Characterizations of Psychosocial and Biological Stress Factors and Associations with Self-Reported Race and Bacterial Vaginosis in Pregnancy Open Access

Calles, Dinorah Lissette (2012)

Permanent URL: https://etd.library.emory.edu/concern/etds/kk91fm187?locale=pt-BR%2A
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Abstract

Bacterial vaginosis (BV) is a reproductive tract infection syndrome whose manifestation is characterized by an overgrowth of anaerobic bacteria, and a corresponding reduction in peroxidase-producing Lactobacillus. Given that BV is an important risk factor associated with preterm birth, and that preterm birth is one of the most relevant contributors to infant morbidity and mortality worldwide, epidemiologic research on the causes and factors associated with BV in pregnancy is of public health importance.

A number of studies have posited the role of maternal chronic and acute stress in negatively impacting immune and hormonal functioning, thus making it biologically plausible for stress to directly affect susceptibility to infection. However, inconsistencies in the conceptualizations of the construct of stress, timing of stress exposure and BV prevalence assessment, differentiation between chronic and acute experience of stress, and the application of different instruments to measure stress further complicate the comparability of results across study populations.

The increased occurrence of BV during pregnancy among African-American women in the U.S. is well-documented. However, an excess occurrence among Afro-descendant women in other racially heterogeneous settings is unclear. Brazil provides an interesting context for testing hypothesized associations of race and BV in pregnancy, given considerable co-occurring social, economic, and racial inequality. To date, there are no published studies investigating the interrelationships of maternal psychosocial stress, race, and BV prevalence in pregnancy in a Brazilian context.

In this study, BV prevalence among black or mixed/mulatta women did not differ from that in white women. However, the excess BV prevalence among black women relative to mixed/mulatta women remained statistically significant, even after multivariate adjustment for life events, state anxiety, perceived stress, intimate partner violence, and potential confounders. These preliminary findings 1) suggest that in Brazilian pregnant women BV prevalence may differ by self-reported race, and that the associations of BV with psychosocial risk factors may differ by race, and 2) support a larger study using more complete characterization, measurement, and analysis of individual and contextual factors by racial self-identity.

Table of Contents

TABLE OF CONTENTS

Chapter

1
LITERATURE REVIEW ................................................................................................... 1


Bacterial vaginosis in pregnancy ........................................................................................ 1

Stress and health outcomes ................................................................................................. 2

Assessment of psychosocial stress and cortisol in pregnancy ............................................ 4

Bacterial vaginosis and psychosocial stress in pregnancy .................................................. 7

Bacterial vaginosis, race, and socioeconomic status (SES) ................................................. 9

Bacterial vaginosis in a Brazilian context ......................................................................... 10

Closing Remarks ............................................................................................................... 12

References ......................................................................................................................... 14

2
STUDY QUESTIONS ...................................................................................................... 24


Primary Questions ............................................................................................................. 24

Secondary Questions ......................................................................................................... 24

3
METHODOLOGY ........................................................................................................... 29


Study design and study population ................................................................................... 29

Assessment of bacterial vaginosis (BV) ............................................................................ 31

Assessment of self-reported race ....................................................................................... 33

Assessment of psychosocial measures ............................................................................... 33

Assessment of salivary cortisol .......................................................................................... 37

Assessment of demographic and medical characteristics ................................................. 40

Statistical Analysis ............................................................................................................ 41

Statistical power considerations ........................................................................................ 50

Organization of results ...................................................................................................... 51

References ......................................................................................................................... 51

4
THE ASSOCIATION OF BACTERIAL VAGINOSIS WITH SELF-IDENTIFIED
RACE, SOCIOECONOMIC, AND PSYCHOSOCIAL STRESS IN A SAMPLE OF
BRAZILIAN PREGNANT WOMEN IN A PUBLIC CARE SETTING ......................... 55

Abstract ............................................................................................................................. 56
Introduction ....................................................................................................................... 57
 Background ........................................................................................................................ 58
 Methods.............................................................................................................................. 62

Participants ............................................................................................................. 62
 Procedures .............................................................................................................. 63

Measures ................................................................................................................ 64
Bacterial vaginosis ..................................................................................... 64
 Self-identified race ..................................................................................... 64
 Socioeconomic status (SES) ...................................................................... 65


Psychosocial measures ........................................................................................... 65


Sociobehavioral factors and covariates .................................................................. 66


Statistical analyses ................................................................................................. 67
Results ................................................................................................................................ 68
 Discussion .......................................................................................................................... 72
 References .......................................................................................................................... 77

5
ASSESSMENT OF THE RELIABILITY AND VALIDITY OF THE PERCEIVED
STRESS SCALE IN A SAMPLE OF BRAZILIAN PREGNANT WOMEN. ................. 95

Abstract ............................................................................................................................. 96
Methods.............................................................................................................................. 98

Participants ............................................................................................................. 98
 Procedures .............................................................................................................. 99
 Measures ................................................................................................................ 99


Analyses ............................................................................................................... 100
Results .............................................................................................................................. 103
 Discussion ........................................................................................................................ 106

References ........................................................................................................................ 110

6
COMMENTARY: RACIAL DIFFERENCES IN SALIVARY CORTISOL
CONCENTRATION AND PSYCHOSOCIAL STRESS SCALES AMONG
PREGNANT WOMEN IN RIO DE JANEIRO, BRAZIL. ............................................. 118



References ........................................................................................................................ 124

7
DISCUSSION .................................................................................................................. 128

References ........................................................................................................................ 135




APPENDIX ...................................................................................................................... 137


A ADDITIONAL RESULTS ....................................................................................... 137


B INFORMED CONSENT FORM AND QUESTIONNAIRE


(BRAZILIAN PORTUGUESE) ............................................................................... 147


LIST OF FIGURES

2.1
Theoretical relationship between self-identified race and

bacterial vaginosis, with hypothesized stress mediators ................................................... 27

2.2
Theoretical relationships among self-identified race,

psychosocial stress scales, and cortisol concentration ...................................................... 28

4.1
Theoretical relationship between self-identified race and

bacterial vaginosis, with hypothesized stress mediators ................................................... 84
5.1
Final confirmatory factor analysis (CFA) model of the

Cohen Perceived Stress Scale (PSS) in pregnant women (n = 142) ............................... 115

LIST OF TABLES

4.1
Descriptive characteristics of a sample of pregnant women between 14-26 weeks'
gestation and unadjusted associations with BV prevalence, Rio de Janeiro,
2008-2009 ......................................................................................................................... 85

4.2
Distribution of stress exposures by bacterial vaginosis (BV) status in a sample of
pregnant women between 14-26 weeks' gestation. Rio de Janeiro, Brazil,
2008-2009. ......................................................................................................................... 87

4.3
Distribution of stress exposures in a sample of pregnant women between 14-26 weeks'
gestation and unadjusted associations with BV prevalence, stratified by self-reported
race. Rio de Janeiro, Brazil, 2008-2009 ........................................................................... 89

4.4
Results of hierarchical robust Poisson regression of socioeconomic and psychosocial
stress associations with bacterial vaginosis, adjusted for covariates and considering white
race as referent (n = 266). Rio de Janeiro, Brazil, 2008-2009 .......................................... 91

4.5
Results of hierarchical robust Poisson regression of socioeconomic and psychosocial
stress associations with bacterial vaginosis, adjusted for covariates and considering mixed
race as referent (n = 205). Rio de Janeiro, Brazil, 2008-2009 ......................................... 93

5.1
Characteristics of the study sample (n=295) .................................................................... 116

5.2
Items Retained in the Perceived Stress Scale (PSS) after Exploratory Factor Analyses
(EFA) and Respective Factor Loadings (N=153) ............................................................ 117

A.1
Characteristics of a sample of pregnant women between 14-26 weeks' gestation (n = 234)
in Rio de Janeiro, Brazil, 2008-2009 ............................................................................... 142

A.2
Cortisol concentration by demographic characteristics in a sample of pregnant women
between 14-26 weeks' gestation (n=234) in Rio de Janeiro, Brazil, 2008-2009 ............. 143

A.3
Measures of psychosocial stress by demographic and medical factors in a sample of
pregnant women between 14-26 weeks' gestation (n = 234) in Rio de Janeiro, Brazil,
2008-2009. ....................................................................................................................... 144

A.4
Spearman correlations among stress measures in a sample of pregnant women between
14-26 weeks' gestation (n = 234) in Rio de Janeiro, Brazil, 2008-2009 ......................... 146

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