What is asthma?
Asthma is a chronic lung disease that can make it hard to breathe. During an asthma attack, the airways of the lungs become inflamed and narrowed. This results in wheezing, coughing, chest tightness and shortness of breath.
Asthma can affect people of all ages. However, it often starts in childhood and is the most common chronic disease in children.
In 2021, around 14.6% of adults and 6.5% of children in the United States reported having asthma. In Massachusetts,16.6% of adults and 9.7% children reported having asthma that same year. You can use the display to review asthma hospitalization or ED rates for any city or town in Massachusetts. For data and information on childhood asthma, see the MA EPHT - Pediatric Asthma page.
Episodes of asthma (often called asthma attacks) can be triggered by common things in the environment like dust, mold, pollen, tobacco smoke, air pollution, and strong smells from chemicals (such as cleaning products). Asthma symptoms can also be triggered by exercise, colds, and other respiratory infections.
Preventing or reducing exposures to these risk factors is possible. Doing so can help prevent asthma from developing or worsening. Prevention starts in the places we live, work, learn and play.
While there is no cure, asthma can be controlled. Individuals with asthma can lead an active and healthy life.
What are risk factors for developing asthma?
It isn’t clear why some people get asthma, while others do not. However, new evidence is emerging on what causes the disease and how it can be prevented. Researchers have learned that many factors in a person’s environment, in combination with their genes (hereditary conditions) can cause asthma.
Learn more in the sections below. Additional information on risk factors for asthma and asthma triggers is available at the risk factors for asthma and asthma and your environment webpages.
Health
The primary risk factor for developing asthma is genetics and family history. According to the American Lung Association (ALA), a person who has a parent with asthma is 3 to 6 times more likely to develop the condition than someone who does not have a parent with asthma.
Other health factors that may increase risk include allergies, such as atopic dermatitis (eczema) and allergic rhinitis (hay fever). Some people who experience viral respiratory infections during infancy and childhood go on to develop chronic asthma. Some co-existing health conditions like obesity may also increase risk. Research shows that hormones may also play a role.
Environment
Both short and long-term exposure to outdoor air pollution is a risk factor for developing asthma. In particular, exposures to particulate matter and ozone can cause asthma. The Massachusetts Department of Environmental Protection (MassDEP) provides a map of the Air Quality Index (AQI) which tells how clean or polluted your air is, and what associated health effects might be a concern for you. Browse air quality data that is monitored at various AQI sites throughout Massachusetts at the MassDEP MassAir Online webpage. Historic particulate matter and ozone data are also available on the MA EPHT outdoor air quality page.
Work-related exposure
It is estimated that 10 to 25% of adult asthma is caused by workplace exposures. This is known as occupational asthma. Some workplace irritants that may lead to asthma include:
- Formaldehyde
- Epoxy
- Isocyanates and other chemicals
- Diesel exhaust, gases, vapors, and fumes
- Dust (industrial or wood)
- Mold
To protect yourself from workplace exposure, be sure to read any safety data sheets, which outline proper handling and storage procedures as well as potential hazards and emergency measures. When appropriate, be sure to wear personal protective equipment (PPE).
Learn more about occupational asthma on the work-related asthma page.
Social determinants of health (SDOH)
Our health is impacted by social determinants of health (SDoH). These are the social, economic, and physical factors where we work, live and play.
Significant inequities in asthma outcomes continue to exist within Massachusetts. Certain groups of people are more likely to develop asthma, including people of color, those identifying as LGBTQIA+, and those experiencing low income. These groups are also more likely to experience worse outcomes due to their asthma. For example, age-adjusted rates of asthma-related ED visits and hospitalizations during 2002-2022 were consistently 2 to 3 times higher for Black, non- Hispanic and Hispanic residents than those of White non-Hispanic residents.
Throughout U.S. history, programs and policies have negatively impacted these groups. For example, zoning laws, housing covenants, and redlining restricted access to housing. Often, these groups live in lower quality housing and in areas with higher pollution due to the lack of safe, affordable housing. People living in these conditions are more likely to have asthma and difficulty managing their asthma. Those identifying as LGBTQIA+ and people of color may also be more likely to face medical discrimination. These groups may also have difficulty accessing inclusive healthcare.
What are some common asthma triggers?
Exposure to outdoor air pollution not only increases the risk of developing asthma as discussed above but also makes asthma symptoms worse. The outdoor air pollutants most linked to asthma attacks are are particulate matter and ozone. Additional outdoor asthma triggers may include wildfire smoke, pollen, and cold, dry air.
The indoor environment is also a source of asthma triggers. Examples of indoor triggers include tobacco smoke (including second-hand smoke), mold, pets, dust mites, pests (like insects, rodents, and other animals), and strong odors or sprays from cleaning or personal care products. Learn about indoor air pollutants and ways to improve building conditions by visiting the MA EPHT indoor air quality page.
Respiratory illness (COVID-19, influenza, and RSV) can also influence the presentation and severity of asthma.
Lastly, changes in the climate will also contribute to increased risks for asthma. Extreme heat events can significantly worsen childhood asthma. These events are associated with increased hospitalization for asthma attacks. Extreme heat events are projected to become more frequent. Similarly, we can expect increased frequency and severity of flooding and extreme weather events. These events can lead to more moisture and mold, both of which can exacerbate asthma.
How can you manage asthma?
Although there is no cure, people with asthma can live healthy, active lives. Well-managed asthma, including a safe and healthy environment, can help reduce and prevent asthma symptoms.
Asthma requires attention, even when you feel well. If you have asthma, talk with your healthcare provider to learn how to care for your asthma. Ask your doctor to fill out an Asthma Action Plan. Using prescribed medications and avoiding asthma triggers are part of an Asthma Action Plan. You can also try to reduce your exposure to environmental triggers, such as indoor and outdoor air pollutants.
The American Lung Association has information on asthma causes and triggers, as well as ways to manage asthma.
Why does MA EPHT track asthma?
MA EPHT provides asthma hospitalization admissions and emergency department (ED) visit rates for adults and children. Tracking hospitalization and ED visits can help us understand uncontrolled asthma conditions, limited access to health care services, and inadequate medical treatment practices.
This data can be used to identify patterns or trends in asthma outcomes. Additionally, we can identify communities and populations that may have barriers to medical care. Knowing this information allows us to monitor the burden of asthma. We can also find how asthma affects health-related quality of life. This information can guide disease prevention and intervention programs.
Childhood asthma emergency department visits is one of four Vulnerable Health Environmental Justice criteria included in the Massachusetts Environmental Justice Policy.
Available data
Use the Explore asthma hospitalization data link on this page to access the following measures:
- Annual number of hospitalizations / ED visits
- Annual crude rate per 100,000 population
- Annual age-adjusted rate per 100,000 population
- Explore data in tables, charts, and maps
MA EPHT presents case counts and crude rates on asthma emergency department and hospital admissions for the following geographies: city/town, county, EP region, EOHHS region, and statewide. Measures are offered by a combination of year, age group, and sex. The most current data is shown. Be sure to check the site periodically as new data is added. To protect privacy, no information is shown that could potentially identify an individual.
Related links
Additional resources
Massachusetts
- DPH Bureau of Climate and Environmental Health - Asthma and your environment: Information, data and resources on how environmental factors can affect asthma
- DPH Bureau of Community Health and Prevention - Asthma Prevention and Control Program: Information on key activities and initiatives to reduce the burden of asthma across the Commonwealth
- DPH Bureau of Community Health and Prevention - Work-related asthma: Information from the Occupational Health Surveillance Program on work-related asthma and intervention efforts
- DPH Massachusetts Essential School Health Services Program: Ongoing school health service systems development and technical assistance to the Commonwealth’s 351 public school districts
- DPH Statistics about asthma: General information on statewide asthma statistics
- DPH Risk factors for asthma: An informational page about asthma, its triggers and its causes
National
- Allergy and Asthma Network: Information about asthma, including symptoms, triggers, and using an asthma action plan
- American Academy of Allergy, Asthma, and Immunology: Information and resources for the public and health care providers about asthma and allergies
- American College of Allergy, Asthma, and Immunology: Information about asthma for health care providers and patients, including resources to find an allergist
- American Lung Association: Information about asthma for patients, caregivers, and health professionals
- Asthma and Allergy Foundation of America, New England Chapter: Asthma services in New England
- CDC National Environmental Public Health Tracking for asthma: View asthma data on the CDC’s National Environmental Public Health Tracking website
- CDC - About asthma: Information about asthma, including resources for health care providers such as a checklist for home visitors to find common asthma triggers
- EPA - Asthma: EPA's coordinated approach on asthma promotes scientific understanding of environmental asthma triggers and ways to manage asthma in community settings through research, education, and outreach
- Department of Housing and Urban Development (HUD): HUD’s main goal is to ensure everyone in the United States can live in an affordable, safe, and healthy home
- National Heart, Lung, and Blood Institute: Fact sheets and handouts about asthma as well as information on how to participate in a clinical trial or study
- Asthma Regional Council of New England: Information on asthma initiatives in New England