The Epigenome at the Crossroad Between Social Factors, Inflammation, and Osteoporosis Risk

Structural Inequity and Socioeconomic Status Link to Osteoporosis Diagnosis in a Population-Based Cohort of Middle-Older-Age Americans

Socioeconomic status (SES) is an important social determinant of health inequities that has been linked to chronic conditions, including osteoporosis, but research tends to focus on socioeconomic disadvantage rather than how socioeconomic advantage may facilitate these inequities. This study accounts for structural inequities and assesses the relationship between early-life and later-life SES, and risk of osteoporosis diagnosis. Data come from the nationally representative, population-based cohort Health and Retirement Study and include individuals ages 50 to 90. The outcome variable is osteoporosis diagnosis. Logistic regression models of the relationship between SES and osteoporosis diagnosis are estimated, accounting for demographic, health, and childhood variables. Higher levels of childhood and adult SES link to lower odds of osteoporosis diagnosis. Structural inequities in income and underdiagnosis of osteoporosis among persons identifying as Black/African American were detected. Accounting for bone density scan access, inequities in osteoporosis diagnosis appear to stem from barriers to accessing health care due to financial constraints. The important role of SES and evidence of structural inequities leading to underdiagnosis suggest the critical importance of clinicians receiving Diversity, Equity, and Inclusion training to reduce health inequities.

How social/environmental determinants and inflammation affect salivary telomere length among middle-older adults in the health and retirement study

Social epidemiology posits that chronic stress from social determinants will lead to a prolonged inflammatory response that may induce accelerated aging as measured, for example, through telomere length (TL). In this paper, we hypothesize variables across demographic, health-related, and contextual/environmental domains influence the body’s stress response, increase inflammation (as measured through high-sensitivity C-reactive protein (hs-CRP)), and thereby lead to shortening of telomeres. This population-based research uses data from the 2008 Health and Retirement Study on participants ages ≤ 54–95 + years, estimating logistic regression and Cox proportional hazards models of variables (with and without confounders) across the domains on shortened TL. A mediation analysis is also conducted. Contrary to expectations, hs-CRP is not associated with risk of shortened TL. Rather, factors related to accessing health care, underlying conditions of frailty, and social inequality appear to predict risk of shorter TL, and models demonstrate considerable confounding. Further, hs-CRP is not a mediator for TL. Therefore, the social determinants of health examined do not appear to follow an inflammatory pathway for shortened TL. The finding of a relationship to social determinants affecting access to health care and medical conditions underscores the need to address social determinants alongside primary care when examining health inequities.

Assessing the roles of demographic, social, economic, environmental, health-related, and political factors on risk of osteoporosis diagnosis among older adults

Chronic stress from social/environmental pressures has been proposed to affect bone health through increased inflammation. We demonstrate that inflammation from prolonged stress does not cause changes to bone health through inflammation but instead impacts access to health care, social inequalities, and overall health, which in turn impact bone health.

PURPOSE

The study provides a comprehensive assessment of how determinants of health across demographic, psychological, mobility-related, health, environmental, and economic domains are associated with the diagnosis of osteoporosis and tests three hypotheses: (1) a diverse set of variables across domains will predict osteoporosis, (2) chronic inflammation as a result of stress (represented by high-sensitivity C-reactive protein) will not be associated with osteoporosis, and (3) the model developed will have high accuracy in predicting osteoporosis.

METHODS

Logistic regression and Cox proportional hazards models of osteoporosis diagnosis were estimated using data from 14,792 and 13,169 participants (depending on model) in the 2012-2016 waves of the Health and Retirement Study, including the Biomarker Study, the Contextual Data Resource, and validated measures of childhood socioeconomic status. Predictive accuracy was assessed using k-Nearest Neighbors Discriminant Analysis.

RESULTS

Demographic, environmental, and health-related factors were associated with osteoporosis diagnosis, and predictive accuracy of the models was good. High-sensitivity C-reactive protein was not associated with osteoporosis diagnosis.

CONCLUSION

Social determinants identified indicate access to health care, inequalities in the greater social environment (e.g., access to resources), and overall health (i.e., underlying medical conditions) are key components for developing osteoporosis and indicate underlying health inequities in this sample. There is a need to further address the interplay between primary health care and social determinants of health.

Extracellular Vesicles: Potential Mediators of Psychosocial Stress Contribution to Osteoporosis?

Osteoporosis is characterized by low bone mass and damage to the bone tissue’s microarchitecture, leading to increased fracture risk. Several studies have provided evidence for associations between psychosocial stress and osteoporosis through various pathways, including the hypothalamic-pituitary-adrenocortical axis, the sympathetic nervous system, and other endocrine factors. As psychosocial stress provokes oxidative cellular stress with consequences for mitochondrial function and cell signaling (e.g., gene expression, inflammation), it is of interest whether extracellular vesicles (EVs) may be a relevant biomarker in this context or act by transporting substances. EVs are intercellular communicators, transfer substances encapsulated in them, modify the phenotype and function of target cells, mediate cell-cell communication, and, therefore, have critical applications in disease progression and clinical diagnosis and therapy. This review summarizes the characteristics of EVs, their role in stress and osteoporosis, and their benefit as biological markers. We demonstrate that EVs are potential mediators of psychosocial stress and osteoporosis and may be beneficial in innovative research settings.

The Challenge by Multiple Environmental and Biological Factors Induce Inflammation in Aging: Their Role in the Promotion of Chronic Disease

The aging process is driven by multiple mechanisms that lead to changes in energy production, oxidative stress, homeostatic dysregulation and eventually to loss of functionality and increased disease susceptibility. Most aged individuals develop chronic low-grade inflammation, which is an important risk factor for morbidity, physical and cognitive impairment, frailty, and death. At any age, chronic inflammatory diseases are major causes of morbimortality, affecting up to 5-8% of the population of industrialized countries. Several environmental factors can play an important role for modifying the inflammatory state. Genetics accounts for only a small fraction of chronic-inflammatory diseases, whereas environmental factors appear to participate, either with a causative or a promotional role in 50% to 75% of patients. Several of those changes depend on epigenetic changes that will further modify the individual response to additional stimuli. The interaction between inflammation and the environment offers important insights on aging and health. These conditions, often depending on the individual's sex, appear to lead to decreased longevity and physical and cognitive decline. In addition to biological factors, the environment is also involved in the generation of psychological and social context leading to stress. Poor psychological environments and other sources of stress also result in increased inflammation. However, the mechanisms underlying the role of environmental and psychosocial factors and nutrition on the regulation of inflammation, and how the response elicited for those factors interact among them, are poorly understood. Whereas certain deleterious environmental factors result in the generation of oxidative stress driven by an increased production of reactive oxygen and nitrogen species, endoplasmic reticulum stress, and inflammation, other factors, including nutrition (polyunsaturated fatty acids) and behavioral factors (exercise) confer protection against inflammation, oxidative and endoplasmic reticulum stress, and thus ameliorate their deleterious effect. Here, we discuss processes and mechanisms of inflammation associated with environmental factors and behavior, their links to sex and gender, and their overall impact on aging.

Survival analysis of the Black Death: Social inequality of women and the perils of life and death in Medieval London

OBJECTIVES

Described as an indiscriminate killer by many chroniclers, the Black Death descended on London during the 14th century. To best understand the pattern of transmission among demographic groups, models should include multiple demographic and health covariates concurrently, something rarely done when examining Black Death, but implemented in this study to identify which demographic groups had a higher susceptibility. Female predisposition to the Black Death was also explored, focusing on whether social inequality added to vulnerability.

MATERIALS AND METHODS

Three attritional cemeteries from the Wellcome Osteological Research Database were compared with the Black Death cemetery, East Smithfield. A Cox proportional hazards regression estimated hazards ratios of dying of the Black Death, using transition analysis ages-at-death as the time variable, and sex and frailty as covariates. Additionally, a binomial logistic regression generated odds ratios for age-at-death, sex, and frailty.

RESULTS

The Cox model produced a significant hazards ratio for individuals deemed frail. Similarly, the logit model calculated significantly increased odds ratios for frail individuals, and decreased odds for individuals aged 65+.

DISCUSSION

The older individuals were not undergoing growth during times of great stress in London pre-dating the Black Death epidemic, which may explain the decreased odds of contracting the Black Death. Further, although women dealt with social inequality, which partially led to the demographic puzzle of the Medieval "missing" women, women's susceptibility to infection by the Black Death was not increased. The phenomenon of the missing women may be due to a combination of factors, including infant and child mortality and preservation.

Enamel neonatal line thickness in deciduous teeth of Australian children from known maternal health and pregnancy conditions

BACKGROUND

Physiological disruptions to early human development have implications for health and disease in later life. Limited research has explored how prenatal factors influence dental development in children of mothers with known pregnancy conditions. Enamel in human deciduous teeth begins forming in utero and is highly susceptible to physiological upsets experienced perinatally. The moment of birth itself is marked in deciduous enamel by the Neonatal Line (NNL) as a baby transitions from the uterine to external environment. This study evaluates the effect of maternal health factors that include stress and alcohol consumption on NNL in teeth from Australian children.

STUDY DESIGN AND SUBJECTS

Mothers (n = 53) were interviewed about their health during pregnancy and experience of birth. Sixty-five deciduous teeth (incisors, molars, one canine) from their children were donated for histological examination. Neonatal line thickness was measured from thin sections and evaluated against maternal and neonatal factors using statistical analyses, controlling for tooth type and birth number.

RESULTS AND CONCLUSIONS

The only maternal factor of a statistically significant effect on NNL thickness was alcohol consumption. Children of mothers who drank occasionally during pregnancy had a thicker NNL when compared to children of mothers who abstained. These results suggest that maternal lifestyle factors influence NNL formation possibly due to physiological changes that disrupt calcium homeostasis during enamel deposition. We highlight large intra-specific variation in human NNL expression. The potential of dental sampling in identifying children with prenatal exposure to alcohol is suggested.

Arthritis in adults, socioeconomic factors, and the moderating role of childhood maltreatment: cross-sectional data from the National Epidemiological Survey on Alcohol and Related Conditions

These data present associations between socioeconomic status (SES), different types of childhood maltreatment (CM) history and family dysfunction, and arthritis in men and women across a wide age range. Arthritis was less likely among those with higher SES, regardless of CM history.

INTRODUCTION

CM has been associated with increased risk of adult-onset arthritis; however, little is known about whether socioeconomic status moderates arthritis risk in those with CM history. We investigated arthritis across education, income, and race/ethnicity and whether CM moderated associations between SES and arthritis.

METHODS

Data were drawn from Wave 2 (2004-2005) of the nationally representative (USA) National Epidemiological Survey on Alcohol and Related Conditions (NESARC, n = 34,563; aged ≥ 20 years). Self-reported CM history included physical abuse, sexual abuse, emotional abuse, emotional neglect, physical neglect, and exposure to intimate partner violence (IPV). We used descriptive statistics and logistic regression to determine relationships between SES, CM, and arthritis. Interaction terms were used to test if CM moderated relationships between SES and arthritis.

RESULTS

Arthritis prevalence was 21.1% (n = 3093) among men and 30.1% (n = 6167) among women. In unadjusted analyses, women (p ≤ 0.001) and older age (both sexes, p ≤ 0.01) were associated with increased odds of arthritis. All CM types were associated with increased odds of arthritis, except exposure to IPV among women. In sex-stratified, age-adjusted analyses, lower education and income, family dysfunction, being Hispanic or Asian/Native Hawaiian/Pacific Islander, and ≥ 1 physical comorbidity were associated with increased odds of arthritis among those with and without CM: trends were similar for both sexes. In age-adjusted two-way interaction terms, CM did not moderate associations between SES and arthritis.

CONCLUSIONS

Although CM was associated with arthritis, associations between SES and arthritis were not amplified. Arthritis was less likely among those with higher SES, regardless of CM history.

Accelerated Aging: The Role of Socioeconomic, Social, Demographic, and Biological Factors on Bone Mineral Density

We investigate socioeconomic, social, demographic, and biological variables that are associated with chronic stress in the body to assess whether they have an effect on bone mineral density (BMD) as an indicator of accelerated aging. Multiple regression models were derived from data in the Midlife in the United States: A National Longitudinal Study of Health and Well-Being, Waves 1 (1995–1996) and 2 (2004–2006). Three BMD variables were used as outcomes: femoral, femoral neck, and spine T scores. The sample included 333 men and women aged 34–80. Poverty and C-reactive protein were related to BMD for spine T scores, partially consistent with hypotheses. But, marital status, perceived support of a partner, and education were not associated. Friend strain was discovered to have a relationship with BMD. More variables, and from a broader context, need to be examined together to understand what affects reduced BMD, given the high costs of accelerated aging.

A multifaceted analysis of social stressors and chronic inflammation

Chronic stress has been linked to negative health outcomes, including increased inflammation, which can be measured by high-sensitivity C-reactive protein (CRP). Prior research has focused almost exclusively on relationships between individual social and demographic stressors and CRP. The objective of this study is to assess the role of multiple potential stressors simultaneously to determine which key stressors are related to risk of high CRP, given that sustained stress and resulting inflammation may have long-term health implications. We hypothesized that negative social and environmental factors would be associated with high CRP. Data from two waves of Midlife in the United States were used to predict high CRP with variable selection procedures and logistic regression. Results indicated females, those with greater BMI, those with improvements in family strain, and those with higher A1c had a greater risk of high CRP. There was limited evidence that negative social factors were associated with CRP to the extent seen in prior literature. A key advantage of the study was testing multiple potential determinants of chronic stress and inflammation simultaneously, advancing the existing literature. Results demonstrate the potential usefulness of a multifaceted approach to evaluating the risk of chronic inflammation and high CRP.

Epigenetics of Skeletal Diseases

PURPOSE OF REVIEW

Epigenetic mechanisms modify gene activity in a stable manner without altering DNA sequence. They participate in the adaptation to the environment, as well as in the pathogenesis of common complex disorders. We provide an overview of the role of epigenetic mechanisms in bone biology and pathology.

RECENT FINDINGS

Extensive evidence supports the involvement of epigenetic mechanisms (DNA methylation, post-translational modifications of histone tails, and non-coding RNAs) in the differentiation of bone cells and mechanotransduction. A variety of epigenetic abnormalities have been described in patients with osteoporosis, osteoarthritis, and skeletal cancers, but their actual pathogenetic roles are still unclear. A few drugs targeting epigenetic marks have been approved for neoplastic disorders, and many more are being actively investigated. Advances in the field of epigenetics underscore the complex interactions between genetic and environmental factors as determinants of osteoporosis and other common disorders. Likewise, they help to explain the mechanisms by which prenatal and post-natal external factors, from nutrition to psychological stress, impact our body and influence the risk of later disease.

Associations between socioeconomic factors and proinflammatory cytokines in children, adolescents and young adults: a systematic review protocol

INTRODUCTION

There is now substantial evidence of a social gradient in bone health. Social stressors, related to socioeconomic status, are suggested to produce an inflammatory response marked by increased levels of proinflammatory cytokines. Here we focus on the particular role in the years before the achievement of peak bone mass, encompassing childhood, adolescence and young adulthood. An examination of such associations will help explain how social factors such as occupation, level of education and income may affect later-life bone disorders. This paper presents the protocol for a systematic review of existing literature regarding associations between socioeconomic factors and proinflammatory cytokines in those aged 6-30 years.

METHODS AND ANALYSIS

We will conduct a systematic search of PubMed, OVID and CINAHL databases to identify articles that examine associations between socioeconomic factors and levels of proinflammatory cytokines, known to influence bone health, during childhood, adolescence or young adulthood. The findings of this review have implications for the equitable development of peak bone mass regardless of socioeconomic factors. Two independent reviewers will determine the eligibility of studies according to predetermined criteria, and studies will be assessed for methodological quality using a published scoring system. Should statistical heterogeneity be non-significant, we will conduct a meta-analysis; however, if heterogeneity prevent numerical syntheses, we will undertake a best-evidence analysis to determine whether socioeconomic differences exist in the levels of proinflammatory cytokines from childhood through to young adulthood.

ETHICS AND DISSEMINATION

This study will be a systematic review of published data, and thus ethics approval is not required. In addition to peer-reviewed publication, these findings will be presented at professional conferences in national and international arenas.