Cardiovascular diseases (CVDs) pose a risk to population health, both globally and in South Africa.¹ Cardiovascular diseases, commonly referred to as heart disease or stroke, are the number one cause of death around the world with a reported one in three deaths globally, yet most premature heart disease and stroke are preventable.¹ Over three-quarters of heart diseases and stroke-related deaths occur in low- and middle-income countries such as South Africa.² Although previously perceived as a disease that affects the elderly, more than 50% of mortalities occur before the age of 65 years.³

In the second National Burden of Disease study based on data from 1997 to 2012, cerebrovascular disease was the leading cause of death in South Africa after HIV and AIDS.⁴ In 2016, the Heart and Stroke Foundation of South Africa reported that CVD was responsible for almost 1 in 6 deaths, amounting to 17.3%.⁵ The data also indicated a daily average of 215 deaths attributed to heart disease or stroke.⁵ Notably, the report revealed that every hour, 5 people have heart attacks and 10 people have strokes, of which 10 people die because of these events.⁵ The most recent data on the causes of death in South Africa for the year 2019 unveiled that diseases of the circulatory system emerged as the predominant category, accounting for 17.5% of all reported deaths.⁶ Of the top 10 underlying causes of mortality, 3 were cardiovascular-related diseases: cerebrovascular diseases (ranked third), hypertensive disease (ranked fifth) and ischaemic heart diseases (ranked seventh).⁶ Among females, cerebrovascular disease was ranked the second leading cause of death followed by hypertensive disease.⁶

The high prevalence of CVD is supported in a recent systematic review, which reported the overall South African national prevalence of coronary heart disease as 1.29 (95% CI = 0.83; 1.75) and 4.29 (95% CI = 3.13; 5.45) for stroke.⁷ A study conducted among older adults in South Africa using the Framingham risk scores (FRS) found a 10-year CVD risk of 17%, which was significantly higher in men compared with women (23.2% vs. 14.3%, p < 0.001).⁸ A pilot study on CVD risk conducted among 489 teachers in Cape Town found that 18.7% were at high risk of a heart attack or stroke within 10 years.⁹

South Africa has a heavy burden of hypertension with an estimated prevalence between 27% and 58%.¹⁰ Differences in prevalence have been reported across various settings. In a rural community in the Eastern Cape, 71% of participants were hypertensive.¹¹ Peer et al. found an age-standardised prevalence of 38.9% in an urban population in Cape Town.¹² The burden of hypertension will increase substantially without effective intervention strategies across the treatment cascade. This includes screening, prevention through the identification of modifiable risk factors, early diagnosis, treatment and follow-up.¹²

The early detection and management of CVD risk may prevent mortality.⁵ An overview of systematic reviews on the effect of using cardiovascular risk scoring in routine risk assessment in primary prevention of CVD found a tendency towards reduction of blood pressure (BP), total cholesterol and smoking levels, especially in high-risk patients.¹³ Jardim et al. aver that CVD is not being optimally managed in some areas of South Africa with significant disparities in the control of CVD risk factors.³ High mortality rates in CVD may stem from inadequate control of risk factors. By enhancing the management of these factors and incorporating community education on lifestyle modification, mortality rates could be effectively reduced.³

The risk factors for CVD include hypertension, overweight and obesity, high cholesterol, diabetes, tobacco use, physical inactivity, unhealthy diet and salt intake.¹⁴ As many people with hypertension and diabetes are unaware of the condition, it often remains undiagnosed, untreated and uncontrolled.^15,16,17 Berry et al. found that among South Africans aged 15 years and older who had hypertension, 48.7% remained unscreened and undiagnosed, 23.1% underwent screening but remained undiagnosed, 5.8% were diagnosed but not receiving treatment, and 13.5% were receiving treatment but had uncontrolled hypertension.¹⁶ About 65.1% of women and almost 31.2% of men are overweight in South Africa and 40.1% of women are obese compared with 11.6% of men.⁵ Those who smoke and those exposed to second-hand smoke have an increased risk of developing CVD.⁵ In addition, physical inactivity contributes much to the increased risk of CVD, especially in our modern world of sedentary lifestyles.⁵ In a Cape Town study among teachers, CVD risk factors included hypertension (48.5%), hypercholesterolaemia (20.5%), smoking (18.0%), diabetes (10.1%) and being overweight or obese (84.7%).⁹

The high prevalence of CVD risk factors in communities and poor access to healthcare may lead to delayed diagnosis and management of CVD risk.¹⁸ Initiatives such as population-wide screening for hypertension and diabetes, engagement of community resources and governance structures as well as geographic decentralisation of care services have been proposed, but the evidence of effectiveness is still lacking.^19,20 In certain communities, community health workers have been successfully trained to conduct cardiovascular risk assessments.²¹ However, a qualitative study on the knowledge and perceptions of cardiovascular risk in a low-income peri-urban community in the Western Cape found that community members had a poor understanding of risk and that this understanding is key to risk assessments in the community.²²

This study was conducted as part of a community outreach project focused on CVD risk identification and prevention. The aim of this study was to determine the cardiovascular risk among community members who attended an outreach programme in three communities in the Cape Metropole of the Western Cape in order to conduct targeted referrals and behaviour change counselling.

Our study found that more than a third (35.9%) of community members (mean age 42.3 years) who attended an outreach programme in three communities in the Cape Metropole of the Western Cape had intermediate (16.6%) or high (19.3%) CVD risk. This is slightly lower than another South African study among older adults (≥ 50 years) in KwaZulu-Natal, where 33.0% of participants had low CVD risk (FRS < 10%), 39.0% intermediate risk (FRS 10.0% – 19.0%) and 28.0% high risk (FRS ≥ 20.0%).⁸ The risk reported in our study is similar to the CVD risk reported among teachers (mean age 46.3 years) in Cape Town where 18.7% of participants had a high (> 20.0%) 10-year CVD risk calculated using the World Health Organization risk predictor charts.⁹ In the same study, the risk was lower (13.9%) when the Framingham risk calculator using the BMI was used.⁹ The risk was significantly higher for males compared with females, which is similar to the findings of the KwaZulu-Natal study.⁸

The Framingham risk calculator includes several factors to estimate an individual’s CVD risk. These factors are age, gender, BMI or cholesterol levels, BP, treatment for hypertension, smoking status and the presence of diabetes.²⁴ Cardiovascular diseases risk factors in this study included high levels of stress and low levels of participation in moderate exercise. Of note is that more than half of the participants were obese (BMI ≥ 30); 65.4% of females and 22.6% of males and females had significantly higher BMIs than males. These findings were higher than the South African prevalence for obesity (50% for women and 23% for males) reported in the World Obesity Atlas 2022.²⁵ However, it was lower than the findings reported among Cape Town teachers, which found that 84.7% of participants were obese.⁹ Andersson et al. observe that a high prevalence of CVD risk factors, such as obesity, physical inactivity and poor diet, has been observed among young individuals (age 18–50 years) living in developed countries.²⁶ This has led to an increase in CVD risk among the younger population, which is also attributable to the higher prevalence of substance use, for example, tobacco smoking and alcohol use.²⁶ When compared with the global burden of CVD, people in Africa are typically younger, predominantly female and mostly from disadvantaged communities.²⁷ Our study found markedly higher levels of stress among females compared with males, which could be a contributing factor to CVD. Even though CVD is the leading cause of death among women globally, it remains understudied.²⁸ The Lancet Commission recommended prioritising funding for CVD health programmes in women from socioeconomic deprived regions and educating healthcare providers and young women regarding the prevention and early detection of CVD among women.²⁸ Despite this, the CVD risk was significantly higher among males compared with females. When comparing the risk factors, significantly more males compared with females had a systolic BP of ≥ 140 mm Hg, smoked and consumed alcohol.

In our study, 23.4% of participants were on treatment for hypertension and 26.0% had a systolic BP of > 140 mm Hg. According to the South African National Health and Nutrition Examination Survey in 2012 and the South African Demographic Health Survey (DHS) in 2016, hypertension prevalence was 38.4% and 48.2%, respectively.²⁹ Our study found a large percentage of persons with potentially untreated hypertension. Similarly, Berry et al. found that 48.7% of people in South Africa with hypertension were undiagnosed and 13.5% were receiving treatment but had uncontrolled hypertension.¹⁶

In the DHS 2016, the observed diabetes prevalence was 22.0%,³⁰ which is higher compared with our study (7.6%). However, we only relied on reported diagnoses and did not test for diabetes in this study. A Cape Town study among teachers reported a diabetes prevalence of 10.1%.⁹

The Prospective Urban Rural Epidemiology (PURE) study across 21 countries identified that 70% of CVD risk factors are modifiable.¹⁵ Behavioural risk factors include low levels of education and ambient air pollution. In low- and middle-income countries, household air pollution, poor diet and low education strongly affect CVD and mortality.¹⁵ Current evidence suggests that hypertension is a multifactorial condition, which is influenced by risk factors such as genetics (non-modifiable factors), sociodemographic and behavioural factors, which can potentially be modified. Furthermore, socioeconomic status is reported to be associated with high BP, awareness of hypertension, health behaviour and access to preventative interventions and measures.¹¹

Various socioeconomic factors impact the life course of CVD, which is often beyond the individual’s control.²⁷ In order to ensure the global goal of a 25% reduction in premature CVD mortality, better evidence-based policies such as tobacco control are needed as well as CVD prevention and management in PHC and community settings. These efforts should be coupled with better health information systems to monitor progress.³¹

The Western Cape Department of Health has recently issued a circular on the recording and reporting of hypertension and diabetes screening (H77/2023), acknowledging the importance of early detection of disease and reducing the hypertension treatment gap (Western Cape Department of Health, Circular H77/2023, personal communication dated 14 June 2023). This is a necessary step towards improving the monitoring of CVD risk in communities, although risk screening should be performed beyond PHC facilities and services.

We found high frequencies of cardiovascular risk factors among community members in this study; 19.3% of the participants have a significant probability of developing heart disease or experiencing a stroke over the next 10 years. The risk is significantly higher among males. There is indeed a need for comprehensive health promotion and behaviour change interventions focused on reducing CVD risk factors on a community level.