The symptoms

If your diabetes isn't treated, it can lead to many different health problems. Large amounts of glucose can damage blood vessels, nerves and organs, and even a mildly raised glucose level that doesn't cause any symptoms can have damaging effects in the long term.

Heart disease and stroke
If you have diabetes, you're up to five times more likely to suffer heart disease and stroke compared with people without diabetes. Prolonged, poorly controlled blood glucose levels increase the likelihood of atherosclerosis (furring up and narrowing of the blood vessels). This may result in poor blood supply to the heart, causing angina. It also increases the chance that a blood vessel in your heart or brain will become completely blocked, causing a heart attack or stroke.

Retinopathy (damage to the retina at the back of the eye)
Blood vessels in the retina of your eye can become blocked, leaky or grow haphazardly. This damage gets in the way of the light passing through to your retina and, if left untreated, can damage vision.

The better you control your blood sugar levels, the less chance you have of serious eye problems. Having an annual eye check by a specialist (an ophthalmologist or an optometrist) can help to pick up signs of any potentially serious eye problems early on, so that they can be treated. However, if you've got eye problems, the Royal National Institute of the Blind (RNIB) offers this advice:

• Don't wait until your vision has deteriorated to have an eye test.
  Most sight-threatening diabetic problems can be managed by laser treatment if it's given early enough.
• Don't be afraid to ask questions or express concerns about your treatment.
  Good sugar, blood pressure and cholesterol control reduces the risk of diabetes-related sight loss.
• Attend your diabetic clinic or GP surgery for regular diabetes health checks, including blood pressure and cholesterol monitoring.
• Smoking increases your risk of diabetes-related sight loss. Your doctor can tell you about NHS stop smoking services in your area.
• The National Diabetic Retinopathy Screening Programme will arrange for you to have your eyes checked every year. From December 2007, everyone on a diabetes register will be offered the opportunity to have a digital picture taken of the back of their eye. To register, speak to your GP.

Diabetic retinopathy can be managed by laser treatment if it's caught early enough. It's important to realise, however, that this will only preserve the sight you have, not make it better. More information about the laser treatment is available from the RNIB.

Foot problems
Damage to the nerves of the foot can mean that small nicks and cuts are not noticed, leading to the development of a foot ulcer. About one in 10 people with diabetes get foot ulcers, which can cause serious infection.

Check your feet every day and report any changes to your doctor, nurse or podiatrist. Danger signs to look out for include sores and cuts that don’t heal, puffiness or swelling and skin that feels hot to the touch. You should also have a foot examination at least once a year.

Podiatry/chiropody (the treatment of abnormalities and conditions of the foot and lower limbs) is usually available on the NHS free of charge. People with diabetes are treated as priority cases, but you'll need a referral from your GP, practise nurse or health visitor. Ask them whether the treatment is available in your area. If it is, your case will be assessed and you'll be added to a waiting list and will receive a letter telling you when your appointment is. If needed, it may be possible to arrange home visits.

If free NHS treatment is not available in your area, you can go to a local clinic for private treatment, but you'll have to pay.