Asthma Metadata: Prevalence


Asthma prevalence data are from the Maine CDC’s Office of Data, Research, and Vital Statistics (ODRVS).

Dates Available:


Geographic Resolution:

State, Public Health District, County


This data set contains information on the percent of adults in Maine with current or lifetime asthma. Data are stratified by geographic location, age, sex, education, and household income. Asthma prevalence data are derived from the Behavior Risk Factor Surveillance System (BRFSS).

The dataset contains the following measures:

  1. Percentage of adults with current asthma
  2. Weighted number of adults with current asthma
  3. Percentage of adults with lifetime asthma
  4. Weighted number of adults with lifetime asthma


This data set supports efforts to improve public health in Maine and contributes to the U.S. CDC’s National Environmental Public Health Tracking (EPHT) Network. A key activity of participants in this network is to track and make available environmental health measures on state and national data portals. Measures derived from the data set described here can be used to compare Asthma prevalence across the state, over time, and in relation to risk factors, exposures, and health outcomes.

The Maine Tracking Network, a member of the National EPHT Network, connects communities, public health professionals, policy makers, state agencies, and others to the data they need to monitor public health, respond to health concerns, prioritize resources for public health action, and evaluate prevention activities. Maine tracks certain health effects, exposures, and environmental hazards that have known relationships, as well as some health effects and environmental hazards that have suspected relationships. By making health and environmental data available through the Maine Tracking Network, more people have access to data they need to think critically and hypothesize about health outcomes and their relationships to conditions in the environment.

Supplemental Information:

Asthma is a chronic disease that affects the lungs and airways. Asthma causes wheezing, breathlessness, chest tightness and coughing at night or early in the morning. There is no cure for asthma but it can be controlled with medication and by avoiding breathing in substances that irritate the lungs.

The BRFSS collects state specific data on health issues via a telephone survey.  Over 8,000 non-institutionalized adults in Maine, 18 years of age or older, participate in the survey each year.  Asthma prevalence questions were first included in the survey in 1999 and are asked annually.

Statistical weighting is an analytical technique used to account for survey non-response, in addition to known distributions of age, race and ethnicity, gender geographic region, and other characteristics of populations. From 1984 to 2010, the BRFSS used a technique called post-stratification to weight BRFSS survey data. In 2011, a new statistical method called raking replaced the older method because it could help record additional population characteristics such as education level, marital status, and home ownership status of respondents. The new method also allows survey organizers to account for the type of telephone respondents used while completing the survey.  Due to these changes in weighting methodology, researchers are advised to avoid comparing data collected and weighted to the individual before the changes (up to 2010) with data collected from 2011 and afterward.

Entity and Attribute Overview:

This dataset includes the following fields: weighted number and percent (with accompanying 95% CI’s) of adults with current asthma, weighted number and percent (with accompanying 95% CI’s) of adults with lifetime asthma, survey year, geographic resolution, age group, sex, and household income.

Data Limitations:

  • Maine adults who are institutionalized, do not have a phone, or cannot communicate over the phone are not interviewed by the survey.
  • Data are based upon self-report, and individuals may or may not be able to report accurately that they have been diagnosed with asthma or currently have asthma. Individuals with mild asthma or with low health care access may not have been diagnosed with asthma by a health care professional.
  • While the prevalence data are statistically weighted to be more representative of the general adult population of Maine and to adjust for non-response, statistical weighting methods are not always perfect in accomplishing this.

Access Constraints:

Publicly available data are suppressed in accordance with the Maine CDC Privacy Policy to protect confidentiality.

More Information:

  • To find more general information on this topic, see the Asthma page of the Maine Tracking Network messaging portal.
  • To find more detailed information about the data source, see the BRFSS metadata.
  • For specific definitions of terms and concepts see the Glossary.
  • For more information on BRFSS, see the BRFSS website.
  • To view data for other states and cities, visit the National Environmental Public Health Tracking Data Portal.

Suggested Citation for Data Displays:

Maine Center for Disease Control and Prevention, Maine Tracking Network. Asthma: Prevalence.  Available online:  Accessed on [date accessed].