When a person has diabetes, they have high levels of blood sugar. Managing these levels can reduce the risk of excess blood sugar causing damage across the body. If glucose levels remain high, many health issues can arise.
Glucose, or blood sugar, is the main energy source for the human body. It comes from the food people eat. The hormone insulin helps the cells of the body to convert glucose into fuel.
Getting an early diagnosis and following a treatment plan that involves regular medical care, lifestyle changes, and medication can help limit the effects of diabetes.
This article looks at some of the long-term complications of diabetes and how to prevent them.
Find out here how to recognize the common symptoms of diabetes.
High blood glucose levels can cause damage to all parts of the cardiovascular system. For this reason, there is a close link between diabetes and cardiovascular problems.
Excess blood sugar decreases the elasticity of blood vessels and causes them to narrow, impeding blood flow. This can lead to a reduced supply of blood and oxygen, increasing the risk of high blood pressure and damage to large and small blood vessels.
Damage to large blood vessels is known as macrovascular disease, while microvascular disease refers to damage to small blood vessels.
Complications from macrovascular disease include:
Microvascular disease can lead to problems with the:
- nervous system
A person with diabetes can reduce the risk of cardiovascular and circulatory problems by:
- managing blood sugar levels
- quitting smoking
- managing blood pressure and lipids
- using prescription medications, such as statin drugs, to lower cholesterol
- monitoring blood pressure
- exercising regularly
- eating a fiber-rich diet
- sodium–glucose cotransporter 2 inhibitors (SGLT2)
- glucagon-like peptide 1 receptor agonists (GLP-1 RA)
These drugs can reduce the risk of high blood sugar and, therefore, cardiovascular disease. The guidelines recommend these for people who have diabetes plus:
These drugs can also reduce the risk of chronic kidney disease progression, cardiovascular events, or both.
The cardiovascular system
According to the CDC, cardiovascular disease is the leading cause of early death among people with diabetes.
The CDC add that people with diabetes are two to three times more likely to have a stroke or die of some form of heart disease than those without diabetes.
People with diabetes also tend to develop more serious heart problems at an earlier age than people without the condition.
An unhealthful diet and a lack of exercise are risk factors for both cardiovascular disease and diabetes.
Wounds and infections
Poor circulation affects the body’s ability to heal when there is a wound or an infection. This is due to a low supply of blood, oxygen, and nutrients.
A person with diabetes should check their skin regularly for wounds and see their doctor if they have any signs of an infection, including redness, swelling, or fever.
Neuropathy, or nerve damage, is a common complication of diabetes.
According to the CDC, symptoms are most likely in people who have had diabetes for 25 years or more, but it can happen much sooner as well.
Neuropathy can affect any part of the nervous system, including the nerves that control autonomic or involuntary functions, such as digestion.
However, the most common form is peripheral neuropathy. This causes pain and numbness in the extremities, specifically:
- the legs, feet, and toes
- the arms, hands, and fingers
Neuropathy can also affect the hips and upper legs.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) say that up to 50 percent of people with diabetes have peripheral neuropathy and more than 30 percent have autonomic neuropathy.
The loss of sensation that occurs with neuropathy can make it harder for a person to notice small wounds. Combined with poor circulation, this can lead to severe complications.
If a person does not notice a blister on their foot, for example, an infection can develop and worsen quickly. Poor circulation contributes to this. Ulceration and tissue death can result, and amputation may be necessary in some cases.
Find out more here about how diabetes affects the feet.
Over time, high blood sugar levels can damage blood vessels in the kidneys. This damage prevents the kidneys from filtering waste out of the blood. In time, kidney failure can result.
The NIDDK describe diabetes as one of the main causes of kidney disease. It affects 1 in 4 people with diabetes.
Diabetic nephropathy is kidney disease that affects people with diabetes. Learn more here.
Diabetes increases the risk of a number of eye problems, some of which can lead to vision loss.
Short-term problems include blurred vision, due to high blood sugar. Long-term complications include:
Having regular eye tests, managing blood sugar, and avoiding or quitting smoking can all help protect eye health with diabetes.
Find out more here about the link between blurry vision and diabetes.
Damage to the nervous system can affect autonomic body functions, including digestion.
Gastroparesis can happen when nerve damage interferes with the ability of the digestive system to move food from the stomach into the small intestine.
The condition can result in:
- acid reflux
- abdominal pain
- weight loss in severe cases
Learn more here about diabetic gastroparesis.
Diabetes-related damage to blood vessels and the autonomic nervous system may have a negative effect on sexual function and the body’s ability to send and respond to sexual stimuli.
Other ways in which diabetes can affect people’s confidence in their sex life include:
- the condition’s impact on mental health
- worry that sex may lower glucose levels, leading to hypoglycemia
- uncertainty about what to do with an insulin pump
However, there are ways of overcoming all of these problems.
Learn more here about how diabetes can affect a person’s sex life and how to manage these complications.
Diabetes can affect fertility in both men and women.
Menstrual irregularities are also common once menstruation starts, and menopause may start earlier.
The research also notes that there are links between type 2 diabetes and infertility, the length of the menstrual cycle, and the age at which menopause starts.
This connection may be due to the high incidence of polycystic ovary syndrome (PCOS) and obesity among people with diabetes, both of which can increase the chance of fertility problems.
Diabetes can also cause pregnancy complications, therefore, good blood sugar management during the entire pregnancy is essential.
Research from 2018 found that men with type 1 and type 2 diabetes tend to have lower sperm quality and a higher risk of infertility.
There are links between diabetes and various skin conditions. Symptoms can range from mild to severe.
Problems include a higher chance of:
- dry skin
- skin tags
- dark patches of skin, known as acanthosis nigricans
- bacterial infections, such as styes or boils
- fungal infections, such as thrush or athlete’s foot
- diabetic dermopathy, which involves harmless but potentially bothersome roundish, brown, scaly patches
Ulcers can develop if a skin infection becomes severe. Ulcers are open wounds that are slow to heal.
Necrobiosis lipoidica diabeticorum (NLD) starts as a raised area of skin that can turn violet and become itchy and sore. NLD is a rare condition that may need treatment if the sores open.
A person with high blood sugar levels may also have high levels of triglyceride, or fat, in the blood. This can lead to eruptive xanthomatosis, a rash of reddish-yellow lesions called xanthomas that can also be a warning sign for pancreatitis.
Calluses, foot sores, and dry skin can also pose problems. If wounds develop from these, ulcers can appear. Without attention, a foot ulcer can become dangerous, possibly resulting in the need for an amputation.
Learn more here about how diabetes can lead to skin problems.
Metabolism is the process by which the body converts nutrients into energy. Disruption to this process can lead to various complications, some of which can be life-threatening.
Diabetic ketoacidosis (DKA) is an acute, life-threatening diabetes complication. It happens when the body cannot use glucose for energy, so it starts to break down fat. As it does this, it releases chemicals known as ketones. High levels of ketones can make the blood too acidic.
Within a few hours, this can lead to various symptoms, including:
Without treatment, DKA can be fatal.
DKA is most likely to affect a person with type 1 diabetes, but it can also happen with type 2 if blood sugar levels rise too far.
Hyperosmolar hyperglycemic state
A hyperosmolar hyperglycemic state (HHS) occurs when blood sugars are extremely high. It is more common in type 2 diabetes.
Symptoms develop gradually and include:
- loss of consciousness and coma
HHS can be fatal if a person does not receive treatment quickly.
Metabolic syndrome refers to a collection of conditions and symptoms, including diabetes, high blood pressure, and obesity.
A doctor may diagnose metabolic syndrome if someone has three out of the following five symptoms:
- high fasting blood sugar
- high LDL (“bad”) cholesterol and low HDL (“good”) cholesterol
- hypertension, or high blood pressure
- a large waist size, due to body fat around the middle
- high levels of triglycerides in the blood
Risk factors for diabetes and other aspects of metabolic syndrome include low physical activity and excess weight.
Diabetes can affect a person’s mental health in various ways. We describe some of these ways here:
- Concerns about treatment, health, and possible complications can give rise to stress, anxiety, and depression.
- People can worry about the cost of treatment and whether or not they are getting it right, especially if symptoms change.
- When a person feels tired, it can be easier to get into bad habits, for example, not exercising.
Learning as much as possible about diabetes can help reduce stress. The more a person knows about their condition, the more control they will feel they have over their diabetes and its treatment.
Knowing what to do in each situation can boost a person’s confidence and leave them feeling better overall.
Working with a healthcare professional can help to minimize these problems. A doctor or counselor can help make a plan to reduce the risk of mental health problems.
Diabetes occurs when a person’s blood sugar levels become too high. In time, high blood sugar levels can affect all parts of the body and result in several complications, some of which can be serious.
In the short-term, a person with high blood glucose levels will notice that they feel thirsty and need to urinate frequently. If this happens, they should see a doctor whether they have a diagnosis of diabetes or not. Without treatment, diabetes can lead to confusion, and possibly a loss of consciousness, coma, and death.
In the long-term, diabetes increases the risk of damage to blood vessels and nerves, resulting in a wide range of complications.
The longer a person has diabetes, the more likely they are to experience heart disease and other problems.
Ways to minimize the risks include:
- managing blood sugar levels through insulin use or medication
- boosting overall health with lifestyle measures, such as having a healthful diet, exercising, and managing blood glucose
- following the treatment plan that the doctor recommends
All forms of diabetes can disrupt daily life, but a person who manages their blood sugar levels well has a good chance of living a full and active life.