Type 2 diabetes: South Asians genetically at risk — study

New data published in The Lancet journal has found that 828 million adults around the world live with type 2 diabetes — an increase of 630 million people between 1990-2022.

While diabetes is a global health concern, research is finding that people from South Asian populations have particularly high health risks associated with the condition.

The research suggests that people from a South Asian background may be four times more likely to develop type 2 diabetes compared to people from a European background. People from a South Asian background may also develop the disease 10 years earlier than other populations, on average.

"Type 2 diabetes is at epidemic proportions in both India and Pakistan and increasing rapidly in Bangladesh as well. The latest estimates show that over 33% of the global burden of type 2 diabetes is from South Asian populations [both migrant and non-migrant)," said Moneeza Siddiqui, an epidemiologist at Queen Mary University of London, UK.

There could be as many as 212 million cases of type 2 diabetes in India and 36 million cases in Pakistan, of whom, we were told, more than half go untreated.

"South Asians are also more likely that Europeans to have poorly controlled type 2 diabetes, more risk of complications, such as heart, kidney or liver disease," Siddiqui said.

Why are people with South Asian heritage more prone to diabetes?

Diabetes is a chronic disease that occurs when the pancreas fails to function properly and produces insufficient insulin. 

Insulin is a vital hormone for regulating blood sugar levels, allowing sugar (glucose) to enter cells.

A lack of insulin means the cells cannot take up the glucose needed to produce energy. Over time this can cause serious damage to the body's systems.

Type 1 diabetes is an autoimmune problem in which the immune system attacks beta cells in the pancreas, reducing insulin production.

Type 2, which accounts for 96% of diabetes cases, is different: It can develop over time through factors such as diet, body mass, and age.

Genetics also play a major role in developing type 2 diabetes.

Alka Kanaya, a clinical scientist at University of California San Francisco, US, said these genetic risk factors cause a "more rapid progression from prediabetes states to diabetes," in people with a South Asian background.

As a result, a person may have less time to adapt and prevent a full onset of the disease, Kanaya told DW via email.

Genetic drivers of diabetes in British Asians

Another new study, published in Nature Medicine, suggests genetics drive an early onset of diabetes in South Asians populations compared to Europeans populations.

The study compared genetic data from British people with Pakistani or Bangladeshi heritage.

It found that those groups had an increased genetic risk of the pancreas failing to produce sufficient insulin over the course of a person's life.

"Within these groups, those of Bangladeshi ancestry have greater genetic burden than those of Pakistani ancestry," said Siddiqui.

The study also found that South Asians have certain genes that causes fat to be stored in unfavorable areas of the body.

"[This means] that South Asians are more likely to have a seemingly normal body mass index [BMI], but that the fat is stored in places such as around the liver and central organs instead of in 'safer' areas of the body, such as around the thighs or arms," said Siddiqui.

These genetic risks were key drivers of an earlier onset of type 2 diabetes and a poorer response to medication among people of a South Asian background, the study found.

"This provides stronger evidence of distinctive [causes] for type 2 diabetes and that we need to start using this available information for creating more targeted prevention and treatment strategies in South Asians," said Kanaya.

'Lifestyle' factors impact diabetes risks, too

Whilst people can't change their genetic backgrounds, health experts say there are so-called lifestyle changes that can help reduce the risk of developing type 2 diabetes.

"Newer studies have started to find that environmental exposure to PM2.5 particles from air pollution are independently associated with higher risk of developing type 2 diabetes. There are also concerns about persistent organic pollutants increasing the risk of fatty liver, insulin resistance, and type 2 diabetes," said Kanaya.

Around 50% of type 2 diabetes cases are linked to high BMI. And eating large amounts of certain foods, such as processed meats, has been linked with higher rates of diabetes.

Experts say daily exercise and avoiding high-sugar foods can help reduce the risk of developing diabetes.

Edited by: Zulfikar Abbany

Sources:

Worldwide trends in diabetes prevalence and treatment from 1990 to 2022: a pooled analysis of 1108 population-representative studies with 141 million participants published by Zhou, Bin et al. in the journal The Lancet (November 2024) https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(24)02317-1/fulltext

Genetic basis of early onset and progression of type 2 diabetes in South Asians, published by Hodgson, S., Williamson, A., Bigossi, M. et al. in the journal Nature Medicine (November 2024) https://www.nature.com/articles/s41591-024-03317-8