Race, Ethnicity, Psychosocial Factors, and Telomere Length in a Multicenter Setting

Influence of breed and environment on leukocyte telomere length in cattle

High milk yield is associated with reduced longevity in high-producing dairy cattle breeds. Pre-term culling leads to high replacement heifer demand and economic losses for the dairy industry. Selection for this trait is limited because of low heritability and difficulties in phenotype measurement. Telomeres are elements found at the ends of chromosomes, consisting of repetitive DNA sequences, several thousand base pairs in length, coupled with nucleoprotein complexes. Eventually, in humans and most other animals, telomere length reduces with age. When telomeric DNA is truncated to a critical length, cell ageing, cell cycle arrest, and apoptosis are induced. As a result, telomere length can be considered as a predictor of health risks and an individual's lifespan. The leukocyte telomere length may be used as a proxy phenotype of productive lifespan to improve cattle selection. Our objectives were to assess the effects of breed and breed group (dairy vs. beef) on the leukocyte telomere length and to estimate the effect of cold climate on this trait in Kalmyk cattle populations from the South (Rostov Oblast) and Far North (Republic of Sakha) regions of Russia. The leukocyte telomere lengths were estimated computationally from whole-genome resequencing data. We leveraged data on leukocyte telomere length, sex, and age of 239 animals from 17 cattle breeds. The breed factor had a significant effect on leukocyte telomere length across our sample. There was no difference in leukocyte telomere length between dairy and beef groups. The population factor had a significant effect on leukocyte telomere length in Kalmyk animals. In conclusion, we found that breed, but not breed group (dairy vs. beef), was significantly associated with leukocyte telomere length in cattle. Residence in colder climates was associated with longer leukocyte telomere length in Kalmyk breed cattle.

Sub-optimal maternal gestational gain is associated with shorter leukocyte telomere length at birth in a predominantly Latinx cohort of newborns

OBJECTIVE

To assess in utero exposures associated with leukocyte telomere length (LTL) at birth and maternal LTL in a primarily Latinx birth cohort.

STUDY DESIGN

Mothers and newborns were recruited postnatally before 24 h of life. Newborn LTL was collected via heelstick at birth and maternal LTL was collected postnatally. LTL was determined by quantitative PCR. Using a longitudinal design, we evaluated associations between neonatal and maternal LTL and appropriate maternal gestational gain as indicated by the American College of Obstetrics and Gynecology (ACOG).

RESULT

Mean infant LTL was 2.02 ± 0.30 T/S (n = 386) and maternal LTL was 1.54 ± 0.26 T/S (n = 58). Independent risk factors for shorter LTL at birth included longer gestational duration (Coeff:-0.03, 95%CI: -0.05-0.01;p < 0.01) and maternal gestational weight gain below ACOG recommendations (Coeff:-0.10, 95%CI: -0.18 - -0.02; p = 0.01).

CONCLUSION

Gestational weight gain below ACOG recommendations may adversely impact neonatal health in Latinx infants as indicated by shorter LTL at birth.

Social Drivers of Cancer Risk and Outcomes Among African American Men

ABSTRACT

Social risk factors play an important role in minority health and cancer health disparities. Exposure to stress and stress responses are important social factors that are now included in conceptual models of cancer health disparities. This report summarizes results from studies that examined stress exposure and responses among African Americans. Data from studies that were conducted as part of a transdisciplinary and translational research center are also presented to provide additional insight about the nature of racial differences in specific stressors among African American and White prostate cancer patients.

Associations of Telomere Length and Change With Cognitive Decline Were Modified by Sex and Race: The REGARDS Study

INTRODUCTION

We examined the associations of baseline telomere length (TL) and TL change with cognitive function over time in older US adults, as well as differences by sex and race.

METHODS

A total of 1820 cognitively healthy individuals (median baseline age: 63 years) were included. Telomere length was measured using qPCR-based method at baseline and among 614 participants in the follow-up examination 10 years later. Cognitive function was assessed by a four-test battery every 2 years.

RESULTS

In multivariable-adjusted linear mixed models, longer baseline TL and smaller attrition/lengthening of TL over time were associated with better Animal Fluency Test score. Longer baseline TL was also linearly associated with better Letter Fluency Test score. The observed associations were consistently more pronounced in women than men and in Black compared to White participants.

DISCUSSION

Telomere length may be a biomarker that predicts long-term verbal fluency and executive function, particularly in women and Black Americans.

Placental telomere length shortening is not associated with severe preeclampsia but the gestational age

Variations in telomere length (TL) have been associated with aging, stress, and many diseases. Placenta TL is an essential molecular component influencing the outcome of birth. Previous investigations into the relationship between placenta TL and preeclampsia (PE) have produced conflicting findings. We conducted a retrospective case-control analysis in this study to address the disparity. We used placenta samples from 224 births received from Hawaii Biorepository (HiBR) between 2006 and 2013, comprising 129 healthy full-term controls and 95 severe PE samples. The average absolute placental TL was calculated using the quantitative polymerase chain reaction (qPCR) technique. We utilized multiple linear regressions to associate placental TL with severe PE and other demographic, clinical and physiological data. The outcome demonstrates that the placental TL of severe PE cases did not significantly differ from that of healthy controls. Instead, there is a strong correlation between gestational age and placenta TL shortening. Placental TL also exhibits racial differences: (1) Latino moms' TL is significantly longer than non-Latino mothers' (p=0.009). (2) Caucasian patients with severe PE have shorter TL than non-Caucasian patients (p=0.0037). This work puts the long-standing question of whether severe PE influences placental TL to rest. Placental TL is not related to severe PE but is negatively associated with gestational age and is also affected by race.

A Time-Varying Effect Model (TVEM) of the Complex Association of Tobacco Use and Smoke Exposure on Mean Telomere Length: Differences between Racial and Ethnic Groups Assessed in the National Health and Nutrition Examination Survey

Telomere length is affected by lifestyle and environmental factors and varies between racial and ethnic groups; however, studies are limited, with mixed findings. This study examined the effects of tobacco use and smoke exposure on mean telomere length to identify critical age periods by race/ethnicity. We used time-varying effect modeling on the National Health and Nutrition Examination Survey for continuous years 1999-2002 to observe the effects of active tobacco use and environmental tobacco smoke-measured through serum cotinine-and mean telomere length for adults 19 to 85 and older (N = 7826). Models were run for Mexican American, other Hispanic, non-Hispanic White, non-Hispanic Black, and other/multi-race categories to allow for time-varying group differences, and controlled for biological sex, socioeconomic status, education, and ever-smoker status. Serum cotinine was found to have an increasing effect on telomere length from age 37 to approximately age 74 among Mexican Americans. Among other/multi-race individuals serum cotinine was found to have a decreasing effect at approximately age 42, and among Blacks, it had an overall decreasing effect from age 61 to 78. Findings reveal a further need to focus additional support and resources to intervene regarding disparate health effects from tobacco use and environmental smoke exposure for already vulnerable groups at particular ages.

Role of genetic factors (biology of telomeres) in cardiac rehabilitation

Cardiac rehabilitation (CR) is one of the effective healthcare types for cardiovascular patients. At the same time, the choice of the most effective CR methods for a particular patient remains a problem. An increasing number of studies are devoted to the application of genetic methods for studying human health. Particular attention is drawn to determining the telomere length. The review purpose was to analyze the literature on various studies on the significance of assessing the chromosome telomeres for characterizing human health and choosing effective CR methods. The article discusses issues related to the relationship between the telomere length and cardiovascular risk factors, dietary pattern, and psychological status of a person. We also assessed the effectiveness of various exercise types at the genetic level. In preparing the review, publications over the past 14 years were searched in the MEDLINE/PubMed, Scopus, Cochrane Library, PEDro, eLIBRARY, and Google Scholar databases. The presented facts indicate the need for further study and effective use of one of the genetic factors protecting chromosome telomeres in CR.

Race Differences in Telomere Length in Benign Prostate Biopsies and Subsequent Risk of Prostate Cancer

BACKGROUND

Telomere shortening is linked to aging and may be associated with increased risk for cancer. Most cancer studies have used telomere length in leukocytes rather than in the target tissue of cancer origin.

METHODS

A case-control study of 524 case-control pairs with a benign prostate biopsy nested within a historical cohort of 10,478 men was conducted to determine whether premalignant prostate telomere length (assessed using a modified qRT-PCR) is associated with prostate cancer risk.

RESULTS

Telomere lengths in benign prostate biopsies of cases versus controls were similar (1.46 ± 0.38 vs. 1.45 ± 0.42; P = 0.49). African American (AA) men had significantly shorter telomeres compared with White men (1.51 ± 0.38 vs. 1.63 ± 0.39; P < 0.0001). In race-stratified analyses, increasing telomere length was more strongly associated with prostate cancer risk in White men, wherein those with telomere length in the highest quartile had 1.9-fold greater adjusted risk of prostate cancer compared with men with prostate telomere lengths in the lowest quartile [OR = 1.90; 95% confidence interval (CI) = 1.08-3.36]. Men in the highest telomere length quartile also had a greater risk of aggressive prostate cancer compared with men with telomere lengths in the lowest quartile (OR = 2.78; 95% CI = 1.25-6.19).

CONCLUSIONS

White men have longer telomeres in benign prostate tissue compared with AA men, and those with the longest telomeres may be at increased risk for prostate cancer, particularly the more aggressive form of the disease.

IMPACT

Race-specific telomere length measures may be an early biomarker of aggressive prostate cancer.

Social Justice and Equity: Why Older Adults With Cancer Belong-A Life Course Perspective

The population of older adults with cancer in the United States is rapidly increasing, which will have a substantial impact on the oncology and public health workforces across the cancer continuum, from prevention to end of life. Unfortunately, inequities in existing social structures that cause increased psychosocial stressors have led to disparities in the incidence of cancer and the morbidity and mortality of cancer for individuals from marginalized backgrounds. It is imperative that older adults, especially those from historically marginalized backgrounds, be adequately represented in all stages of cancer research to address health inequities. Continued efforts and progress toward achieving social justice and health equity require a deeper commitment to and better understanding of the impact of social determinants of health within the cancer domain. Undoubtedly, a more holistic and integrated view that extends beyond the biologic and genetic factors of health must be adopted for health entities to recognize the critical role of environmental, behavioral, and social determinants in cancer health disparities. Against this backdrop, this paper uses a life course approach to present a multifactorial framework for understanding and addressing cancer disparities in an effort to advance social justice and health equity for racially and ethnically diverse older adults.

Association between Telomere Length and Pediatric Obesity: A Systematic Review

Objective: Telomere length (TL) is a robust marker of biological aging, and increased telomere attrition is noted in adults with obesity. The primary objective of this systematic review was to summarize current knowledge on the effects of childhood obesity in TL. The secondary objective was to assess the effect of weight management interventions in TL. Methods: The following databases were searched: PubMed, Scopus, Web of Science and Heal-link.gr from inception to September 2021. The search was performed using the following combinations of terms: “telomer*” [All Fields] AND (“length” [All Fields] OR “lengths” [All Fields]) AND “obes*” [All Fields] AND (“child*” [All Fields] OR “adolescen*” [All Fields]). Results: A total of 16 original articles were included in this systematic review. Eleven of them were cross-sectional and five were lifestyle interventions. Conclusions: There was a tendency towards a negative association between childhood obesity and TL. Life-style interventions in children have been associated with increased TL peripherally, indicating a possible association of the redistribution of younger cells in the periphery with the favorable effect of these interventions. Further prospective studies with larger sample sizes that employ other markers of cell aging would potentially elucidate this important mechanistic relation.

Measurement and initial characterization of leukocyte telomere length in 474,074 participants in UK Biobank

Leukocyte telomere length (LTL) is a proposed marker of biological age. Here we report the measurement and initial characterization of LTL in 474,074 participants in UK Biobank. We confirm that older age and male sex associate with shorter LTL, with women on average ~7 years younger in 'biological age' than men. Compared to white Europeans, LTL is markedly longer in African and Chinese ancestries. Older paternal age at birth is associated with longer individual LTL. Higher white cell count is associated with shorter LTL, but proportions of white cell subtypes show weaker associations. Age, ethnicity, sex and white cell count explain ~5.5% of LTL variance. Using paired samples from 1,351 participants taken ~5 years apart, we estimate the within-individual variability in LTL and provide a correction factor for this. This resource provides opportunities to investigate determinants and biomedical consequences of variation in LTL.

Examining the influence of adversity, family contexts, and a family-based intervention on parent and child telomere length

Background: Exposure to adversity, trauma, and negative family environments can prematurely shorten telomeres, the protective caps at the ends of chromosomes. Conversely, some evidence indicates that positive environments and psychosocial interventions can buffer the shortening of telomere length (TL). However, most work has examined individual aspects of the family environment as predictive of TL with little work investigating multiple risk and protective factors. Further, most research has not examined parent TL relative to child TL despite its heritability. Objective: In the current study, we examined interparental conflict, positive parenting, alcohol use, adverse childhood experiences (ACEs), and a family-based intervention as predictive of parent TL. We also examined interparental conflict, positive parenting, ACEs, and a family-based intervention as predictive of child TL. Method: Parents and adolescents from a sample of divorced families participated in either a 10-session family-based intervention, the New Beginnings Programme (NBP), or a 2-week active control condition. Approximately six years after the intervention, a subsample of parents (n = 45) and adolescents (n = 41) were assessed for TL. Parents reported on interparental conflict, ACEs, and alcohol use. Children reported on interparental conflict, positive parenting, and ACEs. In separate models, these constructs and the NBP intervention condition were examined as predictors of parent TL and child TL. Results: Findings indicated that the family-based intervention was associated with longer TL in parents. Also, positive parenting was associated with longer TL in children. Conclusions: These findings have important implications for the role of the family and family-based preventive interventions in buffering parent and child biological stress.

HIGHLIGHTS

Across multiple indices of psychosocial functioning, we found a family-based intervention associated with longer telomere length in parents and positive parenting associated with longer telomere length in children.

Prospective Associations of Early Pregnancy Metal Mixtures with Mitochondria DNA Copy Number and Telomere Length in Maternal and Cord Blood

BACKGROUND

Metal exposure during pregnancy influences maternal and child health. Oxidative stress and inflammation may mediate adverse effects of heavy metals, whereas essential metals may act as antioxidants. Mitochondrial DNA is a prime target for metal-induced oxidative damage. Telomere dysfunction is attributed to imbalances between reactive oxidant species and antioxidants.

OBJECTIVES

We evaluated individual and joint associations of prenatal metals with mitochondrial DNA copy number (mtDNAcn) and telomere length (TL) in maternal and cord blood as biomarkers of inflammation and oxidative stress.

METHODS

We measured six nonessential metals (arsenic, barium, cadmium, cesium, lead, mercury) and four essential metals (magnesium, manganese, selenium, zinc) in first-trimester maternal red blood cells in Project Viva, a U.S. prebirth cohort. We measured relative mtDNAcn (n=898) and TL (n=893) in second-trimester maternal blood and mtDNAcn (n=419) and TL (n=408) in cord blood. We used multivariable linear regression and quantile g-computation to estimate associations between prenatal metals and the biomarkers. We used generalized additive models and Bayesian kernel machine regression to examine nonlinearity and interactions.

RESULTS

A 2-fold increase in maternal magnesium was associated with lower maternal [β=-0.07, 95% confidence interval (CI): -0.10, -0.01] and cord blood (β=-0.08, 95% CI: -0.20, -0.01) mtDNAcn. Lead was associated with higher maternal mtDNAcn (β=0.04, 95% CI: 0.01, 0.06). Selenium was associated with longer cord blood TL (β=0.30, 95% CI: 0.01 0.50). An association was observed between the nonessential metal mixture and higher maternal mtDNAcn (β=0.04, 95% CI: 0.01, 0.07). There was a nonlinear relationship between cord blood mtDNAcn and magnesium; maternal mtDNAcn and barium, lead, and mercury; and maternal TL and barium.

DISCUSSION

Maternal exposure to metals such as lead, magnesium, and selenium was associated with mtDNAcn and TL in maternal second trimester and cord blood. Future work will evaluate whether these biomarkers are associated with child health. https://doi.org/10.1289/EHP9294.

Inverse Association of Telomere Length With Liver Disease and Mortality in the US Population

Physiologic aging leads to attrition of telomeres and replicative senescence. An acceleration of this process has been hypothesized in the progression of chronic liver disease. We sought to examine the association of telomere length (TL) with liver disease and its impact on mortality risk. A cohort of 7,072 adults with leukocyte TL measurements from the National Health and Nutrition Examination Survey 1999‐2002 with mortality follow‐up through 2015 was analyzed. Liver disease was defined by aminotransferase levels and classified into etiology‐based and advanced fibrosis categories. Multivariable‐adjusted linear regression models estimated effect sizes, with 95% confidence intervals (CIs), of the presence of liver disease on TL. Cox regression models evaluated associations between TL and all‐cause mortality risk using adjusted hazard ratios (HRs). The cohort was representative of the US population with mean age 46.1 years and mean TL 5.79 kilobase pairs. No overall association between TL and liver disease was found; however, there was a significant negative association of TL and advanced liver fibrosis in individuals aged 65 and above. The liver disease cohort (HR 1.22, 95% CI 0.99‐1.51) and those with metabolic syndrome (HR 1.26, 95% CI 0.96‐1.67) had increased mortality risk with shorter TL. The relationship between TL and all‐cause mortality was stronger in women (HR 1.51, 95% CI 1.02‐2.23) and in non‐Hispanic Whites (HR 1.37, 95% CI 1.02‐1.84). Conclusion: Shortened leukocyte TL is independently associated with advanced liver disease at older ages, and with a higher risk of all‐cause mortality in those with liver disease. These associations reaffirm the need to better understand the role of telomeres in the progression of liver disease.

Association of leukocyte telomere length with obesity-related traits in Asian children with early-onset obesity

BACKGROUND

Leukocyte telomere length (LTL) is associated with obesity and obesity-related traits, and there are ethnic-specific determinants of LTL.

OBJECTIVE

To evaluate LTL associations with obesity and metabolic parameters in Asian children with early-onset obesity.

METHODS

Genomic DNA was extracted from peripheral blood leukocytes of a cohort of children with (N = 371) and without obesity (N = 23), and LTL was measured using quantitative PCR (qPCR). Blood plasma was used for metabolic phenotyping. Statistical analysis was performed using SPSS and STATA.

RESULTS

Children with obesity had shorter LTL (coefficient = -0.683, P_Adj = 1.24 × 10^-3 ) as compared to children who were lean. LTL was found to be associated with waist circumference (coefficient = -0.326, P_Adj = 0.044) and skin-fold measures (coefficient between 0.267 and 0.301, P_Adj between 4.27 × 10^-4 and 7.06 × 10^-7 ) in children with obesity. However, no significant associations were observed between LTL and metabolic parameters, and between LTL and inflammatory cytokines. LTL also did not significantly mediate the risk of non-alcoholic fatty liver disease (NAFLD) in children with obesity.

CONCLUSIONS

We showed for the first time that Asian children with severe obesity had shorter LTL, and the shortening of LTL was associated with other adiposity measures including waist circumference and skin-fold measurements.

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.

DNA-methylation-based telomere length estimator: comparisons with measurements from flow FISH and qPCR

Telomere length (TL) is a marker of biological aging associated with several health outcomes. High throughput reproducible TL measurements are needed for large epidemiological studies. We compared the novel DNA methylation-based estimator (DNAmTL) with the high-throughput quantitative PCR (qPCR) and the highly accurate flow cytometry with fluorescent in situ hybridization (flow FISH) methods using blood samples from healthy adults. We used Pearson’s correlation coefficient, Bland Altman plots and linear regression models for statistical analysis. Shorter DNAmTL was associated with older age, male sex, white race, and cytomegalovirus seropositivity (p<0.01 for all). DNAmTL was moderately correlated with qPCR TL (N=635, r=0.41, p < 0.0001) and flow FISH total lymphocyte TL (N=144, r=0.56, p < 0.0001). The agreements between flow FISH TL and DNAmTL or qPCR were acceptable but with wide limits of agreement. DNAmTL correctly classified >70% of TL categorized above or below the median, but the accuracy dropped with increasing TL categories. The ability of DNAmTL to detect associations with age and other TL-related factors in the absence of strong correlation with measured TL may indicate its capture of aspects of telomere maintenance mechanisms and not necessarily TL. The inaccuracy of DNAmTL prediction should be considered during data interpretation and across-study comparisons.

Discrimination and Leukocyte Telomere Length by Depressive Symptomatology: The Jackson Heart Study

Background: Psychosocial stressors, such as perceived discrimination and depressive symptoms, may shorten telomeres and exacerbate aging-related illnesses. Methods: Participants from the Jackson Heart Study at visit 1 (2000–2004) with LTL data and Center for Epidemiological Studies-Depression (CES-D) scores (n = 580 men, n = 910 women) were utilized. The dimensions of discrimination scores (everyday, lifetime, burden of lifetime, and stress from lifetime discrimination) were standardized and categorized as low, moderate, and high. Coping responses to everyday and lifetime discrimination were categorized as passive and active coping. Multivariable linear regression analyses were performed to estimate the mean difference (standard errors-SEs) in LTL by dimensions of discrimination and coping responses stratified by CES-D scores < 16 (low) and ≥ 16 (high) and sex. Covariates were age, education, waist circumference, smoking and CVD status. Results: Neither everyday nor lifetime discrimination was associated with mean differences in LTL for men or women by levels of depressive symptoms. Burden of lifetime discrimination was marginally associated with LTL among women who reported low depressive symptoms after full adjustment (b = 0.11, SE = 0.06, p = 0.08). Passive coping with lifetime discrimination was associated with longer LTL among men who reported low depressive symptoms after full adjustment (b = 0.18, SE = 0.09, p < 0.05); and active coping with lifetime discrimination was associated with longer LTL among men who reported high depressive symptoms after full adjustment (b = 1.18, SE = 0.35, p < 0.05). Conclusions: The intersection of perceived discrimination and depressive symptomatology may be related to LTL, and the effects may vary by sex.

Telomere length determinants in childhood

Telomere length (TL) is a dynamic marker that reflects genetic predispositions together with the environmental conditions of an individual. It is closely related to longevity and a number of pathological conditions. Even though the extent of telomere research in children is limited compared to that of adults, there have been a substantial number of studies providing first insights into child telomere biology and determinants. Recent discoveries revealed evidence that TL is, to a great extent, determined already in childhood and that environmental conditions in adulthood have less impact than first believed. Studies have demonstrated that large inter-individual differences in TL are present among newborns and are determined by diverse factors that influence intrauterine development. The first years of child growth are associated with high cellular turnover, which results in fast shortening of telomeres. The rate of telomere loss becomes stable in early adulthood. In this review article we summarise the existing knowledge on telomere dynamics during the first years of childhood, highlighting the conditions that affect newborn TL. We also warn about the knowledge gaps that should be filled to fully understand the regulation of telomeres, in order to implement them as biomarkers for use in diagnostics or treatment.

Optimism and telomere length among African American adults in the Jackson Heart Study

BACKGROUND

Optimism is linked with greater longevity in both White and African American populations. Optimism may enhance longevity by slowing cellular aging, for which leukocyte telomere shortening is a biomarker. However, limited studies have examined the association of optimism with leukocyte telomere length among African Americans.

METHODS

Data are from 723 men and 1244 women participating in the Jackson Heart Study (age = 21-93 years). We used multivariable linear regression models to conduct cross-sectional analyses examining whether higher optimism was associated with longer mean absolute leukocyte telomere length (assayed with Southern blot analysis). Models adjusted for sociodemographic characteristics, depressive symptomatology, health conditions, and health behavior-related factors. We also considered potential effect modification by key factors.

RESULTS

In the age-adjusted model, optimism, measured as a continuous variable, was not associated with leukocyte telomere length (β = 0.01, 95%CI: -0.02, 0.04). This association remained null in the fully-adjusted model (β = 0.02, 95%CI: -0.02, 0.05) and was also null when considering optimism as a binary measure (higher vs. lower optimism). We found no evidence of effect modification by sex, age, body mass index, income, or chronic conditions.

CONCLUSIONS

Optimism was not associated with leukocyte telomere length among African American adults. Future studies should investigate alternate biological and behavioral mechanisms that may explain the optimism-health association.

Method comparison studies of telomere length measurement using qPCR approaches: A critical appraisal of the literature

Use of telomere length (TL) as a biomarker for various environmental exposures and diseases has increased in recent years. Various methods have been developed to measure telomere length. Polymerase chain reaction (PCR)-based methods remain wide-spread for population-based studies due to the high-throughput capability. While several studies have evaluated the repeatability and reproducibility of different TL measurement methods, the results have been variable. We conducted a literature review of TL measurement cross-method comparison studies that included a PCR-based method published between January 1, 2002 and May 25, 2020. A total of 25 articles were found that matched the inclusion criteria. Papers were reviewed for quality of methodologic reporting of sample and DNA quality, PCR assay characteristics, sample blinding, and analytic approaches to determine final TL. Overall, methodologic reporting was low as assessed by two different reporting guidelines for qPCR-based TL measurement. There was a wide range in the reported correlation between methods (as assessed by Pearson’s r) and few studies utilized the recommended intra-class correlation coefficient (ICC) for assessment of assay repeatability and methodologic comparisons. The sample size for nearly all studies was less than 100, raising concerns about statistical power. Overall, this review found that the current literature on the relation between TL measurement methods is lacking in validity and scientific rigor. In light of these findings, we present reporting guidelines for PCR-based TL measurement methods and results of analyses of the effect of assay repeatability (ICC) on statistical power of cross-sectional and longitudinal studies. Additional cross-laboratory studies with rigorous methodologic and statistical reporting, adequate sample size, and blinding are essential to accurately determine assay repeatability and replicability as well as the relation between TL measurement methods.

Dynamics of leukocyte telomere length in adults aged 50 and older: a longitudinal population-based cohort study

It is well established from previous cross-sectional studies that telomeres shorten with age. However, due to a considerable inter-individual variation in telomere length (TL), its relationship with biological aging is difficult to unpick. Longitudinal repeated assessments of TL changes within individuals should augment our understanding of TL dynamics in aging. This study disentangles within- and inter-individual effects of age on leukocyte telomere length (LTL) dynamics in a large population-based cohort of older adults. A total of 4053 subjects aged 50 and older from the WHO Study on global AGEing and adult health (SAGE) in Shanghai were studied. Relative LTL (T/S ratio) was measured at baseline (2009-2010) and follow-up (2017-2018) by quantitative real-time polymerase chain reaction. We used linear random slope models to analyze LTL dynamics in relation to age and sex and within-subject centering method to distinguish within- versus between-subject effects. We observed LTL shortening in 66.32%, maintenance in 11.23%, and elongation in 22.45% of the study participants. LTL declined significantly with age both cross-sectionally and longitudinally. More importantly, the longitudinal decline in LTL was much greater than the cross-sectional decline (- 0.017 (p < 0.001) versus - 0.002 (p < 0.001) per year). Furthermore, women had a lower within-subject LTL shortening rate than men (- 0.014 versus - 0.020 per year, p < 0.001). The within-individual longitudinal decline in LTL was much greater than the inter-individual cross-sectional decline, indicating that chronological age might impose a greater impact on LTL shortening than other influencing factors combined. Moreover, women showed a lower within-individual LTL shortening rate than men.

Telomere lengths in women treated for breast cancer show associations with chemotherapy, pain symptoms, and cognitive domain measures: a longitudinal study

Background

Survival rates for breast cancer (BC) have improved, but quality of life post-diagnosis/treatment can be adversely affected, with survivors reporting a constellation of psychoneurological symptoms (PNS) including stress, anxiety, depression, pain, fatigue, sleep disturbance, and cognitive dysfunction.

Methods

To assess a potential relationship between telomere length (TL) and the development/persistence of PNS, we longitudinally studied 70 women (ages 23–71) with early stage BC (I-IIIA) at 5 time-points: prior to treatment (baseline), the mid-point of their chemotherapy cycle, 6 months, 1 year, and 2 years following the initiation of chemotherapy.

Measures quantified included assessments of each of the PNS noted above and TL [using both a multiplex qPCR assay and a chromosome-specific fluorescence in situ hybridization (FISH) assay].

Results

Variables associated with qPCR mean TLs were age (p = 0.004) and race (T/S ratios higher in Blacks than Whites; p = 0.019). Significant differences (mostly decreases) in chromosome-specific TLs were identified for 32 of the 46 chromosomal arms at the mid-chemo time-point (p = 0.004 to 0.049). Unexpectedly, the sequential administration of doxorubicin [Adriamycin], cyclophosphamide [Cytoxan], and docetaxel [Taxotere] (TAC regimen) was consistently associated with higher TLs, when compared to TLs in women receiving a docetaxel [Taxotere], Carboplatin [Paraplatin], and trastuzumab [Herceptin] [TCH] chemotherapy regimen [association was shown with both the qPCR and FISH assays (p = 0.036)]. Of the PNS, pain was significantly negatively associated with TL (higher pain; shorter telomeres) for a subset of chromosomal arms (5q, 8p, 13p, 20p, 22p, Xp, Xq) (p = 0.014–0.047). Chromosomal TLs were also associated with 7 of the 8 cognitive domains evaluated, with the strongest relationship being noted for chromosome 17 and the visual memory domain (shorter telomeres; lower scores).

Conclusions

We showed that race and age were significantly associated with telomere length in women treated for early stage BC and that acquired telomere alterations differed based on the woman’s treatment regimen. Our study also demonstrated that pain and cognitive domain measures were significantly related to telomere values in this study cohort. Expanding upon the knowledge gained from this longitudinal study could provide insight about the biological cascade of events that contribute to PNS related to BC and/or its treatment.

Supplementary information

The online version contains supplementary material available at 10.1186/s13058-020-01368-6.

Prenatal toxic metal mixture exposure and newborn telomere length: Modification by maternal antioxidant intake

BACKGROUND

Telomere length (TL) predicts the onset of cellular senescence and correlates with longevity and age-related disease risk. While telomeres erode throughout life, adults display fixed ranking and tracking of TL, supporting the importance of the early environment in determining inter-individual variability across the life course. Given their guanine-rich structure, telomeres are highly susceptible to oxidative stress (OS). We examined maternal metal exposure, which can induce OS, in relation to newborn TL. We also considered the modifying role of maternal antioxidant intake.

METHODS

Analyses included 100 mother-newborn pairs enrolled in the Boston and New York City-based PRogramming of Intergenerational Stress Mechanisms (PRISM) pregnancy cohort. We measured As, Ba, Cd, Ni, and Pb in maternal late-pregnancy urine by ICP-MS and quantified relative leukocyte TL (rLTL) in cord blood using qPCR. We used Weighted Quantile Sum (WQS) regression to estimate the metal mixture - rLTL association and conducted repeated holdout validation to improve the stability of estimates across data partitions. We examined models stratified by high (>median) versus low (≤median) maternal antioxidant intake, estimated from Block98 Food Frequency Questionnaires. We considered urinary creatinine, week of urine collection, maternal age, and race/ethnicity as covariates.

RESULTS

In adjusted models, urinary metals were inversely associated with newborn rLTL (βWQS = -0.50, 95% CI: -0.78, -0.21). The top metals contributing to the negative association included Ba (weight: 35.4%), Cd (24.5%) and Pb (26.9%). In models stratified by antioxidant intake, the significant inverse association between metals and rLTL remained only among mothers with low antioxidant intake (low: βWQS = -0.92, 95% CI: -1.53, -0.30; high: βWQS = -0.03, 95% CI: -0.58, 0.52). Results were similar in unadjusted models.

CONCLUSIONS

Relative LTL was shorter among newborns of mothers with higher exposure to metals during pregnancy. Higher maternal antioxidant intake may mitigate the negative influence of metals on newborn rLTL.

Determinants of telomere length across human tissues

Telomere shortening is a hallmark of aging. Telomere length (TL) in blood cells has been studied extensively as a biomarker of human aging and disease; however, little is known regarding variability in TL in nonblood, disease-relevant tissue types. Here, we characterize variability in TLs from 6391 tissue samples, representing >20 tissue types and 952 individuals from the Genotype-Tissue Expression (GTEx) project. We describe differences across tissue types, positive correlation among tissue types, and associations with age and ancestry. We show that genetic variation affects TL in multiple tissue types and that TL may mediate the effect of age on gene expression. Our results provide the foundational knowledge regarding TL in healthy tissues that is needed to interpret epidemiological studies of TL and human health.

The effect of neighborhood social environment on prostate cancer development in black and white men at high risk for prostate cancer

INTRODUCTION

Neighborhood socioeconomic (nSES) factors have been implicated in prostate cancer (PCa) disparities. In line with the Precision Medicine Initiative that suggests clinical and socioenvironmental factors can impact PCa outcomes, we determined whether nSES variables are associated with time to PCa diagnosis and could inform PCa clinical risk assessment.

MATERIALS AND METHODS

The study sample included 358 high risk men (PCa family history and/or Black race), aged 35-69 years, enrolled in an early detection program. Patient variables were linked to 78 nSES variables (employment, income, etc.) from previous literature via geocoding. Patient-level models, including baseline age, prostate specific antigen (PSA), digital rectal exam, as well as combined models (patient plus nSES variables) by race/PCa family history subgroups were built after variable reduction methods using Cox regression and LASSO machine-learning. Model fit of patient and combined models (AIC) were compared; p-values<0.05 were significant. Model-based high/low nSES exposure scores were calculated and the 5-year predicted probability of PCa was plotted against PSA by high/low neighborhood score to preliminarily assess clinical relevance.

RESULTS

In combined models, nSES variables were significantly associated with time to PCa diagnosis. Workers mode of transportation and low income were significant in White men with a PCa family history. Homeownership (%owner-occupied houses with >3 bedrooms) and unemployment were significant in Black men with and without a PCa family history, respectively. The 5-year predicted probability of PCa was higher in men with a high neighborhood score (weighted combination of significant nSES variables) compared to a low score (e.g., Baseline PSA level of 4ng/mL for men with PCa family history: White-26.7% vs 7.7%; Black-56.2% vs 29.7%).

DISCUSSION

Utilizing neighborhood data during patient risk assessment may be useful for high risk men affected by disparities. However, future studies with larger samples and validation/replication steps are needed.

Demographic and developmental patterns in telomere length across adolescence

Telomere length is often used in studies of adults as a biomarker of cellular aging and an indicator of stress exposure. However, we know little about how telomeres change over time, particularly over the course of the important developmental period of adolescence. We use data on telomere length collected at two points in time spanning adolescence (Years 9 and 15) from the Fragile Families and Child Wellbeing Study to examine longitudinal patterns (n = 1,654) in telomere length. We find a quantitatively small but significant average lengthening in telomere length across adolescence and little evidence of associations between telomere length and pubertal development.

Study of telomere length in men who carry a fragile X premutation or full mutation allele

The fragile X premutation is defined by the expansion of the CGG trinucleotide repeat at the 5' UTR of the FMR1 gene to between 55 and 200 repeats, while repeat tracks longer than 200 are defined as full mutations. Men carrying a premutation are at increased risk for fragile X-associated tremor/ataxia syndrome (FXTAS); those with > 200 repeats have fragile X syndrome, a common genetic form of intellectual disabilities. In our study, we tested the hypothesis that men carrying a fragile X premutation or full mutation are "biologically older", as suggested by the associated age-related disorder in the presence of the fragile X premutation or the altered cellular pathology that affects both the fragile X premutation and full mutation carriers. Thus, we predicted that both groups would have shorter telomeres than men carrying the normal size repeat allele. Using linear regression models, we found that, on average, premutation carriers had shorter telomeres compared with non-carriers (n = 69 vs n = 36; p = 0.02) and that there was no difference in telomere length between full mutation carriers and non-carriers (n = 37 vs n = 29; p > 0.10). Among premutation carriers only, we also asked whether telomere length was shorter among men with vs without symptoms of FXTAS (n = 28 vs n = 38 and n = 27 vs n = 41, depending on criteria) and found no evidence for a difference (p > 0.10). Previous studies have shown that the premutation is transcribed whereas the full mutation is not, and the expanded repeat track in FMR1 transcript is thought to lead to the risk for premutation-associated disorders. Thus, our data suggest that the observed premutation-only telomere shortening may be a consequence of the toxic effect of the premutation transcript and suggest that premutation carriers are "biologically older" than men carrying the normal size allele in the same age group.

Advances in Understanding the Causes and Consequences of Health Disparities in Aging Minorities

PURPOSE OF REVIEW

The purpose was to discuss appropriate methods for advancing our understanding of health disparities or minority aging including life-course perspectives, biological measures, pain measurement, and generational approaches.

RECENT FINDINGS

Life course perspectives provide an orientation for studying older minorities that concomitantly captures exposures and stressors that may lead to earlier onset of disease and premature mortality. The use of biological markers to study health disparities in older minorities is necessary in order to identify pathways between psychosocial factors and health outcomes. Work focusing on pain disparities should include explorations of relationships between psychosocial factors, and subjective and objective measures of pain. Studying families can provide insight into genetic associations and coping styles in older minorities.

SUMMARY

Methodological approaches that take life course, biology, and social factors into account may help identify causal pathways between social determinants of health and health outcomes among older minorities. Once these causal pathways have been identified, more strategies and interventions that strive toward health equity across older adults of all race/ethnic groups can be developed.

Telomere Length and Autism Spectrum Disorder Within the Family: Relationships With Cognition and Sensory Symptoms

Telomeres are repetitive noncoding deoxynucleotide sequences that cap chromosomes to protect DNA. Telomere length (TL) is affected by both genetic and environmental factors, and shortening of telomeres is associated with multiple neuropsychiatric disorders, early life stress, and age-related cognitive dysfunction. Two previous studies associated shorter TL with autism spectrum disorder (ASD). We aimed to replicate this finding, describe TL in unaffected siblings, and explore novel relationships with symptoms and cognitive function in families with ASD. Participants were 212 male children and adolescents ages 1-17 years (86 with ASD, 57 unaffected siblings, and 69 typically developing [TD]) and 64 parents. TL was measured from blood leukocytes with quantitative real-time polymerase chain reaction and results are expressed by relative ratios with a single copy gene. We replicated that children and adolescents with ASD have shorter TL, compared to TD, and show that unaffected siblings have TL in between those of TD and ASD. We present novel associations between TL and sensory symptoms in ASD. Finally, we demonstrate cognitive functions, but not autistic traits, are related to TL in parents of children with ASD. Cognitive function and TL were not related in children and adolescents. As the third replication, our results elicit confidence in the finding that ASD is associated with shorter TL. Our novel sensory investigation suggests that shortened TL may be a biological mechanism of sensory symptoms in ASD. Furthermore, results highlight the need to better understand relationships between cognition, aging, and TL in families with ASD. Autism Res 2020, 13: 1094-1101. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Telomeres cap chromosomes to protect DNA. They progressively shorten as people age and are related to health outcomes. We replicated previous findings that children and adolescents with autism spectrum disorder (ASD) have shorter telomeres, compared to typically developing (TD), and show that unaffected siblings have telomere length (TL) in between those of TD and ASD. We find shortened TL is related to more severe sensory symptoms. This may mean families with ASD, especially those with elevated sensory symptoms, are at risk for worse age-related health outcomes.

Racial discrimination and telomere shortening among African Americans: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

OBJECTIVE

Telomeres are protective sequences of DNA capping the ends of chromosomes that shorten over time. Leukocyte telomere length (LTL) is posited to reflect the replicative history of cells and general systemic aging of the organism. Chronic stress exposure leads to accelerated LTL shortening, which has been linked to increased susceptibility to and faster progression of aging-related diseases. This study examined longitudinal associations between LTL and experiences of racial discrimination, a qualitatively unique source of minority psychosocial stress, among African Americans.

METHOD

Data are from 391 African Americans in the Coronary Artery Risk Development in Young Adults (CARDIA) Telomere Ancillary Study. We examined the number of domains in which racial discrimination was experienced in relation to LTL collected in Years 15 and 25 (Y15: 2000/2001; Y25: 2010/2011). Multivariable linear regression examined if racial discrimination was associated with LTL. Latent change score analysis (LCS) examined changes in racial discrimination and LTL in relation to one another.

RESULTS

Controlling for racial discrimination at Y15, multivariable linear regression analyses indicated that racial discrimination at Y25 was significantly associated with LTL at Y25. This relationship remained robust after adjusting for LTL at Y15 (b = -.019, p = .015). Consistent with this finding, LCS revealed that increases in experiences of racial discrimination were associated with faster 10-year LTL shortening (b = -.019, p = .015).

CONCLUSIONS

This study adds to evidence that racial discrimination contributes to accelerated physiologic weathering and health declines among African Americans through its impact on biological systems, including via its effects on telomere attrition. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Discrimination, social support, and telomere length: the Multi-Ethnic Study of Atherosclerosis (MESA)

PURPOSE

We sought to assess the association of reports of discrimination with leukocyte telomere length (LTL) and effect measure modification by social support.

METHODS

This study used data from the Multi-Ethnic Study of Atherosclerosis Stress Ancillary Study (n = 1153). Discrimination was measured using the everyday discrimination and the major experiences of discrimination scales. LTL was defined as the ratio of telomeric DNA to single-copy control gene (mean = 0.916, SD = 0.205). Linear regression models were used to examine the relationship between discrimination and LTL.

RESULTS

We found no association between either measure of discrimination and LTL, but there was evidence of effect modification by social support (P (χ2) = 0.001) for everyday discrimination only. Among those with low social support, reporting moderate and high everyday discrimination was associated with a 0.35 (95% CI: -0.54 to -0.16) and a 0.17 (95% CI: -0.34 to -0.01) shorter telomere length, respectively, compared to reporting no discrimination, after adjusting for demographic factors, health behaviors, and health conditions. There were no associations between discrimination and LTL among those reporting moderate or high social support.

CONCLUSIONS

These findings underscore the importance of continued investigation of the potential health consequences of chronic unfair treatment in the absence of supportive resources.

Association between leucocyte telomere length and cardiovascular disease in a large general population in the United States

Leucocyte telomere length (LTL) has been reported to be linked to ageing, cancer and cardiovascular disease (CVD). This study aimed to explore the association between LTL and CVD risk in a nationally representative sample of U.S. adults. Complex associations, including nonlinearity and interaction, were also examined. A total of 7,378 subjects from the National Health and Nutrition Examination Survey (NHANES) 1999-2002 were collected. Telomere length was detected from DNA samples and expressed as the mean T/S ratio (telomere repeats per single-copy gene). We performed multiple logistic regression models and interactive analysis to explore the associations between LTL and CVD risk by adjusting for potential confounders. We also performed a sensitivity analysis to investigate the robustness of our results. Among all participants, LTL was associated with the risk of CVD (OR = 0.79, 95% CI: 0.63~0.98, P = 0.033) in a linear manner rather than in a nonlinear manner (P = 0.874). Interaction effects of LTL with both education (P = 0.017) and hypertension (P = 0.007) were observed. Furthermore, using subgroup analyses, protective effects of LTL on CVD risk were found in females and in individuals who were college graduates or above, had serum cotinine >10 ng/ml, did not have hypertension, or had normal white blood cell levels. LTL is linearly inversely associated with CVD risk in the general population of the United States.

Common genetic variation and risk of osteosarcoma in a multi-ethnic pediatric and adolescent population

Osteosarcoma, a malignant primary bone tumor most commonly diagnosed in children and adolescents, has a poorly understood genetic etiology. Genome-wide association studies (GWAS) and candidate-gene analyses have identified putative risk variants in subjects of European ancestry. However, despite higher incidence among African-American and Hispanic children, little is known regarding common heritable variation that contributes to osteosarcoma incidence and clinical presentation across racial/ethnic groups. In a multi-ethnic sample of non-Hispanic white, Hispanic, African-American and Asian/Pacific Islander children (537 cases, 2165 controls), we performed association analyses assessing previously-reported loci for osteosarcoma risk and metastasis, including meta-analysis across racial/ethnic groups. We also assessed a previously described association between genetic predisposition to longer leukocyte telomere length (LTL) and osteosarcoma risk in this independent multi-ethnic dataset. In our sample, we were unable to replicate previously-reported loci for osteosarcoma risk or metastasis detected in GWAS of European-ancestry individuals in either ethnicity-stratified analyses or meta-analysis across ethnic groups. Our analyses did confirm that genetic predisposition to longer LTL is a risk factor for osteosarcoma (ORmeta: 1.22; 95% CI: 1.09-1.36; P = 3.8 × 10-4), and the strongest effect was seen in Hispanic subjects (OR: 1.32; 95% CI: 1.12-1.54, P = 6.2 × 10-4). Our findings shed light on the replicability of osteosarcoma risk loci across ethnicities and motivate further characterization of these genetic factors in diverse clinical cohorts.

Telomere length and cognitive function: Differential patterns across sociodemographic groups

OBJECTIVE

The present study investigates whether associations between telomere length (TL) and cognitive performance across multiple domains are moderated by poverty status and race.

METHOD

Participants were 325 African American and White urban-dwelling adults (M age = 47.9 years; 49.5% African American; 50.2% female; 48.9% living in poverty) from the Healthy Aging in Neighborhoods of Diversity across the Life Span study. TL was assayed from peripheral blood mononuclear cells using quantitative polymerase chain reactions. Multivariable regression analyses examined interactions of TL, poverty status, and race with performance on the following cognitive tests: Trail-Making Test Parts A and B, Digit Span Forward and Backward, semantic verbal fluency, Brief Test of Attention, Benton Visual Retention Test (BVRT), and California Verbal Learning Test-II total learning, short-delay free recall, and long-delay free recall scores. Analyses adjusted for age, sex, and high school-or-greater educational attainment.

RESULTS

Significant three-way interactions of TL × Poverty Status × Race revealed that, among White participants living in poverty, shorter TL was associated with worse performance on Digit Span Forward and Backward (ps<.05). Additionally, significant two-way interactions of TL × Poverty Status revealed that, among all participants living in poverty, shorter TL was associated with worse performance on the Trail-Making Test Part B and the BVRT (ps<.05).

CONCLUSIONS

TL may be differentially associated with aspects of attention, executive functioning, and memory among individuals living in poverty, who may be uniquely vulnerable to adverse effects of shorter telomeres. Replication of these findings is needed to determine their generalizability. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Do black/white differences in telomere length depend on socioeconomic status?

Social and economic disadvantage are hypothesized to increase the risk of disease and death via accelerated biological aging. Given that US blacks are socially and economically disadvantaged relative to whites, health disparities scholars expected that blacks would have shorter telomere length-a biomarker of cell aging-than whites. Yet the majority of studies have found that blacks have longer telomere length than whites. Using data from the National Health and Nutrition Examination Survey (n = 3,761; 28.3% non-Hispanic black, 71.7% non-Hispanic white), we found that leukocyte telomere length was 4.00% (95% CI: 1.12%, 6.87%) longer among blacks compared to whites in the full sample, but differences were greatest among those with lower SES (5.66%; 95% CI: 0.10%, 10.32%), intermediate among those with middle SES (4.14%; 95% CI: 0.05%, 8.24%), and smallest among those with higher SES (2.33%; 95% CI: -3.02%, 7.67%). These results challenge purely genetic explanations for race differences in telomere length and point to a potential social-environmental cause of longer telomere length in US blacks.

Heart-Breaking Telomeres

Telomeres, the protective ends of linear chromosomes, shorten throughout an individual's lifetime. Accumulation of critically short telomeres is proposed to be a primary molecular cause of aging and age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as or telomeropathies. The rate of telomere shortening throughout life is determined by endogenous (genetic) and external (nongenetic) factors. Therapeutic strategies based on telomerase activation are being developed to treat and prevent telomere-associated diseases, namely aging-related diseases and telomeropathies. Here, we review the molecular mechanisms underlying telomere driven diseases with particular emphasis on cardiovascular diseases.

Telomere length and frailty in older adults-A systematic review and meta-analysis

Telomere shortening has been proposed as a potentially useful biomarker of human ageing and age-related morbidity and mortality. We performed a systematic review and meta-analysis to summarize results from individual studies on the telomere length according to the frailty status and frailty index in older adults. We searched the PubMed, SCOPUS and Web of Science databases to identify studies that evaluated the telomere length in frail and non-frail older adults and the relationship between telomere length and frailty index score. We used the base pairs (bp) as a measure of the telomere length. Summary estimates were calculated using random-effects models. Nine studies were included in the present systematic review and a total of 10,079 older adults were analyzed. We found that the frail older adults (n = 355) had shorter telomeres than the non-frail (n = 1894) (Standardized Mean Difference [SMD] -0.41; 95% CI -0.73 to -0.09; P = 0.01; I² = 82%). Significant differences in telomere length between frail and non-frail older adults were identified in Hispanic (SMD -1.31; 95% CI -1.71 to -0.92; P < 0.0001; I² = 0%) but not in Non-Hispanic countries (SMD -0.13; 95% CI -0.26 to 0.00; P = 0.06; I² = 0%). Similar results were found in the adjusted meta-analysis (SMD -0.56; 95% -1.12 to 0.00; P = 0.05; I² = 85%). A significant but weak relationship was found between telomere length and frailty index analyzing 8244 individuals (SMD -0.06; 95% IC -0.10 to 0.01; P = 0.01; I² = 0%). The current available evidence suggests that telomere length may be not a meaningful biomarker for frailty. Because the potential influence of ethnicity in shortening of telomeres and decline in physiologic reserves associated with aging, additional multiethnic studies are needed.

A Cross-Sectional Analysis of Telomere Length and Sleep in the Women's Health Initiative

Telomere length is a heritable marker of cellular age that is associated with morbidity and mortality. Poor sleep behaviors, which are also associated with adverse health events, may be related to leukocyte telomere length (LTL). We studied a subpopulation of 3,145 postmenopausal women (1,796 European-American (EA) and 1,349 African-American (AA)) enrolled in the Women's Health Initiative in 1993-1998 with data on Southern blot-measured LTL and self-reported usual sleep duration and sleep disturbance. LTL-sleep associations were analyzed separately for duration and disturbance using weighted and confounder-adjusted linear regression models in the entire sample (AAs + EAs; adjusted for race/ethnicity) and in racial/ethnic strata, since LTL differs by ancestry. After adjustment for covariates, each additional daily hour of sleep beyond 5 hours, approximately, was associated with a 27-base-pair (95% confidence interval (CI): 6, 48) longer LTL in the entire sample. Associations between sleep duration and LTL were strongest among AAs (adjusted β = 37, 95% CI: 4, 70); a similar, nonsignificant association was observed for EAs (adjusted β = 20, 95% CI: -7, 48). Sleep disturbance was not associated with LTL in our study. Our models did not show departure from linearity (quadratic sleep terms: P ≥ 0.55). Our results suggest that longer sleep duration is associated with longer LTL in postmenopausal women.

Experienced discrimination and racial differences in leukocyte gene expression

Racial disparities in health outcomes between African Americans and European Americans have been well-documented, but not fully understood. Chronic inflammation contributes to several of the diseases showing racial disparities (e.g., Human Immunodeficiency Virus [HIV]), and racial differences in stress exposure (e.g., experiences of racial discrimination) that stimulate pro-inflammatory processes that may contribute to differential health outcomes. We performed a cross-sectional bioinformatic analyses relating perceived discrimination (as measured by the Perceived Ethnic Discrimination Questionnaire [PED-Q]) to the activity of pro-inflammatory, neuroendocrine, and antiviral transcription control pathways relevant to the conserved transcriptional response to adversity (CTRA) in peripheral blood leukocytes. Subjects were 71 individuals (37 HIV-seropositive (HIV+); 34 HIV-seronegative (HIV-)) (mean age = 53 years, range 27-63), who self-identified either as African American/Black (n = 48) or European American/White (n = 23). This provided the opportunity to examine the independent effects of race and HIV, as well as the modifying role of perceived discrimination on pathways involved in CTRA. Exploratory analysis examined the interactive effects of HIV and race on pathways involved in CTRA. Relative to European Americans, African Americans showed increased activity of two key pro-inflammatory transcription control pathways (NF- кB and AP-1) and two stress-responsive signaling pathways (CREB and glucocorticoid receptor); these effects did not differ significantly as a function of HIV infection (HIV x Race interaction, all p > .10). Results suggested that differences in experiences of racial discrimination could potentially account for more than 50% of the total race-related difference in pro-inflammatory transcription factor activity. In sum, differential exposure to racial discrimination may contribute to racial disparities in health outcomes in part by activating threat-related molecular programs that stimulate inflammation and contribute to increased risk of chronic illnesses.

Telomere length in early childhood is associated with sex and ethnicity

Telomeres are repetitive DNA sequences at the end of chromosomes that function to protect chromosomes from degradation. Throughout the life course, telomere length decreases with age and is influenced by environmental factors and health conditions. This study aimed to determine the relative telomere lengths in a diverse cohort of about 4000 four-year-old children in New Zealand. Linear regression was used to investigate the relationship between telomere length, child gender, ethnicity, paternal age and deprivation. We observed substantial variation in telomere length according to sex and self-identified ethnicity. Telomere length was longer in females compared to males (coefficient of 0.042, 95% confidence interval (CI) 0.024-0.060). European children had shorter telomere than both the indigenous Māori (coefficient of 0.03, CI 0.007-0.055) and Pacific children (coefficient of 0.15, CI 0.12-0.18). The data suggest that telomere lengths are highly variable and variability between individuals arise from early age, influenced partly by sex and ethnicity. Longer telomeres in indigenous Māori and Pacific children may reflect the heritability of telomere length in genetically less complex populations. This study increases our understanding of telomere dynamics in young children since the majority of telomere studies are conducted in adults.

Association between internet gaming addiction and leukocyte telomere length in Korean male adolescents

Internet gaming addiction (IGA) has been associated with many negative health outcomes, especially for youth. In particular, the potential association between IGA and leukocyte telomere length (LTL) has yet to be examined. In this study we compared LTL in Korean male adolescents with and without IGA and examined the association between LTL and autonomic functions. Specifically, plasma catecholamine, serum cortisol, and psychological stress levels were measured as autonomic functions. Data were collected using participant blood samples analyzed for LTL, catecholamine, and cortisol levels and a set of questionnaires to assess IGA and psychological stress levels of the participants. The LTL measurements were made using a qPCR-based technique, and the relative LTL was calculated as the telomere/single copy (T/S) ratio. T/S ratio was significantly shorter in the IGA group than in the non-IGA group (150.43 ± 6.20 and 187.23 ± 6.42, respectively; p < .001) after adjusting for age. In a univariate regression analysis, age, daily Internet gaming time, IGA score, and catecholamine level (epinephrine and norepinephrine) were significantly associated with T/S ratio. However, duration of Internet gaming exposure, dopamine, cortisol, and psychological stress levels were not found to be associated with T/S ratio. In the final multiple linear regression model, age, daily Internet gaming time, and epinephrine level showed statistically significant relationships with T/S ratio. Our results indicate that in addition to age, involvement in excessive Internet gaming may induce LTL shortening in male adolescents, which may be partially attributable to changes in autonomic function such as catecholamine level. These findings further understanding of the health effects of IGA and highlight the need for screening and intervention strategies for male adolescents with IGA.

Resilience factors may buffer cellular aging in individuals with and without chronic knee pain

Telomere length, a measure of cellular aging, is inversely associated with chronic pain severity. While psychological resilience factors (e.g., optimism, acceptance, positive affect, and active coping) are associated with lower levels of clinical pain and greater physical functioning, it is unknown whether resilience may buffer against telomere shortening in individuals with chronic pain. Additionally, a broader conceptualization of resilience that includes social and biobehavioral factors may improve our understanding of the relationship between resilience, chronic pain, and health outcomes. In individuals with and without chronic knee pain, we investigated whether (1) psychological resilience would be positively associated with telomere length and if (2) a broader conceptualization of resilience including social and biobehavioral factors would strengthen the association. Seventy-nine adults, 45 to 85 years of age, with and without knee pain completed demographic, health, clinical pain, psychological, social, and biobehavioral questionnaires. Resilience levels were determined by summing the total number of measures indicating resilience based on published clinical ranges and norms. Blood samples were collected, and telomere length was determined. In regression analyses controlling for sex, race, age, and characteristic pain intensity, greater psychological resilience and psychosocial/biobehavioral resilience were associated with longer telomeres ( p = .0295 and p = .0116, respectively). When compared, psychosocial/biobehavioral resilience was significantly more predictive of telomere length than psychological resilience ( p < .0001). Findings are promising and encourage further investigations to enhance understanding of the biological interface of psychosocial and biobehavioral resilience factors in individuals with musculoskeletal chronic pain conditions.

Leukocyte Telomere Length and Chronic Conditions in Older Women of Northeast Brazil: A Cross-Sectional Study

This study assessed whether telomere length is related to chronic conditions, cardiovascular risk factors, and inflammation in women aged 65 to 74 from Northeast Brazil. Participants were selected from two sources, a representative sample of the International Mobility in Aging Study (n = 57) and a convenience sample (n = 49) recruited at senior centers. Leukocyte telomere length was measured by quantitative polymerase chain reaction from blood samples in 83 women. Natural log-transformed telomere/single copy gene ratio was used as the dependent variable in the analysis. Blood analyses included inflammatory markers (high-sensitivity C-reactive protein and interleukin-6), total, low-density lipoprotein and high-density lipoprotein cholesterol, triglycerides, glucose and glycosylated hemoglobin. Self-rated health, chronic conditions, cardiovascular risk factors and inflammatory markers were not associated with telomere length. No significant independent association was found between telomere length and anthropometric measures or blood markers, even after adjusting for age, education and adverse childhood events among these older women in Northeast Brazil. Our results did not confirm the hypothesis that chronic conditions, cardiovascular risk factors or inflammation are associated with shorter telomere length in these women who have exceptional survival relative to the life expectancy of their birth cohort.

Sex-specific associations between telomere length and candidate miRNA expression in placenta

BACKGROUND

In the early-life environment, proper development of the placenta is essential for both fetal and maternal health. Telomere length at birth has been related to life expectancy. MicroRNAs (miRNAs) as potential epigenetic determinants of telomere length at birth have not been identified. In this study, we investigate whether placental miRNA expression is associated with placental telomere length at birth.

METHODS

We measured the expression of seven candidate miRNAs (miR-16-5p, -20a-5p, -21-5p, -34a-5p, 146a-5p, -210-3p and -222-3p) in placental tissue at birth in 203 mother-newborn (51.7% girls) pairs from the ENVIRONAGE birth cohort. We selected miRNAs known to be involved in crucial cellular processes such as inflammation, oxidative stress, cellular senescence related to aging. Placental miRNA expression and relative average placental telomere length were measured using RT-qPCR.

RESULTS

Both before and after adjustment for potential covariates including newborn's ethnicity, gestational age, paternal age, maternal smoking status, maternal educational status, parity, date of delivery and outdoor temperature during the 3rd trimester of pregnancy, placental miR-34a, miR-146a, miR-210 and miR-222 expression were significantly (p ≤ 0.03) and positively associated with placental relative telomere length in newborn girls. In newborn boys, only higher expression of placental miR-21 was weakly (p = 0.08) associated with shorter placental telomere length. Significant miRNAs explain around 6-8% of the telomere length variance at birth.

CONCLUSIONS

Placental miR-21, miR-34a, miR-146a, miR-210 and miR-222 exhibit sex-specific associations with telomere length in placenta. Our results indicate miRNA expression in placental tissue could be an important determinant in the process of aging starting from early life onwards.

Racial differences in maternal and umbilical cord blood leukocyte telomere length and their correlations

PURPOSE

Telomere length at birth sets the baseline for telomere shortening and may influence adult disease risk like cancer. Telomere length is heritable, but may also be a marker of exposures in utero, including those influencing racial differences in risk. We examined racial differences in telomere length in maternal and umbilical cord blood from male neonates, and maternal-neonate correlations to generate hypotheses.

METHODS

Black and white pregnant women were recruited in 2006-2007 and followed to postpartum. Data came from questionnaires and medical records. Relative telomere length was measured by qPCR in leukocyte DNA. We estimated mean telomere length in mothers and neonates (n = 55 pairs) using linear regression and maternal-cord blood Spearman correlations, overall and by race.

RESULTS

Black mothers had shorter age- and plate-adjusted telomere length (2.49, 95% CI 2.11-2.86) than whites (2.92, 95% CI 2.63-3.22; p = 0.1) and black neonates had shorter telomere length (2.58, 95% CI 2.16-3.01) than whites (3.13, 95% CI 2.79-3.47; p = 0.1), though not statistically significant. Differences were attenuated after further adjustment for maternal factors. Maternal-cord blood correlations were moderate (r = 0.53, p < 0.0001), and did not differ by race.

CONCLUSION

Telomere length may differ by race at birth due to both inherited and racial differences in maternal factors. This study was for hypothesis generation and results should be followed up in larger studies.

Telomere Length and Neighborhood Circumstances: Evaluating Biological Response to Unfavorable Exposures

Background: Multilevel frameworks suggest neighborhood circumstances influence biology; however, this relationship is not well studied. Telomere length (TL) shortening has been associated with individual-level and neighborhood-level exposures and disease and may provide insights into underlying biologic mechanisms linking neighborhood with biology. To support neighborhood-biology investigations, we sought to determine the independent effect of neighborhood exposures on TL using standard multilevel linear regression models and quantile regression, a nonlinear, social science method applicable for testing the biologic hypothesis that extremes of the TL distribution are related to poor outcomes.Methods: In a multicenter, cross-sectional study, blood TL was measured in 1,488 individuals from 127 census tracts in three U.S. regions using terminal restriction fragment assays. Multilevel linear and quantile regression models were adjusted for individual-level race, education, perceived stress, and depression. Neighborhood exposures included population density, urban/residential crowding, residential stability/mobility, and socioeconomic status.Results: TL was not associated with any neighborhood variable using linear models, but quantile regression revealed inverse associations between population density and urban crowding at the lower tails of the TL distribution [5th (population density P = 0.03; urban crowding P = 0.002), 50th (both P < 0.001), 75th percentiles (both P < 0.001)]. TL was related to residential stability at the upper tail (95th percentile P = 0.006).Conclusions: Findings support the use of nonlinear statistical methods in TL research and suggest that neighborhood exposures can result in biological effects.Impact: TL may serve as an underlying example of a biologic mechanism that can link neighborhood with biology, thus supporting multilevel investigations in future studies. Cancer Epidemiol Biomarkers Prev; 26(4); 553-60. ©2017 AACRSee all the articles in this CEBP Focus section, "Geospatial Approaches to Cancer Control and Population Sciences."