Diabetes: Cases double in 30 years - and the outlook is bleak

A major international study has revealed the number of adults worldwide with Type 2 diabetes has more than doubled in three decades, soaring to an estimated 347 million.

The research, published yesterday in The Lancet, shows levels have risen or at best remained unchanged in every part of the world. Over the past 30 years, the proportion of men with the condition rose from 8.3 to 9.8 per cent. The proportion of women with diabetes increased from 7.5 to 9.2 per cent.

Professor Majid Ezzati from Imperial College London, who led the research, says that the figures don't reflect the generations of overweight children and young adults who have yet to reach middle age. "We are not at the peak of this wave yet," he said. "And unlike high blood pressure and cholesterol, we still don't have great treatments for [Type 2] diabetes."

Unlike Type 1 diabetes, which is typically diagnosed in childhood and is due to the body's inability to produce insulin, Type 2 is linked to obesity and tends to strike in middle age.

Much of the increase in Type 2 diabetes can be attributed to ageing populations and by population growth, but part of it has also been fuelled by rising obesity rates. The study, the largest of its kind, was co-led by Dr Goodarz Danaei from the Harvard School of Public Health, in collaboration with the World Health Organisation and a number of other institutions.

Blood sugar measurements from 2.7 million participants aged 25 or over from around the world were examined. Professor Ezzati and his colleagues also scrutinised more than 150 national health surveys and studies that tracked Type 2 diabetes in adults over 25 in 199 countries and territories. They used modelling to estimate cases for another 92 countries. With numbers going up almost everywhere, experts said the disease has now become a global crisis. Countries in which the numbers rose fastest include Cape Verde, Samoa, Saudi Arabia, Papua New Guinea and the US. Prevalence rose most sharply in the Pacific Island nations, with the Marshall Islands being the diabetes capital of the world. One in three women and one in four men there have diabetes.

In the UK and elsewhere in Western Europe, there was only a slender rise, despite widening waistlines. Levels were lowest in the Netherlands, Austria and France. Experts admitted they were uncertain why and suggested several theories, including worse detection of the disease, genetic differences, or perhaps that Europeans were better at getting the overweight to reduce their risk factors through public campaigns on healthy eating, smoking and fitness.

Women in Singapore, France, Italy and Switzerland remained relatively slim, with almost no change in diabetes rates. Numbers also stayed flat in sub-Saharan Africa, central Latin America and rich Asian countries.

While increasing lifespan and body weight were acknowledged as two of the strongest factors influencing diabetes rates, especially among women, other factors exist. Genetic factors, nutrition in the womb and after birth, diet and physical activity are also important. South Asians were cited as an example of ethnic genetic factors at play. Men in southern Asia had the second smallest change in BMI (body mass index) of the 21 sub-regional studies, yet the sixth highest rate in mean FPG ("fasting plasma glucose") used to diagnose diabetes. Southern Asian women had the fourth smallest BMI change but the sixth largest rise in FPG, about the same as in high-income North America where female BMI increased three times as much.

Doctors warned of the higher susceptibility of certain groups such as Asians, blacks and Hispanics to diabetes. "Other ethnicities don't have to be as obese as people of European descent to get diabetes," said Dr Aaron Cypess, a physician at Joslin Diabetes Center not linked to the Lancet study. "It may be, for example, that Indians and Chinese store their fat in more dangerous places, like a pot belly," he said, putting forward the theory that this kind of abdominal fat can send out hormones to speed up diabetes.

Between 85 and 95 per cent of all diabetes cases fall into the lifestyle-related Type 2 category. Type 1, or insulin-dependent, diabetes is a separate auto-immune disorder and much less common. This week ,a study gave hope to the 2.9 million Type 2 diabetes sufferers in the UK. Researchers at Newcastle University discovered that an extreme eight-week diet of 600 calories a day can reverse the condition in newly diagnosed people. The study included 11 people following a strict low-calorie diet resulting in pre-breakfast blood sugar levels returning to normal within just a week. Results showed that reduced fat levels in the pancreas and liver helped insulin production return to normal. More research is planned to see whether the reversal is permanent.

The overall outlook, however, is bleak. Hyperglycaemia and diabetes are responsible for more than three million deaths worldwide every year, through both direct clinical complications and indirect health problems such as heart disease and strokes. "Diabetes may well become the defining issue of global health for the next decade," said Professor Ezzati.

Dr Danaei said: "Unless we develop better programmes for detecting people with elevated blood sugar and helping them to improve their diet and physical activity, diabetes will continue to impose a major burden on health systems around the world."

Case studies...

Surjeet Soin; Accountant

Surjeet, 66, an accountant from Luton, was diagnosed with Type 2 diabetes in 1995. It was no surprise when the doctor came back with his glucose test results

"I had all the typical symptoms – I was overweight and had been inactive for years," he says. He started medication and overhauled his lifestyle. He gave up alcohol and took up walking. "I realised I had to do something," he adds. His charity work for Diabetes UK has taken him to the volcanic mountains in Ecuador and the Everest base camp. "I have done the three peaks in Yorkshire every year for many years. It helps me maintain my health." Every three months he goes for a blood test. He runs a local support group offering advice to other diabetics and also participates in Diabetes UK awareness days. Surjeet says he believes patients need to be educated. "It is not a big part of my life but it is something I have to deal with."

Kate Baumber; Development manager

Kate, 42, from Woodhall Spa, Lincolnshire, was diagnosed with Type 1 diabetes aged nine

"Back then insulin injections involved stainless steel needles," she says. It impacted enormously on her life: as a teen she suffered numerous hypoglycaemic episodes (when blood sugar levels fall too low) and struggled during pregnancy. Kate's insulin pump has changed her life immeasurably. "I am a lot more confident, don't have to inject and there are no more comas."

Roger Lewis; Retired drama teacher

Roger, 61, from Watford, was diagnosed with Type 2 diabetes in 2000. He had his leg amputated below the knee after developing ischaemia (blood supply damage)

"I assumed medication was enough. The amputation was one of the most horrible experiences, but I would be dead if I had continued as I was." He no longer smokes, and eats healthily and goes to the gym. Roger has also been invited by Watford General Hospital to talk to prospective amputees, to show them "life isn't over".

Interviews by Katie Binns