One of the most concerning scourges of modern-day living, diabetes affects millions of children and adults around the world. With the prevalence of the disease increasing rapidly across the globe - and in South Africa - diabetes is fast becoming a major epidemic in the current century. According to the World Diabetes Foundation (WDF), in 2010, 285 million people were living with diabetes – approximately 4.6% of the world’s population. The WDF anticipates that these figures will increase to 438 million (7.8%) by 2030.
In November, the global spotlight falls on diabetes via the declaration of November as Diabetes Month and 14 November as World Diabetes Day.
The good news for the millions of diabetic patients is that there are some promising new therapies on the horizon that have the potential to change the face of treatment and the lives of millions of people living with diabetes. This is according to Professor Pankaj Joshi, emeritus ad hominem professor of medicine at Medunsa and director of the Diabetes Care Centre in Pretoria.
Particularly noteworthy is a new class of medications known as incretin-based therapies, which work in a different way from insulin replacement and oral antidiabetic drugs. These treatments target a gut hormone called GLP-1 which is known to be low in diabetics. “Other diabetes treatments don’t address these low levels of GLP-1. The incretins are therefore poised to add a new dimension to diabetes therapy in the future,” says Professor Joshi.
The International Diabetes Federation defines diabetes as a chronic disease that develops when the pancreas does not produce enough insulin or when the body becomes unable to use the insulin it produces effectively. Insulin is a hormone made by the pancreas that enables cells to absorb glucose from the blood and use it for energy. Diabetes leads to raised levels of glucose (sugar) in the blood (hyperglycaemia), which are associated with long-term damage to the body.
“Though diabetes cannot be cured, it can be effectively managed, allowing those with the condition to lead normal, healthy lives,” says Shelley Harris, spokesperson for global diabetes healthcare company, Novo Nordisk.
There are three main types of diabetes: type 1, type 2 and gestational diabetes. Type 1 diabetes usually occurs in children and young adults and is the result of the body’s defence system attacking the insulin-producing cells. These patients require insulin injections every day to control the levels of glucose in their blood. Type 2 diabetes, sometimes referred to as non-insulin dependent diabetes or adult-onset diabetes (although neither of these terms is entirely accurate), accounts for at least 90% of all cases of diabetes. It is characterised by insulin resistance and relative insulin deficiency. Type 2 diabetes can remain undetected for many years. It is often, but not always, associated with obesity, which itself can cause insulin resistance and lead to elevated blood glucose levels. Gestational diabetes is a form of diabetes characterised by high blood glucose levels during pregnancy, usually disappearing thereafter.
Though type 2 diabetes is usually lifestyle associated and often perceived as a disease of affluence, the World Health Organization warns that it is developing countries that will be the hardest hit and that even now, 70% of those with type 2 diabetes live in low- or middle-income countries. South Africa is therefore not exempt.
Type 2 diabetes risk factors
According to statistics provided by Novo Nordisk, the incidence of type 2 diabetes in South Africa is estimated at between 4.5% and 5.6% in individuals aged 20-79 years. This translates into 1.3-2 million diabetes patients. In sub-Saharan Africa as a whole, the figure is estimated to be 12.1 million adults - with only 15% having been diagnosed.
Several risk factors have been associated with type 2 diabetes and include: obesity; poor diet and physical inactivity; increasing age; insulin resistance; a family history of diabetes and ethnicity. In South Africa, those of Indian descent appear to have a gene pool that makes them unusually susceptible to diabetes. Changes in diet and physical activity related to rapid development and urbanisation have led to sharp increases in the numbers of people developing diabetes, especially black South Africans.
“There are a number of pharmaceutical treatments available that help address insulin resistance (including metformin, which is usually the first drug prescribed) but insulin deficiency requires insulin replacement therapy,” says Professor Joshi. He underscores, however, that diet and lifestyle modification – eating correctly and exercising regularly - remain the cornerstone of treating insulin resistance/type 2 diabetes. “In the Diabetes Prevention Study, patients who ate correctly and exercised regularly showed better results than those who only took metformin,” he says.
Though type 2 diabetes can be managed, the decline in pancreatic function was until recently irreversible, decreasing progressively by around 4% per year from diagnosis. The incretins will potentially play a key role here.
“There is clear evidence that these treatments help preserve the pancreas’ functioning, thus maintaining the body’s own source of insulin,” says Professor Joshi. “In addition, they also have benefits on the heart and blood vessels, and are associated with lowering body weight. Most other diabetes treatments, apart from metformin, have a tendency actually to promote weight gain – so this is a particularly encouraging development, given that excess weight and obesity are risk factors for type 2 diabetes and weight loss/maintaining a healthy weight an important component of its treatment. The incretin-based therapies are therefore very exciting and potentially a tremendous addition to the therapies currently available,” he says.
- Novo Nordisk press release