The Behavioral Risk Factor Surveillance System (BRFSS) is a federally funded randomized telephone survey of Iowa residents ages 18 and older. The questions collect data related to a variety of health behaviors, conditions, and preventative health practices. All 50 states, the District of Columbia and three U.S. territories conduct the survey in partnership with the Centers for Disease Control and Prevention (CDC). The Iowa BRFSS is an important tool for data-driven decision making in the public health community.
In 1981, the CDC began assisting states in conducting risk factor surveys. One year later, a point-in-time survey was first conducted in Iowa. In 1988, Iowa began fully participating in CDC's Behavioral Risk Factor Surveillance System.
Each year, the CDC provides states with a standard questionnaire, and states can choose to tailor their surveys by adding in optional question modules or additional state-added content. The CDC also provides technical assistance and a detailed survey protocol so that standardized data comparisons can be made across the nation.
The Iowa BRFSS asks questions about different health behaviors to adults aged 18 and older using telephone interviews. Each month a random sample of telephone numbers are contacted to participate in the survey over the phone. Questions in the survey cover many topics, including nutrition, physical activity, tobacco use, hypertension, blood cholesterol, alcohol use, and access to health care.
Iowa BRFSS survey data is used to design, implement, and support public health activities with the goal of reducing chronic diseases and other leading causes of death for Iowans. The survey is conducted every year, which allows for health trends to be compared over time.
BRFSS data is also used to measure the progress made towards the state’s Healthy Iowans: Health Improvement Plan and the national Healthy People 2030 Objectives. These plans aim to improve the health of Iowa and the nation.
Older reports and publications can be found on the Iowa Publications site.
- 2023 Iowa BRFSS Questionnaire (Please note: the 2023 survey is currently being fielded and subject to change)
Select BRFSS data, organized by each of the 99 Iowa counties, is provided below. State rates and rates grouped by the state's six regional community health consultant region assignments are also provided for comparison.
Topics include: alcohol consumption, tobacco use, gambling, chronic health indicators, disability status, depression, physical activity, overweight/obesity, immunization, health status, days of poor health and healthcare access/coverage.
Please note: Iowa BRFSS county data is grouped together by 4-year time increments. Combining multiple years increases the sample size per county (and region) for the reported prevalence rates. Having a larger sample size increases the reliability of the data, allowing for better estimation. Smaller counties may not contain enough data to report reliable estimates, even with the combination of 4 consecutive years. In this case, regional prevalence rates may be of particular use, at a sub-state level. In the files provided, the bolded estimates represent weighted data, which means that these estimates are representative of the state, region or county. The non-bolded estimates represent only the responses of the BRFSS respondents in the aggregate years specified for counties.
- BRFSS Data by County (2021)
- BRFSS Data by County (2020)
- BRFSS Data by County (2018-2021)
- BRFSS Data by County (2017-2020)
If you would like to request additional Iowa BRFSS data, please fill out this BRFSS data request form
The BRFSS questionnaire three sections:
- Core Component: The fixed core contains standard questions that are asked by every state each year. There is also a rotating core, which consists of questions that are collected every other year by every state. In off years, the rotating core questions are offered as optional modules.
- Optional Modules: Each year, the CDC offers a selection of standardized optional modules that states can elect to add to their questionnaire. Data processing for optional modules is completed by the CDC. The CDC requires that, if the modules are used, they must be used in their entirety without any modification. If optional modules are altered, they are considered state-added questions (see below).
- State-Added Questions: These are questions of special interest to the state that are not offered as optional modules. The CDC does not complete any of the data processing necessary for analysis of state added questions. Additionally, state-added questions are not necessarily comparable to other states. However, state-added questions allow states the flexibility to address their unique health issues.
Sometimes, there is an emerging core. It is a small group of questions that are added to the core section. These are usually time-sensitive, topical questions. An example of an emerging core question would be one to collect information on a nationwide outbreak.
Each summer, the BRFSS Coordinator contacts Iowa Department of Health and Human Services (Iowa HHS) program managers and external organization partners to invite them to request questions that benefit program efforts to be included in the survey for the following year. Requested questions can include optional CDC modules or state-added questions which are developed by programs to address data needs that may not be addressed through CDC core questions or optional modules. The Iowa BRFSS program understands the importance of the inclusion of program-specific questions in the survey, however, available space to include state-added questions is limited.
Once requests for all state-added questions/modules for an upcoming survey year are collected, the Iowa HHS BRFSS Advisory Committee reviews the requests and selects questions determined by Iowa HHS priorities. The committee considers factors such as how well the questions will work in a telephone survey, how recently the questions have been asked in past surveys, how the program plans to use the collected data, and how the questions align with the Department’s strategic plan and Iowa’s top health issues. The committee’s recommendations are ultimately approved by the Iowa HHS Chief of Strategic Operations.
The BRFSS is a telephone-based survey. The BRFSS collects data from adults aged 18 years or older. Households are randomly selected from blocks of potential phone numbers in an area (including unlisted numbers). One adult in the household is randomly selected to be interviewed. Participants are chosen at random to ensure that the collected data is generalizable to other residents in our state.
Once responses are compiled, the CDC analyzes the demographic characteristics of the sample and assigns weights to each of the responses to ensure estimates are reflective of the known population. This weighting allows us to generalize the results of the BRFSS survey to the population as a whole. Because some groups are harder to reach than others, the CDC also weights to compensate for non-selection or non-response bias. In other words, the CDC adjusts for over-representation or under-representation of certain groups in the sample.
The BRFSS is used to generate prevalence estimates, which are estimates of the true incidence of a particular phenomenon for the population the sample is supposed to represent. Like data compiled from any survey, there are certain limitations associated with the BRFSS data and various ways that error can be introduced into the data.
The reliability of the estimate is directly related to the number of actual unweighted responses for each category or subgroup. If the number of collected responses is small, the estimate may be misleading. Measurement error can occur if a question is not understood by a respondent or if an interviewer states the question in a way that alters the understanding of the question. Non-response bias is always present in any survey. It is impossible to know whether those who refused to participate in the survey would have answered the questions similarly to those who did. Some examples of response error are when a person does not answer a question accurately because they cannot recall the right information or the data collector codes the response incorrectly. Social desirability is a phenomenon where a respondent alters their answer to present a favorable impression to the interviewer or to avoid association with socially stigmatized behaviors.
Additional Iowa BRFSS Information
- Explore Iowa BRFSS data related to general health status, diabetes, substance use, tobacco, and obesity through the Iowa Public Health Tracking Portal
- Visit the BRFSS Methodology section to learn more about questionnaire development, sampling, and weighting information
- Review the Iowa BRFSS Frequently Asked Questions tab for answers to common questions about the program
- Need to request additional Iowa BRFSS data? Please fill out this BRFSS data request form
National BRFSS Information
- Learn more about the national BRFSS program from the CDC BRFSS webpage
- National BRFSS and states data, organized by year and by topic, can be found through the CDC BRFSS Prevalence Data & Data Analysis Tools webpage
- The CDC BRFSS survey data and documentation webpage contains information about survey methodology, weighting of BRFSS data, and downloading of data