variations in study populations, geographical locations, diagnostic definitions and methodologies, but collectively indicate a substantial national burden. Such a high prevalence creates the possibility that many adults in local communities may have elevated blood pressure without being aware of it or without receiving adequate management (Adeloye et al., 2021; 2026).

The problem is particularly relevant to Lagos State and Agege LGA because available studies have demonstrated considerable hypertension burden among residents of Lagos. A large urban population-based survey included Agege among the Lagos LGAs studied, while a 2023 survey covering Agege, Alimosho and Ifako-Ijaiye reported a hypertension prevalence of 39.5%. More recent screening evidence from Lagos also identified substantial levels of hypertension and newly detected cases. However, these findings arise from studies with different populations, sampling approaches and geographical coverage, making it inappropriate to assume that their estimates precisely represent adults in every community within Agege LGA (Ejim et al., 2019; Bankole et al., 2025; 2026).

Another important problem is the need to identify the factors associated with hypertension within specific communities. Although age, obesity, unhealthy diet, physical inactivity, alcohol consumption, tobacco use and family history are recognised risk factors, their distribution and relative importance can vary across populations. Evidence from Lagos has demonstrated associations between hypertension and demographic, anthropometric and lifestyle characteristics, while WHO recommends attention to both modifiable and non-modifiable risk factors in prevention and control (Eze et al., 2025; WHO, 2025). Without community-specific information on both prevalence and associated risk factors, health interventions may be less precisely targeted. Therefore, there is a need to investigate the prevalence and risk factors of hypertension among adults in selected communities in Agege LGA, Lagos State, in order to provide evidence that can support community-based prevention, screening, health education and appropriate referral.

1.3 Purpose of the Study

The main purpose of this study is to assess the prevalence and risk factors of hypertension among adults in selected communities in Agege Local Government Area, Lagos State.

Specifically, the study seeks to:

1. determine the prevalence of hypertension among adults in selected communities in Agege LGA;
2. determine the prevalence of hypertension according to selected socio-demographic characteristics of the respondents;
3. examine the association between selected lifestyle factors and hypertension among adults in the study area;
4. assess the relationship between selected anthropometric factors, particularly body weight/BMI, and hypertension

1.4 Research Questions

The following research questions will guide the study:

1. What is the prevalence of hypertension among adults in selected communities in Agege LGA, Lagos State?
2. What is the prevalence of hypertension according to the selected socio-demographic characteristics of adults in the study area?
3. What lifestyle factors are associated with hypertension among adults in the selected communities?
4. What is the relationship between selected anthropometric factors and hypertension among adults in the study area?

1.5 Research Hypothesis

The following null hypothesis will be tested at 0.05 level of significance:

H₀: There is no statistically significant association between selected risk factors and the prevalence of hypertension among adults in selected communities in Agege Local Government Area, Lagos State.

1.6 Significance of the Study

The study will be significant to public-health practitioners because it will provide community-level information on the burden of hypertension and the factors associated with its occurrence. Such information can assist public-health personnel in designing appropriate screening, health education and lifestyle-modification activities.

The study will also be useful to adults and community residents because the findings may increase awareness of hypertension and its risk factors. Greater awareness of factors such as excessive salt intake, physical inactivity, overweight and obesity, harmful alcohol consumption and tobacco use may encourage individuals to adopt healthier behaviours and seek blood-pressure checks.

The findings will be relevant to health-care providers and primary healthcare facilities within and around Agege LGA. Information concerning the prevalence and risk factors of hypertension can support routine blood-pressure screening, early identification of high-risk individuals, counselling, referral and follow-up of adults with elevated blood pressure.

The study will also be useful to Local Government health authorities and policymakers. Community-specific evidence can assist in identifying areas where hypertension screening and prevention activities may be strengthened. The evidence may also contribute to planning interventions that address behavioural and lifestyle-related risk factors.

The study will be beneficial to community leaders and non-governmental organisations involved in health promotion. Findings can provide evidence for community sensitisation programmes addressing hypertension prevention, healthy dietary practices, physical activity and appropriate health-seeking behaviour.

Finally, the study will contribute to the academic and research literature on hypertension in Nigeria, particularly literature relating to urban communities in Lagos State. It may serve as a reference for future researchers investigating hypertension, cardiovascular risk factors and non-communicable diseases in Agege and similar urban communities.

1.7 Scope of the Study

The study will focus on the prevalence and risk factors of hypertension among adults in selected communities in Agege Local Government Area, Lagos State.

The geographical scope will be limited to selected communities within Agege LGA. The population scope will comprise adult residents who meet the eligibility criteria established for the study.

The content scope will cover the prevalence of hypertension and selected associated factors. These factors will include socio-demographic characteristics, family history of hypertension, dietary practices, physical activity, alcohol consumption, tobacco use and anthropometric characteristics such as weight and body mass index.

The study will focus on hypertension among adults and will not primarily investigate hypertension during pregnancy or paediatric hypertension. The assessment will be based on blood-pressure measurements and relevant information obtained from respondents using the study instruments and procedures described in Chapter Three.

1.8 Operational Definition of Terms

Adult: A person aged 18 years and above who resides in the selected communities and meets the inclusion criteria for participation in the study.

Blood Pressure: The force exerted by circulating blood against the walls of the arteries, expressed as systolic blood pressure over diastolic blood pressure in millimetres of mercury (mmHg).

Hypertension: Persistently elevated blood pressure, operationally defined in this study according to the adopted diagnostic criteria as systolic blood pressure of ≥140 mmHg and/or diastolic blood pressure of ≥90 mmHg, or relevant documented use of antihypertensive medication, consistent with WHO criteria.

Prevalence: The proportion or percentage of adults in the study population who meet the study’s criteria for hypertension at the time of assessment.

Risk Factor: A characteristic, behaviour, exposure or condition that is statistically associated with an increased likelihood of hypertension. In this study, selected risk factors include age, sex, family history, BMI, dietary practices, physical inactivity, alcohol consumption and tobacco use.

Body Mass Index (BMI): A measure calculated from an individual’s weight in kilograms divided by the square of height in metres (kg/m²), used in this study as an indicator of body size and weight status.

Lifestyle Factors: Behavioural characteristics that may influence health, including dietary habits, physical activity, alcohol consumption and tobacco use.

Family History of Hypertension: A respondent’s report that one or more close biological relatives, particularly parents or siblings, have been diagnosed with hypertension.

Selected Communities: The communities within Agege Local Government Area that will be purposively or randomly selected according to the sampling procedure specified in Chapter Three.

Project – Prevalence and Risk Factors of Hypertension among Adults in Selected Communities in Agege LGA, Lagos State.