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Racial Disparities in Elevated Prenatal Depressive Symptoms Among Black and White Women in Eastern North Carolina
Racial Disparities in Elevated Prenatal Depressive Symptoms Among Black and White Women in Eastern North Carolina SUEZANNE T. ORR, PHD, DAN G. BLAZER, MD, PHD, AND SHERMAN A. JAMES, PHD
PURPOSE: Black women have an increased risk for preterm birth compared with white women, and prior research indicated that maternal prenatal depressive symptoms are associated with increased risk for preterm outcomes among black women. Race-related differences in prenatal depression could be of etiologic significance in understanding racial disparities in preterm birth. Our study focused on Center for Epidemiologic Studies’ Depression Scale (CES-D) scores of pregnant black and white women. METHODS: Women were administered the CES-D at the time of their first visit to hospital-based prenatal clinics. Two cutoff scores for the CES-D were used: 16 or higher, which indicates ‘‘significant’’ depressive symptoms, and 23 or higher, which indicates major depressive disorder. RESULTS: For the sample of 1163 women, mean CES-D scores were significantly higher among black (17.4) than white (13.7) women. Of black women, 49% had CES-D scores higher than 15 compared with 33.5% of white women. Also, 27.5% of black women had scores higher than 22 compared with 16% of white women. After adjustment for maternal age, marital status, and education, odds ratios for race for both CES-D cutoff scores were approximately 1.5. CONCLUSIONS: Results of this study indicate that black women have greater rates of prenatal depression than white women. Ann Epidemiol 2006;16:463–468. Ó 2006 Elsevier Inc. All rights reserved. KEY WORDS: Depression, Center for Epidemiologic Studies’ Depression Scale (CES-D), Racial Disparities, Pregnancy.
INTRODUCTION Prior research has clearly shown large black–white racial disparities in poor pregnancy outcomes (1, 2). Black women have approximately double the risk of white women for preterm (births at ! 37 weeks’ completed gestation) and low birth weight (births at 2500 g to <5.5 lb) outcomes. The increased risk for preterm and low birth weight births among black women contributes to the high rate of infant mortality (deaths in the first year of life) among blacks and the large excess risk for mortality among black compared with white infants (3). Racial disparities in harmful pregnancy outcomes have been relatively unchanged for decades and are very poorly
From the Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Greenville, NC (S.T.O.); Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC (D.G.B.); and Institute for Public Policy Studies, Duke University, Durham, NC (S.A.J.). Address correspondence to: Suezanne T. Orr, Ph.D., Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Christenbury 200, Greenville, NC 27858. Tel.: (252) 328-2526; fax: (252) 328-1285. E-mail: [email protected]. edu. Received April 20, 2005; accepted August 13, 2005. Ó 2006 Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010
understood. Racial disparities in poor pregnancy outcomes cannot be explained adequately by differences in established risk factors for preterm birth and low birth weight, such as maternal age, education, smoking, or medical factors (4, 5). Reductions in the racial disparity in deleterious pregnancy outcomes will require knowledge about additional factors that increase the risk of black women for these outcomes. Prior research suggests that elevated maternal prenatal depressive symptoms are associated with increased risk for poor pregnancy outcomes, including preterm birth, among black women (6, 7). However, prior research has not focused on racial disparities in risk for elevated prenatal depressive symptoms. Race-related differences in elevated prenatal depressive symptoms potentially could help explain the excess risk for preterm birth among black compared with white women. Overall, one in five women will experience an episode of major depressive disorder during her lifetime (8, 9), and depression has been termed a major public health problem (10) because of its high prevalence, especially in women. The usual age of onset of depression in women is during the childbearing years (11), and rates of depression and elevated depressive symptoms are very common in women of childbearing age (10, 11). Moreover, elevated depressive symptoms are very common in pregnant women, with as 1047-2797/06/$–see front matter doi:10.1016/j.annepidem.2005.08.004
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Orr et al. RACIAL DISPARITIES IN PRENATAL DEPRESSION
Selected Abbreviations and Acronyms CES-D Z Center for Epidemiologic Studies’ Depression Scale CI Z confidence interval
many as half the pregnant women attending prenatal clinics experiencing elevated levels of depressive symptoms (6, 7, 12). Despite the potential etiologic importance of depression and elevated depressive symptoms for preterm birth among black women, there are few studies of black–white racial disparities in depression or elevated depressive symptoms among pregnant women and women of childbearing ages. In addition, there is a lack of prior studies that control for covariates associated with risk for depression, such as socioeconomic status. In the research reported here, we examine racial differences in elevated symptoms of depression among pregnant black and white women seeking prenatal care. We assessed these differences, adjusting for education as a proxy for maternal socioeconomic status, and also for age and marital status. The overall objective of the research is to show the extent of racial disparities in elevated prenatal depressive symptoms, controlling for socioeconomic status and other variables associated with increased risk for depression.
METHODS Enrollment in this study occurred from March 2001 through December 2002. Women were enrolled in the research at the prenatal clinics of the Departments of Obstetrics and Gynecology and Family Medicine, Brody School of Medicine, East Carolina University, Greenville, NC. The clinics serve Greenville and surrounding Pitt County and other nearby counties. This geographic area has high rates of low birth weight, preterm birth, and infant mortality. A trained research assistant approached all women aged 16 years and older while they were waiting to be seen for their first prenatal visit and invited them to participate, and informed consent was obtained. Women who agreed to participate (>95%) were administered the study interview at that time. Most women seeking care at these clinics are enrolled for prenatal care by the end of the second trimester. Among the sample, slightly more than one half of the women (51.9%) enrolled for prenatal care during the first trimester of pregnancy, and an additional 36.6% enrolled during the second trimester. The study interview contained items to assess demographic factors (maternal race, age, education, and marital status), as well as depressive symptoms. Education was
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assessed as the highest grade in school completed and dichotomized as 12 years or fewer and more than 12 years. Age was dichotomized as younger than 20 years and 20 years or older. Marital status was assessed by using an item that allowed a woman to indicate if she was married and living with her husband; unmarried, but living with a male partner; or unmarried and living without a male partner (including single, separated, and divorced women). Responses were dichotomized as married and living with a partner/unmarried and living with a partner versus unmarried/living without a partner. Depressive symptoms were assessed by using the Center for Epidemiologic Studies’ Depression Scale (CES-D) (13). The CES-D contains 20 items and was developed by the National Institute of Mental Health in the 1970s to permit ascertainment of epidemiologic characteristics of depression in community samples (13). CES-D items assess the presence of salient symptoms of depression (e.g., sadness, hopelessness, fatigue, crying, low self-esteem, and changes in sleep or appetite) within the past 7 days. Scores on the instrument can range from zero to 60, with a customary cutoff score of 16 or higher used to identify those with ‘‘elevated’’ (clinically relevant) levels of depressive symptoms (13). The 16-or-higher cutoff score has been used in most prior research with the CES-D. In addition, Radloff and Locke (14) proposed a second cutoff value of 23 or higher, suggesting that this score can be used to indicate the presence of major depressive disorder (14). The CES-D has been shown to be a valid and reliable measure of depressive symptoms in diverse samples (15– 19) and has been used widely in epidemiologic research. CES-D scores decrease with treatment of depression and correlate well with diagnoses of major depressive disorder made by clinicians (13, 16). For analyses of prenatal CES-D scores for this research, both suggested cutoff scores were used to identify the group with elevated scores. The first cutoff value was the traditional cutoff score of 16 or higher (13). We also conducted analyses using the cutoff score of 23 or higher (14). A score of 23 or higher is thought to indicate the presence of major depressive disorder (14). This second cutoff score was especially useful for our purposes because CES-D scores can be inflated in pregnant women because of overlap of certain symptoms of depression with symptoms of pregnancy (e.g., appetite change and fatigue) (6). It is extremely unlikely that a woman could achieve a score of 23 or higher based solely on symptoms associated with pregnancy. Unadjusted associations between race and depressive symptoms were evaluated first by using bivariate tables, odds ratios, and 95% confidence intervals (CIs). Next, logistic regression models were used to obtain adjusted estimates of odds ratios and 95% CIs, controlling for potential confounding by demographic factors associated with depression,
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such as marital status and education. Beta coefficients from the models were used to estimate odds ratios.
RESULTS As listed in Table 1, of the enrolled sample of 1163 women, approximately 70% identified their race as black (N Z 811), and 30%, as white (N Z 352). Approximately 20% of women were younger than 20 years. Approximately 29% of women had more than a high school education. Two thirds of the women in the sample (67.8%) were enrolled in the Medicaid program for the pregnancy. The remaining women had either private health insurance (23.1%) or were uninsured (6%). Forty-four percent of women in the sample were married and living with a partner or not married and living with a partner. The remaining 56% were unmarried and not living with a partner. Approximately half the women enrolled for prenatal care during the first trimester of pregnancy. There were statistically significant differences between black and white women in the sample on several covariates of interest (Table 1). Black women (27.5%) were less likely than white women (33.8%) to have completed more than a high school education and more likely to be enrolled in
TABLE 1. Characteristics of the sample by race Full sample Black women White women (N Z 1163) (N Z 811) (N Z 352)
Age (years) !20 >20 Educationa (years) <12 O12 Health insuranceb Medicaid Private None Other Marital statusb Married/living with partner Single/separated/divorced Trimester enrolled First Second, third Depressive symptomsb 0–15 (low) 16C (high) Depressive symptomsb 0–22 (low) 23C (high) a
p! 0.02. p ! 0.01.
b
N
%
N
%
N
%
253 910
21.8 78.2
178 633
21.9 78.1
75 277
21.3 78.7
821 342
70.6 29.4
588 223
72.5 27.5
233 119
66.2 33.8
788 269 70 36
67.8 23.1 6.0 3.1
582 163 40 26
71.8 20.1 4.9 3.2
206 106 30 10
58.5 30.1 8.5 2.8
515 646
44.4 55.6
277 534
34.2 65.8
238 112
68.0 32.0
599 555
51.9 48.1
418 387
51.9 48.1
181 168
51.9 48.1
647 516
55.6 44.4
413 398
50.9 49.1
234 118
66.5 33.5
883 280
75.9 24.1
588 223
72.5 27.5
295 57
83.8 16.2
465
the Medicaid program (71.8% and 58.5%, respectively). Black women also were less likely than their white counterparts to be to be married or living with a partner (34.2% and 68%, respectively). Scores on the CES-D ranged from 0 to 55, with a mean of 16.24 and median of 14.0 for the full sample. Mean CES-D score for black women was 17.37 (SD Z 10.86); for white women, mean CES-D score was 13.65 (SD Z 9.54; p ! 0.001). As listed in Table 2, almost half the black women (49.1%) had CES-D scores of 16 or higher compared with 33.5% of white women (unadjusted odds ratio, 1.91; 95% CI, 1.47–2.48). Other variables associated with a CES-D score of 16 or higher in unadjusted analysis included younger maternal age, lower level of maternal education, living without a partner, and later enrollment in prenatal care (Table 2). Unadjusted analyses of CES-D scores of 23 or higher showed similar patterns of racial disparities. More than one quarter (27.5%) of black women had scores of 23 or higher on the CES-D compared with 16.2% of white women (unadjusted odds ratio, 1.96; 95% CI, 1.42–2.71). Other variables associated with a CES-D score of 23 or higher included lower levels of maternal education and living without a partner (Table 3). Results of logistic regression analyses are listed in Table 4. This table lists results separately for CES-D scores of 16 or higher and 23 or higher. In addition to race, independent variables included in regression models were maternal age (!20 versus >20 years), marital status (married or living with a partner versus not living with a partner), and education (<12 versus O12 years). As listed in Table 4, adjusted
TABLE 2. Variables associated with prenatal CES-D score of 16 or higher
Variable Race Black White Age (years) !20 >20 Education (years) <12 O12 Marital status Single/separated/divorced Married/living with partner Trimester enrolled First Second, third
%Elevated 95% depressive Unadjusted Confidence symptoms (>16) odds ratio interval 49.1 33.5
1.91
1.47–2.48
51.7 42.8
1.43
1.03–1.97
48.7 33.9
1.85
1.42–2.40
52.3 34.6
2.08
1.64–2.63
41.2 47.7
1.30
1.03–1.64
CES-D Z Center for Epidemiologic Studies’ Depression Scale.
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TABLE 3. Variables associated with prenatal CES-D score of 23 or higher
Variable Race Black White Age (years) !20 >20 Education (years) <12 O12 Marital status Single/separated/divorced Married/living with Trimester enrolled First Second, third
TABLE 4. Logistic regression models for prenatal CES-D scores of 16 or higher and 23 or higher CES-D> 16
% Elevated 95% depressive Unadjusted Confidence symptoms (>23) odds ratio interval. Variables 27.5 16.2
1.96
1.42–2.71
24.4 23.9
1.03
0.71–1.50
26.2 19.0
1.51
1.11–2.06
CES-D> 23
Adjusted 95% Adjusted 95% odds Confidence odds Confidence ratio interval. ratio interval
Race (0 Z white; 1 Z black) Age (0 Z !20; 1 Z >20 years) Education (0 Z O12; 1 Z <12 years) Marital status (0 Z married or living with PARTNER; 1 Z single/separated/divorced)
1.54 1.54 1.62
1.16–2.05 0.76–1.50 1.22–2.15
1.51 1.03 1.51
1.06–2.13 0.71–1.50 1.11–2.06
1.72
1.31–2.23
2.01
1.51–2.66
CES-D Z Center for Epidemiologic Studies’ Depression Scale.
29.6 17.3
2.01
1.51–2.66
22.2 26.5
1.26
0.96–1.65
CES-D Z Center for Epidemiologic Studies’ Depression Scale.
odds ratios for the associations of race with elevated CES-D scores were approximately 1.5 for both cutoff scores used, and 95% CIs did not include the null value. In addition, adjusted odds ratios for race were of a similar magnitude to those for maternal education and marital status, both established risk factors for depression. We did not include trimester of enrollment for prenatal care in the final logistic regression models because there was no association between the exposure variable (race) with trimester, and associations with the outcome were weak. When we repeated logistic regression analyses with trimester of enrollment included as a covariate, results for race essentially were unchanged, and 95% CIs for trimester encompassed one.
DISCUSSION In this hospital-based prenatal-clinic sample of pregnant women, blacks had an approximately 50% greater prevalence of elevated depressive symptoms (measured as a score either >16 or >23 on the CES-D) than whites after adjusting for maternal age, education, and marital status. Because elevated CES-D scores have been associated with preterm birth in black women (6), this racial difference in depression symptoms could have etiologic significance for the increased risk for preterm birth and low birth weight outcomes routinely reported for black women. Unfortunately, a limitation of the current study is that we did not have data on pregnancy outcomes and therefore could not test for associations between racial disparities in depressive symptoms with preterm birth or low birth weight.
Although this was a sample of women attending hospitalbased prenatal clinics, the sample was fairly heterogeneous in socioeconomic status. Approximately two thirds of the women were Medicaid recipients, and 23% had private health insurance. Also, approximately 30% of the women had more than a high school education. (There was a statistically significant association between education and receipt of Medicaid in that women with lower levels of education were more likely than those with higher levels to be Medicaid enrollees. This suggests that maternal education was a valid proxy measure of socioeconomic status in our study.) To ascertain whether findings would differ according to education level, we repeated the analyses separately for women with a high school education or less versus those with more than a high school education. In both resulting strata, there was significant black–white racial disparity in CES-D scores of 16 or higher and 23 or higher. Gazmararian et al. (20) found black–white differences in CES-D scores only among poor women, and Kessler and Neighbors (21) suggested, based on a review of epidemiologic studies, that race differences in distress are found primarily among persons of lower socioeconomic status. Our results show black–white disparities in CES-D scores among pregnant women in both lower and higher educational groups. However, caution is warranted in comparing results of our study with the other two studies. First, our research focused on pregnant women seen for care in prenatal settings in eastern North Carolina, and analyses of Gazmararian et al. (20) were based on a sample of the US population. Also, the work of Kessler and Neighbors (21) was a review of prior epidemiologic research and focused on ‘‘distress,’’ not depression or depressive symptoms per se (21). A number of studies examined epidemiologic characteristics of depression and elevated depressive symptoms. Overall, most of these studies suggested that any excess risk for depression (or elevated depressive symptoms) for blacks compared with whites disappeared after controlling for
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socioeconomic status (22–24). However, these prior studies generally did not stratify by sex or examine race-related differences in depression or depressive symptoms among women of various ages to focus on women of childbearing age. The few studies that focused on racial disparities in depression among women of childbearing age showed that black women in this age group had an increased risk for depression (10, 25). For example, Blazer et al. (10) compared the 30-day prevalence of depression between black and white women of various ages by using data from the National Comorbidity Survey, a nationwide survey of mental disorders in adults aged 15 to 54 years. Black women aged 35 to 44 years had the greatest (9.7%) 30-day prevalence rates of any age- and sex-specific group, and total 30-day prevalence was greater for black (5.7%) than white (5.4%) women. Somervell et al. (25) analyzed data from the Epidemiologic Catchment Area Study and found that in all five sites sampled, black women aged 18 to 24 years had a greater 6-month prevalence of major depression than their white counterparts of the same age. Both these studies showed a greater prevalence of depression in black compared with white women of childbearing ages. However, neither study controlled for socioeconomic status or other variables associated with increased risk for depression in women, such as marital status, and neither study focused on prenatal depression. In the study reported here, we found increased risk in black compared with white women for elevated prenatal depressive symptoms, after controlling for socioeconomic status and marital status. One might speculate about the reasons for the black– white racial disparity in elevated prenatal depressive symptoms. Prior research suggested that exposure to racial discrimination is associated with deleterious mental health outcomes, such as increased distress, decreased life satisfaction, and increased major depressive disorder (26). This may help explain our findings. We have no measure of exposure to racial discrimination, but the relationship between exposure to discrimination and racial disparities in prenatal depressive symptoms would be an informative topic for future research. Additional studies of depressive symptoms and major depressive disorder in pregnant black and white women and the relationship between racial disparities in these disorders and pregnancy outcome clearly are needed, given the potential etiologic significance of depression with respect to poor birth outcomes and racial disparities in these outcomes. The women in our sample had a high prevalence of elevated depressive symptoms, and one quarter of the black women had levels of depressive symptoms consistent with major depressive disorder. Clinicians caring for pregnant women should be aware of the high prevalence of depression in patients in prenatal clinic settings. Ultimately, learning more about the cause and management of prenatal depression may lead to
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improvements in pregnancy outcomes and the quality of women’s lives. REFERENCES 1. Blackmore CA, Ferre CD, Rowley DL, Hogue CJ, Gaiter J, Atrash H. Is race a risk factor or a risk marker for preterm delivery? Ethn Dis. 1993; 3:372–377. 2. Wise PH. Confronting racial disparities in infant mortality: Reconciling science and politics. Am J Prev Med. 1993;9(suppl):7–16. 3. Centers for Disease Control and Prevention. Differences in infant mortality between blacks and whitesdUnited States, 1980-1991. MMWR Morbid Mortal Wkly Rep. 1994;43:288–289. 4. Goldenberg RL, Cliver SP, Mulvihill FX, Hickey CA, Hoffman HJ, Klerman LV, et al. Medical, psychosocial, and behavioral risk factors do not explain the increased risk for low birth weight among black women. Am J Obstet Gynecol. 1996;175:1317–1324. 5. Rowley DL, Hogue CJ, Blackmore CA, Ferre CD, Hatfield-Timajchy K, Branch P, et al. Preterm delivery among African-American women: A research strategy. Am J Prev Med. 1993;9:1–6. 6. Orr ST, Miller CA. Maternal depressive symptoms and the risk of poor pregnancy outcome. Review of the literature and preliminary findings. Epidemiol Rev. 1995;17:165–171. 7. Orr ST, James SA, Blackmore Prince C. Maternal prenatal depressive symptoms and spontaneous preterm births among African-American women in Baltimore, Maryland. Am J Epidemiol. 2002;156:797–802. 8. Weissman MM. Advances in psychiatric epidemiology: Rates and risks for major depression. Am J Public Health. 1987;77:445–451. 9. Kessler RC, Zhao S, Blazer DG, Swartz M. Prevalence, correlates, and course of minor depression and major depression in the National Comorbidity Survey. J Affect Disord. 1997;45:19–30. 10. Blazer DG, Kessler RC, McGonagle KA, Swartz MS. The prevalence and distribution of major depression in a national community sample: The National Comorbidity Survey. Am J Psychiatry. 1994;151:979–986. 11. Weissman MM, Olfson M. Depression in women: Implications for health care research. Science. 1995;269:799–801. 12. Zuckerman B, Amaro H, Bauchner H, Cabral H. Depressive symptoms during pregnancy: Relationship to poor health behaviors. Am J Obstet Gynecol. 1989;160:1107–1111. 13. Radloff LS. The CES-D scale: A self-report depression scale for research in the general population. Appl Psychol Meas. 1977;1:385–401. 14. Radloff LS, Locke BZ. The Community Mental Health Assessment Survey and CES-D scale. In: Weissman MM, Myers JK, eds. Community Surveys of Psychiatric Disorders. New Brunswick, NJ: Rutgers University Press; 1986:177–187. 15. Markush RE, Favero RV. Epidemiologic assessment of stressful life events, depressed mood, and psychophysiological symptomsdA preliminary report. In: Dohrenwend BS, Dohrenwend BP, eds. Stressful Life Events: Their Nature and Effects. New York: Wiley; 1974:171–190. 16. Husaini BA, Neff JA, Stone RH. Psychiatric impairment in rural communities. J Comm Psychol. 1979;7:137–146. 17. Beekman AT, Deeg DJ, Van Limbeek J, Braam AW, De Vries MZ, Van Tilburg W. Criterion validity for the Center for Epidemiologic Studies Depression Scale (CES-D): Results from a community based sample of older subjects in the Netherlands. Psychol Med. 1997;27:231–235. 18. Weissman MM, Sholomskas D, Pottenger M, Prusoff BA, Locke BZ. Assessing depressive symptoms in five psychiatric populations: A validation study. Am J Epidemiol. 1977;106:203–214. 19. Roberts RE. Reliability of the CES-D Scale in different ethnic contexts. Psychiatry Res. 1980;2:125–134. 20. Gazmararian JA, James SA, Lepkowski JM. Depression in black and white women: The role of marriage and socioeconomic status. Ann Epidemiol. 1995;5:455–463.
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21. Kessler RC, Neighbors HW. A new perspective on the relationships among race, social class, and psychological distress. J Health Soc Behav. 1986;27:107–115. 22. Neighbors HW. The distribution of psychiatric morbidity in black Americans: Review and suggestions for research. Community Ment Health J. 1984;20:169–181. 23. Jones-Webb R, Snowden L. Symptoms of depression among blacks and whites. Am J Public Health. 1993;83:240–244.
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24. Eaton WW, Kessler LG. Rates of symptoms of depression in a national sample. Am J Epidemiol. 1981;114:528–538. 25. Somervell PD, Leaf PJ, Weissman MM, Blazer DG, Bruce ML. The prevalence of major depression in black and white adults in five United States communities. Am J Epidemiol. 1989;130:725–735. 26. Williams DR, Neighbors HW, Jackson JS. Racial/ethnic discrimination and health: Findings from community studies. Am J Public Health. 2003; 93:200–208.
PURPOSE: Black women have an increased risk for preterm birth compared with white women, and prior research indicated that maternal prenatal depressive symptoms are associated with increased risk for preterm outcomes among black women. Race-related differences in prenatal depression could be of etiologic significance in understanding racial disparities in preterm birth. Our study focused on Center for Epidemiologic Studies’ Depression Scale (CES-D) scores of pregnant black and white women. METHODS: Women were administered the CES-D at the time of their first visit to hospital-based prenatal clinics. Two cutoff scores for the CES-D were used: 16 or higher, which indicates ‘‘significant’’ depressive symptoms, and 23 or higher, which indicates major depressive disorder. RESULTS: For the sample of 1163 women, mean CES-D scores were significantly higher among black (17.4) than white (13.7) women. Of black women, 49% had CES-D scores higher than 15 compared with 33.5% of white women. Also, 27.5% of black women had scores higher than 22 compared with 16% of white women. After adjustment for maternal age, marital status, and education, odds ratios for race for both CES-D cutoff scores were approximately 1.5. CONCLUSIONS: Results of this study indicate that black women have greater rates of prenatal depression than white women. Ann Epidemiol 2006;16:463–468. Ó 2006 Elsevier Inc. All rights reserved. KEY WORDS: Depression, Center for Epidemiologic Studies’ Depression Scale (CES-D), Racial Disparities, Pregnancy.
INTRODUCTION Prior research has clearly shown large black–white racial disparities in poor pregnancy outcomes (1, 2). Black women have approximately double the risk of white women for preterm (births at ! 37 weeks’ completed gestation) and low birth weight (births at 2500 g to <5.5 lb) outcomes. The increased risk for preterm and low birth weight births among black women contributes to the high rate of infant mortality (deaths in the first year of life) among blacks and the large excess risk for mortality among black compared with white infants (3). Racial disparities in harmful pregnancy outcomes have been relatively unchanged for decades and are very poorly
From the Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Greenville, NC (S.T.O.); Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC (D.G.B.); and Institute for Public Policy Studies, Duke University, Durham, NC (S.A.J.). Address correspondence to: Suezanne T. Orr, Ph.D., Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Christenbury 200, Greenville, NC 27858. Tel.: (252) 328-2526; fax: (252) 328-1285. E-mail: [email protected]. edu. Received April 20, 2005; accepted August 13, 2005. Ó 2006 Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010
understood. Racial disparities in poor pregnancy outcomes cannot be explained adequately by differences in established risk factors for preterm birth and low birth weight, such as maternal age, education, smoking, or medical factors (4, 5). Reductions in the racial disparity in deleterious pregnancy outcomes will require knowledge about additional factors that increase the risk of black women for these outcomes. Prior research suggests that elevated maternal prenatal depressive symptoms are associated with increased risk for poor pregnancy outcomes, including preterm birth, among black women (6, 7). However, prior research has not focused on racial disparities in risk for elevated prenatal depressive symptoms. Race-related differences in elevated prenatal depressive symptoms potentially could help explain the excess risk for preterm birth among black compared with white women. Overall, one in five women will experience an episode of major depressive disorder during her lifetime (8, 9), and depression has been termed a major public health problem (10) because of its high prevalence, especially in women. The usual age of onset of depression in women is during the childbearing years (11), and rates of depression and elevated depressive symptoms are very common in women of childbearing age (10, 11). Moreover, elevated depressive symptoms are very common in pregnant women, with as 1047-2797/06/$–see front matter doi:10.1016/j.annepidem.2005.08.004
464
Orr et al. RACIAL DISPARITIES IN PRENATAL DEPRESSION
Selected Abbreviations and Acronyms CES-D Z Center for Epidemiologic Studies’ Depression Scale CI Z confidence interval
many as half the pregnant women attending prenatal clinics experiencing elevated levels of depressive symptoms (6, 7, 12). Despite the potential etiologic importance of depression and elevated depressive symptoms for preterm birth among black women, there are few studies of black–white racial disparities in depression or elevated depressive symptoms among pregnant women and women of childbearing ages. In addition, there is a lack of prior studies that control for covariates associated with risk for depression, such as socioeconomic status. In the research reported here, we examine racial differences in elevated symptoms of depression among pregnant black and white women seeking prenatal care. We assessed these differences, adjusting for education as a proxy for maternal socioeconomic status, and also for age and marital status. The overall objective of the research is to show the extent of racial disparities in elevated prenatal depressive symptoms, controlling for socioeconomic status and other variables associated with increased risk for depression.
METHODS Enrollment in this study occurred from March 2001 through December 2002. Women were enrolled in the research at the prenatal clinics of the Departments of Obstetrics and Gynecology and Family Medicine, Brody School of Medicine, East Carolina University, Greenville, NC. The clinics serve Greenville and surrounding Pitt County and other nearby counties. This geographic area has high rates of low birth weight, preterm birth, and infant mortality. A trained research assistant approached all women aged 16 years and older while they were waiting to be seen for their first prenatal visit and invited them to participate, and informed consent was obtained. Women who agreed to participate (>95%) were administered the study interview at that time. Most women seeking care at these clinics are enrolled for prenatal care by the end of the second trimester. Among the sample, slightly more than one half of the women (51.9%) enrolled for prenatal care during the first trimester of pregnancy, and an additional 36.6% enrolled during the second trimester. The study interview contained items to assess demographic factors (maternal race, age, education, and marital status), as well as depressive symptoms. Education was
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assessed as the highest grade in school completed and dichotomized as 12 years or fewer and more than 12 years. Age was dichotomized as younger than 20 years and 20 years or older. Marital status was assessed by using an item that allowed a woman to indicate if she was married and living with her husband; unmarried, but living with a male partner; or unmarried and living without a male partner (including single, separated, and divorced women). Responses were dichotomized as married and living with a partner/unmarried and living with a partner versus unmarried/living without a partner. Depressive symptoms were assessed by using the Center for Epidemiologic Studies’ Depression Scale (CES-D) (13). The CES-D contains 20 items and was developed by the National Institute of Mental Health in the 1970s to permit ascertainment of epidemiologic characteristics of depression in community samples (13). CES-D items assess the presence of salient symptoms of depression (e.g., sadness, hopelessness, fatigue, crying, low self-esteem, and changes in sleep or appetite) within the past 7 days. Scores on the instrument can range from zero to 60, with a customary cutoff score of 16 or higher used to identify those with ‘‘elevated’’ (clinically relevant) levels of depressive symptoms (13). The 16-or-higher cutoff score has been used in most prior research with the CES-D. In addition, Radloff and Locke (14) proposed a second cutoff value of 23 or higher, suggesting that this score can be used to indicate the presence of major depressive disorder (14). The CES-D has been shown to be a valid and reliable measure of depressive symptoms in diverse samples (15– 19) and has been used widely in epidemiologic research. CES-D scores decrease with treatment of depression and correlate well with diagnoses of major depressive disorder made by clinicians (13, 16). For analyses of prenatal CES-D scores for this research, both suggested cutoff scores were used to identify the group with elevated scores. The first cutoff value was the traditional cutoff score of 16 or higher (13). We also conducted analyses using the cutoff score of 23 or higher (14). A score of 23 or higher is thought to indicate the presence of major depressive disorder (14). This second cutoff score was especially useful for our purposes because CES-D scores can be inflated in pregnant women because of overlap of certain symptoms of depression with symptoms of pregnancy (e.g., appetite change and fatigue) (6). It is extremely unlikely that a woman could achieve a score of 23 or higher based solely on symptoms associated with pregnancy. Unadjusted associations between race and depressive symptoms were evaluated first by using bivariate tables, odds ratios, and 95% confidence intervals (CIs). Next, logistic regression models were used to obtain adjusted estimates of odds ratios and 95% CIs, controlling for potential confounding by demographic factors associated with depression,
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such as marital status and education. Beta coefficients from the models were used to estimate odds ratios.
RESULTS As listed in Table 1, of the enrolled sample of 1163 women, approximately 70% identified their race as black (N Z 811), and 30%, as white (N Z 352). Approximately 20% of women were younger than 20 years. Approximately 29% of women had more than a high school education. Two thirds of the women in the sample (67.8%) were enrolled in the Medicaid program for the pregnancy. The remaining women had either private health insurance (23.1%) or were uninsured (6%). Forty-four percent of women in the sample were married and living with a partner or not married and living with a partner. The remaining 56% were unmarried and not living with a partner. Approximately half the women enrolled for prenatal care during the first trimester of pregnancy. There were statistically significant differences between black and white women in the sample on several covariates of interest (Table 1). Black women (27.5%) were less likely than white women (33.8%) to have completed more than a high school education and more likely to be enrolled in
TABLE 1. Characteristics of the sample by race Full sample Black women White women (N Z 1163) (N Z 811) (N Z 352)
Age (years) !20 >20 Educationa (years) <12 O12 Health insuranceb Medicaid Private None Other Marital statusb Married/living with partner Single/separated/divorced Trimester enrolled First Second, third Depressive symptomsb 0–15 (low) 16C (high) Depressive symptomsb 0–22 (low) 23C (high) a
p! 0.02. p ! 0.01.
b
N
%
N
%
N
%
253 910
21.8 78.2
178 633
21.9 78.1
75 277
21.3 78.7
821 342
70.6 29.4
588 223
72.5 27.5
233 119
66.2 33.8
788 269 70 36
67.8 23.1 6.0 3.1
582 163 40 26
71.8 20.1 4.9 3.2
206 106 30 10
58.5 30.1 8.5 2.8
515 646
44.4 55.6
277 534
34.2 65.8
238 112
68.0 32.0
599 555
51.9 48.1
418 387
51.9 48.1
181 168
51.9 48.1
647 516
55.6 44.4
413 398
50.9 49.1
234 118
66.5 33.5
883 280
75.9 24.1
588 223
72.5 27.5
295 57
83.8 16.2
465
the Medicaid program (71.8% and 58.5%, respectively). Black women also were less likely than their white counterparts to be to be married or living with a partner (34.2% and 68%, respectively). Scores on the CES-D ranged from 0 to 55, with a mean of 16.24 and median of 14.0 for the full sample. Mean CES-D score for black women was 17.37 (SD Z 10.86); for white women, mean CES-D score was 13.65 (SD Z 9.54; p ! 0.001). As listed in Table 2, almost half the black women (49.1%) had CES-D scores of 16 or higher compared with 33.5% of white women (unadjusted odds ratio, 1.91; 95% CI, 1.47–2.48). Other variables associated with a CES-D score of 16 or higher in unadjusted analysis included younger maternal age, lower level of maternal education, living without a partner, and later enrollment in prenatal care (Table 2). Unadjusted analyses of CES-D scores of 23 or higher showed similar patterns of racial disparities. More than one quarter (27.5%) of black women had scores of 23 or higher on the CES-D compared with 16.2% of white women (unadjusted odds ratio, 1.96; 95% CI, 1.42–2.71). Other variables associated with a CES-D score of 23 or higher included lower levels of maternal education and living without a partner (Table 3). Results of logistic regression analyses are listed in Table 4. This table lists results separately for CES-D scores of 16 or higher and 23 or higher. In addition to race, independent variables included in regression models were maternal age (!20 versus >20 years), marital status (married or living with a partner versus not living with a partner), and education (<12 versus O12 years). As listed in Table 4, adjusted
TABLE 2. Variables associated with prenatal CES-D score of 16 or higher
Variable Race Black White Age (years) !20 >20 Education (years) <12 O12 Marital status Single/separated/divorced Married/living with partner Trimester enrolled First Second, third
%Elevated 95% depressive Unadjusted Confidence symptoms (>16) odds ratio interval 49.1 33.5
1.91
1.47–2.48
51.7 42.8
1.43
1.03–1.97
48.7 33.9
1.85
1.42–2.40
52.3 34.6
2.08
1.64–2.63
41.2 47.7
1.30
1.03–1.64
CES-D Z Center for Epidemiologic Studies’ Depression Scale.
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TABLE 3. Variables associated with prenatal CES-D score of 23 or higher
Variable Race Black White Age (years) !20 >20 Education (years) <12 O12 Marital status Single/separated/divorced Married/living with Trimester enrolled First Second, third
TABLE 4. Logistic regression models for prenatal CES-D scores of 16 or higher and 23 or higher CES-D> 16
% Elevated 95% depressive Unadjusted Confidence symptoms (>23) odds ratio interval. Variables 27.5 16.2
1.96
1.42–2.71
24.4 23.9
1.03
0.71–1.50
26.2 19.0
1.51
1.11–2.06
CES-D> 23
Adjusted 95% Adjusted 95% odds Confidence odds Confidence ratio interval. ratio interval
Race (0 Z white; 1 Z black) Age (0 Z !20; 1 Z >20 years) Education (0 Z O12; 1 Z <12 years) Marital status (0 Z married or living with PARTNER; 1 Z single/separated/divorced)
1.54 1.54 1.62
1.16–2.05 0.76–1.50 1.22–2.15
1.51 1.03 1.51
1.06–2.13 0.71–1.50 1.11–2.06
1.72
1.31–2.23
2.01
1.51–2.66
CES-D Z Center for Epidemiologic Studies’ Depression Scale.
29.6 17.3
2.01
1.51–2.66
22.2 26.5
1.26
0.96–1.65
CES-D Z Center for Epidemiologic Studies’ Depression Scale.
odds ratios for the associations of race with elevated CES-D scores were approximately 1.5 for both cutoff scores used, and 95% CIs did not include the null value. In addition, adjusted odds ratios for race were of a similar magnitude to those for maternal education and marital status, both established risk factors for depression. We did not include trimester of enrollment for prenatal care in the final logistic regression models because there was no association between the exposure variable (race) with trimester, and associations with the outcome were weak. When we repeated logistic regression analyses with trimester of enrollment included as a covariate, results for race essentially were unchanged, and 95% CIs for trimester encompassed one.
DISCUSSION In this hospital-based prenatal-clinic sample of pregnant women, blacks had an approximately 50% greater prevalence of elevated depressive symptoms (measured as a score either >16 or >23 on the CES-D) than whites after adjusting for maternal age, education, and marital status. Because elevated CES-D scores have been associated with preterm birth in black women (6), this racial difference in depression symptoms could have etiologic significance for the increased risk for preterm birth and low birth weight outcomes routinely reported for black women. Unfortunately, a limitation of the current study is that we did not have data on pregnancy outcomes and therefore could not test for associations between racial disparities in depressive symptoms with preterm birth or low birth weight.
Although this was a sample of women attending hospitalbased prenatal clinics, the sample was fairly heterogeneous in socioeconomic status. Approximately two thirds of the women were Medicaid recipients, and 23% had private health insurance. Also, approximately 30% of the women had more than a high school education. (There was a statistically significant association between education and receipt of Medicaid in that women with lower levels of education were more likely than those with higher levels to be Medicaid enrollees. This suggests that maternal education was a valid proxy measure of socioeconomic status in our study.) To ascertain whether findings would differ according to education level, we repeated the analyses separately for women with a high school education or less versus those with more than a high school education. In both resulting strata, there was significant black–white racial disparity in CES-D scores of 16 or higher and 23 or higher. Gazmararian et al. (20) found black–white differences in CES-D scores only among poor women, and Kessler and Neighbors (21) suggested, based on a review of epidemiologic studies, that race differences in distress are found primarily among persons of lower socioeconomic status. Our results show black–white disparities in CES-D scores among pregnant women in both lower and higher educational groups. However, caution is warranted in comparing results of our study with the other two studies. First, our research focused on pregnant women seen for care in prenatal settings in eastern North Carolina, and analyses of Gazmararian et al. (20) were based on a sample of the US population. Also, the work of Kessler and Neighbors (21) was a review of prior epidemiologic research and focused on ‘‘distress,’’ not depression or depressive symptoms per se (21). A number of studies examined epidemiologic characteristics of depression and elevated depressive symptoms. Overall, most of these studies suggested that any excess risk for depression (or elevated depressive symptoms) for blacks compared with whites disappeared after controlling for
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socioeconomic status (22–24). However, these prior studies generally did not stratify by sex or examine race-related differences in depression or depressive symptoms among women of various ages to focus on women of childbearing age. The few studies that focused on racial disparities in depression among women of childbearing age showed that black women in this age group had an increased risk for depression (10, 25). For example, Blazer et al. (10) compared the 30-day prevalence of depression between black and white women of various ages by using data from the National Comorbidity Survey, a nationwide survey of mental disorders in adults aged 15 to 54 years. Black women aged 35 to 44 years had the greatest (9.7%) 30-day prevalence rates of any age- and sex-specific group, and total 30-day prevalence was greater for black (5.7%) than white (5.4%) women. Somervell et al. (25) analyzed data from the Epidemiologic Catchment Area Study and found that in all five sites sampled, black women aged 18 to 24 years had a greater 6-month prevalence of major depression than their white counterparts of the same age. Both these studies showed a greater prevalence of depression in black compared with white women of childbearing ages. However, neither study controlled for socioeconomic status or other variables associated with increased risk for depression in women, such as marital status, and neither study focused on prenatal depression. In the study reported here, we found increased risk in black compared with white women for elevated prenatal depressive symptoms, after controlling for socioeconomic status and marital status. One might speculate about the reasons for the black– white racial disparity in elevated prenatal depressive symptoms. Prior research suggested that exposure to racial discrimination is associated with deleterious mental health outcomes, such as increased distress, decreased life satisfaction, and increased major depressive disorder (26). This may help explain our findings. We have no measure of exposure to racial discrimination, but the relationship between exposure to discrimination and racial disparities in prenatal depressive symptoms would be an informative topic for future research. Additional studies of depressive symptoms and major depressive disorder in pregnant black and white women and the relationship between racial disparities in these disorders and pregnancy outcome clearly are needed, given the potential etiologic significance of depression with respect to poor birth outcomes and racial disparities in these outcomes. The women in our sample had a high prevalence of elevated depressive symptoms, and one quarter of the black women had levels of depressive symptoms consistent with major depressive disorder. Clinicians caring for pregnant women should be aware of the high prevalence of depression in patients in prenatal clinic settings. Ultimately, learning more about the cause and management of prenatal depression may lead to
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