Conditions such as heart disease, stroke, and respiratory infections account for the majority of deaths each year around the world. Some preventive measures may help lower your risk.

When people think of the deadliest diseases in the world, their minds probably jump to the fast-acting, incurable ones that grab headlines from time to time. However, many of these types of diseases don’t rank in the top 10 causes of worldwide deaths.

An estimated 55.4 million people passed away worldwide in 2019, and 74% of these deaths were because of noncommunicable diseases, or chronic conditions that progress slowly.

Perhaps even more surprising is that several of the deadliest diseases are partially preventable. Non-preventable factors include where a person lives, access to preventive care, and quality of healthcare, all of which factor into risk.

But there are several steps that everyone can take to lower their risk.

Read on to see 10 of the deadliest diseases worldwide.

The deadliest disease in the world is coronary artery disease (CAD).

Also called ischemic heart disease, CAD occurs when the blood vessels that supply blood to the heart become narrowed. Untreated CAD can lead to chest pain, heart failure, and arrhythmias.

Impact of CAD across the world

Although it’s still the leading cause of death, mortality rates have declined in many European countries and in the United States.

This may be because of better public health education, access to healthcare, and other forms of prevention. However, in many developing nations, mortality rates for CAD are on the rise.

An increasing life span, socioeconomic changes, and lifestyle risk factors play a role in this rise.

Risk factors and prevention

Risk factors for CAD include:

Talk with a doctor or healthcare professional if you have one or more of these risk factors.

You can prevent CAD with medications and by taking steps to improve heart health. Some of the ways you can decrease your risk include:

  • exercising regularly
  • reaching or maintaining a moderate weight
  • eating a balanced diet that’s low in sodium and high in fruits and vegetables
  • avoiding smoking, if applicable
  • drinking only in moderation

A stroke occurs when an artery in your brain is blocked or leaks. This causes the oxygen-deprived brain cells to begin dying within minutes.

During a stroke, you feel sudden numbness and confusion or have trouble walking and seeing. If left untreated, a stroke can cause long-term disability.

In fact, strokes are the leading cause of long-term disabilities. People who receive treatment within 3 hours of having a stroke are less likely to have disabilities.

The Centers for Disease Control and Prevention (CDC) reports that one survey found that 93% of people knew sudden numbness on one side was a symptom of stroke. However, only 38% knew all the symptoms that would prompt them to look for emergency care.

Risk factors and prevention

Risk factors for stroke include:

  • high blood pressure
  • family history of stroke
  • smoking, especially when combined with oral contraceptives
  • being African American
  • being female

Some risk factors of strokes can be lowered with preventive care, medications, and lifestyle changes. In general, good health habits can lower your risk.

Stroke prevention methods may include controlling high blood pressure with medications. You should also maintain a healthy lifestyle, complete with regular exercise and a balanced diet that’s low in sodium.

If you smoke, consider quitting and drink only in moderation, as these activities increase your risk of stroke.

A lower respiratory infection is an infection in your airways and lungs. It can be due to:

Though viruses usually cause lower respiratory infections, they can also be caused by bacteria.

Coughing is the main symptom of a lower respiratory infection. It may produce blood sputum. You may also have a fever, sweating, or chills or experience breathlessness, wheezing, and a tight feeling in your chest.

Risk factors and prevention

Risk factors for lower respiratory infection include:

  • the flu
  • poor air quality or frequent exposure to lung irritants
  • smoking
  • a weak immune system
  • crowded child care settings, which mainly affect infants
  • asthma
  • HIV

One of the best preventive measures you can take against lower respiratory infections is to get the flu shot every year. People at high risk of pneumonia can also get a vaccine.

Be sure to wash your hands regularly with soap and water to avoid transmitted bacteria, especially before touching your face or eating.

If you have a respiratory infection, stay at home and rest until you feel better, as rest improves healing.

Chronic obstructive pulmonary disease (COPD) is a long-term, progressive lung disease that makes breathing difficult. Chronic bronchitis and emphysema are types of COPD.

In 2018, about 16.4 million people in the United States reported a diagnosis of any type of COPD.

Risk factors and prevention

Risk factors for COPD include:

  • smoking or secondhand smoke
  • lung irritants such as chemical fumes
  • family history, with the alpha-1 antitrypsin deficiency gene being linked to COPD
  • history of respiratory infections as a child

There’s no cure for COPD, but its progression can be slowed with medication.

The best ways to prevent COPD are to stop smoking, if applicable, and avoid secondhand smoke and other lung irritants. If you experience any COPD symptoms, getting treatment as soon as possible improves your outlook.

Respiratory cancers include cancers of the trachea, larynx, bronchus, and lungs.

The main causes are smoking, secondhand smoke, and environmental toxins. However, household pollutions, such as fuels and mold, also contribute.

Impact of respiratory cancers around the world

A 2015 study reports that there are around 18 million new cases of lung cancer annually. In developing countries, researchers project an 81% to 100% increase in respiratory cancers because of pollution and smoking.

Many Asian countries, especially India, still use coal for cooking. Solid fuel emissions account for 17% of lung cancer deaths in males and 22% in females.

Risk factors and prevention

Trachea, bronchus, and lung cancers can affect anyone, but they’re most likely to affect those who have a history of smoking or tobacco use.

Other risk factors for these cancers include family history and exposure to environmental factors such as diesel fumes.

Aside from avoiding fumes and tobacco products, it isn’t known if there’s anything else that can be done to prevent lung cancers. However, routine lung scans and early detection can result in more effective treatment and an improved outlook.

Diabetes is a group of diseases that affect the production or use of insulin.

In type 1 diabetes, the pancreas is unable to produce insulin. This type of diabetes is believed to be caused by an autoimmune reaction.

In type 2 diabetes, the pancreas doesn’t produce enough insulin, or insulin can’t be used effectively. Type 2 diabetes can be caused by a number of factors, including poor diet and physical inactivity.

Impact of diabetes around the world

Over time, uncontrolled diabetes can cause damage to the nerves and blood vessels. This can lead to complications such as impaired wound healing, kidney failure, and blindness.

People in low- and middle-income countries are more likely to die of complications from diabetes because of limited access to medications and technologies needed to manage blood sugar levels.

Risk factors and prevention

Risk factors for diabetes include:

  • having overweight or obesity
  • high blood pressure
  • older age
  • not exercising regularly
  • an unhealthy diet

While diabetes isn’t always preventable, you can control the severity of symptoms by exercising regularly and following a well-rounded, nutritious diet. Adding more fiber to your diet can also help with controlling blood sugar levels.

Alzheimer’s disease is a progressive disease that destroys memory, interferes with decision making, and interrupts normal cognitive functions. These include thinking, reasoning, and other everyday behaviors.

Alzheimer’s disease is the most common type of dementia and accounts for about 60 to 70% of cases.

The disease starts off by causing mild memory problems, difficulty recalling information, and slips in recollection. Over time, however, the disease progresses, and you may not have memory of large periods of time.

Risk factors and prevention

Risk factors for Alzheimer’s disease include:

There’s not currently a way to prevent Alzheimer’s disease, and researchers aren’t sure why some people develop it and others don’t. As they work to understand this, they’re also working to find preventive techniques.

One thing that may be helpful in lowering your risk of the disease is following a healthy diet. In fact, some research suggests that eating plenty of fruits, vegetables, whole grains, heart-healthy fats, and legumes could support brain function and prevent cognitive decline.

Diarrhea is when you pass three or more loose stools in a day. If your diarrhea lasts more than a few days, your body loses too much water and salt. This causes dehydration, which can be fatal in severe cases.

Diarrhea is usually caused by an intestinal virus or bacteria transmitted through contaminated water or food. It’s particularly widespread in areas with poor sanitary conditions.

Impact of diarrheal diseases around the world

Diarrheal disease is the second leading cause of death in children younger than 5 years old. About 525,000 children die from diarrheal diseases each year.

Risk factors and prevention

Risk factors for diarrheal diseases include:

  • living in an area with poor sanitary conditions
  • not having access to clean water
  • age, with children being the most likely to experience severe symptoms of diarrheal diseases
  • malnourishment
  • a weakened immune system

The best method of prevention is practicing good hygiene. Handwashing, improved sanitization and water quality, and access to early medical treatment can also help prevent diarrheal diseases.

TB is a lung condition caused by bacteria called Mycobacterium tuberculosis. It’s a treatable airborne bacterium, although some strains are resistant to conventional treatments.

TB is one of the top causes of death in people who have HIV. Furthermore, people who have HIV are 18 times more likely to develop active TB.

Impact of TB around the world

The cases of TB have fallen 2% each year between 2015 and 2020.

One of the targets of the United Nations Sustainable Development Goals is to end the TB epidemic by 2030.

Risk factors and prevention

Risk factors for TB include:

  • diabetes
  • HIV infection
  • a lower body weight
  • proximity to others with TB
  • regular use of certain medications such as corticosteroids or drugs that suppress the immune system

The best prevention against TB is to get the bacillus Calmette-Guerin vaccine, which is commonly given to infants and children in areas where TB is common.

If you think you’ve been exposed to TB bacteria, a doctor can prescribe preventive medications (chemoprophylaxis) to lower the likelihood of developing an active infection.

Cirrhosis is the result of chronic or long-term scarring and damage to the liver. The damage may be the result of a kidney disease, or it can be caused by conditions such as hepatitis, alcoholic liver disease, or nonalcoholic fatty liver disease.

A healthy liver filters harmful substances from your blood and sends healthy blood into your body. As substances damage the liver, scar tissue forms. As more scar tissue forms, the liver has to work harder to function properly and may eventually stop working.

Risk factors and prevention

Risk factors for cirrhosis include:

  • chronic alcohol use
  • fat accumulation around the liver (nonalcoholic fatty liver disease)
  • chronic viral hepatitis

Moderating alcohol intake can help prevent liver damage and cirrhosis.

Likewise, you can prevent nonalcoholic fatty liver disease by enjoying a nutritious diet rich in fruits and vegetables and low in sugar and fat.

Lastly, you can lower the likelihood of contracting viral hepatitis by using barrier methods each time you engage in sexual activity and by avoiding sharing anything that could have traces of blood such as needles, razors, or toothbrushes.

How many rare diseases are there?

A rare disease is usually defined as a disease or condition that affects fewer than 200,000 people in the United States.

According to most scientists and clinicians, there are around 7,000 different rare diseases. However, this estimate can vary from 5,000 to 8,000 rare diseases, depending on the source.

It’s believed that around 1 in 10 people in the United States, or around 30 million people in total, has a rare disease.

Some rare diseases are hereditary and can be passed from parent to child. Some may be visible from birth, while others might show up later in life.

Which disease has no cure?

There’s no known cure for many conditions, including several on the list of the deadliest diseases.

This also includes conditions such as cancer, Alzheimer’s disease, multiple sclerosis, and muscular dystrophy.

In many cases, certain lifestyle factors, such as smoking cessation and modifying your diet or exercise routine, may lower the risk of developing some of these conditions.

In other cases, a combination of lifestyle changes, medications, and other treatment methods might help manage or reduce symptoms of a condition, though it may not necessarily cure it.

What’s the deadliest disease?

Ischemic heart disease is the leading cause of death around the globe. Other conditions, such as stroke, COPD, lower respiratory infections, and respiratory cancers, also account for a significant portion of deaths each year.

While deaths from certain diseases have increased, those from more serious conditions have also decreased.

Several factors, such as an increasing life span, naturally increase the prevalence of age-related diseases such as CAD, stroke, and heart disease.

However, many of the diseases on this list are preventable and treatable, and as medicine continues to advance and prevention education grows, we may see improved outcomes for many of these diseases.

A good approach to lowering your risk of any of these conditions is to follow a balanced diet, live a healthy lifestyle, and stay active.

Moderating your alcohol intake and quitting smoking, if applicable, can also help.

For bacterial or viral infections, proper handwashing can help prevent or lower your risk.