The Diabetes Epidemic in South Africa: What You Need to Know

Diabetes is one of the fastest-growing chronic conditions in South Africa. Current estimates suggest that the age-standardised prevalence of diabetes in South African adults is approximately 10% to 15%, with type 2 diabetes accounting for roughly 90% of all cases. Many of those affected do not yet know it: national data from the SANHANES-1 survey found that over 45% of South Africans with diabetes had never been screened, and a further 15% had been screened but remained undiagnosed. The condition is largely preventable through lifestyle changes and early detection, which makes understanding your risk, and acting on it, genuinely important.

Understanding type 2 diabetes

Type 2 diabetes is a metabolic condition in which the body becomes less responsive to insulin, a hormone that helps move glucose (sugar) from the bloodstream into cells for energy. This reduced responsiveness is called insulin resistance. Over time, the insulin-producing cells in the pancreas (called beta cells) struggle to keep up with the increased demand, and blood glucose levels rise above normal.

This process develops gradually, often over many years. Most people with type 2 diabetes have had elevated glucose levels long before they receive a diagnosis. The condition is strongly associated with being overweight, physical inactivity, family history, and age, though it can occur in people without obvious risk factors.

Type 2 diabetes is not the same as type 1 diabetes, which is an autoimmune condition in which the body's immune system destroys insulin-producing cells. Type 1 diabetes is less common, typically presents in younger people, and always requires insulin treatment. Type 2 diabetes, by contrast, is initially managed with lifestyle changes and oral medication in most cases.

The scale of the problem in South Africa

South Africa faces a particularly challenging diabetes burden. A systematic review and meta-analysis of South African prevalence studies found a pooled prevalence of 15.25% for type 2 diabetes in adults aged 25 and older, with 8.29% representing newly diagnosed cases, meaning these individuals did not know they had diabetes until they were tested.

The diabetes care cascade in South Africa reveals significant gaps at every stage. Among South Africans with diabetes, only about 19% are treated and adequately controlled. The remainder are either unscreened, undiagnosed, untreated, or treated but with glucose levels that remain above target. More recent data from the National Health Laboratory Service database found that fewer than 10% of patients with a laboratory diagnosis of diabetes achieved glycaemic control within 24 months.

Sub-Saharan Africa is projected to experience the highest relative increase in diabetes prevalence globally over the coming decades, driven by rapid urbanisation, changing dietary patterns, and rising rates of overweight and obesity. South Africa, as one of the most urbanised countries on the continent, is at the forefront of this trend. The incidence of type 2 diabetes in South Africa has been measured at 21.8 cases per 1,000 person-years in middle-aged adults, the highest rate among four sub-Saharan African countries studied.

Early warning signs

Type 2 diabetes frequently goes undiagnosed for years because hyperglycaemia develops gradually and, at earlier stages, may not produce noticeable symptoms. Most people with type 2 diabetes are asymptomatic at diagnosis and are only identified through screening blood tests.

When symptoms do develop, they typically include:

• Excessive thirst (polydipsia) and frequent urination (polyuria), particularly at night
• Unexplained fatigue
• Blurred vision
• Slow-healing wounds or frequent infections
• Tingling or numbness in the hands and feet (peripheral neuropathy)
• Unexplained weight loss

These symptoms reflect significantly elevated blood glucose levels and are associated with the degree of hyperglycaemia rather than the duration of diabetes. Many people attribute these symptoms to stress, ageing, or general tiredness, which delays diagnosis and increases the risk of complications developing before treatment begins.

The absence of symptoms does not mean the absence of risk. People with undiagnosed diabetes are exposed to variable degrees of untreated hyperglycaemia and are at increased risk of developing both macrovascular complications (heart disease, stroke, peripheral vascular disease) and microvascular complications (damage to the eyes, kidneys, and nerves).

Risk factors

Several factors increase the likelihood of developing type 2 diabetes. Some are modifiable, meaning they can be changed, while others are not.

Non-modifiable risk factors:

• Age 45 or older. Risk increases with age, though type 2 diabetes is increasingly diagnosed in younger adults.
• Family history. Having a parent or sibling with type 2 diabetes significantly raises risk. A family history of diabetes was associated with a 3.9-fold increase in odds of having diabetes in a sub-Saharan African study.
• Ethnicity. In South Africa, Indian, Coloured, and Black African populations have higher prevalence rates compared with White populations. Prevalence was significantly higher among participants who identified as Indian, followed by White and Coloured populations in the SANHANES-1 analysis.
• Previous gestational diabetes. Women who developed diabetes during pregnancy have a substantially elevated lifetime risk of type 2 diabetes.

Modifiable risk factors:

• Overweight and obesity, particularly abdominal (central) obesity. In South Africa, waist circumference thresholds indicating increased metabolic risk are 94 cm or more for men and 80 cm or more for women (90 cm or more for men of South Asian descent).
• Physical inactivity. Sedentary behaviour contributes to insulin resistance and weight gain. Adequate physical activity was associated with a 13% lower risk of incident diabetes in the AWI-Gen study across four sub-Saharan African countries.
• Diet high in refined carbohydrates and sugars. Diets emphasising processed foods, sugar-sweetened beverages, and refined grains are associated with increased diabetes risk.
• Hypertension. High blood pressure frequently coexists with insulin resistance and was independently associated with a 21% higher risk of incident diabetes.

South Africa's high rates of obesity and rapid urbanisation are major contributors to the diabetes epidemic. Urban residence is associated with a two- to five-fold increased risk of diabetes compared with rural residence across sub-Saharan Africa, driven by changes in diet, physical activity patterns, and socioeconomic factors.

Screening and early detection

Because type 2 diabetes is frequently asymptomatic in its early stages, screening is the most reliable way to detect the condition before complications develop. A simple blood test can identify diabetes or prediabetes (the stage before diabetes, where glucose levels are elevated but not yet in the diabetic range).

Recommended screening tests:

• Fasting plasma glucose (FPG): Requires an overnight fast of at least 8 hours. A result of 7.0 mmol/L or higher indicates diabetes; 6.0 to 6.9 mmol/L indicates impaired fasting glucose (prediabetes).
• HbA1c: Reflects average blood glucose over the preceding 2 to 3 months. A result of 6.5% or higher indicates diabetes. HbA1c does not require fasting, making it convenient, though SEMDSA 2017 recommends glucose-based tests (FPG or OGTT) as the preferred method for diagnosing prediabetes in South Africa.
• Oral glucose tolerance test (OGTT): The most sensitive test, measuring glucose before and 2 hours after drinking a standardised glucose solution. A 2-hour result of 11.1 mmol/L or higher indicates diabetes; 7.8 to 11.0 mmol/L indicates impaired glucose tolerance (prediabetes).

Abnormal results should be confirmed with a second test on another day before a definitive diagnosis is made.

Who should be screened?

SEMDSA 2017 and international guidelines recommend screening for:

• All adults over 45, annually
• Anyone with risk factors (at any age), including overweight, family history, previous gestational diabetes, hypertension, or membership of a high-risk ethnic group
• Women with a history of gestational diabetes or polycystic ovary syndrome

If you have not had your blood glucose checked recently and you have one or more risk factors, a screening test is a straightforward first step. Your GP can arrange this as part of a routine consultation.

Why early detection matters

The consequences of undiagnosed and untreated diabetes are serious. Chronic hyperglycaemia increases the risk of both microvascular complications (damage to the small blood vessels supplying the eyes, kidneys, and nerves) and macrovascular complications (heart disease, stroke, and peripheral vascular disease).

Eye disease (diabetic retinopathy): Damage to the blood vessels in the retina can develop without symptoms and, if untreated, can lead to visual impairment and blindness. Retinopathy causes visual impairment in 5% to 10% of people with diabetes.

Kidney disease (diabetic nephropathy): Diabetes is a principal cause of chronic kidney disease. Kidney disease occurs in 20% to 40% of people with diabetes and can progress to kidney failure requiring dialysis.

Nerve damage (diabetic neuropathy): Reduced sensation, particularly in the feet, increases the risk of ulcers, infections, and, in severe cases, amputation.

Cardiovascular disease: People with type 2 diabetes have a two- to three-fold higher risk of cardiovascular disease compared with those without diabetes. Heart disease and stroke account for approximately 50% of deaths in people with type 2 diabetes.

The UK Prospective Diabetes Study (UKPDS) and subsequent research have demonstrated that achieving good glycaemic control early, particularly in the first years after diagnosis, has a lasting protective effect against complications, a phenomenon termed the "legacy effect." This underscores the importance of early detection and prompt treatment.

Prevention

Type 2 diabetes is largely preventable. The strongest evidence comes from several landmark clinical trials demonstrating that lifestyle intervention can reduce the risk of progression from prediabetes to diabetes by up to 58% over three years.

The Diabetes Prevention Program (DPP), the largest and most influential of these trials, showed that participants who achieved at least 7% weight loss and 150 minutes of moderate-intensity physical activity per week reduced their diabetes risk by 58% compared with those who received standard care. Long-term follow-up confirmed sustained benefit: a 39% reduction at 30 years in the Da Qing study, and a 24% reduction at 21 years in the DPP follow-up.

Weight loss is the single most important factor. Even modest weight loss of 5% to 10% of body weight significantly reduces diabetes risk. For someone weighing 90 kg, that means losing 4.5 to 9 kg. The relationship between weight loss and diabetes prevention is linear: any amount of weight loss provides benefit, with greater weight loss conferring greater protection.

Physical activity provides independent benefit even without achieving weight loss goals. In the DPP, participants who met the 150-minute weekly activity target but did not reach their weight loss goal still reduced diabetes incidence by 44%.

Prevention centres on sustainable lifestyle changes:

• Maintain a healthy weight. If overweight, aim for gradual weight loss of 0.5 to 1 kg per week.
• Exercise at least 150 minutes per week. Brisk walking counts. Spread activity over at least three days, and include resistance training two to three times per week.
• Choose whole grains over refined carbohydrates. Replace white bread, white rice, and sugary cereals with whole-grain alternatives.
• Increase vegetable and fibre intake. Aim for at least 14 grams of fibre per 1,000 calories consumed. Emphasise non-starchy vegetables, legumes, and whole fruits.
• Limit sugary drinks. Sugar-sweetened beverages are strongly associated with increased diabetes risk. Water, unsweetened tea, and rooibos are better choices.
• Follow a balanced eating pattern. Evidence supports Mediterranean-style eating patterns, the DASH diet, and plant-based dietary approaches for diabetes prevention. These patterns emphasise vegetables, legumes, whole grains, nuts, seeds, fish, and healthy fats whilst limiting processed foods, red meat, and refined sugars.

A South African Diabetes Prevention Programme (SA-DPP) has been developed and is being tested in local communities, adapting the international evidence to the South African context with culturally appropriate dietary and physical activity interventions delivered by non-professional health workers.

If you have been diagnosed with prediabetes, these changes can significantly reduce your risk of progressing to type 2 diabetes. Book a screening consultation to know your numbers. We do HbA1c testing on-site at NeoHealth, so the bloods are drawn at the same visit. For a deeper look at prediabetes specifically, see our guide on prediabetes: what it means and what to do next.

When to see your GP

If you have any of the risk factors listed above, or if you are experiencing symptoms such as increased thirst, frequent urination, unexplained fatigue, or blurred vision, a consultation with your GP is the appropriate next step. A GP can arrange the relevant blood tests, interpret results in the context of your full medical history, assess your overall cardiovascular risk, and develop a personalised plan.

Even without symptoms, regular screening is recommended for adults over 45 and for anyone with risk factors at any age. This kind of preventive lifestyle screening is also covered as a benefit on most major medical aid schemes. Early detection of either prediabetes or diabetes allows for timely intervention, which has been shown to reduce the risk of serious complications.

Type 2 diabetes is a Prescribed Minimum Benefit (PMB) condition under the Council for Medical Schemes (CMS) Chronic Disease List (CDL) in South Africa. This means all registered medical schemes are legally required to cover diagnosis, treatment, and ongoing management. Your GP can submit a chronic application on your behalf to activate these benefits.

For a comprehensive approach to diabetes screening and chronic disease care, see our approach to chronic disease care, built around evidence-based prevention and long-term management. If you have just been diagnosed, our guide on the first six months after a type 2 diabetes diagnosis walks through what to expect.

Discovery Health members with confirmed diabetes can be enrolled on the Diabetes Care Programme at NeoHealth, while members identified as high-risk by Discovery's predictive model may qualify for the Disease Prevention Programme.