Decoding the disease: does Asia have a future with diabetes?

PUBLISHED : Tuesday, 27 November, 2012, 12:00am
UPDATED : Tuesday, 04 December, 2012, 5:24pm

According to the updated fifth edition of the International Diabetes Federation's Diabetes Atlas 2012, released on World Diabetes Day earlier this month, there are 371 million people in the world with diabetes. If urgent action is not taken, that figure will grow to 552 million by 2030.

China leads the figures with 92.3 million people with diabetes, 57 per cent of whom are undiagnosed. Dr Jenny Leung, president of Diabetes HK, says Hong Kong is experiencing a diabetes calamity, too. "We estimate that 10 per cent of the population, or 700,000 people, have diabetes in Hong Kong, but only 350,000 know it."

In Singapore, diabetes statistics are similar. Singapore's health minister Gan Kim Yong, speaking on World Diabetes Day, said: "Today, more than 400,000 Singaporeans over 40 live with diabetes, and by 2030 it is estimated to increase to 600,000." With a population of just over five million, Singapore would cross the 10 per cent population threshold next year.

Are East Asians more at risk for type-2 diabetes than are other ethnic groups? To find out, a team of 75 scientists from 27 universities and institutions worldwide are conducting a genetic study involving five major ancestry groups.

The study involves 10,000 participants of East Asian, South Asian, European, Hispanic and African-American descent, half of whom have diabetes. The sequencing of 18,000 of each participants' protein-coding genes will be completed this year.

By comparing the DNA of individuals with type-2 diabetes and controls, the scientists hope to isolate genes or variants that increase or reduce an individual's predisposition for developing the disease, says T.M. Teslovich, research fellow in statistical genetics at the University of Michigan.

"If different variants are associated with different populations, that has implications for risk prediction and [eventually] treatment," she says. "Knowing which variants are causal can lead to the development of new drug therapies. But it takes time to go from variant to treatment."

The study is a project sponsored by the US National Institutes of Health called T2D-Genes, or type-2 diabetes genetic exploration by next-generation sequencing in multi-ethnic samples. Chinese University is part of the T2D-Genes consortium, with Dr Ronald Ma, professor at the department of medicine and therapeutics, as lead investigator.

Ma, who is also an honorary consultant at the Prince of Wales Hospital, says that while Hong Kong samples were not included in T2D-Genes, he and his team are replicating the study. He believes this is one of the most significant studies to date because so little is known about the genetics of diabetes. "We have found only 10 per cent of the genes that are linked to diabetes," he says. "There are still many unexplained risks and the T2D study will provide some answers."

Diabetes can strike an individual at any age. Type-1, type-2 and gestational diabetes are the three main kinds of the illness.

Type-1 diabetes, also known as juvenile diabetes or insulin-dependent diabetes, is usually first diagnosed in children, teenagers or young adults. Type-2 diabetes, also known as adult-onset diabetes or non-insulin-dependent diabetes, is the most common form of the illness. One can develop type-2 diabetes at any age. Some women develop gestational diabetes during the late stages of pregnancy. Although this usually goes away after the baby is born, a woman who has had it is more likely to develop type-2 diabetes later in life.

Type-2 diabetes is nearly at crisis level in Hong Kong because, while incidence is growing steadily, funding for the condition is not. "A doctor typically has no more than 10 minutes with each patient, and that's not a lot of time to discuss prevention, risks and the importance of adherence to treatment," Diabetes HK president Dr Jenny Leung says.

According to Ma, awareness of diabetes symptoms is also low and patients ignore the risks. "Diagnosed cases don't take their condition seriously because they think it will always be silent," he says. "But half of all people who are blind have diabetes, and the same is true for kidney disease."

Both Ma and Leung believe that campaigns like World Diabetes Day help generate greater public awareness by emphasising the seriousness of the illness. This year's campaign focuses on the urgency for action to protect the health of our future generations, reflecting the rising incidence of type-2 diabetes in children and adolescents globally.

According to the Asia Diabetes Foundation, there are an estimated 60 to 70 new cases of type-1 and about 250 new cases of type-2 diabetes among Hong Kong children each year.

In Hong Kong, childhood obesity increased from 9.3 per cent overweight and 2.6 per cent obese children in 1993 to 13 per cent and 3.7 per cent respectively in 2006.

IDF practice guidelines state that metabolic syndrome can be diagnosed in children over age 10 with abdominal obesity and the presence of two or more other clinical features, such as elevated triglycerides, low HDL cholesterol, high blood pressure and increased plasma glucose.

But not only overweight and obese people get diabetes, and misconceptions may lead to adverse outcomes, says Dr Yao Ho-chung, resident specialist with the department of paediatrics at Prince of Wales Hospital. "Non-obese children with type-2 diabetes will probably be missed," he says

Joanna Hotung, co-founder and chairwoman of the Hong Kong Juvenile Diabetes Association, thinks it may be time for her organisation to cater to the rising incidence of type-2 diabetes among children. Most of its members who receive general and emotional support have type-1 diabetes.

The campaign, launched jointly by the Education Bureau, the Health Department and Diabetes HK in 2009, is still going strong. The campaign, which promotes healthy eating practices among students, has been successfully conducted in 54 primary schools.

New estimates predict that this year 4.8 million people will die from diabetes and that half of them will be under the age of 60. The IDF says that if we don't change our behaviour, our kids may be "the first generation where children may die before their parents".