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 diseases don’t rank in the top 10 causes of worldwide deaths.

An estimated 68 million people passed away worldwide in 2021, and 38% of these deaths were because of noncommunicable diseases, or chronic conditions that progress slowly.

Perhaps even more surprising is that several deadliest diseases are partially preventable. Non-preventable factors that contribute to risk include:

  • where a person lives
  • access to preventive care
  • quality of healthcare

However, 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 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 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 alcohol only in moderation

In 2021, COVID-19 replaced stroke as the second most deadly disease worldwide and pushed many of the diseases in the list down since 2020.

Impact of COVID-19 around the world

COVID-19 was responsible for 8.8 million deaths in 2021. It was a leading cause of death across different socioeconomic groups.

With the introduction of the COVID-19 vaccine in 2021, rates are expected to decrease the next time the Global Burden of Disease study is conducted.

Risk factors and prevention

Risk factors for death from COVID-19 infection include:

  • older age
  • diabetes
  • asthma
  • cerebrovascular and cardiovascular disease
  • cancer, chronic lung, liver, or kidney diseases
  • diabetes
  • neurological conditions like dementia
  • mental health conditions like schizophrenia
  • pregnancy and recent pregnancy
  • inactivity
  • smoking
  • immunocompromised status
  • tuberculosis

Getting the COVID-19 vaccine can reduce the risk of severe disease and death from COVID-19.

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.

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 older survey found that 93% of people knew sudden numbness on one side was a stroke symptom. However, only 38% knew all the symptoms that would prompt them to seek 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

You can lower some stroke risk factors 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 alcohol only in moderation or not at all, as these activities increase your risk of stroke.

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 2022, about 11.7 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.

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 bloody sputum, or mucus. You may also have:

  • fever
  • sweating
  • chills
  • breathlessness
  • wheezing
  • 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 reduce bacteria, especially before touching your face or eating.

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

Respiratory cancers include trachea, larynx, bronchus, and lung cancer.

The main causes are:

  • smoking
  • secondhand smoke
  • environmental toxins

However, household pollutants, such as fuels and mold, also contribute.

Impact of respiratory cancers around the world

The American Cancer Society estimates 226,650 new cases of lung cancer to be diagnosed in the United States in 2025.

An older 2015 study reports that there are around 18 million new cases of lung cancer annually worldwide. 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.

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

Alzheimer’s disease is a neurodegenerative disease that destroys memory, interferes with decision making, and interrupts 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.

Early symptoms include:

  • mild memory problems
  • difficulty recalling information
  • slips in recollection

Over time, however, the disease progresses, and people may not remember large periods of time and require assistance to complete daily tasks.

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.

Eating a nutritious diet may help lower one’s risk of the disease. Research suggests that eating plenty of fruits, vegetables, whole grains, heart-healthy fats, and legumes may support brain function and prevent cognitive decline.

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. Experts believe this type of diabetes results from an autoimmune reaction in which the immune damages insulin-producing cells.

In type 2 diabetes, the pancreas doesn’t produce enough insulin or insulin can’t be used effectively. They may become less sensitive to insulin over time.

Impact of diabetes around the world

Over time, unmanaged diabetes can cause damage to the nerves and blood vessels. This can lead to complications such as:

  • impaired wound healing
  • kidney failure
  • 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:

  • family history of type 2 diabetes
  • being overweight or having obesity
  • having non-alcoholic fatty liver disease (NAFLD)
  • not getting enough regular physical activity
  • high blood pressure
  • older age

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 manage your blood sugar levels.

Kidney diseases include chronic and acute kidney disease. Chronic kidney disease (CKD) develops over time while acute kidney disease develops suddenly, usually from an infection.

Other health conditions, including diabetes, can contribute to kidney disease.

CKD refers to progressive and irreversible damage to the kidneys that develops gradually. It usually doesn’t cause symptoms until the later stages, so many people with it may be unaware they have CKD.

Impact of kidney diseases around the world

Most cases of CKD worldwide are in low- to middle-income countries where people may not have access to treatment.

Experts predict that cases and deaths due to kidney disease will continue to rise through 2040.

Risk factors and prevention

Risk factors for developing CKD include underlying health conditions such as:

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 16 times more likely to develop active TB.

Impact of TB around the world

The cases of TB have fallen by 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.

In the United States, a disease is considered rare if it is affects fewer than 200,000 Americans.

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

It’s believed that around 1 in 10 people in the United States, or around 30 million people in total, have 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.

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

This also includes conditions such as some types of cancer, Alzheimer’s disease, multiple sclerosis, and COPD.

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

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.

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 (or stopping) alcohol intake and quitting smoking, if applicable, can also help.

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