About Adult Self-Reported Lifetime and Current Asthma Prevalence
Behavioral Risk Factor Surveillance System (BRFSS) - 2008
In 2008, the BRFSS survey was conducted in all 50 states, the District of Colombia and in three US territories (Guam, Puerto Rico and the Virgin Islands). In each area where interviews are conducted, respondents are randomly selected from noninstitutionalized civilian adults (18 years of age or older) living in households with a telephone. Asthma prevalence data are produced from the responses to two asthma questions on the year 2008 BRFSS Core Questionnaire.
Lifetime asthma: Question number 9.1
Have you ever been told by a doctor, nurse, or other health professional that you had asthma?
Current asthma: Question number 9.2
If the response to 9.1 was Yes, then question 9.2 was asked: Do you still have asthma?
BRFSS Survey Analyses
The BRFSS 2008 survey data file was used to analyze lifetime and current asthma prevalence by selected sociodemographic groups. Prevalence and standard error estimates were calculated using SUDAAN Release 10.0.0 (Research Triangle Institute, P.O. Box 12194, Research Triangle Park, NC 27709).
Number of people affected was estimated by multiplying the prevalence rate against the US or New York State population in that particular subgroup.
The 95% Confidence Intervals(CI) were calculated using the following formula:
- Lower 95% Confidence Interval = % prevalence – t(sep)
- Upper 95% Confidence Interval = % prevalence + t(sep)
Where sep is the standard error of the prevalence percent and t equals the z distribution value of 1.96 for state level prevalence in the Table titled "Overall Adult Asthma Prevalence in The US and New York State - 2008 BRFSS ". For other tables with smaller sample sizes due to the use of demographic subcategories, the exact value from the t distribution appropriate to the sample size for the percent prevalence was used instead of the approximate z-value of 1.96. Because of the use of the more exact t-value, 95% Confidence Intervals in the tables may differ slightly from those presented in other representations of these data.
Subgroup tables are based on data analyzed by the following variables:
- Gender: Male and Female
- Age Group: 18-24, 25-34, 35-44, 45-54, 55-64, and 65+
- Race: White, Black, Other, and Multi Race
- Race/Ethnicity:White NH(non-Hispanic), Black NH, Other NH, Multirace NH, and Hispanic
- Education: HS Nongrad(High School non-Graduate), HS Grad, Some Coll(College), and Coll Grad
- Income: $0-$14,999, $15,000-$24,999, $25,000-$49,999, $50,000-$74,999, and $75,000+
Note: The asthma prevalence data presented were extracted from the The Centers for Disease Control and Prevention (CDC) Asthma Data: Prevalence Tables and Maps website. For more technical information, please visit 2008 Asthma BRFSS Technical Information, CDC website.