Elsevier

Social Science & Medicine

Volume 67, Issue 5, September 2008, Pages 824-833
Social Science & Medicine

Racial disparity in bacterial vaginosis: the role of socioeconomic status, psychosocial stress, and neighborhood characteristics, and possible implications for preterm birth

https://doi.org/10.1016/j.socscimed.2008.05.017Get rights and content

Abstract

Racial disparity in preterm birth is one of the most salient, yet least well-understood health disparities in the United States. The preterm birth disparity may be due to differences in how women experience their racial identity in light of neighborhood factors, psychosocial stress, or the prevalence of or response to genital tract infections such as bacterial vaginosis (BV). The latest research emphasizes a need to explore all these factors simultaneously. This cross-sectional study of parous women in King County, Washington, USA investigated the effects of household income, psychosocial stress, and neighborhood socioeconomic characteristics on risk of BV after accounting for known individual-level risk factors. Relevant demographic, socioeconomic, and medical data were linked to U.S. census socioeconomic data by geocoding subjects' residential addresses. It was found that having a low income was significantly associated with an increased prevalence of BV among African American but not White American women. A higher number of stressful life events was significantly associated with higher BV prevalence among both African American and White American women. However, perceived stress was not related to BV risk among either group of women. Among White American women, neighborhood socioeconomic status (SES) was univariately associated with increased BV prevalence by principal components analysis, but was no longer significant after adjusting for individual-level risk factors. No neighborhood SES effects were observed for African American women. These results suggest that both the effects of individual- and neighborhood-level risk factors for BV may differ importantly by racial group, and stressful life events may have physiological effects independent of perceived stress.

Introduction

Prematurity is the leading cause of infant mortality in the United States (Callaghan, MacDorman, Rasmussen, Qin, & Lackritz, 2006) and the racial disparity in preterm birth is one of the most salient, yet least well-understood health disparities. Even after adjustment for differences in known risk factors, African American women are consistently observed to be at approximately twice the risk of delivering prematurely compared to White American women (Behrman & Butler, 2006).

The persistence of the preterm birth disparity is puzzling. Although reasons for preterm birth are complex, as a health disparity, preterm birth must be studied in relation to the social conditions that influence women's premature birth outcomes differentially and unequally. Preterm birth disparity may be due in part to social context differences in how women experience their racial identity in light of neighborhood factors (Stancil, Hertz-Picciotto, Schramm, & Watt-Morse, 2000), stress perception (Hogue & Bremner, 2005) or the prevalence of or response to genital tract infections such as bacterial vaginosis (BV) (Hitti et al., 2007, Royce et al., 1999). The latest research emphasizes a need to explore all these factors simultaneously to develop models for understanding preterm birth disparity (Reagan & Salsberry, 2005).

Here we review the theories about the preterm birth disparity in the context of BV, psychosocial stress, and neighborhood socioeconomic characteristics, and we then present results of a research study designed to further explore these relationships.

Section snippets

Preterm birth and bacterial vaginosis

Bacterial vaginosis (BV) is often hypothesized as a potential mechanism to explain preterm birth disparity because it is consistently observed to occur more commonly in African American than White American women (Holzman et al., 2001, Ness et al., 2003, Royce et al., 1999). The Preterm Prediction Study observed that not only was BV more common, but the association between BV and preterm birth was stronger among African American women (Goldenberg et al., 1998). In that cohort, BV was estimated

Individual data

Data for this study came from the “A Better Chance” (ABC) Project, a population-based cohort study including 400 parous women in King County, Washington, which aimed to investigate mechanisms for racial disparity in preterm birth rates. The ABC Project was granted Human Subjects approval by the Washington State Institutional Review Board (WSIRB), as was a specific amendment allowing for this secondary analysis.

The present analysis is cross-sectional in design, utilizing only data collected at

Individual-level analyses

Seventeen percent (17%) of White American women were BV-positive by Gram stain, compared to 45% of African American women (P < 0.001). Overall, African American women were slightly younger (29.8 vs. 33.0 years, P < 0.001) and were more likely to be single (36% vs. 12%, P < 0.001), to be unemployed (25% vs. 9%, P < 0.001), and to have a low income (80% vs. 29%, P < 0.001). African American women were also more likely to have a history of douching (85% vs. 38%, P < 0.001), to be current smokers

Discussion

Among African American women, having a low income was strongly associated with elevated BV prevalence, but this effect was not observed among White American women. Other significant predictors of BV among African American women were being married or partnered, smoking cigarettes, and reporting a higher number of stressful life events. In contrast, among White American women, only history of STI and stressful life events were significant predictors of BV prevalence. These findings may reflect

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    This research was supported by NIH grant HD-41682.

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