We performed a cross-sectional analysis using data from the Behavioral Risk Factor Surveillance System (BRFSS), a state-based, random-digit–dialed telephone survey of the US noninstitutionalized, civilian population aged 18 years or older. In particular, we analyzed self-reported data from 341,989 women of reproductive age (18-44 y), who participated in the 2001, 2003, 2005, 2007, and 2009 BRFSS surveys and lived in 1 of the 50 states or the District of Columbia. Data from odd years were selected for this analysis because questions related to risk factors and chronic conditions are asked only in odd years. The Council of American Survey Research Organizations (CASRO) response rate reflects both telephone sampling efficiency and the degree of participation among eligible respondents contacted (
18). In 2009, the median CASRO rate was 53% and ranged from 38% to 67%. The median CASRO rates were 51%, 53%, 51%, and 51% in 2001, 2003, 2005, and 2007, respectively, with similar ranges. The cooperation rate reflects the proportion who completed an interview among eligible people contacted. The median cooperation rate for BRFSS in 2009 was 75% and ranged from 55% to 88%. The median cooperation rates were 71%, 75%, 75%, and 72% in 2001, 2003, 2005, and 2007, respectively. Relative to other surveys, data from BRFSS have acceptable reliability and validity for several chronic disease risk factors and conditions (
19,
20). Detailed information on the sampling methodology, survey weighting procedures, quality assurance of the survey, and other aspects of this survey is available online (
www.cdc.gov/brfss/index.htm).
Outcomes
We examined 4 risk factors (smoking, physical inactivity, heavy drinking, and obesity) and 4 chronic conditions (chronic high blood pressure, high cholesterol, chronic diabetes, and asthma) among women of reproductive age. Smoking was defined by self-report of smoking at least 100 cigarettes in one's lifetime and still smoking at the time of the survey. Current physical inactivity was defined as a response of no to the question: "During the past month, other than your regular job, did you participate in any physical activities or exercises such as running, calisthenics, golf, gardening, or walking for exercise?" Heavy drinking was defined by self-reported daily alcohol consumption of more than 1 drink per day in the past 30 days. Obesity was defined as having a body mass index (BMI) of at least 30.0 kg/m2 based on self-reported weight and height. The chronic conditions (chronic high blood pressure, high cholesterol, chronic diabetes, and asthma) were considered present if the woman reported she had ever been told by a doctor or other health professional that she had the condition. For high blood pressure, we restricted the analysis from 2003 to 2009 because a substantially different question related to high blood pressure was asked in the 2001 survey. For all other measures, 2001 to 2009 was the period assessed.
Covariates
We categorized age into 3 groups (18-24, 25-34, and 35-44 y). Self-identified race/ethnicity included non-Hispanic white, non-Hispanic black, Hispanic (any race), Asian, American Indian or Alaska Native (AI/AN), or all others. The "all others" group represented just over 3% of the weighted population of women of reproductive age for each year, and analysis excluding them did not significantly change the conclusions. Therefore, they were maintained as their own group to increase sample size of the study. Education levels were based on highest grade or year of school completed and were categorized as not completing high school (<12 y), completing high school or its equivalent (12 y), some college course work, or college graduate or more. Access to health care was defined as having any health care coverage on the basis of the question "Do you have any kind of health care coverage, including health insurance, prepaid plans such as HMOs, or government plans such as Medicare?" Because of possible variation in risk factors or chronic conditions related to state of residence, a variable representing each state was included as a covariate in the analysis.
Exclusions
A total of 341,989 women of reproductive age were surveyed over these 5 periods. Exclusion criteria included women pregnant at the time of the survey (4.1%, n = 14,072). Pregnant women are likely to change their behaviors and report different risks, particularly smoking and alcohol intake during pregnancy, so we chose to exclude them from the analyses. This resulted in an overall sample size of 327,917. Women with missing information on any risk factor, chronic condition, or covariates were excluded from specific analyses. Missing information ranged from 0.05% for diabetes (n = 179) to 6.4% for obesity (n = 21,148).
Statistical analysis
Annual prevalence estimates and 95% confidence intervals (CIs) were calculated for each risk factor and chronic condition. Estimates were plotted over the 5 periods, except for high blood pressure, which was only measured for 4 periods. An approach using predicted marginals estimated prevalence ratios for each risk factor and chronic condition; survey year was the primary variable, following recommendations for complex national surveys (
21). We evaluated the overall trend for significance, accounting for differences in the individual covariates of age, race/ethnicity, education, health care coverage, and a variable representing each state. Data were weighted to reflect each state's non-institutionalized civilian population. SAS version 9.2 and SAS-callable SUDAAN version 10.0 (SAS Institute, Inc, Cary, North Carolina) were used to account for the complex sampling design in order to provide population estimates and calculate accurate variance estimates.
Amy Z. Fan, MD, PhD, Ruben A. Smith, PhD, MS, and Jennifer M. Bombard, MPH
This article has been corrected. See 