Morbidity vs. Mortality: What's the Difference?

The two sound similar but have different meanings

Morbidity and mortality are two similar terms that mean different things. Morbidity refers to an illness or disease. Mortality refers to death. Both terms are often used in statistics about health, such as the incidence or rate with which diseases and death occur.

This article explains the difference between morbidity and mortality. It also takes a look at ways to prevent morbidities and protect your health.

Most Common Morbidities

Verywell / Hugo Lin

What Is Morbidity?

Morbidity is any condition that isn't healthy. It can refer to mental or physical illness.

Morbidity often refers to chronic (long-term) and age-related diseases. These conditions can worsen over time and lower your quality of life.

A person with a morbidiity may not live as long as someone who is healthy. However, morbidity doesn't always mean you are in danger of dying right away. However, if an illness gets worse over time, it could raise your risk of mortality.

What Is Mortality?

When an epidemiologist uses the term mortality, it usually means the number of deaths caused by an event or illness over a specific period of time. Health insurance providers use these statistics too, as well as industry experts who assess the impact of access to insurance and health services.

Researchers often talk about "mortality rates." A mortality rate states the number of deaths as a proportion of a larger group of people. For example, an illness might cause "150 deaths per 100,000 people per year."

What Is Co-Morbidity?

Co-morbidity means that a person has more than one illness. Co-morbid conditions don't always have the same cause, but they may occur together and worsen each other. For example, high cholesterol, depression, and diabetes are often co-morbid.

Morbidity and mortality aren't the same thing. Morbidity is an illness or loss of function in your body or mind. Mortality means death. Someone can have several morbidities at the same time called co-morbidities. Morbidities don't necessarily cause death.

Most Common Causes of Death

Around 75% of deaths in the U.S. in 2019 were caused by:

Seven of the 10 leading causes of death are chronic or long-term diseases. These morbidities raise your risk of mortality.

The number of people with chronic or long-term diseases has been steadily increasing over the past few decades. For example, the percentage of people with diabetes, cancer, and stroke is increasing; however, heart disease rates are coming down.

In recent years, though, there has also been an uptick in infectious diseases further driving up morbidity numbers. Examples of these infectious diseases are SARS, MERS, flu variants, Ebola, Zika virus, and now COVID-19. Food-borne illness, food-related infections, and sexually transmitted diseases are also raising morbidity rates in America.

When an event or a disease causes more deaths than expected, it's called "excess mortality." COVID-19 is a good example of an illness causing excess mortality. In some hard-hit countries, data shows that COVID-19 caused 50% more deaths than were expected in a specific period of time. In the U.S., there was a 19% increase in mortality between 2019 and 2020.

Researchers also say COVID-19 was the leading cause of a drop in life expectancy in the U.S. during 2020, especially among men, aging populations, and certain ethnic/racial groups starting with American Indian/Alaska Native people, followed by non-Hispanic White and Black people, respectively.

Preventing Morbidities

Morbidity rates may come down if more people have early health screenings. Early diagnosis can lead to a better quality of life. Early treatment may mean people recover faster.

If people are diagnosed and treated early, they may have fewer complications. Their risk of dying from an illness may also decrease.

Morbidity also drops when people are educated and have access to good care. For example, one way to lower morbidity for pregnant women is to provide access to family planning education. Safe abortions, prenatal care during pregnancy, and postpartum care after delivery also help.

Most deaths in America are caused by a handful of long-term diseases. If people learn about these conditions, they may be able to prevent them. Early health screenings can also keep people healthier.


Morbidity and mortality don't mean the same thing. Morbidity refers to any condition that isn't healthy. Mortality refers to death.

You can have more than one morbidity, and they may not raise your risk of mortality unless they worsen over time. You can prevent some morbidities by learning healthy habits and having regular health screenings.

A Word From Verywell

People are living longer. To make sure they stay healthy longer, it's important to improve health education and access to preventive care. When people have good health information and regular check-ups, they can build healthy habits before any signs of disease show up.

Frequently Asked Questions

  • What is a mortality rate?

    A mortality rate records the number of deaths in proportion to a group of people. For example, in 2019, the total number of deaths in the U.S. was 2,854,838, which means the death rate was 869.7 deaths per 100,000 people.

  • Which disease has the highest mortality rate?

    Heart disease has the highest mortality rate in the U.S. In 2019, it was responsible for one in every four deaths, with a total of 659,000 deaths.

  • What does morbidity mean?

    Morbidity is used to define any physical or mental condition that is considered unhealthy. It is often used in reference to long-term (chronic) or age-related diseases. A few common morbidities include heart disease, Alzheimer's disease, and cancer.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Sharon Basaraba
Sharon Basaraba is an award-winning reporter and senior scientific communications advisor for Alberta Health Services in Alberta, Canada.