Smoking and perceived stress in relation to short salivary telomere length among caregivers of children with disabilities

Burnout among high school students is linked to their telomere length and relatedness with peers

School burnout is a serious concern, as it impairs students' health and academic success. According to the Conservation of Resources Theory, burnout results from the depletion of personal coping resources and can be counteracted by supportive social relationships. However, it is not yet clear how students' relatedness with their peers is linked to their burnout. Next to students' self-reported fatigue, biomarkers such as telomere length (TL), which presents an indicator of aging, complement stress research. To identify school-related factors that may prevent students from experiencing burnout and to link TL to students' self-reported burnout, the current study investigated how relatedness with peers as well as TL at the beginning of the school year explained students' burnout at the end of the school year. The sample included 78 students (Mage = 13.7 ± 0.7 years; 48% girls). Results of multilevel analysis in Mplus indicate that, over the school year, students with higher TL and those who experienced relatedness with their peers reported lower levels of burnout. Moreover, students who felt related to their peers exhibited a longer TL. The study implies that students' relatedness with their peers may be a promising setscrew to prevent students' burnout and support their physical health. This is one of the first studies to link TL with school-related variables such as burnout and relatedness to peers in a non-clinical student sample, providing a baseline for interventions and future interdisciplinary studies in the field of education and stress.

A Lens on Caregiver Stress in Cancer: Longitudinal Investigation of Cancer-Related Stress and Telomere Length Among Family Caregivers of Adult Patients With Cancer

OBJECTIVE

Family members are typically the primary caregivers of patients with chronic illnesses. Family caregivers of adult relatives with cancer are a fast-growing population, yet the physical consequences of their stress due to the cancer in the family have been poorly understood. This study examined the bidirectional relations of the perceived stress of family caregivers of individuals recently diagnosed with cancer and leukocyte cellular aging indexed by telomere length for 2 years.

METHODS

Family caregivers ( N = 168; mean age = 51 years, 70% female, 46% Hispanic, 36% spouse to the patient) of patients with colorectal cancer provided psychological data and peripheral blood samples approximately 4 (T1), 12 (T2), and 21 months (T3) after diagnosis. Time-lagged cross-panel modeling was used to test the associations of perceived cancer-related stress and telomere length, controlling for age, sex, and body mass index.

RESULTS

Cancer-related stress was highest at T1 and decreased by 1 year. Greater cancer-related stress predicted longer telomere length at subsequent assessments for 2 years ( β ≥ 0.911, p ≤ .019). However, telomere length did not change significantly for 2 years overall and did not prospectively predict cancer-related stress over this period.

CONCLUSIONS

Findings suggest the need to better understand how the perceived stress of colorectal cancer caregivers, which tends to be intense for a relatively short period compared with dementia caregiving, may impact immune cell distributions and telomere length. These findings emphasize the need for further knowledge about psychobiological mechanisms of how cancer caregiving may impact cellular aging.

A standalone approach to utilize telomere length measurement as a surveillance tool in oral leukoplakia

Oral squamous cell carcinoma (OSCC) is often preceded by a white patch on a surface of the mouth, called oral leukoplakia (OL). As accelerated telomere length (TL) shortening in dividing epithelial cells may lead to oncogenic transformation, telomere length measurement could serve as a predictive biomarker in OL. However, due to high variability and lack of a universal reference, there has been a limited translational application. Here, we describe an approach of evaluating TL using paired peripheral blood mononuclear cells (PBMC) as an internal reference and demonstrate its translational relevance. Oral brush biopsy and paired venous blood were collected from 50 male OL patients and 44 male healthy controls (HC). Relative TL was measured by quantitative PCR. TL of each OL or healthy sample was normalized to the paired PBMC sample (TL ratio). In OL patients, the mean TL ratio was significantly smaller not only in the patch but also in distal normal oral tissue, relative to healthy controls without a high‐risk oral habit. Dysplasia was frequently associated with a subgroup that showed a normal TL ratio at the patch but significantly smaller TL ratio at a paired normal distal site. Our data suggest that evaluation of TL attrition using a paired PBMC sample eliminates the requirement of external reference DNA, makes data universally comparable and provides a useful marker to define high‐risk OL groups for follow‐up programs. Larger studies will further validate the approach and its broader application in other premalignant conditions.

Telomeres: New players in immune-mediated inflammatory diseases?

Telomeres are repetitive DNA sequences located at the ends of linear chromosomes that preserve the integrity and stability of the genome. Telomere dysfunctions due to short telomeres or altered telomere structures can ultimately lead to replicative cellular senescence and chromosomal instability, both mechanisms being hallmarks of ageing. Chronic inflammation, oxidative stress and finally telomere length (TL) dynamics have been shown to be involved in various age-related non-communicable diseases (NCDs). Immune-mediated inflammatory diseases (IMIDs), including affections such as inflammatory bowel disease, psoriasis, rheumatoid arthritis, spondyloarthritis and uveitis belong to this group of age-related NCDs. Although in recent years, we have witnessed the emergence of studies in the literature linking these IMIDs to TL dynamics, the causality between these diseases and telomere attrition is still unclear and controversial. In this review, we provide an overview of available studies on telomere dynamics and discuss the utility of TL measurements in immune-mediated inflammatory diseases.

Long-term tobacco exposure and immunosenescence: Paradoxical effects on T-cells telomere length and telomerase activity

Immunosenescence are alterations on immune system that occurs throughout an individual life. The main characteristic of this process is replicative senescence, evaluated by telomere shortening. Several factors implicate on telomere shortening, such as smoking. In this study, we evaluated the influence of smoking and Chronic Obstructive Pulmonary Disease (COPD) on cytokines, telomere length and telomerase activity. Blood samples were collected from subjects aged over 60 years old: Healthy (never smokers), Smokers (smoking for over 30 years) and COPDs (ex-smokers for ≥15 years). A young group was included as control. PBMCs were cultured for assessment of telomerase activity using RT-PCR, and cytokines secretion flow cytometry. CD4+ and CD8+ purified lymphocytes were used to assess telomere length using FlowFISH. We observed that COPD patients have accelerated telomere shortening. Paradoxically, smokers without lung damage showed preserved telomere length, suggesting that tobacco smoking may affect regulatory mechanisms, such as telomerase. Telomerase activity showed diminished activity in COPDs, while Smokers showed increased activity compared to COPDs and Healthy groups. Extracellular environment reflected this unbalance, indicated by an anti-inflammatory profile in Smokers, while COPDs showed an inflammatory prone profile. Further studies focusing on telomeric maintenance may unveil mechanisms that are associated with cancer under long-term smoking.

Testing Two Student Nurse Stress Instruments in Chinese Nursing Students: A Comparative Study Using Exploratory Factor Analysis

Background

The development and transformation of nursing within professional tertiary education have exerted a great pressure and challenge upon nursing students. Stress experienced by nursing students is a common precursor of psychological distress and attrition. However, no scale is specifically used to evaluate the sources of stress experienced by nursing students in Mainland China. Aims and Objective. This study is aimed at testing and comparing the reliability and validity including sensitivity and specificity of two nursing students' stress instruments, the Chinese version of Student Nurse Stress Index Scale (SNSI-CHI), and the Stressors in Student Nursing Scale (SINS-CN) in Chinese nursing students, and describing the stress status of nursing students in China.

Methods

A cross-sectional survey was conducted in two nursing schools in Henan Province from August 2017 to January 2018. Data were collected by using a questionnaire comprising the Chinese version of SNSI (SNSI-CHI), the Chinese version of SINS (SINS-CN), and the Chinese Perceived Stress Scale (CPSS). Homogeneity and stability, content, construct and concurrent validity, and sensitivity and specificity were assessed.

Results

The Cronbach's alpha (α) of SNSI-CHI was 0.90, and the item-to-total correlations ranged from 0.35 to 0.66. The Cronbach's α of SINS-CN was 0.93, and the item-to-total correlations ranged from 0.19 to 0.61. The findings of exploratory factor analysis (EFA) confirmed a good construct validity of SNSI-CHI and SINS-CN. The Pearson's rank correlation coefficients, between total scores of SNSI-CHI and CPSS and SINS-CN and CPSS, were assessed to 0.38 (P < 0.01) and 0.39 (P < 0.01), respectively. Regarding the CPSS, as the criterion, the cut-points of SNSI-CHI and SINS-CN for the area under the receiver operator characteristic (ROC) curve were 0.77and 0.66, respectively.

Conclusion

Both scales are valid and reliable for evaluating the source of stress of student nurses in China. Each has its own characteristics, but the SNSI-CHI demonstrated marginal advantage over the SINS-CN. The SNSI-CHI is short, is easily understood, and with clear dimension for the nursing students, and the SNSI-CHI is more acceptable for the users in China.

Social inequalities in accelerated aging among southern U.S. women: an analysis of the biosocial and behavioral pathways linking social determinants to telomere length

Few studies have examined the biosocial pathways linking socioeconomic status (SES) to accelerated aging in a population-based sample of southern US women. Even fewer have examined the importance of chronic compared to perceived stress in linking SES to women's salivary telomere length (STL). Using data from a probability-based sample of 156 US women and structural equation modeling, we examined three pathways - chronic stress exposure, stress appraisal, and coping behavior - linking SES to STL. SES was positively associated with STL (β_TE = 0.16, p < .05). Everyday discrimination was negatively associated with STL (β_DE = -0.21, p < .05), but perceived stress was positively associated with STL (β_DE = 0.20, p < .05). Current smoking decreased STL (β_DE = -0.19, p < .01). Perceived stress acted to suppress the negative relationship of chronic stress exposure on STL. Given the dearth of STL studies that include measures of both perceived and chronic stress, our study supports the importance of disentangling stress measures and a biosocial approach to the study of accelerated aging.

Sex-specific educational attainment is associated with telomere length in an Australian rural population

BACKGROUND

There is limited understanding on whether and how socioeconomic status (SES), particularly educational attainment and household income, impacts on telomere length in an Australian rural context. Additionally, it is unknown whether access to health services via the Australian public or private health system influences telomere length.

AIM

This study investigates whether there is a relationship between telomere length and SES indicators (income, education) as well as health insurance status in a rural Australian population.

METHODS

Samples were drawn from the Australian Rural Victoria cross-sectional Crossroads Study. Leucocyte telomere length (LTL) was measured using a multiplex quantitative polymerase chain reaction method.

RESULTS

Among 1424 participants, we did not find a significant main effect association with LTL across education, income level and health insurance. An exploratory finding was sex may influence the relationship between educational attainment and LTL (P = 0.021). In males, but not females, higher education was associated with longer LTL by 0.033 [95% confidence interval (CI) 0.002-0.063, P = 0.035]; in those with low education attainment, male participants had shorter LTL by 0.058 (95% CI -0.086 to -0.029) than female participants (P < 0.0001).

CONCLUSION

Being male and having lower education attainment was associated with shorter telomere length in our rural population. Evidence from our study supports the importance of education on LTL in males in rural Australia. Our studies also support previous findings that LTL in later life may not be closely associated with indicators of SES.

Social Relationships and Salivary Telomere Length Among Middle-Aged and Older African American and White Adults

OBJECTIVES

A common mechanism underlying premature morbidity may be accelerated biological aging as reflected by salivary telomere length (STL). This study examined the extent to which social relationships, both positive and negative, can be protective or confer risk relative to biological aging.

METHOD

Data from the Health and Retirement Study and multiple regression were used to examine cross-sectional associations between STL, self-reported social support, and negative interaction (e.g., conflict, criticism) with family in a nationally representative sample of African American and non-Hispanic White middle-aged and older adults (N = 4,080).

RESULTS

Social support from family was associated with shorter STL. Negative interaction with family had no main effect on STL but interactions characterized by high social support and more frequent negative interactions were associated with longer STL. Negative interaction with family was negatively associated with STL for African Americans and Whites but the magnitude of the effect was greater for African Americans.

DISCUSSION

Study findings highlight the role of social relationships in physiological deterioration among middle-aged and older adults and identify a potential mechanism whereby race is linked to accelerated biological aging. Findings highlight the importance of considering positive and negative aspects of social relationships to understand the consequences of social connections for cellular aging in diverse populations.

Psychosocial Stressors and Telomere Length: A Current Review of the Science

A growing literature suggests that exposure to adverse social conditions may accelerate biological aging, offering one mechanism through which adversity may increase risk for age-related disease. As one of the most extensively studied biological markers of aging, telomere length (TL) provides a valuable tool to understand potential influences of social adversity on the aging process. Indeed, a sizeable literature now links a wide range of stressors to TL across the life span. The aim of this article is to review and evaluate this extant literature with a focus on studies that investigate psychosocial stress exposures and experiences in early life and adulthood. We conclude by outlining potential biological and behavioral mechanisms through which psychosocial stress may influence TL, and we discuss directions for future research in this area.

Telomere length analysis from minimally-invasively collected samples: Methods development and meta-analysis of the validity of different sampling techniques: American Journal of Human Biology

OBJECTIVES

Telomeres are the protective caps of chromosomes. They shorten with cell replication, age, and possibly environmental stimuli (eg, infection and stress). Short telomere length (TL) predicts subsequent worse health. Although venous whole blood (VWB) is most commonly used for TL measurement, other, more minimally invasive, sampling techniques are becoming increasingly common due to their field-friendliness, allowing for feasible measurement in low-resource contexts. We conducted statistical validation work for measuring TL in dried blood spots (DBS) and incorporated our results into a meta-analysis evaluating minimally invasive sampling techniques to measure TL.

METHODS

We isolated DNA extracts from DBS using a modified extraction protocol and tested how they endured different shipping conditions and long-term cryostorage. We then included our in-house DBS TL validation statistics (correlation values with VWB TL and age) in a series of meta-analyses of results from 24 other studies that published similar associations for values between TL measured in DBS, saliva, and buccal cells.

RESULTS

Our modified DBS extraction technique produced DNA yields that were roughly twice as large as previously recorded. Partially extracted DBS DNA was stable for 7 days at room temperature, and still provided reliable TL measurements, as determined by external validation statistics. In our meta-analysis, DBS TL had the highest external validity, followed by saliva, and then buccal cells-possibly reflecting similarities/differences in cellular composition vs VWB.

CONCLUSIONS

DBS DNA is the best proxy for VWB from the three minimally-invasively specimen types evaluated and can be used to expand TL research to diverse settings and populations.

Shortened telomere length is associated with unfair treatment attributed to race in African Americans living in Tallahassee, Florida

OBJECTIVES

Experiences of interpersonal discrimination are pervasive stressors in the lives of African Americans. Increased discrimination stress may cause premature aging. Telomere length (TL) is a plastic genetic trait that is an emerging indicator of cellular health and aging. Short TL is a risk factor for the earlier onset of disease. TL shortens with age, a process that may be accelerated by psychosocial stress. Our study explores the relationship between TL and experiences of discrimination in the form of self-reported unfair treatment (UT).

METHODS

Using a qPCR-based method, we measured TL in DNA from saliva samples provided by 135 African American adults from Tallahassee, FL. We developed discrimination measures using a modified survey that explores nine social domains of self-reported unfair treatment experienced both directly and indirectly. We used multiple regression to examine associations between UT and TL.

RESULTS

We found that racial discrimination in the form of self-reported unfair treatment attributed to race (UT-Race-Self) is inversely associated with TL.

CONCLUSIONS

The significant association between increased UT-Race-Self and shorter telomeres supports the hypothesis that psychosocial stress stemming from racial discrimination may affect TL. The potential impact of discrimination on TL may contribute to premature biological aging and racial health inequalities seen in African Americans.

Cross-cultural validation of the Student Nurse Stress Index Scale: A descriptive survey targeting student nurses in China

BACKGROUND

Currently, relatively little is known regarding the sources and levels of stress experienced by nursing students in China. This is largely because there is no reliable and valid, culturally appropriate measure of student nurse' stress. A culturally acceptable, Chinese Version of the Student Nurse Stress Index Scale (SNSI-CHI), with established reliability and validity, is needed to identify sources of stress in Chinese nursing students.

METHODS

This validation study used a cross-sectional descriptive survey design. Stratified cluster random sampling was used to collect data from August 2017 to January, 2018 from 1100 nursing students in Henan Province, China. A demographic questionnaire, SNSI-CHI and Perceived Stress Scale (PSS-14) were administered. Exploratory and confirmatory factor analysis was carried out on two randomly selected samples (each N = 538) from the overall return. The content, construct, predictive and concurrent validity of the translated SNSI-CHI were examined.

RESULTS

1076 nursing students returned the survey (97.82% response rate). The average total score of SNSI-CHI was 58.455 ± 13.903. The internal consistency, test-retest reliability and content validity of the SNSI-CHI was excellent with a content validity index of 0.954. A four factor simple structure was revealed and confirmed using exploratory (explaining 75% of the variance) and confirmatory factor analysis (x²/df = 1.347, GFI = 0.956, AGFI = 0.945, RMR = 0.032, RMSEA = 0.025, NFI = 0.974, IFI = 0.993, TLI = 0.992, CFI = 0.993). This structure, i.e. academic load, clinical concerns, interface worries and personal problems compared well with the original SNSI. The SNSI-CHI totals and subscales showed good concurrent and predictive validity with the PSS-14 as comparator or criterion. A score of higher than 65 on the SNSI-CHI indicates high levels of perceived stress symptoms. Some 10.5% of respondents experience high levels of stressful demand. Sensitivity and specificity values of 71.7% and 75.1% respectively, demonstrated good predictive validity.

LIMITATIONS

This study sample was confined to the Henan Province, which may limit its generalizability. A larger and more diverse sample is needed in the future research.

CONCLUSIONS

The SNSI-CHI is both reliable and valid and culturally appropriate for use in China and its structure enables cross-cultural comparison.

Evaluating minimally invasive sample collection methods for telomere length measurement

OBJECTIVES

Telomere length (TL) is a biomarker of aging and age-related decline. Although venous blood is considered the "gold standard" for TL measurement, its collection is often not feasible or desired in nonclinical settings. Saliva and dried blood spots (DBS) have been used as alternatives when venipuncture cannot be performed. However, it is not known whether these sample types yield TL measurements comparable to those obtained from venous blood. We sought to determine whether different samples from the same individual yield comparable TL measurements.

METHODS

We extracted DNA from matched buffy coat, saliva (Oragene and Oasis), and DBS (venous and capillary) samples from 40 women aged 18-77 years. We used the monochrome multiplex qPCR (MMQPCR) assay to measure TL in all sample types for each participant and applied quality control measures to retain only high-quality samples for analysis. We then compared TL from buffy coat and saliva to examine how these measurements differ and to test if TL is correlated across sample types.

RESULTS

TL differed significantly across buffy coat, Oragene saliva, and Oasis saliva samples. TL from buffy coat and Oragene saliva was moderately correlated (ρ = 0.48, P = .002) and the most similar in size. Oasis saliva TL was not correlated with buffy coat or Oragene saliva TL, and was the shortest. DBS DNA yields were inadequate for TL measurement using the MMQPCR assay.

CONCLUSIONS

Using a matched dataset we demonstrate that sample type significantly influences the TL measurement obtained using the MMQPCR assay.

Depressive Symptoms and Salivary Telomere Length in a Probability Sample of Middle-Aged and Older Adults

OBJECTIVE

To examine the association between depressive symptoms and salivary telomere length in a probability sample of middle-aged and older adults, and to evaluate age and sex as potential moderators of this association and test whether this association was incremental to potential confounds.

METHODS

Participants were 3,609 individuals from the 2008 wave of the Health and Retirement Study. Telomere length assays were performed using quantitative real-time polymerase chain reaction on DNA extracted from saliva samples. Depressive symptoms were assessed via interview, and health and lifestyle factors, traumatic life events, and neuroticism were assessed via self-report. Regression analyses were conducted to examine the associations between predictor variables and salivary telomere length.

RESULTS

After adjusting for demographics, depressive symptoms were negatively associated with salivary telomere length (b = -.003; p = .014). Furthermore, this association was moderated by sex (b = .005; p = .011), such that depressive symptoms were significantly and negatively associated with salivary telomere length for men (b = - .006; p < .001) but not for women (b = - .001; p = .644). The negative association between depressive symptoms and salivary telomere length in men remained statistically significant after additionally adjusting for cigarette smoking, body mass index, chronic health conditions, childhood and lifetime exposure to traumatic life events, and neuroticism.

CONCLUSIONS

Higher levels of depressive symptoms were associated with shorter salivary telomeres in men, and this association was incremental to several potential confounds. Shortened telomeres may help account for the association between depression and poor physical health and mortality.

Hostility and telomere shortening among U.S. military veterans: Results from the National Health and Resilience in Veterans Study

Chronic disorders of aging are critical concerns for the U.S. veteran population, which is, on average, two decades older than the non-veteran population. Characterization of risk factors that may accelerate biological aging is important in identifying targets for prevention and intervention. In the current study, we analyzed data from a contemporary, and nationally representative sample of U.S. veterans to evaluate the relationship between a broad range of sociodemographic, military, and clinical variables, and peripheral telomere length, which is an indicator of biological age and linked to risk for aging-related disorders and mortality. Data from 468U.S. military veterans who participated in the National Health and Resilience in Veterans Study were analyzed. Telomere length was assessed from cells isolated from saliva using quantitative polymerase chain reaction methods. A multivariable binary logistic regression analysis was conducted to evaluate the relations between hostility and telomere length, while controlling for sociodemographic, military, and clinical variables. Greater scores on a measure of hostility were independently associated with telomere shortening, even after adjustment for a broad range of other variables (odds ratio [OR]=1.58, 95% confidence interval [CI]=1.15-2.18). Secondary analyses revealed that this association was driven by difficulties controlling anger (OR=1.72, 95%CI=1.14-2.61), which reflect the external manifestation of hostility, rather than aggressive urges or impulses. Hostility, particularly difficulties controlling anger, is associated with peripheral telomere shortening in U.S. military veterans. Prevention and treatment efforts designed to reduce hostility may help mitigate risk for accelerated cellular aging in this growing segment of the U.S.

Animal and human models to understand ageing

Human ageing is the gradual decline in organ and tissue function with increasing chronological time, leading eventually to loss of function and death. To study the processes involved over research-relevant timescales requires the use of accessible model systems that share significant similarities with humans. In this review, we assess the usefulness of various models, including unicellular yeasts, invertebrate worms and flies, mice and primates including humans, and highlight the benefits and possible drawbacks of each model system in its ability to illuminate human ageing mechanisms. We describe the strong evolutionary conservation of molecular pathways that govern cell responses to extracellular and intracellular signals and which are strongly implicated in ageing. Such pathways centre around insulin-like growth factor signalling and integration of stress and nutritional signals through mTOR kinase. The process of cellular senescence is evaluated as a possible underlying cause for many of the frailties and diseases of human ageing. Also considered is ageing arising from systemic changes that cannot be modelled in lower organisms and instead require studies either in small mammals or in primates. We also touch briefly on novel therapeutic options arising from a better understanding of the biology of ageing.

Perceived stress and telomere length: A systematic review, meta-analysis, and methodologic considerations for advancing the field

IMPORTANCE

Psychological stress contributes to numerous diseases and may do so in part through damage to telomeres, protective non-coding segments on the ends of chromosomes.

OBJECTIVE

We conducted a systematic review and meta-analysis to determine the association between self-reported, perceived psychological stress (PS) and telomere length (TL).

DATA SOURCES

We searched 3 databases (PubMed, PsycInfo, and Scopus), completed manual searches of published and unpublished studies, and contacted all study authors to obtain potentially relevant data.

STUDY SELECTION

Two independent reviewers assessed studies for original research measuring (but not necessarily reporting the correlation between) PS and TL in human subjects. 23 studies met inclusion criteria; 22 (totaling 8948 subjects) could be meta-analyzed.

DATA EXTRACTION AND SYNTHESIS

We assessed study quality using modified MINORS criteria. Since not all included studies reported PS-TL correlations, we obtained them via direct calculation from author-provided data (7 studies), contact with authors (14 studies), or extraction from the published article (1 study).

MAIN OUTCOMES AND MEASURES

We conducted random-effects meta-analysis on our primary outcome, the age-adjusted PS-TL correlation. We investigated potential confounders and moderators (sex, life stress exposure, and PS measure validation) via post hoc subset analyses and meta-regression.

RESULTS

Increased PS was associated with a very small decrease in TL (n=8724 total; r=-0.06; 95% CI: -0.10, -0.008; p=0.01; α=0.025), adjusting for age. This relationship was similar between sexes and within studies using validated measures of PS, and marginally (nonsignificantly) stronger among samples recruited for stress exposure (r=-0.13; vs. general samples: b=-0.11; 95% CI: -0.27, 0.01; p=0.05; α=0.013). Publication bias may exist; correcting for its effects attenuated the relationship.

CONCLUSIONS AND RELEVANCE

Our analysis finds a very small, statistically significant relationship between increased PS (as measured over the past month) and decreased TL that may reflect publication bias, although fully parsing the effects of publication bias from other sample-size correlates is challenging, as discussed. The association may be stronger with known major stressors and is similar in magnitude to that noted between obesity and TL. All included studies used single measures of short-term stress; the literature suggests long-term chronic stress may have a larger cumulative effect. Future research should assess for potential confounders and use longitudinal, multidimensional models of stress.

Marital disruption is associated with shorter salivary telomere length in a probability sample of older adults

RATIONALE

Marital disruption (i.e., marital separation, divorce) is associated with a wide range of poor mental and physical health outcomes, including increased risk for all-cause mortality. One biological intermediary that may help explain the association between marital disruption and poor health is accelerated cellular aging.

OBJECTIVE

This study examines the association between marital disruption and salivary telomere length in a United States probability sample of adults ≥50 years of age.

METHOD

Participants were 3526 individuals who participated in the 2008 wave of the Health and Retirement Study. Telomere length assays were performed using quantitative real-time polymerase chain reaction (qPCR) on DNA extracted from saliva samples. Health and lifestyle factors, traumatic and stressful life events, and neuroticism were assessed via self-report. Linear regression analyses were conducted to examine the associations between predictor variables and salivary telomere length.

RESULTS

Based on their marital status data in the 2006 wave, people who were separated or divorced had shorter salivary telomeres than people who were continuously married or had never been married, and the association between marital disruption and salivary telomere length was not moderated by gender or neuroticism. Furthermore, the association between marital disruption and salivary telomere length remained statistically significant after adjusting for demographic and socioeconomic variables, neuroticism, cigarette use, body mass, traumatic life events, and other stressful life events. Additionally, results revealed that currently married adults with a history of divorce evidenced shorter salivary telomeres than people who were continuously married or never married.

CONCLUSION

Accelerated cellular aging, as indexed by telomere shortening, may be one pathway through which marital disruption is associated with morbidity and mortality.

Epigenetic Biomarkers of Preterm Birth and Its Risk Factors

A biomarker is a biological measure predictive of a normal or pathogenic process or response. Biomarkers are often useful for making clinical decisions and determining treatment course. One area where such biomarkers would be particularly useful is in identifying women at risk for preterm delivery and related pregnancy complications. Neonates born preterm have significant morbidity and mortality, both in the perinatal period and throughout the life course, and identifying women at risk of delivering preterm may allow for targeted interventions to prevent or delay preterm birth (PTB). In addition to identifying those at increased risk for preterm birth, biomarkers may be able to distinguish neonates at particular risk for future complications due to modifiable environmental factors, such as maternal smoking or alcohol use during pregnancy. Currently, there are no such biomarkers available, though candidate gene and epigenome-wide association studies have identified DNA methylation differences associated with PTB, its risk factors and its long-term outcomes. Further biomarker development is crucial to reducing the health burden associated with adverse intrauterine conditions and preterm birth, and the results of recent DNA methylation studies may advance that goal.

Associations of self-reported and objectively measured sleep disturbances with depression among primary caregivers of children with disabilities

OBJECTIVE

The objective of this study was to determine the association between sleep and depression using both self-reported (subjective) and actigraphic (objective) sleep traits.

METHODS

A cross-sectional study was conducted among 175 female primary caregivers of children with disabilities receiving care at a rehabilitation center in Punta Arenas, Chile. The eight-item Patient Health Questionnaire was used to ascertain participants' depression status. The Pittsburgh Sleep Quality Index was used to define subjective, or perceived, sleep quality. Wrist-worn actigraph monitors, worn for seven consecutive nights, were used to characterize objective sleep quality and disturbances. Interviewer-administered questionnaires were used to collect information on sociodemographic and lifestyle factors. Linear regression models were fit using continuous sleep parameters as the dependent variables and depression status as the independent variable. Multivariable models were adjusted for body mass index, marital status, smoking status, education level, and children's disabilities.

RESULTS

Using an eight-item Patient Health Questionnaire score ≥10, 26.3% of participants presented with depression. Depressed women were more likely to self-report overall poorer (subjective) sleep compared to non-depressed women; however, differences in sleep were not consistently noted using actigraphic (objective) sleep traits. Among the depressed, both sleep duration and total time in bed were significantly underestimated. In multivariable models, depression was negatively associated with sleep duration using both subjective (β=-0.71, standard error [SE] =0.25; P=0.006) and objective sleep (β=-0.42, SE =0.19; P=0.026).

CONCLUSION

The association between sleep and depression differed comparing subjective and objective methods of assessment. Research strategies allowing for the integration of both perceived and objective measures of sleep traits are encouraged.

Evaluation of actigraphy-measured sleep patterns among children with disabilities and associations with caregivers' educational attainment: results from a cross-sectional study

OBJECTIVES

To use wrist-actrigrphy to collect objective measures of sleep and to characterise actigraphy-measured sleep patterns among children with disabilities. We also assessed the extent to which, if at all, caregivers' education is associated with children's sleep disturbances.

DESIGN

Cross-sectional study.

SETTING

A rehabilitation centre in the Patagonia region, Chile.

METHODS

This study was conducted among 125 children aged 6-12 years with disabilities (boys: 55.2%) and their primary caregivers in Chile. Children wore ActiSleep monitors for 7 days. A general linear model was fitted to generate least-square means and SEs of sleep efficiency (proportion of the sleep period spent asleep) across caregivers' education levels adjusting for children's age, sex, disability type, caregiver-child relationship and caregivers' age. Multivariable logistic regression analyses were conducted to estimate ORs and 95% CIs of longer sleep latency (≥ 30 min) and longer wake after sleep onset (WASO) (≥ 90 min) (a measure of sleep fragmentation) in relation to caregivers' educational attainment.

RESULTS

Median sleep latency was 27.3 min, WASO 88.1 min and sleep duration 8.0 h. Mean sleep efficiency was 80.0%. Caregivers' education was positively and significantly associated with children's sleep efficiency (p trend<0.001). Adjusted mean sleep efficiency was 75.7% (SE=1.4) among children of caregivers high school education. Compared to children whose caregivers had >high school, children of caregivers with

CONCLUSIONS

Children with disabilities experience difficulties initiating sleep (prolonged sleep latency) and maintaining sleep (long WASO, low sleep efficiency). Among children with disabilities, lower level of caregivers' education is associated with more sleep disturbances.

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Key Words

• EPIDEMIOLOGY
• PUBLIC HEALTH
• SLEEP MEDICINE

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MESH Headings

• Actigraphy/instrumentation
• Actigraphy/methods
• Adult
• Caregivers/education
• Caregivers/psychology
• Child
• Chile/epidemiology
• Cross-Sectional Studies
• Disabled Children/psychology
• Educational Status
• Female
• Humans
• Male
• Sleep Wake Disorders/epidemiology
• Sleep Wake Disorders/etiology
• Sleep Wake Disorders/psychology
• Surveys and Questionnaires

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Grants

• T37 MD001449 NIMHD NIH HHS
• UL1 TR000170 NCATS NIH HHS
• 8UL1TR000170-07 NCATS NIH HHS
• T37-MD001449 NIMHD NIH HHS

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Affiliation(s)

Xiaoli Chen Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
Juan Carlos Velez Centro de Rehabilitación Club de Leones Cruz del Sur, Punta Arenas, Chile
Clarita Barbosa Centro de Rehabilitación Club de Leones Cruz del Sur, Punta Arenas, Chile
Micah Pepper Centro de Rehabilitación Club de Leones Cruz del Sur, Punta Arenas, Chile
Bizu Gelaye Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
Susan Redline Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, Massachusetts, USA Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
Michelle A Williams Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA

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Social Determinants and Health Behaviors: Conceptual Frames and Empirical Advances

Health behaviors shape health and well-being in individuals and populations. Drawing on recent research, we review applications of the widely applied "social determinants" approach to health behaviors. This approach shifts the lens from individual attribution and responsibility to societal organization and the myriad institutions, structures, inequalities, and ideologies undergirding health behaviors. Recent scholarship integrates a social determinants perspective with biosocial approaches to health behavior dynamics. Empirical advances model feedback among social, psychological and biological factors. Health behaviors are increasingly recognized as multidimensional and embedded in health lifestyles, varying over the life course and across place and reflecting dialectic between structure and agency that necessitates situating individuals in context. Advances in measuring and modeling health behaviors promise to enhance representations of this complexity.

Telomere length is highly inherited and associated with hyperactivity-impulsivity in children with attention deficit/hyperactivity disorder

Telomere length (TL) is highly heritable, and a shorter telomere at birth may increase the risk of age-related problems. Additionally, a shorter TL may represent a biomarker of chronic stress and has been associated with psychiatric disorders. However, no study has explored whether there is an association between TL and the symptoms of one of the most common neurodevelopmental disorders in childhood: Attention Deficit/Hyperactive Disorder (ADHD). We evaluated 61 (range, 6–16 years) ADHD children and their parents between 2012 and 2014. TL was measured with a quantitative polymerase chain reaction method with telomere signal normalized to the signal from a single copy gene (36B4) to generate a T/S ratio. Family data was processed through a generalized estimated equations (GEE) model to determine the effect of parental TL on children TL. Inattentive and hyperactive-impulsive symptoms were also evaluated in relation to TL. For the first time, we found general heritability to be the major mechanism explaining interindividual TL variation in ADHD (father-child: 95% CI = 0.35/0.91, p < 0.001; mother-child: 95% CI = 0.38/0.74, p < 0.001). The hyperactive-impulsive dimension of ADHD was related with children’s TL (r = −339, p = 0.008) and maternal TL (r = −264, p = 0.047), but not with paternal TL (p > 0.05). The ADHD inattentive dimension was not significant associated with TL in this study (p > 0.05). TL was shown to be a potential biomarker of the ADHD symptoms burden in families affected by this neurodevelopmental disorder. However, it is crucial that future studies investigating the rate of telomere attrition in relation to psychiatric problems to consider the strong determination of TL at birth by inheritance.

Not all biofluids are created equal: chewing over salivary diagnostics and the epigenome

PURPOSE

This article describes progress to date in the characterization of the salivary epigenome and considers the importance of previous work in the salivary microbiome, proteome, endocrine analytes, genome, and transcriptome.

METHODS

PubMed and Web of Science were used to extensively search the existing literature (original research and reviews) related to salivary diagnostics and biomarker development, of which 125 studies were examined. This article was derived from the most relevant 74 sources highlighting the recent state of the evolving field of salivary epigenomics and contributing significantly to the foundational work in saliva-based research.

FINDINGS

Validation of any new saliva-based diagnostic or analyte will require comparison to previously accepted standards established in blood. Careful attention to the collection, processing, and analysis of salivary analytes is critical for the development and implementation of newer applications that include genomic, transcriptomic, and epigenomic markers. All these factors must be integrated into initial study design.

IMPLICATIONS

This commentary highlights the appeal of the salivary epigenome for translational applications and its utility in future studies of development and the interface among environment, disease, and health.

Caregivers' hair cortisol: a possible biomarker of chronic stress is associated with obesity measures among children with disabilities

BACKGROUND

The stress of caring for a loved one with chronic illness has been associated with childhood obesity. Hair cortisol has been proposed as a novel biomarker of chronic psychological stress. This study aimed to evaluate the associations between caregivers' chronic stress evaluated by hair cortisol concentrations (HCC) and obesity measures among children with disabilities such as autism.

METHODS

Eighty-five dyads of children with disabilities and their primary caregivers participated in the study between April and July 2013 in the Patagonia Region, Chile. Trained research staff conducted anthropometric measurements of children and caregivers. Cortisol concentrations, extracted from hair samples with methanol, were quantified using liquid chromatography tandem mass spectrometry. Pearson's correlation coefficients and linear regression models were used to examine the associations between caregiver HCC (log-transformed) and child obesity measures with adjustment for covariates.

RESULTS

Caregiver HCC were positively and significantly correlated with child weight (child age- and sex-adjusted r =0.23, P = 0.036), body mass index (BMI) (r = 0.23, P = 0.035), circumferences of neck (r = 0.30, P = 0.006), waist (r = 0.27, P = 0.014), and hip (r = 0.22, P = 0.044). After adjustment for children's age and sex, caregiver HCC were significantly related to child weight (kg) (beta = 4.47, standard error (SE) = 2.09), BMI (kg/m(2)) (beta = 1.52, SE = 0.71), neck circumference (cm) (beta = 1.20, SE = 0.43), waist circumference (cm) (beta = 3.75, SE = 1.50), and hip circumference (cm) (beta = 3.02, SE = 1.48). Caregiver HCC were also positively but not statistically significantly associated with child waist-to-hip ratio (beta = 0.01, SE = 0.01; P = 0.191) or body fat percentage (%) (beta = 2.11, SE = 1.28; P = 0.104). Further adjustment for other covariates including child disability diagnosis and caregiver age, sex, education, current smoking, perceived stress, and caregiver BMI did not change the results substantially.

CONCLUSIONS

Chronic stress of caregivers, evaluated by increased cortisol concentrations in hair, was positively associated with obesity measures among children with disabilities.