We analyzed data from the 2006, 2008, and 2010 BRFSS, a state-based random-digit–dialed survey of the noninstitutionalized US population aged 18 years or older. In 2006, 38 states and the District of Columbia, in 2008, 16 states, and in 2010, 20 states used an optional module on anxiety and depression, which included the 8-question Patient Health Questionnaire (PHQ-8) screener for depression, adapted from the 9-item PHQ-9 (9
), which has a sensitivity of 73% and specificity of 94% for major depression (12
). The PHQ-8 omits 1 question on suicidal ideation because interviewers are unable to intervene. We limited all analyses for this report to nonpregnant women of reproductive age (18-44 y) because associations may differ by pregnancy status and BRFSS surveyed too few pregnant women to provide reliable estimates for this group. For 2006, 2008, and 2010, the median state cooperation rates (percentage contacted who completed an interview) were 75% to 76% and the median response rates (percentage eligible for whom an interview was completed) were 51% to 55%. BRFSS has Centers for Disease Control and Prevention institutional review board approval.
We categorized women into 1 of 4 levels of depression status (current major depression, current minor depression, past diagnosis of depression, and no depression) on the basis of their responses to the PHQ-8 screener and 1 additional question assessing whether the woman had ever received a clinical diagnosis of depression. We defined major and minor depression on the basis of responses to the PHQ-8 assessing number of days experiencing anxiety or depression over the last 2 weeks: 1) had little interest or pleasure in doing things; 2) felt down, depressed, or hopeless; 3) had trouble falling asleep; 4) felt tired or had little energy; 5) had a poor appetite or ate too much; 6) felt bad about yourself or that you were a failure; 7) had trouble concentrating on things; and 8) moved or spoke so slowly that other people could have noticed, or the opposite — were so fidgety or restless that you were moving around a lot more than usual. Similar to PHQ-9 methodology (9
), we coded major depression as reporting at least 7 days of having little interest or pleasure in doing things or feeling down, depressed, or hopeless and reporting at least 7 days to at least 5 questions total. We coded current minor depression as reporting at least 7 days of having little interest or pleasure in doing things or feeling down, depressed, or hopeless and reporting at least 7 days to 2 to 4 questions total. We further classified the remaining women who did not screen positive for current depression into 2 groups: those with a self-reported previous clinical diagnosis of depression, as an indicator of history of depression, and those with no depression.
Chronic disease conditions and modifiable risk factors inquired of in 2006, 2008, and 2010 included self-reported clinician diagnosis of diabetes or prediabetes, current smoking, binge drinking (>4 drinks at any 1 time) or heavy drinking (>1 drink/d in the past 30 days), overweight (body mass index [BMI] 25.0-29.9 kg/m2) or obesity (BMI ≥30.0 kg/m2), and physical inactivity (no physical activity in past 30 days aside from regular job).
Initially, we examined differential distribution of demographic characteristics by depression status using χ2 tests. Next, we assessed unadjusted associations between depression and 1) diabetes and prediabetes and 2) risk factors for chronic diseases. We also examined the distribution of number of chronic disease conditions and risk factors (0, 1, 2, or ≥3) by depression status using a χ2 test. To assess overall odds of 1 or more chronic conditions, in a multivariable multinomial logistic regression model, we calculated the odds ratios (ORs) for 1, 2, and 3 or more chronic conditions and risk factors, compared with 0, among depressed women and those with a past diagnosis of depression compared to women with no depression, adjusted for demographic characteristics. We included demographic characteristics in the multivariable model that, in univariate analyses among all women, were associated with depression status and, in univariate analyses among nondepressed women, were associated with number of chronic conditions and risk factors.
BRFSS surveyed a total of 75,450 women in the states that included the Depression and Anxiety optional module in 2006 (n = 42,444), 2008 (n = 16,261), and 2010 (n = 16,745 women). A total of 69,043 nonpregnant women aged 18 to 44 (91.5%) had information on depression and were included in this report. Of those, 4,895 (7.1%) women did not have information on 1 or more chronic conditions or risk factors, and 5,545 (8.0%) women did not have information on 1 or more demographic characteristics, 93% of whom were missing data on income. Therefore, the regression model included 58,603 (84.9%) women with information on depression status and who were not missing chronic disease or demographic information. We conducted all analyses in SUDAAN (RTI International, Research Triangle Park, North Carolina) to account for the complex sampling design and used weights to produce unbiased prevalence and adjusted odds ratio (AOR) estimates and 95% confidence intervals (CIs).