Epigenetic Pathways in Human Disease: The Impact of DNA Methylation on Stress-Related Pathogenesis and Current Challenges in Biomarker Development

HPA axis genes implicated in glucocorticoid regulation play an important role in regulating the physiological impact of social and environmental stress, and have become a focal point for investigating the role of glucocorticoid regulation in the etiology of disease. We conducted a systematic review to critically assess the full range of clinical associations that have been reported in relation to DNA methylation of CRH, CRH-R1/2, CRH-BP, AVP, POMC, ACTH, ACTH-R, NR3C1, FKBP5, and HSD11β1/2 genes in adults. A total of 32 studies were identified. There is prospective evidence for an association between HSD11β2 methylation and hypertension, and functional evidence of an association between NR3C1 methylation and both small cell lung cancer (SCLC) and breast cancer. Strong associations have been reported between FKBP5 and NR3C1 methylation and PTSD, and biologically-plausible associations have been reported between FKBP5 methylation and Alzheimer's Disease. Mixed associations between NR3C1 methylation and mental health outcomes have been reported according to different social and environmental exposures, and according to varying gene regions investigated. We conclude by highlighting key challenges and future research directions that will need to be addressed in order to develop both clinically meaningful prognostic biomarkers and an evidence base that can inform public policy practice.

Attendance at Religious Services, Prayer, Religious Coping, and Religious/Spiritual Identity as Predictors of All-Cause Mortality in the Black Women's Health Study

Previous longitudinal studies have consistently shown an association between attendance at religious services and lower all-cause mortality, but the literature on associations between other measures of religion and spirituality (R/S) and mortality is limited. We followed 36,613 respondents from the Black Women's Health Study from 2005 through December 31, 2013 to assess the associations between R/S and incident all-cause mortality using proportional hazards models. After control for numerous demographic and health covariates, together with other R/S variables, attending religious services several times per week was associated with a substantially lower mortality rate ratio (mortality rate ratio = 0.64, 95% confidence interval: 0.51, 0.80) relative to never attending services. Engaging in prayer several times per day was not associated with mortality after control for demographic and health covariates, but the association trended towards a higher mortality rate ratio when control was made for other R/S variables (for >2 times/day vs. weekly or less, mortality rate ratio = 1.28, 95% confidence interval: 0.99, 1.67; P-trend < 0.01). Religious coping and self-identification as a very religious/spiritual person were associated with lower mortality when adjustment was made only for age, but the association was attenuated when control was made for demographic and health covariates and was almost entirely eliminated when control was made for other R/S variables. The results indicate that service attendance was the strongest R/S predictor of mortality in this cohort.

Childhood abuse, promoter methylation of leukocyte NR3C1 and the potential modifying effect of emotional support

AIM

To investigate childhood abuse victimization in relation to adult DNA methylation levels in a novel region of NR3C1, with emotional support as a possible modifier.

MATERIALS & METHODS

295 participants from the Black Women's Health Study. Multivariable linear regression models were used to compute differences in mean percent methylation levels.

RESULTS

Women reporting childhood abuse victimization exhibited higher mean NR3C1 methylation levels than nonabused women, with a clear dose-response relationship. Childhood emotional support appeared to attenuate associations only among women with the highest levels of physical and sexual abuse.

CONCLUSION

NR3C1 mean methylation was higher among women who reported childhood abuse. Further research is warranted to clarify whether or the extent to which childhood emotional support buffers the association.

Understanding and effectively addressing breast cancer in African American women: Unpacking the social context

Black women have a higher incidence of breast cancer before the age of 40 years, more severe disease at all ages, and an elevated mortality risk in comparison with white women. There is limited understanding of the contribution of social factors to these patterns. Elucidating the role of the social determinants of health in breast cancer disparities requires greater attention to how risk factors for breast cancer unfold over the lifecourse and to the complex ways in which socioeconomic status and racism shape exposure to psychosocial, physical, chemical, and other individual and community-level assaults that increase the risk of breast cancer. Research that takes seriously the social context in which black women live is also needed to maximize the opportunities to prevent breast cancer in this underserved group. Cancer 2016;122:2138-49. © 2016 American Cancer Society.

Adverse maternal exposures, methylation of glucocorticoid-related genes and perinatal outcomes: a systematic review

Aim: Maternal environmental exposures affect perinatal outcomes through epigenetic placental changes. We examine the literature addressing associations between adverse maternal exposures, perinatal outcomes and methylation of key genes regulating placental cortisol metabolism. Methods: We searched three databases for studies that examined NR3C1 and HSD11β1/HSD11 β 2 methylation with maternal exposures or perinatal outcomes. Nineteen studies remained after screening. We followed Cochrane's PRISMA reporting guidelines (2009). Results: NR3C1 and HSD11 β methylation were associated with adverse infant neurobehavior, stress response, blood pressure and physical development. In utero exposure to maternal stress, nutrition, preeclampsia, smoking and diabetes were associated with altered NR3C1 and HSD11 β methylation. Conclusion: NR3C1 and HSD11 β methylation are useful biomarkers of specific environmental stressors associated with important perinatal outcomes that determine pediatric and adult disease risk.

How Community Clergy Provide Spiritual Care: Toward a Conceptual Framework for Clergy End-of-Life Education

CONTEXT

Community-based clergy are highly engaged in helping terminally ill patients address spiritual concerns at the end of life (EOL). Despite playing a central role in EOL care, clergy report feeling ill-equipped to spiritually support patients in this context. Significant gaps exist in understanding how clergy beliefs and practices influence EOL care.

OBJECTIVES

The objective of this study was to propose a conceptual framework to guide EOL educational programming for community-based clergy.

METHODS

This was a qualitative, descriptive study. Clergy from varying spiritual backgrounds, geographical locations in the U.S., and race/ethnicities were recruited and asked about optimal spiritual care provided to patients at the EOL. Interviews were audio taped, transcribed, and analyzed following principles of grounded theory. A final set of themes and subthemes were identified through an iterative process of constant comparison. Participants also completed a survey regarding experiences ministering to the terminally ill.

RESULTS

A total of 35 clergy participated in 14 individual interviews and two focus groups. Primary themes included Patient Struggles at EOL and Clergy Professional Identity in Ministering to the Terminally Ill. Patient Struggles at EOL focused on existential questions, practical concerns, and difficult emotions. Clergy Professional Identity in Ministering to the Terminally Ill was characterized by descriptions of Who Clergy Are ("Being"), What Clergy Do ("Doing"), and What Clergy Believe ("Believing"). "Being" was reflected primarily by manifestations of presence; "Doing" by subthemes of religious activities, spiritual support, meeting practical needs, and mistakes to avoid; "Believing" by subthemes of having a relationship with God, nurturing virtues, and eternal life. Survey results were congruent with interview and focus group findings.

CONCLUSION

A conceptual framework informed by clergy perspectives of optimal spiritual care can guide EOL educational programming for clergy.

Hair cortisol in relation to sociodemographic and lifestyle characteristics in a multiethnic US sample

PURPOSE

We investigated the feasibility of obtaining hair samples from men and women at community-based barbershops and hair salons for analysis of cortisol and assessed sociodemographic and lifestyle correlates of hair cortisol concentrations (HCCs). A total of 102 participants completed the study.

METHODS

Research staff interviewed participants using a structured questionnaire, and samples of hair were collected. HCCs were determined using liquid chromatography-tandem mass spectrometry. Age- and sex-adjusted linear regression models were used to evaluate the association of HCC with covariates.

RESULTS

Analyses by race/ethnicity showed highest median HCC in blacks (12.5 [6.9-29.3]) pg/mg) followed by Hispanics (10.7 [5.8-14.9] pg/mg), whites (5.0 [3.8-10.8] pg/mg), and other participants (4.2 [3.3-15.7] pg/mg), P < .01. Current smokers had significantly higher median HCC (11.7 [8.8-18.9] pg/mg) compared with former smokers (4.6 [3.5-14.6] pg/mg) and those who had never smoked (6.9 [4.7-12.8] pg/mg), P = .04. After adjustment for age and sex, geometric mean HCC was 0.72 pg/mg lower in dyed hair compared with hair that was not dyed (β = -0.72, standard error = 0.30, 95% confidence interval, -1.29 to -0.15, P = .02).

CONCLUSIONS

HCC can be assessed in community-based studies. Future HCC studies should consider cosmetic hair treatment, cigarette smoking, and the potential role of psychosocial stressors in the association between race/ethnicity and HCC.

Correlates of cortisol in human hair: implications for epidemiologic studies on health effects of chronic stress

Assessment of cortisol concentrations in hair is one of the latest innovations for measuring long-term cortisol exposure. We performed a systematic review of correlates of cortisol in human hair to inform the design, analysis, and interpretation of future epidemiologic studies. Relevant publications were identified through electronic searches on PubMed, WorldCat, and Web of Science using keywords, "cortisol," "hair," "confounders," "chronic," "stress," and "correlates." Thirty-nine studies were included in this review. Notwithstanding scarce data and some inconsistencies, investigators have found hair cortisol concentrations to be associated with stress-related psychiatric symptoms and disorders (e.g., post-traumatic stress disorder), medical conditions indicating chronic activation of the hypothalamic-pituitary-adrenal axis (e.g., Cushing's syndrome), and other life situations associated with elevated risk of chronic stress (e.g., shiftwork). Results from some studies suggest that physical activity, adiposity, and substance abuse may be correlates of hair cortisol concentrations. In contrast to measures of short-term cortisol release (saliva, blood, and urine), cigarette smoking and use of oral contraceptives appear not to be associated with hair cortisol concentrations. Studies of pregnant women indicate increased hair cortisol concentrations across successive trimesters. The study of hair cortisol presents a unique opportunity to assess chronic alterations in cortisol concentrations in epidemiologic studies.

Looking to the future: incorporating genomic information into disparities research to reduce measurement error and selection bias

OBJECTIVE

To extend recent conceptual and methodological advances in disparities research to include the incorporation of genomic information in analyses of racial/ethnic disparities in health care and health outcomes.

DATA SOURCES

Published literature on human genetic variation, the role of genetics in disease and response to treatment, and methodological developments in disparities research.

STUDY DESIGN

We present a conceptual framework for incorporating genomic information into the Institute of Medicine definition of racial/ethnic disparities in health care, identify key concepts used in disparities research that can be informed by genomics research, and illustrate the incorporation of genomic information into current methods using the example of HER-2 mutations guiding care for breast cancer.

PRINCIPAL FINDINGS

Genomic information has not yet been incorporated into disparities research, though it has direct relevance to concepts of race/ethnicity, health status, appropriate care, and socioeconomic status. The HER-2 example demonstrates how available genetic information can be incorporated into current disparities methods to reduce selection bias and measurement error. Advances in health information infrastructure may soon make standardized genetic information more available to health services researchers.

CONCLUSION

Genomic information can refine measurement of racial/ethnic disparities in health care and health outcomes and should be included wherever possible in disparities research.

Discovering how environmental exposures alter genes could lead to new treatments for chronic illnesses

Emerging research demonstrates that diet, pollution, and other environmental triggers can alter both the function and expression of human genes and lead to a heightened disease risk. These environment-gene interactions can cause so-called epigenetic changes in gene expression-patterns of which genes are switched "on" or "off"-that may account for the rising mortality from chronic diseases in industrialized nations. In this paper, we call for a new transdisciplinary approach to public health that would examine how environmental exposures, both physical and social, influence gene expression and a person's susceptibility to chronic disease. This initiative could lead to new ways to prevent and treat such illnesses.

Ethical concerns related to developing pharmacogenomic treatment strategies for addiction

Pharmacogenomics (PGx) research is poised to enable physicians to identify optimally effective treatments for individual substance abusers based on their genetic profiles. This paper addresses ethical issues related to PGx treatment strategies for addiction, focusing especially on the use of race variables in genomics research and ensuring equitable access to novel PGx treatments. Unless the field addresses the ethical challenges posed by these issues, PGx treatment innovations for addiction threaten to exacerbate already dramatic disparities in the burden of drug dependence for minority and other underserved populations.

Black and White adults' perspectives on the genetics of nicotine addiction susceptibility

AIMS

Emerging research may soon lead to improved quit rates via genetically-tailored smoking cessation treatment. The purpose of this study was to explore individuals' beliefs and attitudes about genetic testing in this context, and how these may differ across racial groups.

DESIGN

Two site qualitative study.

METHODS

Eleven focus groups were conducted in 2007 with 51 Black and 55 White adult participants in Montgomery, AL and Baltimore, MD.

MEASUREMENTS

Questions were asked about smoking as an addiction, the role of genetics in nicotine addiction susceptibility, and undergoing genetic testing to receive tailored smoking cessation treatment. Data were analyzed using content analysis.

FINDINGS

Most participants believed that smoking was an addiction yet were unwilling to endorse the notion that genetics played a role in nicotine addiction susceptibility. However, 91% of White participants and 62% of Black participants indicated that they would likely take a genetic test that would match them to their optimal smoking cessation treatment. The primary potential benefit was a vague sense that additional knowledge about oneself would be of value. Primary barriers included disinterest and skepticism about the test, unwillingness to believe that genetics played a role in nicotine addiction or treatment response, and concerns about psychological consequences.

CONCLUSIONS

The majority of participants, particularly Black participants, did not believe that genetics played a significant role in nicotine addiction susceptibility but were willing to undergo genetic testing. Participants identified some benefit to tailoring smoking treatment by genotype. However, participants also expressed skepticism about the test and concerns about its consequences; these issues would need to be addressed in the clinical encounter.

Physician barriers to incorporating pharmacogenetic treatment strategies for nicotine dependence into clinical practice

Advances in genomics research may improve health outcomes by tailoring treatment according to patients' genetic profiles. The treatment of nicotine dependence, in particular, may soon encompass pharmacogenetic treatment models. Realizing the benefits of such treatment strategies may depend on physicians' preparedness to incorporate genetic testing into clinical practice. This article describes barriers to clinical integration of pharmacogenetic treatments that will need to be addressed to realize the benefits of individualized smoking-cessation treatment.

Effectiveness of extended-duration transdermal nicotine therapy: a randomized trial

BACKGROUND

Tobacco dependence is a chronic, relapsing condition that may require extended treatment.

OBJECTIVE

To assess whether extended-duration transdermal nicotine therapy increases abstinence from tobacco more than standard-duration therapy in adult smokers.

DESIGN

Parallel randomized, placebo-controlled trial from September 2004 to February 2008. Participants and all research personnel except the database manager were blinded to randomization. (ClinicalTrials.gov registration number: NCT00364156)

SETTING

Academic center.

PARTICIPANTS

568 adult smokers.

INTERVENTION

In an unstratified small block-randomization scheme, participants were randomly assigned to standard therapy (Nicoderm CQ [GlaxoSmithKline, Research Triangle Park, North Carolina], 21 mg, for 8 weeks and placebo for 16 weeks) or extended therapy (Nicoderm CQ, 21 mg, for 24 weeks).

MEASUREMENTS

The primary outcome was biochemically confirmed point-prevalence abstinence at weeks 24 and 52. Secondary outcomes were continuous and prolonged abstinence, lapse and recovery events, cost per additional quitter, and side effects and adherence.

RESULTS

At week 24, extended therapy produced higher rates of point-prevalence abstinence (31.6% vs. 20.3%; odds ratio, 1.81 [95% CI, 1.23 to 2.66]; P = 0.002), prolonged abstinence (41.5% vs. 26.9%; odds ratio, 1.97 [CI, 1.38 to 2.82]; P = 0.001), and continuous abstinence (19.2% vs. 12.6%; odds ratio, 1.64 [CI, 1.04 to 2.60]; P = 0.032) versus standard therapy. Extended therapy reduced the risk for lapse (hazard ratio, 0.77 [CI, 0.63 to 0.95]; P = 0.013) and increased the chances of recovery from lapses (hazard ratio, 1.47 [CI, 1.17 to 1.84]; P = 0.001). Time to relapse was slower with extended versus standard therapy (hazard ratio, 0.50 [CI, 0.35 to 0.73]; P < 0.001). At week 52, extended therapy produced higher quit rates for prolonged abstinence only (P = 0.027). No differences in side effects and adverse events between groups were found at the extended-treatment assessment.

LIMITATION

The generalizability of the findings may be limited because participants were smokers without medical comorbid conditions who were seeking treatment, and differences in adherence across treatment groups were detected.

CONCLUSION

Transdermal nicotine for 24 weeks increased biochemically confirmed point-prevalence abstinence and continuous abstinence at week 24, reduced the risk for smoking lapses, and increased the likelihood of recovery to abstinence after a lapse compared with 8 weeks of transdermal nicotine therapy.

PRIMARY FUNDING SOURCE

National Institutes of Health.

A four-system comparison of patients with chronic illness: the Military Health System, Veterans Health Administration, Medicaid, and commercial plans

We compared chronic care utilization in four major health systems in the U.S.: the military health system (TRICARE), the Department of Veterans Affairs (VA), Medicaid, and employer-sponsored commercial plans. Prevalence rates and key performance indicators were constructed from administrative data in federal fiscal year 2003 for eight chronic conditions: hypertension, major depression, diabetes, tobacco dependence, ischemic heart disease, severe mental illness, persistent asthma, and stroke. Continuously enrolled beneficiaries under 65 years old were studied: TRICARE (N = 2,963,987), VA (N = 2,114,739), Medicaid enrollees in five states (N = 5,554,974), and commercial insurance (N = 5,212,833). Condition-specific adjusted prevalence rates and measures were compared using the standardized rate ratio. For the majority of the conditions, the estimated prevalence rates were highest in the VA and Medicaid populations. Prevalence rates were generally lower in TRICARE and commercial plans. Medicaid beneficiaries had the highest hospitalization rates in four of the six conditions where hospitalization rates were measured. These results provide empirical evidence of differences in chronically ill patient populations in several of the major U.S. health insurance systems.

Evidence of an emerging digital divide among hospitals that care for the poor

Some hospitals that disproportionately care for poor patients are falling behind in adopting electronic health records (EHRs). Data from a national survey indicate early evidence of an emerging digital divide: U.S. hospitals that provide care to large numbers of poor patients also had minimal use of EHRs. These same hospitals lagged others in quality performance as well, but those with EHR systems seemed to have eliminated the quality gap. These findings suggest that adopting EHRs should be a major policy goal of health reform measures targeting hospitals that serve large populations of poor patients.

Primary care physicians' willingness to offer a new genetic test to tailor smoking treatment, according to test characteristics

Emerging pharmacogenetics research may improve clinical outcomes for common complex conditions typically treated in primary care settings. Physicians' willingness to offer genetically-tailored treatments to their patients will be critical to realizing this potential. According to recent research, it is likely that genotypes used to tailor smoking will have pleiotropic associations with other addictions and diseases, and may have different frequencies across populations. These additional features may pose an additional barrier to adoption. To assess physicians' willingness to offer a new test to individually tailor smoking treatment according to specific test characteristics, we conducted a national mailed survey of 2,000 U.S. primary care physicians (response rate: 62.3%). Physicians responded to a baseline scenario describing a new test to tailor smoking treatment, and three additional scenarios describing specific test characteristics based on published research; there was random assignment to one of two survey conditions in which the test was described as a genetic or non-genetic test. Our findings indicate physicians' self-reported likelihood (0-100 scale) that they would offer a new test to tailor smoking cessation treatment ranged from 69%-78% across all scenarios. Relative to baseline scenario responses, physicians were significantly less likely to offer the test when informed that the same genotypes assessed for treatment tailoring: (1) may also identify individuals predisposed to become addicted to nicotine (p<.001), (2) differ in frequency by race (p<.004), and (3) may have associations with other conditions (e.g., alcohol and cocaine addiction, attention deficit hyperactivity disorder ADHD and Tourette Syndrome) (p<.01). Describing a new test to individually tailor smoking treatment as a "genetic" versus non-genetic test significantly reduced physicians' likelihood of offering the test across all scenarios, regardless of specific test characteristics (p<.0007). Effective education of primary care physicians will be critical to successful integration of promising new pharmacogenetic treatment strategies for smoking.

Translating basic science to improve pharmacotherapy for nicotine dependence

Nicotine dependence has a complex multifactorial etiology, underscoring the value of applying a transdisciplinary research model. The important goal of treating nicotine dependence can be realized by transdisciplinary research that translates discoveries in basic neuroscience, pharmacology, genetics, and behavioral science to develop new treatment models that can be translated readily into the clinic and community. As part of this special issue highlighting work at the Transdisciplinary Tobacco Use Research Centers (TTURCs), we describe transdisciplinary research at the University of Pennsylvania TTURC aimed at elucidating the neurobiological and genetic basis of nicotine dependence, the development of novel medications, and the translation of this research to practice.

Electronic health records in ambulatory care--a national survey of physicians

BACKGROUND

Electronic health records have the potential to improve the delivery of health care services. However, in the United States, physicians have been slow to adopt such systems. This study assessed physicians' adoption of outpatient electronic health records, their satisfaction with such systems, the perceived effect of the systems on the quality of care, and the perceived barriers to adoption.

METHODS

In late 2007 and early 2008, we conducted a national survey of 2758 physicians, which represented a response rate of 62%. Using a definition for electronic health records that was based on expert consensus, we determined the proportion of physicians who were using such records in an office setting and the relationship between adoption and the characteristics of individual physicians and their practices.

RESULTS

Four percent of physicians reported having an extensive, fully functional electronic-records system, and 13% reported having a basic system. In multivariate analyses, primary care physicians and those practicing in large groups, in hospitals or medical centers, and in the western region of the United States were more likely to use electronic health records. Physicians reported positive effects of these systems on several dimensions of quality of care and high levels of satisfaction. Financial barriers were viewed as having the greatest effect on decisions about the adoption of electronic health records.

CONCLUSIONS

Physicians who use electronic health records believe such systems improve the quality of care and are generally satisfied with the systems. However, as of early 2008, electronic systems had been adopted by only a small minority of U.S. physicians, who may differ from later adopters of these systems.