Stress, bacterial vaginosis, and the role of immune processes

Investigations of microbiota composition and neuroactive pathways in association with symptoms of stress and depression in a cohort of healthy women

Background

Despite mounting evidence of gut-brain involvement in psychiatric conditions, functional data remain limited, and analyses of other microbial niches, such as the vaginal microbiota, are lacking in relation to mental health. This aim of this study was to investigate if the connections between the gut microbiome and mental health observed in populations with a clinical diagnosis of mental illness extend to healthy women experiencing stress and depressive symptoms. Additionally, this study examined the functional pathways of the gut microbiota according to the levels of psychological symptoms. Furthermore, the study aimed to explore potential correlations between the vaginal microbiome and mental health parameters in young women without psychiatric diagnoses.

Methods

In this cross-sectional study, 160 healthy Danish women (aged 18-40 years) filled out questionnaires with validated scales measuring symptoms of stress and depression and frequency of dietary intake. Fecal and vaginal microbiota samples were collected at the beginning of the menstrual cycle and vaginal samples were also collected at cycle day 8-12 and 18-22. Shotgun metagenomic profiling of the gut and vaginal microbiome was performed. The Kyoto Encyclopedia of Genes and Genomes (KEGG) was used for functional profiling and 56 Gut Brain Modules were analyzed in the fecal samples.

Results

The relative abundance in the gut of the genera Escherichia, Parabacteroides, and Shigella was higher in women with elevated depressive symptoms. Women with high perceived stress showed a tendency of increased abundance of Escherichia, Shigella, and Blautia. Amongst others, the potentially pathogenic genera, Escherichia and Shigella correlate with alterations in the neuroactive pathways such as the glutamatergic, GABAeric, dopaminergic, and Kynurenine pathways. Vaginosis symptoms were more prevalent in women reporting high levels of stress and depressive symptoms.

Conclusions

The findings of this study support the concept of a microbiota-associated effect on the neuroactive pathways even in healthy young women. This suggest, that targeting the gut microbiome could be a promising approach for future psychiatric interventions.

The role of neighborhood deprivation in the cervicovaginal microbiota

BACKGROUND

Lactobacillus-deficient cervicovaginal microbiota is associated with spontaneous preterm birth and is more common among Black individuals. Persistent racial segregation in the United States has led to differential neighborhood exposures by race that can affect pregnancy outcomes. The extent to which neighborhood exposures may explain racial differences in the cervicovaginal microbiota is unknown.

OBJECTIVE

This study aimed to determine whether neighborhood deprivation, defined as material community deprivation, is associated with a Lactobacillus-deficient cervicovaginal microbiota in a prospective cohort of pregnant individuals. Our hypothesis was that racial differences in neighborhood deprivation may explain the higher prevalence of Lactobacillus-deficient cervicovaginal microbiota in Black birthing people.

STUDY DESIGN

This study analyzed data from Motherhood and Microbiome, a prospective pregnancy cohort enrolled from prenatal clinics in a single hospital system 2013-2016 in which a Lactobacillus-deficient cervicovaginal microbiota was previously shown to be associated with spontaneous preterm birth. This study geocoded addresses to obtain census tract neighborhood deprivation data from the Brokamp Nationwide Community Deprivation Index that uses weighted proportions of poverty, income, public assistance, lack of health insurance, and vacant housing. Generalized linear mixed models quantified associations of deprivation with the cervicovaginal microbiota accounting for geographic clustering by census tract and potential confounders. Because of different distributions of neighborhood deprivation and the cervicovaginal microbiota, race-stratified models were used. Mediation analyses quantified the extent to which deprivation may contribute to racial differences in the cervicovaginal microbiota.

RESULTS

Higher neighborhood deprivation was associated with a Lactobacillus-deficient cervicovaginal microbiota. Per standard deviation increment of deprivation, participants had 28% higher adjusted odds (adjusted odds ratio, 1.28; 95% confidence interval, 1.04-1.58) of a Lactobacillus-deficient microbiota. Black participants had higher odds of a Lactobacillus-deficient microbiota than White participants (adjusted odds ratio, 4.00; 95% confidence interval, 2.05-8.26), and mediation analysis revealed that deprivation accounted for 22% (P=.046) of that disparity.

CONCLUSION

Neighborhood deprivation was associated with Lactobacillus-deficient cervicovaginal microbiota and may partially explain Black-White disparities in the cervicovaginal microbiota. Mechanistic studies to explore how environmental exposures modify the cervicovaginal microbiota are warranted to identify novel opportunities for future interventional strategies to prevent preterm birth. As the findings demonstrate a potential biological effect from neighborhood conditions, policies that drive urban planning should be explored to improve pregnancy outcomes.

Structural Racism and Adverse Pregnancy Outcomes Through the Lens of the Maternal Microbiome

Microbiome science offers a glimpse into personalized medicine by characterizing health and disease states according to an individual's microbial signatures. Without a critical examination of the use of race as a variable, microbiome studies may be susceptible to the same pitfalls as other areas of science grounded in racist biology. We will examine the use of race as a biological variable in pregnancy-related microbiome research. Emerging data from studies that investigate the intestinal microbiome in pregnancy suggest strong influence of a poor diet on adverse pregnancy outcomes. Differences in the vaginal microbiome implicated in adverse pregnancy outcomes are frequently attributed to race. We review evidence that links systemic racism to pregnancy health outcome differences with a focus on the vaginal and intestinal microbiomes as well as diet. We also review how structural racism ultimately contributes to inequitable access to healthy food and higher risk environmental exposures among pregnant people of lower socioeconomic status and exacerbates common pregnancy comorbidities.

Joint effects of individual socioeconomic status and residential neighborhood context on vaginal microbiome composition

Introduction

The vaginal microbiome is a dynamic ecosystem that is important for women's health. Its composition has been associated with risk for menopausal symptoms, sexually transmitted infections, gynecologic cancer, and preterm birth. Conventional risk factors for a vaginal microbiome linked with these adverse health outcomes include sexual behaviors, hygiene practices, individual social factors, and stress levels. However, there has been limited research on socio-contextual determinants, and whether neighborhood context modifies the association with individual socioeconomic factors.

Methods

Socioeconomically diverse pregnant African American women in Atlanta, Georgia (n = 439) provided residential addresses and first trimester vaginal swab samples, which underwent sequencing, taxonomic classification, and assignment into mutually exclusive CST (community state types) via hierarchical clustering. Linear probability models were used to estimate prevalence differences (PD) for the associations of neighborhood factors with vaginal microbiome CST and to evaluate for additive interaction with maternal level of education, health insurance type, and recruitment hospital.

Results

Factors such as higher (vs. lower) maternal education, private (vs. public) insurance, and private (vs. public) hospital were associated with higher prevalence of Lactobacillus-dominant vaginal microbiome CSTs typically associated with better health outcomes. When considering the joint effects of these individual socioeconomic status and residential neighborhood factors on vaginal microbiome CST, most combinations showed a greater than additive effect among the doubly exposed; however, in the case of local income homogeneity and local racial homogeneity, there was evidence of a crossover effect between those with less-advantaged individual socioeconomic status and those with more-advantaged individual socioeconomic status. Compared to women at the public hospital who lived in economically diverse neighborhoods, women at the private hospital who lived in economically diverse neighborhoods had a 21.9% higher prevalence of Lactobacillus-dominant CSTs, while women at the private hospital who lived in less economically diverse neighborhoods (the doubly exposed) had only an 11.7% higher prevalence of Lactobacillus-dominant CSTs, showing a crossover effect (interaction term p-value = 0.004).

Discussion

In this study, aspects of residential neighborhood context were experienced differently by women on the basis of their individual resources, and the joint effects of these exposures on vaginal microbiome CST showed a departure from simple additivity for some factors.

Preconception stress exposure from childhood to adolescence and birth outcomes: The impact of stress type, severity and consistency

The negative effects of prenatal stress on offspring health are well established, but there remains little understanding of the influence of stress prior to conception despite known effects on biological systems that are important for a healthy pregnancy. Furthermore, operational definitions of stress vary considerably, and exposure is often characterized via summed, ordinal scales of events. We hypothesized that type, severity, and consistency of preconception stress would be associated with birthweight and gestational age (GA) at birth. Data were drawn from a subsample of participants in the 21-year longitudinal Pittsburgh Girls Study (PGS, N = 2,450) that has followed women annually since childhood. Prior work in the PGS derived three domains of stress exposure between ages 7-17 years related to subsistence (e.g., resource strain, overcrowding), safety (e.g., community violence, inter-adult aggression), and caregiving (e.g., separation, maternal depression). We tested the effects of dimensions of preconception stress on birthweight and GA among offspring of 490 PGS participants who delivered at age 18 or older (n = 490; 76% Black, 20% White, 4% Multiracial). Our hypotheses were partially supported with results varying by stress type and severity and by infant sex. Severity of preconception exposure to subsistence stress was prospectively associated with lower offspring birthweight (B = -146.94, SE = 69.07, 95% CI = -282.66, -11.22). The association between severity of caregiving stress in childhood and adolescence and GA at birth was moderated by infant sex (B = 0.85, SE = .41, 95% CI = 0.04, 1.66), suggesting greater vulnerability to this type of stress for male compared to female infants. Exposure to safety stressors did not predict birth outcomes. Infants of Black compared with White mothers had lower birthweight in all models regardless of preconception stress type, severity or consistency. However, we observed no moderating effects of race on preconception stress-birth outcome associations. Demonstrating specificity of associations between preconception stress exposure and prenatal health has the potential to inform preventive interventions targeting profiles of exposure to optimize birth outcomes.

Psychosocial impact of recurrent urogenital infections: a review

Recurrent urogenital infections such as bacterial vaginosis, vulvovaginal candidiasis, and urinary tract infections have a high prevalence and pronounced psychosocial impact. However, no review has compared the psychosocial impacts across infection types. This narrative review discusses the impact of common recurrent urogenital infections on psychosocial aspects, including quality of life, stress, mental health, sexual health, work productivity, race and ethnicity, and satisfaction of medical care. Validated questionnaires show that women with recurrent vulvovaginal candidiasis and urinary tract infections have decreased scores on all aspects of quality of life. Those with recurrent vulvovaginal candidiasis and urinary tract infections show lower mental health scores compared to the general population, with increased risk of anxiety and depression. Recurrent urogenital infections affect sexual relationships and intimacy, including avoidance due to symptoms or as a method of prevention. Recurrent infections also increase medical cost and negatively affect work productivity, leading to a combined estimated cost of over US$13 billion per year. There are clear effects of racial inequality involving minority populations that affect diagnosis, treatment, prevalence, and reporting of recurrent urogenital infections. Satisfactory medical treatment improves quality of life and mental health in those suffering from these conditions. Research evaluating psychosocial aspects of recurrent urogenital infections is variable and is not comparable across vulvovaginal conditions. Even so, psychosocial factors are important in understanding contribution and consequence of urogenital infections. Education, awareness, normalization, community support, and access to care can help to alleviate the negative implications of recurrent urogenital infections.

The female reproductive tract microbiotas, inflammation, and gynecological conditions

The intricate interactions between the host cells, bacteria, and immune components that reside in the female reproductive tract (FRT) are essential in maintaining reproductive tract homeostasis. Much of our current knowledge surrounding the FRT microbiota relates to the vaginal microbiota, where ‘health’ has long been associated with low bacterial diversity and Lactobacillus dominance. This concept has recently been challenged as women can have a diverse vaginal microbial composition in the absence of symptomatic disease. The structures of the upper FRT (the endocervix, uterus, Fallopian tubes, and ovaries) have distinct, lower biomass microbiotas than the vagina; however, the existence of permanent microbiotas at these sites is disputed. During homeostasis, a balance exists between the FRT bacteria and the immune system that maintains immune quiescence. Alterations in the bacteria, immune system, or local environment may result in perturbances to the FRT microbiota, defined as dysbiosis. The inflammatory signature of a perturbed or “dysbiotic” FRT microbiota is characterized by elevated concentrations of pro-inflammatory cytokines in cervical and vaginal fluid. It appears that vaginal homeostasis can be disrupted by two different mechanisms: first, a shift toward increased bacterial diversity can trigger vaginal inflammation, and second, local immunity is altered in some manner, which disrupts the microbiota in response to an environmental change. FRT dysbiosis can have negative effects on reproductive health. This review will examine the increasing evidence for the involvement of the FRT microbiotas and inflammation in gynecologic conditions such as endometriosis, infertility, and endometrial and ovarian cancer; however, the precise mechanisms by which bacteria are involved in these conditions remains speculative at present. While only in their infancy, the use of antibiotics and probiotics to therapeutically alter the FRT microbiota is being studied and is discussed herein. Our current understanding of the intimate relationship between immunity and the FRT microbiota is in its early days, and more research is needed to deepen our mechanistic understanding of this relationship and to assess how our present knowledge can be harnessed to assist in diagnosis and treatment of gynecologic conditions.

Puberty- and Menstruation-Related Stressors Are Associated with Depression, Anxiety, and Reproductive Tract Infection Symptoms Among Adolescent Girls in Tanzania

BACKGROUND

Puberty and menstruation are significant stressors for adolescent girls and young women in low-resource settings in sub-Saharan Africa. However, little is known about the impact of these stressors on girls' mental health and reproductive health.

METHODS

In 2018, a cross-sectional self-report survey was conducted with 581 adolescent girls and young women between 13 to 21 years old who had reached menarche and were attending secondary school in Moshi, Tanzania. Structural equation modeling was used to examine the relationships of puberty-related stressors and menstruation-related stressors (menstrual deficits, movement/activity difficulties, and menstrual symptoms) to depression, anxiety, and the likelihood of reporting reproductive tract infection (RTI) symptoms.

RESULTS

Puberty-specific stressors, menstrual symptoms, and menstrual deficits were associated with depression and anxiety. Movement/activity difficulties were associated with anxiety. Increases in menstrual symptoms, menstrual deficits, puberty stressors, and depression were associated with an increased likelihood of reporting a lifetime RTI. However, the relationship of puberty stressors and depression with RTIs was no longer significant in two of three models after correcting for Type I error.

CONCLUSIONS

Overall, puberty- and menstruation-related stressors were associated with mental health and symptoms of reproductive tract infections. This suggests there is an important relationship between stressors specific to adolescent girls and young women during puberty, mental health, and reproductive health. There is a need for adolescent-tailored interventions to reduce the negative impact of stressors among girls transitioning through puberty in sub-Saharan Africa.

Vaginal microbiota of American Indian women and associations with measures of psychosocial stress

Molecular-bacterial vaginosis (BV) is characterized by low levels of vaginal Lactobacillus species and is associated with higher risk of sexually transmitted infections (STI). Perceived psychosocial stress is associated with increased severity and persistence of infections, including STIs. American Indians have the highest rates of stress and high rates of STIs. The prevalence of molecular-BV among American Indian women is unknown. We sought to evaluate measures of psychosocial stress, such as historic loss (a multigenerational factor involving slavery, forced removal from one's land, legally ratified race-based segregation, and contemporary discrimination) and their association with the vaginal microbiota and specific metabolites associated with BV, in 70 Northwestern Plains American Indian women. Demographics, perceived psychosocial stressors, sexual practices, and known BV risk factors were assessed using a modified version of the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project survey. Self-collected mid-vaginal swabs were profiled for bacterial composition by 16S rRNA gene amplicon sequencing and metabolites quantified by targeted liquid-chromatography mass spectrometry. Sixty-six percent of the participants were classified as having molecular-BV, with the rest being either dominated by L. crispatus (10%) or L. iners (24%). High levels of lifetime trauma were associated with higher odds of having molecular-BV (adjusted Odds Ratio (aOR): 2.5, 95% Credible Interval (CrI): 1.1-5.3). Measures of psychosocial stress, including historic loss and historic loss associated symptoms, were significantly associated with lifestyle and behavioral practices. Higher scores of lifetime trauma were associated with increased concentrations of spermine (aFC: 3.3, 95% CrI: 1.2-9.2). Historic loss associated symptoms and biogenic amines were the major correlates of molecular-BV. Historical loss associated symptoms and lifetime trauma are potentially important underlying factors associated with BV.

Perceived Stress and Molecular Bacterial Vaginosis in the National Institutes of Health Longitudinal Study of Vaginal Flora

Vaginal microbiota provide the first line of defense against urogenital infections primarily through protective actions of Lactobacillus species Perceived stress increases susceptibility to infection through several mechanisms, including suppression of immune function. We investigated whether stress was associated with deleterious changes to vaginal bacterial composition in a subsample of 572 women in the Longitudinal Study of Vaginal Flora, sampled from 1999 through 2002. Using Cox proportional hazards models, both unadjusted and adjusted for sociodemographic factors and sexual behaviors, we found that participants who exhibited a 5-unit-increase in Cohen's Perceived Stress Scale had greater risk (adjusted hazard ratio (HR) = 1.40, 95% confidence interval (CI): 1.13, 1.74) of developing molecular bacterial vaginosis (BV), a state with low Lactobacillus abundance and diverse anaerobic bacteria. A 5-unit increase in stress score was also associated with greater risks of transitioning from the L. iners-dominated community state type (26% higher) to molecular-BV (adjusted HR = 1.26, 95% CI: 1.01, 1.56) or maintaining molecular-BV from baseline (adjusted HR = 1.23, 95% CI: 1.01, 1.47). Inversely, women with baseline molecular-BV reporting a 5-unit stress increase were less likely to transition to microbiota dominated by L. crispatus, L. gasseri, or L. jensenii (adjusted HR = 0.81, 95% CI: 0.68, 0.99). These findings suggest that psychosocial stress is associated with vaginal microbiota composition, inviting a more mechanistic exploration of the relationship between psychosocial stress and molecular-BV.

High fitness levels offset the increased risk of chronic obstructive pulmonary disease due to low socioeconomic status: A cohort study

OBJECTIVE

Evidence suggests that higher cardiorespiratory fitness (CRF) levels can offset the increased risk of adverse outcomes due to other risk factors. The impact of high CRF levels on the increased risk of chronic obstructive pulmonary disease (COPD) due to low socioeconomic status (SES) is unknown. We aimed to assess the combined effects of SES and CRF on the future risk of COPD.

METHODS

We employed a prospective cohort of 2312 Finnish men aged 42-61 years at study entry. Socioeconomic status was self-reported and CRF was objectively assessed using respiratory gas exchange analyzers. Both exposures were categorized as low and high based on median cutoffs. Multivariable-adjusted hazard ratios (HRs) with confidence intervals (CIs) were estimated.

RESULTS

During 26.0 years median follow-up, 120 COPD cases occurred. Low SES was associated with increased COPD risk and high CRF was associated with reduced COPD risk. Compared with high SES-low CRF, low SES-low CRF was associated with an increased COPD risk 2.36 (95% CI: 1.44-3.87), with no evidence of an association for low SES-high CRF and COPD risk 1.46 (95% CI:0.82-2.60).

CONCLUSION

In middle-aged Finnish men, SES and CRF are each independently associated with COPD risk. However, high CRF levels offset the increased COPD risk related to low SES.

Exploring the global vaginal microbiome and its impact on human health

Around the world, more than 175,000,000 women are diagnosed every year with gynaecological disease, in many cases contributing to high morbidity and mortality. For this reason, knowledge of the composition of the vaginal microbiome and its variations represents a real health challenge, as this is key to improving therapeutic management. This review traces the history of the poorly known vaginal microbiome and focuses on the latest findings concerning this ecosystem. Studies in the past decade have targeted complex bacterial communities within the vagina. However, due to the development of technology and the emergence of next generation sequencing (NGS), the exact definition of the vaginal microbiome has changed and can no longer be linked solely to the presence of bacteria. In order to reach a global view of the vaginal microbiome, it is essential to take into account all microorganisms that the vagina harbours, including fungi, viruses, archaea, and candidate phyla radiation. Although these communities represent only a minimal percentage of the vaginal microbiome, they may act as modifiers of its basic physiology and may play a key role in the maintenance of microbial communities, as well as metabolic and immune functions. Studies of the complex interactions between these different microorganisms have recently begun and are not yet fully understood. Results to date indicate that these microbial communities together constitute the first line of defence against infections. On the other hand, the slightest disturbance in this microbiome may lead to disease. For this reason, enhanced knowledge of these associations is critical to better identify predispositions to certain illnesses, which may open new therapeutic avenues. Currently however, only the tip of the iceberg is understood and current research on this ecosystem is revolutionising our knowledge and understanding of human health and disease.

[Ten questions about bacterial vaginosis]

The physiopathology of bacterial vaginosis (BV), the ultimate stage of vaginal dysbiosis, has benefited from recent advances in molecular biology, highlighting, among others, the important role of A. vaginae. Certain immunological specificities (variants of TLR4, elevation of IL-1β, for example) explain the variations in the prevalence of this infection, the poor clinical and cellular inflammatory response and the promoting influence of BV on the acquisition and progression of some sexually transmitted infections. These advances do not fully elucidate the causes of the high rate of recurrences. Some risk factors for relapses of BV have been identified such as tobacco use, stress or hygienic errors have been associated to relapses of BV. However, other paths are beginning to be explored such as the role of sexual transmission, the resistance of certain bacteria associated to BV to nitroimidazoles or the lack of efficacy of conventional treatments on dysbiosis itself. Taking into acount this vaginal dysbiosis appears to be important or even essential to better control the natural history of HPV-hr infection or improve the success rate of IVF, for example. Despite heterogeneous results, the use of probiotics as a complement to conventional treatments (nitroimidazoles, dequalinium chloride) has demonstrated a preventive effect on BV recurrences. Further studies are needed to customize the contribution of probiotics (or synbiotics) according to the individual specificities of the vaginal microbiome.

Socioeconomic Position and the Incidence, Severity, and Clinical Outcomes of Hospitalized Patients With Community-Acquired Pneumonia

OBJECTIVES

The influence of socioeconomic disparities on adults with pneumonia is not well understood. The objective of our study was to evaluate the relationship between community-level socioeconomic position, as measured by an area deprivation index, and the incidence, severity, and outcomes among adults with community-acquired pneumonia (CAP).

METHODS

This was an ancillary study of a population-based, prospective cohort study of patients hospitalized with CAP in Louisville, Kentucky, from June 1, 2013, through May 31, 2015. We used a race-specific, block group-level area deprivation index as a proxy for community-level socioeconomic position and evaluated it as a predictor of CAP incidence, CAP severity, early clinical improvement, 30-day mortality, and 1-year mortality.

RESULTS

The cohort comprised 6349 unique adults hospitalized with CAP. CAP incidence per 100 000 population increased significantly with increasing levels of area deprivation, from 303 in tertile 1 (low deprivation), to 467 in tertile 2 (medium deprivation), and 553 in tertile 3 (high deprivation) (P < .001). Adults in medium- and high-deprivation areas had significantly higher odds of severe CAP (tertile 2 odds ratio [OR] = 1.2 [95% confidence interval (CI), 1.06-1.39]; tertile 3 OR = 1.4 [95% CI, 1.18-1.64] and 1-year mortality (tertile 2 OR = 1.3 [95% CI, 1.11-1.54], tertile 3 OR = 1.3 [95% CI, 1.10-1.64]) than adults in low-deprivation areas.

CONCLUSIONS

Compared with adults residing in low-deprivation areas, adults residing in high-deprivation areas had an increased incidence of CAP, and they were more likely to have severe CAP. Beyond 30 days of care, we identified an increased long-term mortality for persons in high-deprivation areas. Community-level socioeconomic position should be considered an important factor for research in CAP and policy decisions.

How the evolving epidemics of opioid misuse and HIV infection may be changing the risk of oral sexually transmitted infection risk through microbiome modulation

The epidemiology of sexually transmitted infections (STI) is constantly evolving, and the mechanisms of infection risk in the oral cavity (OC) are poorly characterized. Evidence indicates that microbial community (microbiota) compositions vary widely between the OC, genitalia and the intestinal and rectal mucosa, and microbiome-associated STI susceptibility may also similarly vary. The opioid misuse epidemic is at an epidemic scale, with >11 million US residents misusing in the past 30 days. Opioids can substantially influence HIV progression, microbiota composition and immune function, and these three factors are all mutually influential via direct and indirect pathways. While many of these pathways have been explored independently, the supporting data are mostly derived from studies of gut and vaginal microbiotas and non-STI infectious agents. Our purpose is to describe what is known about the combination of these pathways, how they may influence microbiome composition, and how resultant oral STI susceptibility may change. A better understanding of how opioid misuse influences oral microbiomes and STI risk may inform better mechanisms for oral STI screening and intervention. Further, the principles of interaction described may well be applied to other aspects of disease risk of other health conditions which may be impacted by the opioid epidemic.

Perceived stress and incident sexually transmitted infections in a prospective cohort

PURPOSE

Psychosocial stress has been associated with susceptibility to many infectious pathogens. We evaluated the association between perceived stress and incident sexually transmitted infections (STIs; Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis genital infections) in a prospective study of women. Stress may increase vulnerability to STIs by suppressing immune function and altering the protective vaginal microbiota.

METHODS

Using the 1999 Longitudinal Study of Vaginal Flora (n = 2439), a primarily African American cohort of women, we fitted Cox proportional hazards models to examine the association between perceived stress and incident STIs. We tested bacterial vaginosis (measured by Nugent Score) and sexual behaviors (condom use, number of partners, and partner concurrence) as mediators using VanderWeele's difference method.

RESULTS

Baseline perceived stress was associated with incident STIs both before and after adjusting for confounders (adjusted hazard ratio = 1.015; 95% confidence interval, 1.005-1.026). Nugent score and sexual behaviors significantly mediated 21% and 65% of this adjusted association, respectively, and 78% when included together in the adjusted model.

CONCLUSIONS

This study advances understanding of the relationship between perceived stress and STIs and identifies high-risk sexual behaviors and development of bacterial vaginosis-both known risk factors for STIs-as mechanisms underlying this association.

Psychosocial Stress, Cortisol Levels, and Maintenance of Vaginal Health

Stress stimuli are ubiquitous and women do not enjoy any exemptions. The physiologic "fight-or-flight" response may be deleterious to the female lower genital tract microbiome if the stress stimuli persist for longer than necessary. Persistent exposure to psychosocial stress and stimulation of the hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) axes, and associated hormones are risk factors for several infections including genitourinary tract infections. Though this could be due to a dysregulated immune response, a cortisol-induced inhibition of vaginal glycogen deposition may be involved especially in the instance of vaginal infection. The estrogen-related increased vaginal glycogen and epithelial maturation are required for the maintenance of a healthy vaginal ecosystem (eubiosis). The ability of cortisol to disrupt this process as indicated in animal models is important in the pathogenesis of vaginal dysbiosis and the subsequent development of infection and inflammation. This phenomenon may be more crucial in pregnancy where a healthy Lactobacillus-dominated vaginal microbiota is sacrosanct, and there is local production of more corticotropin-releasing hormone (CRH) from the decidua, fetal membranes and placenta. To highlight the relationship between the stress hormone cortisol and the vaginal microbiomial architecture and function, the potential role of cortisol in the maintenance of vaginal health is examined.

The Maternal Gut Microbiome During Pregnancy

The gut microbiome is a critical component of an individual's metabolism and overall health. The prenatal period is marked by unique inflammatory and immune changes that alter maternal gut function and bacterial composition as the pregnancy advances. The composition of the maternal gut microbiome contributes to obstetric outcomes with long-term health sequelae for mother and child. Estrogen and progesterone also have an impact on gut function, especially during the prenatal period. These physiologic changes in pregnancy allow for adjustments in maternal metabolism and weight necessary to support the pregnancy. Normal hormonal, metabolic, and immunologic changes to the maternal gut microbiome throughout the prenatal period are reviewed, including relevant implications for nurses providing care for pregnant women.

Women view key sexual behaviours as the trigger for the onset and recurrence of bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) affects a third of women of reproductive age in the US and there is increasing evidence to suggest it may be sexually transmitted. This study aimed to extend and validate the findings of our earlier smaller qualitative study by exploring in detail women's views and experiences of the triggering factors associated with BV onset and recurrence.

METHODS

Women aged 20-49, who had experienced one or more symptomatic episode of BV within 6 months, were opportunistically recruited to complete a 38-item questionnaire on their experience of BV.

RESULTS

103 women completed the questionnaire. Women were significantly more likely to report sexual than lifestyle factors triggered BV onset and recurrence (p<0.001). The top 3 factors women attributed to both BV onset and recurrence were identical-and all sexual. They included, in order: 1) unprotected sex; 2) sex with a new male partner; and 3) sex in general. The main lifestyle factors nominated included stress, diet, menstruation and the use of feminine hygiene products. While many women felt their BV had been transmitted through sexual contact (54%) and developed as a result of sexual activity (59%), few considered BV a sexually transmitted infection (STI) (10%). Despite this 57% felt partners should also be treated for BV.

CONCLUSION

These data concur with our earlier qualitative findings that women believe BV is triggered by sexual activity. While many women felt BV was sexually transmitted and supported partner treatment, they did not consider BV an STI. This contradiction is likely due to information conveyed to women based on current guidelines. In the absence of highly effective BV treatments, this study highlights the need for guidelines to indicate there is scientific uncertainty around the pathogenesis of BV and to contain clear health messages regarding the evidence for practices shown to be associated with a reduced risk of BV (i.e. consistent condom use.

Prenatal Stress, Prematurity, and Asthma

Asthma is the most common chronic disease of childhood, affecting millions of children in the United States and worldwide. Prematurity is a risk factor for asthma, and certain ethnic or racial minorities such as Puerto Ricans and non-Hispanic blacks are disproportionately affected by both prematurity and asthma. In this review, we examine current evidence to support maternal psychosocial stress as a putative link between prematurity and asthma, while also focusing on disruption of the hypothalamic-pituitary-adrenal (HPA) axis and immune responses as potential underlying mechanisms for stress-induced "premature asthma." Prenatal stress may cause not only abnormalities in the HPA axis but also epigenetic changes in the fetal glucocorticoid receptor gene (NR3C1), leading to impaired glucocorticoid metabolism. Moreover, maternal stress can alter fetal cytokine balance, favoring TH2 (allergic) immune responses characteristic of atopic asthma: interleukin 6 (IL-6), which has been associated with premature labor, can promote TH2 responses by stimulating production of IL-4 and IL-13. Given a link among stress, prematurity, and asthma, future research should include birth cohorts aimed at confirming and better characterizing "premature asthma." If confirmed, clinical trials of prenatal maternal stress reduction would be warranted to reduce the burden of these common comorbidities. While awaiting the results of such studies, sound policies to prevent domestic and community violence (eg, from firearms) are justified, not only by public safety but also by growing evidence of detrimental effects of violence-induced stress on psychiatric and somatic health.

Evaluation of Health Disparity in Bacterial Vaginosis and the Implications for HIV-1 Acquisition in African American Women

There is a health disparity for both bacterial vaginosis (BV) and human immunodeficiency virus type 1 (HIV-1) infection in African American women that may be linked. The evidence that BV predisposes women to higher risk for HIV infection is well documented. The underlying mechanisms to support the epidemiological connections will require further investigations. This review explores the risk factors for BV disease with implications for HIV-1 acquisition in the context of race as a potential driver of the 20-fold increase in HIV-1 acquisition for African American women compared to white women. Specifically, it explores (i) disparities for BV in African American women, (ii) racial disparity for HIV-1 acquisition in African American women, (iii) common factors associated with BV and HIV acquisition in African American women, and (iv) potential mechanisms of the enhancement of HIV-1 transmission by BV.

Socioeconomic-related risk and sexually transmitted infection among African-American adolescent females

PURPOSE

Virtually no studies have examined the potential role that chronic stress, particularly the stress associated with socioeconomic status (SES) strain, may play on sexually transmitted infection (STI) risk. This study examined the association between SES-related risk at baseline to STI acquisition and reinfection over 36 months of follow-up.

METHODS

Six hundred twenty-seven African-American female adolescents, ages 14-20 years, recruited from sexual health clinics in Atlanta, GA, participated in a randomized controlled HIV prevention trial and returned for at least one follow-up assessment. Following baseline assessment, six waves of data collection occurred prospectively over 36 months. Chronic SES-related risk was assessed as a sum of yes-no exposure to seven risk indicators. Laboratory-confirmed tests for Chlamydia trachomatis and Neisseria gonorrhoeae were performed at each follow-up.

RESULTS

In multivariable regression analysis, SES-related risk significantly predicted STI acquisition over 36 months (adjusted odds ratio = 1.22) and STI reinfection (adjusted odds ratio = 1.16) above and beyond other known correlates of STI.

CONCLUSIONS

Findings demonstrate that SES-related risk was predictive of both STI acquisition and reinfection among young African-American females. They are consistent with propositions that some health disparities observed in adulthood may be linked to earlier chronically stress-inducing life experiences, particularly experiences associated with low SES conditions. Although various explanations exist for the observed connection between SES-related risk and subsequent STI acquisition and/or reinfection across 36 months of follow-up, these findings highlight the need for further research to elucidate the exact pathway(s) by which SES-related risk influences later STI acquisition to refine STI prevention interventions for this population.

Preconception stress, birth weight, and birth weight disparities among US women

OBJECTIVES

We examined the impact of preconception acute and chronic stressors on offspring birth weight and racial/ethnic birth weight disparities.

METHODS

We included birth weights for singleton live first (n = 3512) and second (n = 1901) births to White, Mexican-origin Latina, other-origin Latina, and Black women reported at wave IV of the National Longitudinal Study of Adolescent Health (2007-2008; ages 24-32 years). We generated factor scores for preconception acute and chronic stressors from wave I (1994-1995; ages 11-19 years) or wave III (2001-2002; ages 18-26 years) for the same cohort of women.

RESULTS

Linear regression models indicated that chronic stressors, but not acute stressors, were inversely associated with birth weight for both first and second births (b = -192; 95% confidence interval = -270, -113; and b = -180; 95% confidence interval = -315, -45, respectively), and partially explained the disparities in birth weight between the minority racial/ethnic groups and Whites.

CONCLUSIONS

Preconception chronic stressors contribute to restricted birth weight and to racial/ethnic birth weight disparities.

Differences in vaginal microbiome in African American women versus women of European ancestry

Women of European ancestry are more likely to harbour a Lactobacillus-dominated microbiome, whereas African American women are more likely to exhibit a diverse microbial profile. African American women are also twice as likely to be diagnosed with bacterial vaginosis and are twice as likely to experience preterm birth. The objective of this study was to further characterize and contrast the vaginal microbial profiles in African American versus European ancestry women. Through the Vaginal Human Microbiome Project at Virginia Commonwealth University, 16S rRNA gene sequence analysis was used to compare the microbiomes of vaginal samples from 1268 African American women and 416 women of European ancestry. The results confirmed significant differences in the vaginal microbiomes of the two groups and identified several taxa relevant to these differences. Major community types were dominated by Gardnerella vaginalis and the uncultivated bacterial vaginosis-associated bacterium-1 (BVAB1) that were common among African Americans. Moreover, the prevalence of multiple bacterial taxa that are associated with microbial invasion of the amniotic cavity and preterm birth, including Mycoplasma, Gardnerella, Prevotella and Sneathia, differed between the two ethnic groups. We investigated the contributions of intrinsic and extrinsic factors, including pregnancy, body mass index, diet, smoking and alcohol use, number of sexual partners, and household income, to vaginal community composition. Ethnicity, pregnancy and alcohol use correlated significantly with the relative abundance of bacterial vaginosis-associated species. Trends between microbial profiles and smoking and number of sexual partners were observed; however, these associations were not statistically significant. These results support and extend previous findings that there are significant differences in the vaginal microbiome related to ethnicity and demonstrate that these differences are pronounced even in healthy women.

Vaginal microbiome changes with levonorgestrel intrauterine system placement

OBJECTIVE

To investigate changes in female genital tract bacterial ecology associated with levonorgestrel intrauterine system (LNG IUS) use.

STUDY DESIGN

Study participants were regularly cycling Caucasian women without recent history of pregnancy or exogenous hormone use. Vaginal, cervical and uterine samples were obtained at nine time intervals, from 1 week before to 12 weeks after LNG IUS placement. Replicate paired vaginal and cervical specimens were collected to determine the consistency of specimen collection and processing.

RESULTS

A total of 406 samples from 11 women were available for analysis after DNA extraction, amplification and species identification. Of the 355 bacterial species or genera detected, Lactobacillus crispatus was most prevalent representing 48.9% of over 6 million total reads. L. crispatus reads of replicate vaginal samples were not significantly different [odds ratio (OR) 0.79, 0.36-1.73]. In addition, L. crispatus reads of vaginal and cervical samples from the same visit were not significantly different (OR 0.69, 0.31-1.51). Compared to sampling visits prior to LNG IUS placement, sampling visits after LNG IUS insertion were more likely to have L. crispatus reads greater than 50% of total reads (OR 2.13, 1.01-4.48). Of the 63 uterine samples demonstrating bacteria, Burkholderia genus proteobacteria, a common environmental contaminant, were most prevalent both before and after LNG IUS insertion accounting for 48.0% of all uterine sample reads.

CONCLUSION

The vaginal microbiome changes very little in response to LNG IUS placement. Further study is needed to place this finding in context with clinical outcomes.

IMPLICATIONS

There do not appear to be any clinically important differences in the vaginal microbiome in response to insertion of the LNG IUS.

Analysis of stress-responsive transcriptome in the intestine of Asian seabass (Lates calcarifer) using RNA-seq

Identification of differentially expressed genes (DEGs) and regulated pathways in response to stressors using a whole-genome approach is critical to understanding the mechanisms underlying stress responses. We challenged Asian seabass with lipopolysaccharide (LPS), Vibrio harveyi, high salinity and fasting, and sequenced six cDNA libraries of intestine samples using Roche 454 RNA-seq. Over 1 million reads (average size: 516 bp) were obtained. The de novo assembly obtained 83 911 unisequences with an average length of 747 bp. In total, 62.3% of the unisequences were annotated. We observed overall similar expression profiles among different challenges, while a number of DEGs and regulated pathways were identified under specific challenges. More than 1000 DEGs and over 200 regulated pathways for each stressor were identified. Thirty-seven genes were differentially expressed in response to all challenges. Our data suggest that there is a global coordination and fine-tuning of gene regulation during different challenges. In addition, we detected dramatic immune responses in intestines under different stressors. This study is the first step towards the comprehensive understanding of the mechanisms underlying stress responses and supplies significant transcriptome resources for studying biological questions in non-model fish species.

Understanding vaginal microbiome complexity from an ecological perspective

The various microbiota normally associated with the human body have an important influence on human development, physiology, immunity, and nutrition. This is certainly true for the vagina wherein communities of mutualistic bacteria constitute the first line of defense for the host by excluding invasive, nonindigenous organisms that may cause disease. In recent years much has been learned about the bacterial species composition of these communities and how they differ between individuals of different ages and ethnicities. A deeper understanding of their origins and the interrelationships of constituent species is needed to understand how and why they change over time or in response to changes in the host environment. Moreover, there are few unifying theories to explain the ecological dynamics of vaginal ecosystems as they respond to disturbances caused by menses and human activities such as intercourse, douching, and other habits and practices. This fundamental knowledge is needed to diagnose and assess risk to disease. Here we summarize what is known about the species composition, structure, and function of bacterial communities in the human vagina and the applicability of ecological models of community structure and function to understanding the dynamics of this and other ecosystems that comprise the human microbiome.

Metropolitan isolation segregation and Black-White disparities in very preterm birth: a test of mediating pathways and variance explained

Residential isolation segregation (a measure of residential inter-racial exposure) has been associated with rates of preterm birth (<37 weeks gestation) experienced by Black women. Epidemiologic differences between very preterm (<32 weeks gestation) and moderately preterm births (32-36 weeks) raise questions about whether this association is similar across gestational ages, and through what pathways it might be mediated. Hierarchical Bayesian models were fit to answer three questions: is the isolation-prematurity association similar for very and moderately preterm birth; is this association mediated by maternal chronic disease, socioeconomic status, or metropolitan area crime and poverty rates; and how much of the geographic variation in Black-White very preterm birth disparities is explained by isolation segregation? Singleton births to Black and White women in 231 U.S. metropolitan statistical areas in 2000-2002 were analyzed and isolation segregation was calculated for each. We found that among Black women, isolation is associated with very preterm birth and moderately preterm birth. The association may be partially mediated by individual level socioeconomic characteristics and metropolitan level violent crime rates. There is no association between segregation and prematurity among White women. Isolation segregation explains 28% of the geographic variation in Black-White very preterm birth disparities. Our findings highlight the importance of isolation segregation for the high-burden outcome of very preterm birth, but unexplained excess risk for prematurity among Black women is substantial.

Parental occupation and preterm births: a nationwide epidemiological study in Sweden

The hypothesis was that some occupations could lead to preterm birth (PTB) because of potential exposures to various agents. The objective in this nationwide follow-up study was to analyse the association between PTB and parental occupational groups, controlling for potential confounders. Data from the Swedish Medical Birth Register, in which all children born in Sweden from 1990 onward are registered with their parents, were linked to census data. Inclusion criteria for the study population were employment (both women and men) and age >20 years (women). There were 816,743 first singleton live births from 1990 to 2004, of whom 43,956 were PTBs. A total of 7659 of the 43,956 PTBs were very PTBs. Odds ratios (ORs) with 95% confidence intervals were calculated separately for mothers and fathers to estimate the odds of PTB and very PTB in 51 occupational groups (reference groups: mothers or fathers who were 'Technical, science research-related workers and physicians') and by family income level. Women and men with low family incomes had increased ORs of PTB and very PTB. Significantly increased ORs of PTB (including very PTB) were found in four maternal and nine paternal occupational groups after accounting for family income, geographic region of residence, civil status, smoking habits, maternal age at infant's birth and period of birth. Further studies should examine specific agents in those parental occupations that were associated with increased odds of PTB and very PTB.

Socioeconomic and racial/ethnic disparities in the incidence of bacteremic pneumonia among US adults

OBJECTIVES

We examined associations between the socioeconomic characteristics of census tracts and racial/ethnic disparities in the incidence of bacteremic community-acquired pneumonia among US adults.

METHODS

We analyzed data on 4870 adults aged 18 years or older with community-acquired bacteremic pneumonia identified through active, population-based surveillance in 9 states and geocoded to census tract of residence. We used data from the 2000 US Census to calculate incidence by age, race/ethnicity, and census tract characteristics and Poisson regression to estimate rate ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

During 2003 to 2004, the average annual incidence of bacteremic pneumonia was 24.2 episodes per 100 000 Black adults versus 10.1 per 100 000 White adults (RR = 2.40; 95% CI = 2.24, 2.57). Incidence among Black residents of census tracts with 20% or more of persons in poverty (most impoverished) was 4.4 times the incidence among White residents of census tracts with less than 5% of persons in poverty (least impoverished). Racial disparities in incidence were reduced but remained significant in models that controlled for age, census tract poverty level, and state.

CONCLUSIONS

Adults living in impoverished census tracts are at increased risk of bacteremic pneumonia and should be targeted for prevention efforts.

What causes racial disparities in very preterm birth? A biosocial perspective

Very preterm birth (<32 weeks' gestation) occurs in approximately 2% of livebirths but is a leading cause of infant mortality and morbidity in the United States. African-American women have a 2-fold to 3-fold elevated risk compared with non-Hispanic white women for reasons that are incompletely understood. This paper reviews the evidence for the biologic and social patterning of very preterm birth, with attention to leading hypotheses regarding the etiology of the racial disparity. A systematic review of the literature in the MEDLINE, CINAHL, PsycInfo, and EMBASE indices was conducted. The literature to date suggests a complex, multifactorial causal framework for understanding racial disparities in very preterm birth, with maternal inflammatory, vascular, or neuroendocrine dysfunction as proximal pathways and maternal exposure to stress, racial differences in preconceptional health, and genetic, epigenetic, and gene-environment interactions as more distal mediators. Interpersonal and institutionalized racism are mechanisms that may drive racially patterned differences. Current literature is limited in that research on social determinants and biologic processes of prematurity has been generally disconnected. Improved etiologic understanding and the potential for effective intervention may come with better integration of these research approaches.

Predicting risk of bacterial vaginosis: the role of race, smoking and corticotropin-releasing hormone-related genes

Bacterial vaginosis (BV) is one of the most prevalent vaginal disorders in adult women and is associated with adverse pregnancy outcomes such as pre-term birth. Genetic factors, particularly in genes involved in inflammation and infection, are associated with this condition. Additionally, environmental risk factors including stress and smoking are associated with BV. The purpose of this study was to identify genetic variants in stress-related genes such as corticotropin-releasing hormone (CRH), receptor 1, receptor 2 and binding protein (CRH-BP) that associate with BV. Also gene-environment effects with smoking are determined. BV was quantified using the Nugent score in 82 white and 65 black women in the first trimester of pregnancy. Associations between Nugent score, genotype and smoking were analyzed using Kruskal-Wallis and Wilcoxon rank sum non-parametric tests. In white women, non-smokers with the CT genotype at CRH-BP + 17487 have lower Nugent scores (median: 0, range: 0-0) than non-smokers with the TT genotype (median: 2, range: 0-8) (P = 0.002); whereas smokers with the CT genotype have higher Nugent scores (median: 6, range: 0-10) than smokers with the TT genotype (median: 1, range: 0-10) (P = 0.021). In black women, the AG genotype at CRH + 3362 or CRH - 1667 is associated with lower Nugent scores (median for both: 3, range: 0-10) compared with the homozygous genotypes (median for each homozygous genotype: 8, range: 0-10). Also, in black women, models remain significant after adjusting for smoking (P = 0.04 for both). These data indicate that susceptibility to BV is affected by patterns of genetic variation in stress-related genes and smoking plays an important role.

Intraocular inflammation: its causes and investigations

Intraocular inflammation, or uveitis, incorporates a diverse group of infectious and immune-mediated disorders. In addition, some conditions masquerade as uveitis. However, classifying uveitis according to anatomic location in adult and pediatric populations, and appreciating the effect of immune status and regional differences, refines the list of potential causes. In this way, a select few investigations can be performed, rather than a nondirected battery of tests.