If a person has high glucose levels due to diabetes, this can lead to many health issues that can affect the body and organs. Managing these levels can reduce the risk of damage across the body.

Getting an early diagnosis of diabetes, as well as 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.

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 convert glucose into fuel.

In type 1 diabetes, the body’s immune system attacks cells in the pancreas and stops them from making insulin. In type 2 diabetes, the body is not able to make insulin or the insulin does not work as it should.

In both types of diabetes, the amount of sugar in the blood becomes higher than it should be.

Type 2 is more common. It develops over time and is often related to a lack of exercise, an unhealthful diet, or obesity, though other factors may also predispose a person to develop it. Type 1 is usually genetic and most common in children and adolescents, though it can develop at any age.

Both types of diabetes can cause a variety of damage to the body if a person does not control the condition.

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.

Blood vessels

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.

High blood pressure is a risk factor for heart disease. Nearly 74% of adults with diabetes have hypertension.

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 also lead to problems with the:

  • eyes
  • kidneys
  • 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

For some people with type 2 diabetes, current guidelines recommend that doctors prescribe sodium-glucose cotransporter 2 inhibitors (SGLT2) and glucagon-like peptide 1 receptor agonists (GLP-1 RA).

These drugs can reduce the risk of high blood sugar and cardiovascular disease. They also work to decrease weight, lower blood pressure, reduce systemic inflammation, and improve cardiac function.

The guidelines recommend these for people who have diabetes, plus those with atherosclerotic cardiovascular disease with a high risk of heart failure, and chronic kidney disease.

These drugs can also reduce the risk of chronic kidney disease progression. A doctor may also prescribe them to treat atherosclerosis with no relation to heart failure.

The cardiovascular system

According to the Centers for Disease Control and Prevention (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.

In addition, diabetes often occurs alongside other conditions that stress the heart, such as obesity, hypertension, and high cholesterol.

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. About 10–20% of people with an initial diagnosis of diabetes will have nerve damage. The longer a person is living with diabetes, the higher their chance of getting neuropathy.

More than half of people living with diabetes will eventually get the condition.

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, arms, hands, and fingers.

Neuropathy can also affect the hips and upper legs.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says that up to half of people with diabetes have peripheral neuropathy and more than 30% have autonomic neuropathy.

Click here to find out more about diabetic 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 about how diabetes affects the feet here.

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 describes diabetes as one of the main causes of kidney disease. It affects 1 in 3 people with diabetes.

Diabetic nephropathy is a 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 about the link between blurry vision and diabetes here.

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:

  • nausea
  • vomiting
  • acid reflux
  • bloating
  • abdominal pain
  • weight loss in severe cases

Learn more about diabetic gastroparesis here.

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.

Erectile dysfunction is more than three times more likely to develop in men with diabetes, and it can appear 10–15 years earlier than in those without the condition.

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 about how diabetes can affect a person’s sex life and how to manage these complications here.

Diabetes can affect fertility in both men and women.

A 2020 review of 28 studies shows an association between the risk of type 2 diabetes and the earlier onset of puberty in girls.

Menstrual irregularities are also common once menstruation starts, a female may experience heavier periods, and menopause can start earlier.

There is also a 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.

Another study 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
  • itching
  • diabetic dermopathy, which involves harmless but potentially bothersome roundish, brown, scaly patches
  • blisters

Studies have also found links between the incidence of type 2 diabetes and psoriasis.

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 of 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 about how diabetes can lead to skin problems here.

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

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:

  • a dry mouth
  • nausea and vomiting
  • stomach pains
  • shortness of breath
  • a loss of consciousness and coma

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 diabetes 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:

HHS can be fatal if a person does not receive treatment quickly.

Metabolic syndrome

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 some of the following 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. It may cause:

  • concerns about treatment, health, and possible complications that can give rise to stress, anxiety, and depression
  • concerns about the cost of treatment and whether or not they are getting it right, especially if symptoms change
  • mood disorders that make it difficult for a person to keep a healthy lifestyle

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.

The following are answers to some common questions about diabetes.

How do I reduce the risk of diabetes 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

What are the first signs of diabetes?

Early signs of diabetes include frequent urination, excessive thirst or hunger, fatigue, and numbness in the hands or feet.

Learn about other early signs of diabetes here.

What is gestational diabetes?

This is another type of diabetes that only develops during pregnancy. Hormones from the placenta prevent the insulin in the body from properly storing glucose and the body does not make enough insulin to counteract this. Gestational diabetes usually goes away after delivery.

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 or not they have a diagnosis of diabetes.

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. 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.