bitter sweet: the future of type 2 diabetes
by Jenny Bryan
When Bristol doctors recently reported the first four cases of type 2 diabetes in white British teenagers, it came as little surprise to those who have been treating the growing epidemic of the disease in the UK.
© iStockphoto / Brian Wilke
They predict that, by 2010, the number of people with diabetes will have doubled from 1.4 million to 3 million. Nine out of ten will have type 2 diabetes – a condition which used to be called maturity-onset. But not any more.
In the past, children and teenagers only had type 1 diabetes (insulin dependent) – a lifelong problem which occurs when cells in the pancreas fail to produce insulin, so the body cannot control sugar levels in the bloodstream. In contrast, type 2 diabetes (non insulin dependent) was only seen in middle-aged and elderly people who no longer responded properly to insulin and had some pancreatic failure. But the age barriers are coming down.
Dr Anne Dornhorst, from Charing Cross Hospital, London, explains that in the USA, if you are diagnosed with diabetes in your late teens or early 20s, you are now more likely to have type 2 diabetes than type 1. In the UK, it's just a matter of time before more white adolescents join the African Caribbean and Asian teenagers that Dr Dornhorst and her colleagues have been seeing in their clinics for some time.
'The African Caribbean and Asian populations have a genetic predisposition to type 2 diabetes,' she explains. 'We see the parents in the diabetes clinic and then if their children become overweight because they eat the wrong things and don't do any exercise, we find they have diabetes too.'
The mothers of two of the four white teenagers diagnosed with type 2 diabetes in Bristol had the disease themselves, and a third mother had early signs. Such findings add to growing evidence that babies who are exposed to high sugar levels in the womb risk type 2 diabetes at an earlier age than seen in previous generations.
genetically programmed for type 2
The highest levels of diabetes in the world are found in the Pima Indians of Arizona. Over half of Pima Indians who live on US reservations develop type 2 diabetes, thanks to a genetic predisposition which appears to be activated by an unhealthy diet and sedentary lifestyle.
Recent research has suggested that exposure to high sugar levels in the womb also plays a role. Seventy per cent of Pima children whose mothers had diabetes when they were pregnant went on to develop diabetes by the time they were 25-34. Those born after their mothers developed diabetes were nearly four times more likely to develop diabetes than those born before their mother developed the disease.
'The children were getting the same genes from their parents and the same lifestyle after they were born, but the sugary environment in the womb was different,' says Dr Dornhorst.
Yet, although diabetes is in their genes, Pima Indians don't always get the disease. Some Indians have chosen to stay in the mountains of Mexico, away from the reservations, where they maintain a more physically demanding lifestyle. They too have the genes for type 2 diabetes, but fewer than 1 in 15 of them get the disease.
sugar in the womb
Until recently, the Pima Indian story has only been of academic interest. But the rise in type 2 diabetes, especially in younger people, has brought renewed interest in prenatal exposure to high sugar levels.
Dr Dornhorst explains that if a baby is exposed to high sugar levels when its pancreas is forming in the womb, its insulin-producing cells may be over-stimulated or damaged, and its tissues may be incorrectly programmed in the way they respond to insulin.
'When type 2 diabetes only occurred in middle-aged and elderly people, there was no risk of babies being exposed to these high sugar levels in the womb. But now that type 2 diabetes is in women of childbearing age, we are seeing their children becoming obese and getting type 2 diabetes a good decade earlier than they used to,' she says.
is prevention possible?
Newly published evidence from a US diabetes prevention programme shows that it is possible to slow or even prevent the development of type 2 diabetes by losing weight and taking more exercise. Most people have type 2 diabetes for several years before they are diagnosed and, by the time they get the news, at least a third are already showing signs of the eye, kidney, nerve and heart disease complications which result from too much sugar in the bloodstream.
But before thirst, tiredness, weight loss and other symptoms of diabetes take them to their doctor, most will have passed through a pre-diabetic phase, called impaired glucose tolerance, when they are starting to lose control of their blood sugar levels (see abc of body and abc of food under 'diabetes').
The new American research has shown that, over three years, it is possible to more than halve the risk of developing type 2 diabetes in people with impaired glucose tolerance. It doesn't need a miracle drug – just a healthy diet and less than three hours of exercise a week.
could screening help?
If more studies show that early intervention can prevent people from progressing from impaired glucose tolerance to full-blown type 2 diabetes, diabetes specialists will put pressure on the government to introduce mass screening.
In preliminary guidance to doctors about how to improve diabetes care, the Department of Health recently committed the NHS to 'develop, implement and monitor strategies to identify people who do not know they have diabetes.' But Diabetes UK – the charity which campaigns for a better deal for people with diabetes – is not optimistic that the DoH's commitment will translate into a national screening programme.
Simon O'Neill from Diabetes UK explains that GPs will probably be encouraged to use patient records to identify people who might be at risk of diabetes, for example, those who are overweight or have high blood pressure or other signs of heart disease. But it is unlikely that they will be asked to do more than test high risk individuals for diabetes when they come to surgery for some other reason – so called opportunistic screening.
who to test
Diabetes UK supports a more pro-active approach, with blood tests for those at risk being carried out routinely in doctors' surgeries and possibly at pharmacies and mobile testing centres. It recommends that four key groups should be tested:
- Caucasian people aged over 40 and those from black, Asian and minority ethnic groups aged over 25:
- with a first degree family history of diabetes
- who are overweight (body mass index [BMI] of 25-30 kg/m2 and above [see abc of food under 'body mass index']), and who have a sedentary lifestyle
- who have circulatory diseases affecting the heart, brain or limbs
- women who have diabetes during pregnancy
- women with polycystic ovary syndrome (see abc of body under 'polycystic ovary syndrome') who are obese (BMI of 30 or more)
- those with impaired glucose tolerance or impaired fasting glucose control
'We are calling for targeted early identification of people with diabetes. Rather than relying on opportunistic testing, we would like to see practices going through their registers and identifying everyone who falls into these groups so they can be offered tests,' says Simon O'Neill.
At present, testing means at least one measurement of glucose levels in the blood after an overnight fast and/or a glucose test two hours after swallowing a specific amount of glucose (see abc of body and abc of food under 'diabetes'). But other methods, including a blood test which measures overall glucose levels during the previous three months, are being considered.
healthier lifestyle
Testing for type 2 diabetes will identify those who need dietary and possibly drug treatment. But it won't solve the growing problem of type 2 diabetes in our increasingly overweight and inactive population. Over half of people with type 2 diabetes die from heart disease and a further 15% die from strokes.
Only a healthier lifestyle, starting in childhood, can have any real impact on such statistics. As Simon O'Neill points out:
'There is a desperate need for healthy eating to be more promoted in schools and for children to do more physical activity.'
Without a major change in educational policy towards dietary options at mealtimes and sporting activities in schools, type 2 diabetes in adolescence will soon be so commonplace that it no longer makes headlines.
help and info
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organisations
Diabetes UK
10 Parkway
London NW1 7AA
Careline: 0845 120 2960 (Mon-Fri 9am-5pm)
Textphone: 020 7424 1031
E-mail: careline@diabetes.org.uk
Website: www.diabetes.org.uk
Campaigns on behalf of people with diabetes, provides support and information, and funds research. The Careline has trained counsellors who can be contacted for support and current information on diabetes, however they cannot give individual medical advice. Also operates an e-mail enquiry service.
Diabetes Research & Wellness Foundation
Office 101-102
Northney Marina
Hayling Island PO11 0NH
Tel: 023 9263 7808
E-mail: drwf@diabeteswellnessnet.org.uk
Website: www.diabeteswellnessnet.org.uk
Established to fund research and offer support to people living with diabetes. DRWF brings professionals, patients, their parents and friends together in a 'Diabetes Wellness Network,' providing information to help improve diabetes self-management through newsletters, advice leaflets and a programme of patient events.
Juvenile Diabetes Research Foundation
19 Angel Gate
City Road
London EC1V 2PT
Tel: 020 7713 2030
E-mail: info@jdrf.org.uk
Website: www.jdrf.org.uk
Juvenile Diabetes Research Foundation funds research to find a cure for diabetes, and provides information on diabetes, new developments in treatment and research. A range of leaflets on living with diabetes and its complications are available free of charge.
websites
BUPA
http://hcd2.bupa.co.uk/fact_sheets/html/diabetes2.html
Information on Type 2 diabetes from BUPA including a PDF factsheet to download.
Children with Diabetes
www.childrenwithdiabetes.com/index_cwd.htm
A US-based site geared towards promoting understanding of the care and treatment of diabetes, especially in children. Described as an 'online community for kids, families and adults with diabetes.'
Diabetes Insight
www.diabetes-insight.info
UK website aiming to provide information to people with diabetes in a positive manner, to help them live an active life. Operates an e-mail support group and an online discussion forum, Diabetes Support.
reading
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Parenting a Child with Diabetes by Gloria Loring (Contemporary Books, 2000) |
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When Diabetes Complicates Your Life: Controlling Diabetes and Related Complications by Joseph Juliano (John Wiley and Sons Inc, 1998) |
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'Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin' by the Diabetes Prevention Program Research Group in New England Journal of Medicine, vol 346 (7 Feb 2002) pages 393-403
To read about preventing 'hypos' (low blood sugar levels), see the article diabetes control – without the hypos, also in this illness section.
(March 2002, resources updated January 2005)
