Effect of obesity on telomere length: Systematic review and meta-analysis

Shorter telomeres among individuals with physical disability: The moderating role of perceived stress

OBJECTIVES

Evidence suggests that individuals with physical disability may suffer from psychological distress and accelerated cellular aging, manifested by shortened telomere length (TL), compared with healthy individuals. Studies indicate that high levels of perceived stress and depression may increase the physiological susceptibility and thus, may contribute to a short TL. However, the moderating role of perceived stress and depression within the relationship between physical disability and TL remains unknown.

METHODS

The participants consisted of 119 male subjects (mean age 54.36 years, range 35-70). Of them, 30 were able-bodied and 86 had a physical disability: 34 were due to Poliomyelitis (polio) and 55 were due to spinal cord injury (SCI). Blood samples for TL analysis were collected; the participants completed questionnaires and underwent disability evaluation.

RESULTS

Participants with disability had a shorter TL as well as elevated levels of perceived stress and depression compared with able-bodied controls. Both the perceived stress and depression were correlated with a shorter TL. Nonetheless, perceived stress, rather than depression, moderated the relationship between disability and TL; among participants with higher perceived stress levels, in particular, individuals with physical disability had a shorter TL than the able-bodied controls.

DISCUSSION

The present findings suggest that individuals with physical disability and who exhibit high levels of perceived stress may be particularly vulnerable for accelerated cellular aging, suggesting that perceived stress can be used as a valuable target for intervention.

Association Between Body Weight and Telomere Length Is Predominantly Mediated Through C-Reactive Protein

CONTEXT

Both obesity and inflammation are related to accelerated aging. It is not yet known whether inflammation mediates the effects of obesity on aging.

OBJECTIVE

This work aims to dissect the direct effect of body mass index (BMI) and its indirect effect through C-reactive protein (CRP) on leukocyte telomere length (LTL) to determine the mediation effect of CRP on the BMI-LTL association.

METHODS

The study cohort included 5451 adults (1404 Mexican American, 3114 White, and 933 Black individuals; 53.5% male; mean age = 49.2 years) from the 1999 to 2002 National Health and Nutrition Examination Survey. General mediation models were used to examine the mediation effect of CRP on the BMI-LTL association.

RESULTS

After adjusting for age, race, sex, physical activity, alcohol use, and serum cotinine, the total effect of BMI on LTL was significant (standardized regression coefficient, β = -.054, P < .001) without CRP included in the model. With inclusion of CRP in the model, the indirect effect of BMI on LTL through CRP was estimated at β equal to -.023 (P < .001), and the direct effect of BMI on LTL in its absolute value decreased to β equal to -.031 (P = .025). The mediation effect of CRP was estimated at 42.6%. The mediation model parameters did not differ significantly between race and sex groups.

CONCLUSION

These results suggest that the inverse BMI-LTL association is partly mediated by obesity-induced inflammation. The significant direct effect of BMI on LTL with removal of the mediation effect through CRP indicates that obesity is associated with LTL attrition also through other noninflammatory mechanisms.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Systematic review and meta-analysis of the association between paediatric obesity and telomere length

AIM

This systematic review and meta-analysis aimed to assess the association between paediatric obesity and telomere length.

METHODS

We conducted a comprehensive literature search for original studies assessing the associations between obesity and telomere length in children. Fixed or random effects with inverse-variance meta-analysis were used to estimate the standardised mean difference (SMD) and its 95% confidence interval (95% CI) between overweight or obese and normal-weight children. Heterogeneity was assessed using the I² statistic, and meta-regression analyses were used to evaluate the potential source of heterogeneity. Subgroup analysis was further conducted by sex.

RESULTS

A total of 11 studies were included. The meta-analysis showed that children who were overweight or obese had shorter telomere length than normal-weight children (SMD: -0.85; 95% CI: -1.42 to -0.28; p < 0.01). However, significant heterogeneity was present (I²  = 97%; p < 0.01). Study design, methods used for measuring telomere length, tissue types, mean age, and percentage of boys were not the source of heterogeneity revealed by meta-regression analysis. The inverse trend was significant only in boys, but not in girls.

CONCLUSION

There was a negative association between paediatric obesity and telomere length. Weight control in children might have beneficial effect on telomere length.

T Cell Immunosenescence in Aging, Obesity, and Cardiovascular Disease

Although advances in preventive medicine have greatly improved prognosis, cardiovascular disease (CVD) remains the leading cause of death worldwide. This clearly indicates that there remain residual cardiovascular risks that have not been targeted by conventional therapies. The results of multiple animal studies and clinical trials clearly indicate that inflammation is the most important residual risk and a potential target for CVD prevention. The immune cell network is intricately regulated to maintain homeostasis. Ageing associated changes to the immune system occurs in both innate and adaptive immune cells, however T cells are most susceptible to this process. T-cell changes due to thymic degeneration and homeostatic proliferation, metabolic abnormalities, telomere length shortening, and epigenetic changes associated with aging and obesity may not only reduce normal immune function, but also induce inflammatory tendencies, a process referred to as immunosenescence. Since the disruption of biological homeostasis by T cell immunosenescence is closely related to the development and progression of CVD via inflammation, senescent T cells are attracting attention as a new therapeutic target. In this review, we discuss the relationship between CVD and T cell immunosenescence associated with aging and obesity.

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.

A Systematic Review of the Association Between Muscular Fitness and Telomere Length Across the Adult Lifespan

This study aimed to systematically review the association between telomere length (TL) and muscular fitness. In October 2020, an articles search was applied to PubMed, Scopus, and Web of Science. Eligibility criteria included: cross-sectional, prospective, and experimental study design; outcomes included TL; results expressed the relationship between muscular fitness and TL; studies published in English, Portuguese, or Spanish. Nine studies were included in the review. Results from the four prospective studies are mixed. In one study, the changes in TL were associated with grip strength. Another study concluded that longer mid-life TL was associated with increased grip strength later in life. However, in the other two studies, the association between TL and sarcopenia was not strong. Nevertheless, longer TL was associated with a slower decline in grip strength in older people. From the four cross-sectional studies, three indicated that TL was associated with muscular fitness. On the other hand, in a study with powerlifters, TL remained within the range of values found in subjects with no history of regular strength training, supporting the notion that muscular fitness was not associated with TL. The cross-sectional and prospective studies showed that the relationship between TL and muscular fitness is not conclusive. It seems that there is a positive association between TL and muscular fitness in middle-aged and older adults. However, among younger adults, this relationship was not observed.

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.

Obesity and telomere status in the prognosis of patients with colorectal cancer submitted to curative intention surgical treatment

The risk of colorectal cancer (CRC) development has been associated with telomere dysfunction and obesity. However, clinical relevance of these parameters in CRC prognosis is not clear. Therefore, the aim of the present study was to evaluate the impact of obesity and telomere status in the prognosis of patients affected by CRC and submitted to curative surgical treatment. According to published data, this is the first work in which obesity and telomere status are jointly considered in relation to CRC prognosis. A prospective study including 162 patients with CRC submitted to curative surgical treatment was performed. Subjects were classified according to their BMI. Telomere status was established through telomere length and telomerase activity evaluation. Statistical analyses were performed using the SPSS software package version 22. Telomere shortening was inversely associated with BMI in patients with CRC. Notably, among patients with CRC, subjects with obesity exhibited less shortening of tumor telomeres than non-obese patients (P=0.047). Patients with shorter telomeres, both in the tumor (median telomere length <6.5 kb) and their non-tumor paired tissues (median telomere length <7.1 kb), had the best clinical evolution, regardless of the Dukes' stage of cancers (P=0.025, for tumor samples; P=0.003, for non-tumor samples). Additionally, subjects with a BMI >31.85 kg/m² showed the worse clinical outcomes compared with subjects with other BMI values. Interestingly, the impact of BMI showed sex dependence, since only the group of men displayed significant differences in CRC prognosis in relation to obesity status (P=0.037). From the results of the present study, based on a multivariate prediction model to establish prognosis, it was concluded that telomere length is a useful biomarker to predict prognosis in patients with CRC. Regardless of BMI values, the improved clinical evolution was associated with shorter telomeres. The impact of BMI seems to be associated with other factors, such as sex.

Telomere Length and Pediatric Obesity: A Review

Obesity is a chronic disease, which needs to be early detected early and treated in order prevent its complications. Changes in telomere length (TL) have been associated with obesity and its complications, such as diabetes mellitus and metabolic syndrome. Therefore, we conducted a systematic review to summarize results of studies that have measured TL in children and adolescents with obesity. Fourteen studies aiming to assess TL in pediatric patients with either obesity or who were overweight were included in this review. In conclusion, obesity and adiposity parameters are negatively associated with TL. Shorter telomeres are observed in children with obesity compared with their lean counterparts. Factors involved in obesity etiology, such as diet and physical activity, may contribute to maintenance of TL integrity. In the long term, TL change could be used as a biomarker to predict response to obesity treatment.

Serum gamma-glutamyl transferase, a marker of alcohol intake, is associated with telomere length and cardiometabolic risk in young adulthood

Studies based on self-reported alcohol consumption and telomere length show inconsistent results. Therefore, we studied the association between gamma-glutamyl transferase (GGT), a widely used biomarker of alcohol intake, and telomere length. The possible health relevance in young adulthood was explored by investigating cardiometabolic risk factors. Mixed modelling was performed to examine GGT and alcohol consumption in association with telomere length in buccal cells of 211 adults between 18 and 30 years old of the East Flanders Prospective Twin Survey. In addition, we investigated the association between GGT and cardiometabolic risk factors; waist circumference, systolic blood pressure, fasting glucose, HDL cholesterol, and triglycerides. Although we did not observe an association between self-reported alcohol consumption and telomere length, our results show that a doubling in serum GGT is associated with 7.80% (95% CI − 13.9 to − 1.2%; p = 0.02) shorter buccal telomeres, independently from sex, chronological age, educational level, zygosity and chorionicity, waist-to-hip ratio and smoking. The association between GGT was significant for all five cardiometabolic risk factors, while adjusting for age. We show that GGT, a widely used biomarker of alcohol consumption, is associated with telomere length and with risk factors of cardiometabolic syndrome, despite the young age of this study population.

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.

Influence of Body Fat on Oxidative Stress and Telomere Length of Master Athletes

ABSTRACT

Aguiar, SS, Rosa, TS, Sousa, CV, Santos, PA, Barbosa, LP, Deus, LA, Rosa, EC, Andrade, RV, and Simões, HG. Influence of body fat on oxidative stress and telomere length of master athletes. J Strength Cond Res 35(6): 1693-1699, 2021-The present investigation analyzed the role of body fat and training history on biological aging of master athletes by comparing and verifying the relationships between markers of adiposity, oxidative balance, and telomere length (TL) in middle-aged runners and untrained individuals. Master athletes (sprinters and endurance runners, n = 21; 51.62 ± 8.19 years) and untrained age-matched controls (n = 11; 45.41 ± 10.34 years) had blood samples collected for biochemical and biomolecular analyzes. Pro-oxidant and antioxidant measures as well as DNA extraction were performed using commercial kits. Relative TL (T/S) was determined in leukocytes through quantitative polymerase chain reaction analyses. Master athletes had lower body fat and longer TL than untrained controls (body fat: 12.21 ± 4.14% vs. 26.03 ± 4.29%; TL: 1.10 ± 0.84 vs. 0.56 ± 0.56 T/S; p < 0.05). Furthermore, master athletes also showed a better oxidative balance than untrained controls (p < 0.05). A negative correlation was observed between TL and body fat (r = -0.471; p = 0.007), and conicity index (r = -0.407; p = 0.021), catalase activity (r = -0.569; p = 0.001), and CAT/TBARS ratio (r = -0.463; p = 0.008) for the whole sample. In conclusion, master athletes have longer TL, better oxidative profile, and lower body fat than untrained individuals. Moreover, for this middle-aged sample, body fat was inversely correlated with both TL and markers of oxidative balance, demonstrating the key role of adiposity in biological aging.

Minimal changes in telomere length after a 12-week dietary intervention with almonds in mid-age to older, overweight and obese Australians: results of a randomised clinical trial

Diet is a modifiable risk factor for chronic disease and a potential modulator of telomere length (TL). The study aim was to investigate associations between diet quality and TL in Australian adults after a 12-week dietary intervention with an almond-enriched diet (AED). Participants (overweight/obese, 50-80 years) were randomised to an AED (n 62) or isoenergetic nut-free diet (NFD, n 62) for 12 weeks. Diet quality was assessed using a Dietary Guideline Index (DGI), applied to weighed food records, that consists of ten components reflecting adequacy, variety and quality of core food components and discretionary choices within the diet. TL was measured by quantitative PCR in samples of lymphocytes, neutrophils, and whole blood. There were no significant associations between DGI scores and TL at baseline. Diet quality improved with AED and decreased with NFD after 12 weeks (change from baseline AED + 9·8 %, NFD - 14·3 %; P < 0·001). TL increased in neutrophils (+9·6 bp, P = 0·009) and decreased in whole blood, to a trivial extent (-12·1 bp, P = 0·001), and was unchanged in lymphocytes. Changes did not differ between intervention groups. There were no significant relationships between changes in diet quality scores and changes in lymphocyte, neutrophil or whole blood TL. The inclusion of almonds in the diet improved diet quality scores but had no impact on TL mid-age to older Australian adults. Future studies should investigate the impact of more substantial dietary changes over longer periods of time.

Stapleless vs Stapled Gastric Bypass vs Hypocaloric Diet: a Three-Arm Randomized Controlled Trial of Body Mass Evolution with Secondary Outcomes for Telomere Length and Metabolic Syndrome Changes

BACKGROUND

Obesity and metabolic syndrome (MetS) reduce life expectancy and are challenging to resolve. This randomized controlled trial (RCT) of patients with obesity and MetS undergoing surgical vs nonsurgical treatment compared changes in BMI, and secondarily, telomere length (as a biomarker of life expectancy) and changes in MetS components (insulin resistance, dyslipidemia, hypertension).

METHODS

Study design was a single-center, prospective, three-arm RCT. Group 1 patients underwent novel unstapled laparoscopic one anastomosis gastric bypass with an obstructive stapleless pouch and anastomosis (LOAGB-OSPAN); Group 2, stapled laparoscopic mini-gastric bypass-one anastomosis gastric bypass (LMGB-OAGB); and Group 3, nonsurgical weight loss therapy via a hypocaloric diet with energy restriction (HDER). The primary outcome measure was change in BMI; secondary outcome measures included change in leukocyte telomere length and other MetS components.

RESULTS

Of 96 participants screened, 60 were randomly allocated to 3 groups: LOAGB-OSPAN group (n = 20), LMGB-OAGB group (n = 20), and HDER group (n = 20). At post-treatment month 12, respective BMI changes: BMI -12.13 (-8.34, -15.93); -16.04 (-11.7, 20.37); -2,76 (-3.84, -9.36) (p < 0.01). The two surgical groups experienced significant change in telomere length: LOAGB-OSPAN 2.02 (1.61, 2.41), p = 0.001; LMGB-OAGB 2.07 (1.72, 2.43), p = 0.001; and HDER 0.28 (0.22, 0.78), p = 0.26. The surgical groups were also more effective in treating MetS components. There were no deaths. Adverse events: LOAGB-OSPAN (n = 2) (Clavien-Dindo grade II); LMGB-OAGB (n = 8) (grade I (n = 6) and grade II (n = 2).

CONCLUSIONS

Compared with hypocaloric diet therapy, both bariatric procedures resulted in greater BMI loss, and secondarily, a significant increase in telomere length, and greater MetS resolution.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT03667469, registered on 11 September 2018.

Genetics of Cardiovascular Disease: How Far Are We from Personalized CVD Risk Prediction and Management?

Despite the rapid progress in diagnosis and treatment of cardiovascular disease (CVD), this disease remains a major cause of mortality and morbidity. Recent progress over the last two decades in the field of molecular genetics, especially with new tools such as genome-wide association studies, has helped to identify new genes and their variants, which can be used for calculations of risk, prediction of treatment efficacy, or detection of subjects prone to drug side effects. Although the use of genetic risk scores further improves CVD prediction, the significance is not unambiguous, and some subjects at risk remain undetected. Further research directions should focus on the "second level" of genetic information, namely, regulatory molecules (miRNAs) and epigenetic changes, predominantly DNA methylation and gene-environment interactions.

Vitamin D Deficiency and Risk of Metabolic Syndrome in Aging Men

The elderly population is rapidly increasing; hence, the disability due to age-related diseases has become an important socioeconomic burden. Amongst age-related diseases cardiovascular ones (CVD) have a huge impact on morbidity and mortality and are associated with metabolic syndrome (MetS). Several studies investigated the role of hypovitaminosis D in the pathogenesis of MetS and of CVD, this review unravels the relationship between aging/senescence, vitamin D, gender, and pathogenesis of MetS.

Cytomegalovirus Infection and Its Relationship with Leukocyte Telomere Length: A Cross-Sectional Study

Background

Telomeres undergo shortening with each cell division, which could be accelerated by infection. The association between virus infection and telomere length is poorly understood. In the present study, we investigated the putative associations between leukocyte telomere length (TL), cytomegalovirus (CMV) infection, and C-reactive protein (CRP) in a national representative sample of noninstitutionalized population.

Methods

We analyzed data that was collected in a cross-sectional setting, where 3,987 participants were enrolled with available data on telomere length. The association between telomere length with previous CMV infection and CRP was analyzed using multivariable linear regression models. We further tested if obesity, measured by body mass index (BMI), and smoking could modify this relationship.

Results

In total, around 46% percent of the study population were men and 54% were women. Average ages were 35.1 years for men and 35.0 years for women. One unit increase of CMV antibody IgG titer was associated with -0.07 (95% confidence interval: -0.12, -0.01) unit decrease of leukocyte TL when sex was adjusted for. After additionally adjusting for BMI and smoking status, the magnitude of the association was only slightly decreased to -0.06 (95% confidence interval: -0.11, -0.01). The effect sizes were comparable after additionally adjusting for CRP. These analyses imply that previous CMV infection affects leukocyte TL through pathways other than CRP.

Conclusions

Previous CMV infection was associated with shorter leukocyte TL. This association was independent of CRP.

Telomere Length as a Marker of Biological Age: State-of-the-Art, Open Issues, and Future Perspectives

Telomere shortening is a well-known hallmark of both cellular senescence and organismal aging. An accelerated rate of telomere attrition is also a common feature of age-related diseases. Therefore, telomere length (TL) has been recognized for a long time as one of the best biomarkers of aging. Recent research findings, however, indicate that TL per se can only allow a rough estimate of aging rate and can hardly be regarded as a clinically important risk marker for age-related pathologies and mortality. Evidence is obtained that other indicators such as certain immune parameters, indices of epigenetic age, etc., could be stronger predictors of the health status and the risk of chronic disease. However, despite these issues and limitations, TL remains to be very informative marker in accessing the biological age when used along with other markers such as indices of homeostatic dysregulation, frailty index, epigenetic clock, etc. This review article is aimed at describing the current state of the art in the field and at discussing recent research findings and divergent viewpoints regarding the usefulness of leukocyte TL for estimating the human biological age.

Telomere Dysfunction in Oocytes and Embryos From Obese Mice

Maternal obesity impairs oocyte quality and embryo development. However, the potential molecular pathways remain to be explored. In the present study, we examined the effects of obesity on telomere status in oocytes and embryos obtained from mice fed with high-fat diet (HFD). Of note, telomere shortening was observed in both oocytes and early embryos from obese mice, as evidenced by the reduced expression of telomerase reverse transcriptase and activity of telomerase. Moreover, quantitative analysis of telomere dysfunction-induced foci (TIFs) revealed that maternal obesity induces the defective telomeres in oocytes and embryos. Meanwhile, the high frequency of aneuploidy was detected in HFD oocytes and embryos as compared to controls, accompanying with the increased incidence of apoptotic blastocysts. In conclusion, these results indicate that telomere dysfunction might be a molecular pathway mediating the effects of maternal obesity on oocyte quality and embryo development.

Telomere Length as a Biomarker for Race-Related Health Disparities

Disparities between the races have been well documented in health and disease in the USA. Recent studies show that telomere length, a marker of aging, is associated with obesity and obesity-related diseases, such as heart disease and diabetes. The current study aimed to evaluate the connection between telomere length ratio, blood pressure, and childhood obesity. The telomere length ratio was measured in 127 children from both European American (EA) and African American (AA) children, aged 6-10 years old. AA children had a significantly high relative telomere to the single copy gene (T/S) ratio compared to EA children. There was no significant difference in the T/S ratio between normal weight (NW) and overweight/obese (OW/OB) groups of either race. Blood pressure was significantly elevated in AA children with respect to EA children. Hierarchical regression analysis adjusted for race, gender, and age expressed a significant relationship between the T/S ratio and diastolic pressure. Low T/S ratio participants showed a significant increase in systolic pressure, while a high T/S ratio group showed an increase in diastolic pressure and heart rate of AA children. In conclusion, our findings show that AA children have high T/S ratio compared to EA children. The high T/S ratio is negatively associated with diastolic pressure.

Association of telomere length and telomerase methylation with n-3 fatty acids in preschool children with obesity

BACKGROUND

Telomeres play a crucial role in cellular survival and its length is a predictor for onset of chronic non-communicable diseases. Studies on association between telomeres and obesity in children have brought discrepant results and the underlying mechanisms and influential factors are to be elucidated. This study aimed to investigate changes in telomere length and telomerase reverse transcriptase (TERT) DNA methylation, and further to determine their correlation with n-3 polyunsaturated fatty acids (PUFAs) in preschool children with obesity.

METHODS

Forty-six preschool children with obesity aged 3 to 4 years were included in the study, with equal numbers of age- and gender-matched children with normal weight as control. Leukocyte telomere length was determined by the ratio of telomeric product and single copy gene obtained using real-time qPCR. DNA methylation of TERT promoter was analyzed by bisulfite sequencing. Fatty acids in erythrocytes were measured by gas chromatography with a total of 15 fatty acids analyzed. The total saturated fatty acids (SFAs), total n-6 PUFAs, total n-3 PUFAs, and the ratio of arachidonic acid (AA) to docosahexaenoic acid (DHA) were calculated. Then the correlation between leukocyte telomere length, TERT promoter methylation and fatty acids was determined.

RESULTS

In preschool children with obesity, leukocyte telomeres were shortened and had a negative association with the body mass index. The methylated fractions in 13 of 25 CpG sites in the TERT promoter were increased by approximately 3 to 35% in the children with obesity compared to the normal weight children. Erythrocyte lauric acid and total SFAs, lenoleic acid and total n-6 PUFAs were higher, and DHA was lower in the children with obesity than those in the children with normal weight. Correlative analysis showed that leukocyte telomere length had a positive association with total SFAs and DHA, and a negative association with the AA/DHA ratio. However, no association between erythrocyte DHA and the TERT promoter methylation was found.

CONCLUSION

These data indicate that the reduced body DHA content and increased AA/DHA ratio may be associated with shortened leukocyte telomeres in child obesity, which is probably not involved in the TERT promoter methylation.

Maternal psychosocial functioning, obstetric health history, and newborn telomere length

There is growing interest in elucidating the determinants of newborn telomere length, given its potential as a biomarker of lifetime disease risk affected by prenatal exposures. There is limited evidence that increased maternal stress during pregnancy predicts shorter newborn telomere length. However, the few studies published to date have been conducted primarily with small samples utilizing inconsistent definitions of maternal stress. Moreover, the potential influence of fetal sex as a moderator of maternal stress effects on newborn telomere length has been largely ignored despite compelling evidence of likely impact. In a prospective cohort study of pregnant women seeking routine prenatal care, we tested whether a range of maternal measures of stressor exposures, subjective feelings of stress, and mental health (depression, anxiety) were associated with newborn telomere length assessed from cord blood among 146 pregnant women and their newborn infants. We further examined whether the pattern of associations differed by infant sex. Sociodemographic and maternal and newborn health indicators were considered as potential covariates. When examined within the whole sample, none of the maternal psychosocial measures were associated with newborn telomere length. Among potential covariates, maternal history of smoking and preeclampsia in a previous pregnancy were negatively associated with newborn telomere length. In adjusted linear regression analyses that considered potential sex-specific effects, maternal depression, general anxiety, and pregnancy-specific anxiety symptoms were positively associated with newborn telomere length among males. Overall, the findings provide some evidence for an association between maternal psychosocial wellbeing in pregnancy and newborn telomere length in males, although in the opposite direction than previously reported. Maternal smoking and obstetric history prior to conception may be associated with shorter offspring telomere length.

Age-associated telomere attrition in adipocyte progenitors predisposes to metabolic disease

White and beige adipocytes in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) are maintained by proliferation and differentiation of adipose progenitor cells (APCs). Here we use mice with tissue-specific telomerase reverse transcriptase (TERT) gene knockout (KO), which undergo premature telomere shortening and proliferative senescence in APCs, to investigate the effect of over-nutrition on APC exhaustion and metabolic dysfunction. We find that TERT KO in the Pdgfra⁺ cell lineage results in adipocyte hypertrophy, inflammation and fibrosis in SAT, while TERT KO in the Pdgfrb⁺ lineage leads to adipocyte hypertrophy in both SAT and VAT. Systemic insulin resistance is observed in both KO models and is aggravated by a high-fat diet. Analysis of human biopsies demonstrates that telomere shortening in SAT is associated with metabolic disease progression after bariatric surgery. Our data indicate that over-nutrition can promote APC senescence and provide a mechanistic link between ageing, obesity and diabetes.

Shorter telomere length, higher telomerase activity in association with tankyrase gene polymorphism contribute to high-altitude pulmonary edema

High-altitude pulmonary edema (HAPE) is a noncardiogenic form of pulmonary edema, which is induced upon exposure to hypobaric hypoxia at high altitude (HA). Hypobaric hypoxia generates reactive oxygen species that may damage telomeres and disturb normal physiological processes. Telomere complex comprises of multiple proteins, of which, tankyrase (TNKS) is actively involved in DNA damage repairs. We hence investigated the association of TNKS and telomeres with HAPE to delineate their potential role at HA. The study was performed in three groups, High-altitude pulmonary edema patients (HAPE-p, n = 200), HAPE-resistant sojourners (HAPE-r, n = 200) and highland permanent healthy residents (HLs, n = 200). Variants of TNKS were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Plasma TNKS level was estimated using enzyme-linked immunosorbent assay, expression of TNKS and relative telomere length were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and telomerase activity was assessed by the telomere repeat amplification protocol assay. TNKS poly-ADP ribosylates the telomere-repeat factor (TRF), which is a negative regulator of telomere length. Consequently, TRF expression was also measured by RT-qPCR. The TNKS heterozygotes rs7015700GA were prevalent in HLs compared to the HAPE-p and HAPE-r. The plasma TNKS was significantly decreased in HAPE-p than HAPE-r (P = 0.006). TNKS was upregulated 9.27 folds in HAPE-p (P = 1.01E-06) and downregulated in HLs by 3.3 folds (P = 0.02). The telomere length was shorter in HAPE-p compared to HAPE-r (P = 0.03) and HLs (P = 4.25E-4). The telomerase activity was significantly higher in HAPE-p compared to both HAPE-r (P = 0.01) and HLs (P = 0.001). HAPE-p had the lowest TNKS levels (0.186 ± 0.031 ng/μl) and the highest telomerase activity (0.0268 amoles/μl). The findings of the study indicate the association of TNKS and telomeres with HA adaptation/maladaptation.

Modifiable mediators associated with the relationship between adiposity and leukocyte telomere length in US adults: The National Health and Nutrition Examination Survey

Obesity is associated with age-related health conditions and telomere attrition - a marker of cellular aging. Obesity is attributable to adverse modifiable lifestyle factors. Little is known about the mediation effect of lifestyle factors associated with the relationship between obesity and telomere length. Our objective was to examine this association in the US. Pack years smoked, drinking level per day, physical activity (PA) per week and diet based on Healthy Eating Index (HEI) were assessed as mediators associated with the relationship between adiposity measures and leukocyte telomere length (LTL); adiposity measures included body mass index (BMI), % total body fat (TBF) and waist circumference (WC). Separate adjusted linear regressions and mediation analysis were conducted on a total of 4919 respondents aged 20-84 years using cross-sectional 1999-2002 data from the US National Health and Nutrition Examination Survey. Inadequate PA correlated with 1.28% shorter LTL and was a factor accounting for 35% of the relationship between BMI and LTL (β = -0.0128, 95% CI = 0.0259, 0.0004, p = .05). Smoking 30-≥59 pack years correlated with 4% shorter LTL and accounted for 21% of the relationship between %TBF and LTL (β = -0.0386, 95% CI = -0.0742, -0.0030, p = .03). Improvement in diet correlated with 0.11% longer LTL and contributed 25% of the association between %TBF and LTL (β = 0.0011, 95%CI =0.0004, 0.0018, p = .01). Diet correlated with 0.11% longer LTL and correspond to 28% of the relationship between WC and LTL (β = 0.0011, 95%CI = 0.0004, 0.0018, p = .03). Interventions to improve modifiable behaviors may ameliorate cellular aging and aging related health conditions due to obesity among US adults.

[Telomere biology and metabolic disorders: the role of insulin resistance and type 2 diabetes]

BACKGROUND

Insulin resistance accelerates the aging process, but its speed depends on the individual characteristics of the metabolism. One of the reasons for the different aging rates in individuals with insulin resistance is the initially different "genetic protection" of cells, which many scientists associate with replicative cellular aging.

AIMS

to study the relationship between the state of carbohydrate metabolism and markers of replicative cell aging in individuals with different sensitivity to insulin.

MATERIALS AND METHODS

The observation study included 305 patients. The parameters of glucose metabolism and telomere biology were studied.

RESULTS

The mean age of the patients was 51.5±13.3 years. Patients were divided into three groups depending on presence of insulin resistance: healthy, with insulin resistance and with type 2 diabetes. The mean age of healthy patients was 48.82±13.87 years, in insulin resistance group - 53.04±12.8, in 2 diabetes mellitus - 58.4±7.90. The median telomere length was 9.76. The median telomerase activity was 0.48. Both telomere length and telomerase activity progressively decrease as insulin resistance increases. In patients with diabetes, short telomere lengths and low telomerase activity predominated. The insulin resistance index has the greatest impact on the risk of detecting "short" telomeres. In patients with insulin resistance, an increase in glycated hemoglobin increases the likelihood of detecting short telomeres by 2.4 times, and in diabetes mellitus by 4.26 times, an increase in fasting plasma glucose by 90%, and an increase in HOMA-IR by 35%. An increase in insulin resistance increases the risk of detecting «low» telomerase activity by 53% and the risk of detecting «very low» telomerase activity by 92%. A decrease in synsulin resistance increases the chance of increasing telomerase activity to «very high» by 51%.

CONCLUSION

Shorter telomeres are associated with more pronounced disorders of carbohydrate metabolism and a higher degree of insulin resistance. Further studies of metabolic status are necessary to personalize their lifestyle and treatment goals.

Subcutaneous adipose tissue distribution and telomere length

Background Overweight and obese individuals have a reduced life expectancy due to cardiovascular disease (CVD), type 2 diabetes, stroke and cancer. Systemic inflammation and premature telomere shortening have been discussed as potential mechanisms linking these conditions. We investigated the relation of subcutaneous adipose tissue (SAT) distribution to leukocyte relative telomere length (RTL). Methods We measured RTL in 375 participants of the observational STYJOBS/EDECTA cohort (ClinicalTrials.gov Identifier NCT00482924) using a qPCR based method. SAT distribution was determined by lipometry yielding a percent body fat value and SAT thicknesses at 15 standardized locations across the entire body. A correlation analysis between RTL, age, sex, lipometry data and conventional body measures (body mass index [BMI], waist-, hip circumference, waist-to-hip ratio, waist-to-height ratio) was calculated. The strongest determinants of RTL were determined by a stepwise multiple regression analysis. Results RTL was not associated with age or sex. RTL was significantly negatively correlated with BMI, percent body fat, waist-, hip circumference and waist-to-height ratio. Furthermore, RTL correlated with SAT at the following locations: neck, triceps, biceps, upper back, front chest, lateral chest, upper abdomen, lower abdomen, lower back, hip, front thigh, lateral thigh, rear thigh and calf. Stepwise regression analysis revealed nuchal and hip SAT as the strongest predictors of RTL. No significant association was seen between RTL and waist-to-hip ratio. Conclusions RTL is negatively associated with parameters describing body fat composure. Nuchal and hip SAT thicknesses are the strongest predictors of RTL. Central obesity appears to correlate with premature genomic aging.

Objectively measured sleep and telomere length in a population-based cohort of children and midlife adults

STUDY OBJECTIVES

Poor sleep patterns in older adults are associated with chromosomal telomere shortening, a marker of cellular senescence. However, studies have relied on self-reported sleep characteristics, with few data for younger individuals. We investigated whether sleep measured via actigraphy was cross-sectionally associated with telomere length in children and midlife adults.

METHODS

A population-based sample of 1874 11-12 year olds and midlife adults (mean age 44 years, SD 5.1) had biological and physical assessments at centers across Australia in 2015-2016. Sleep characteristics, including duration, onset, offset, day-to-day variability, and efficiency, were derived from actigraphy. Relative telomere length (T/S ratio) was measured by quantitative polymerase chain reaction on genomic DNA from peripheral blood. Multivariable regression models estimated associations, adjusting for prespecified confounders.

RESULTS

Both sleep and telomere data were available for 728 children and 1070 adults. Mean (SD) T/S ratio was 1.09 (0.55) in children and 0.81 (0.38) in adults. T/S ratio was not predicted by sleep duration (β 0.04, 95% confidence interval [CI] -0.02 to 0.09, p = .16, children; β -0.004, 95% CI -0.03 to 0.02, p = .70, adults) or most other sleep metrics. The only exception was a weak association between later sleep timing (the midpoint of sleep onset and offset) and longer telomeres in adults (β 0.03, 95% CI 0.01 to 0.06, p = .01).

CONCLUSIONS

Objective sleep characteristics show no convincing associations with telomere length in two largely healthy populations up to at least midlife. Sleep-telomere associations may be a late-life occurrence or may present only with a trigger such as presence of other morbidities.

Adiposity and Leukocyte Telomere Length in US Adults by Sex-Specific Race/Ethnicity: National Health and Nutrition Examination Survey

Objective

Little is known about the relationship between adiposity and telomere length in the United States population. The objective of our research was to examine this relationship in a representative, socioeconomically and sex-specific, diverse racial/ethnic population in the United States.

Methods

Body mass index (BMI), % total body fat (TBF) and waist circumference (WC) with leukocyte telomere length (LTL) were examined according to sex-specific race/ethnicity using separate adjusted multivariate linear regressions on a sample of 4,919 respondents aged 20-84 years from the National Health and Nutrition Examination Survey's 1999-2002 data.

Results

LTL was shortened .41%, .44%, and .16% in African American (AA) women and was associated with increasing BMI, %TBF, and WC, (β:-.0041, 95%CI: -.0070, -.0012; P=.007; β:-.0044, 95% CI: -.0081, -.0007; P=.02; β:-.0016, 95%CI: -.0031, -.0001; P=.04, respectively). LTL was shortened .29% in White women and was associated with increasing %TBF (β:-.0029, 95%CI: -.0048, -.0009; P=.006). There were no associations among AA men, White men or Mexican American men and women.

Conclusions

LTL is associated with an obesity phenotype in AA women. Tailored intervention is needed to ameliorate the burden of excess adiposity and subsequent cellular aging.

The hallmarks of severe pulmonary arterial hypertension: the cancer hypothesis-ten years later

Severe forms of pulmonary arterial hypertension (PAH) are most frequently the consequence of a lumen-obliterating angiopathy. One pathobiological model is that the initial pulmonary vascular endothelial cell injury and apoptosis is followed by the evolution of phenotypically altered, apoptosis-resistant, proliferating cells and an inflammatory vascular immune response. Although there may be a vasoconstrictive disease component, the increased pulmonary vascular shear stress in established PAH is caused largely by the vascular wall pathology. In this review, we revisit the "quasi-malignancy concept" of severe PAH and examine to what extent the hallmarks of PAH can be compared with the hallmarks of cancer. The cancer model of severe PAH, based on the growth of abnormal vascular and bone marrow-derived cells, may enable the emergence of novel cell-based PAH treatment strategies.

Patterns of change in telomere length over the first three years of life in healthy children

There is growing interest in the use of telomere length as a biomarker of health and a predictor of later morbidity and mortality. However, little is known about developmentally expected telomere erosion over the first years of life. This gap hinders our ability to interpret the meaning of relative telomere length and rate of attrition in relation to risk factors and health outcomes. The overall goal of this study was to examine the rate of relative telomere length attrition in a large, normative sample of healthy children (N = 630) followed from infancy to three years of age. A secondary goal was to explore associations between sociodemographic characteristics and telomere erosion over this time period. Relative telomere length was assessed from DNA in saliva samples collected in infancy (M = 8.6 months), age 2 years (M = 25.2 months), and age 3 years (M = 38.3 months). In the sample as a whole, relative telomere length decreased from infancy to 2 years but remained stable from 2 years to 3 years. Notably, increases in relative telomere length were observed in 29 % of children between infancy and 2 years of age and in 46 % of children between 2 and 3 years of age; 62 % of children showed both increases and decreases in relative telomere length across the study period. Females showed longer relative telomere length than males, regardless of timepoint. There was some evidence that parental age and family finances were associated with changes in child relative telomere length across time. Overall, the findings suggest that telomere length attrition is not uniform across the early years of life, with the most rapid attrition occurring during the first two years, and that increases as well as decreases in telomere length during this period are commonly observed.

Telomere shortening associates with elevated insulin and nuchal fat accumulation

Obesity and relative leucocyte telomere length (RTL) are both linked to accelerated aging and premature mortality. We examined if nuchal subcutaneous adipose tissue (SAT) thickness, a surrogate marker of central trunk-weighted obesity, is an independent predictor of RTL that provides information beyond BMI, metabolic and inflammatory markers. RTL and nuchal SAT thickness were determined in 362 participants of the STYJOBS/EDECTA study (STYrian Juvenile Obesity Study, Early DEteCTion of atherosclerosis), which included overweight individuals and matched eutrophic controls. Fasting plasma samples were used for the measurement of leptin, resistin, adiponectin, glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), liver enzymes, creatinine, cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, oxidized LDL, triglycerides, homocysteine and uric acid. Furthermore, all participants underwent carotid artery ultrasound. Obese individuals had markedly higher body mass index (BMI), nuchal SAT thickness, hip and waist circumferences and carotid intima media thickness (IMT) than eutrophic controls. In addition, they showed typical biochemical abnormalities related to energy metabolism, systemic inflammation and liver function. RTL was inversely correlated with nuchal SAT thickness, IMT, hs-CRP, alkaline phosphatase, insulin, resistin, and leptin. Positive correlations were seen with homocysteine and creatinine. Stepwise linear regression analyses identified nuchal SAT thickness and insulin as the only significant predictors of RTL. In conclusion, nuchal SAT thickness is a robust predictor of RTL that provides information beyond traditional obesity-related metabolic and inflammatory biomarkers. This suggests an important role of fat depots at the neck for accelerated telomere shortening.

Associations of telomere length with anthropometric and glucose changes after a lifestyle intervention in abdominal obese children

BACKGROUND AND AIMS

In lifestyle intervention studies, we demonstrated that changes in telomere length (TL) were associated with changes in anthropometric indices. Therefore, our new hypothesis is that TL could be a predictor of changes in anthropometric or metabolic measures in children with abdominal obesity. The aim of the study was to evaluate the association between anthropometric and biochemical measurements with TL before and after an 8-week lifestyle intervention in children with abdominal obesity (7-16 years old).

METHODS AND RESULTS

We assessed anthropometric and biochemical outcomes at baseline and after 8-week lifestyle intervention in 106 children with abdominal obesity (11.30 ± 2.49 years old, 63% girls). TL was measured by monochrome multiplex real-time quantitative PCR. After the lifestyle intervention, anthropometric parameters and glucose metabolism indicators significantly improved in the participants. TL did not change after the intervention in participants. Significant negative correlations between baseline TL and anthropometric measures (BMI, body weight and waist circumference) were observed. Furthermore, baseline TL was a predictor for changes in blood glucose levels after the lifestyle intervention.

CONCLUSIONS

An inverse correlation between TL and obesity traits was observed in children with abdominal obesity. Interestingly, we found that baseline TL could predict changes in blood glucose levels.

CLINICAL TRIAL

NCT03147261. Registered 10 May 2017.

Oxidative stress, telomeres and cellular senescence: What non-drug interventions might break the link?

Telomeres are higher order structures that cap and protect chromosome ends. Telomeric DNA naturally shortens during somatic cell division and as a result of oxidative stress. Excessive shortening disrupts the integrity of the telomere, causing cellular senescence, one of the hallmarks of organismal ageing. The accumulation of senescent cells with ageing contributes to the loss of tissue homeostasis and the development of age-related pathologies. Hence, counteracting telomere shortening may be one relevant approach to develop strategies for healthier ageing. In this review I present the case for the existence of a link between oxidative stress, accelerated telomere shortening and cellular senescence. I also examine findings from human observational studies exploring associations between telomere length and oxidative stress-related parameters. Finally, I discuss results from randomised control trials testing the impact of non-pharmacological lifestyle interventions on the maintenance of telomere length, considering the potential mechanisms that might be involved.

Walking and biologic ageing: Evidence based on NHANES telomere data

The length of telomeres is an objective measure of biologic ageing. This study evaluated the extent minutes of walking per week are associated with leukocyte telomere length (LTL) in a random sample of 5,823 U.S. adults. The investigation was cross-sectional and data were obtained from the National Health and Nutrition Examination Survey (NHANES). LTL was measured by the quantitative polymerase chain reaction method. Walking minutes was calculated from walking frequency and duration measures. Results showed that for each year of chronological age, telomeres were 15.6 base pairs shorter (P < 0.0001). With walking minutes and LTL treated as continuous variables, the relationship was quadratic, not linear (F = 11.2, P = 0.0023). With walking time divided into three categories, adults who performed ≥ 150 minutes of walking per week had longer telomeres than those who did no regular walking, and those who did some, but less than the recommendation (F = 5.0, P = 0.0137). Regular walkers were estimated to have a biologic ageing advantage associated with 6.5-7.6 years less biologic ageing compared to non-walkers, after adjusting for covariates. Additional investigations designed to study causality and the mechanisms associated with the walking and LTL relationship are needed.

The Impact of Health Promotion Interventions on Telomere Length: A Systematic Review

Objectives:

The aim of this study was to evaluate the effectiveness of health promotion interventions in delaying telomere shortening (a biomarker for aging).

Data Source:

PubMed, PsychINFO, EMBASE, CINAHL, and Cochrane Library databases.

Study Inclusion and Exclusion Criteria:

Inclusion criteria: (1) empirical studies involving human subjects; (2) health promotion intervention studies including both randomized control trials (RCTs) and non-RCTs.; (3) measured telomere length as an intervention outcome; and (4) were written in English. Exclusion criteria: (1) observational studies without any health promotion intervention practices and (2) did not report intervention effects.

Data Extraction:

Data extraction was performed by two reviewers following the preferred reporting items for systematic reviews and meta-analysis guidelines.

Data Synthesis:

Substantial heterogeneity in intervention type and study design in the included studies precluded a meta-analysis. We conducted a narrative synthesis instead.

Results:

Thirty studies were included in the review, of which 16 were RCTs. One-third of the included studies reported significant intervention impacts in delaying telomere shortening, with relatively consistent significant results emerged from weight-loss interventions and interventions involving multiple lifestyle modification components (eg, diet and exercise). Most of supplement intervention studies observed null effects in telomere length.

Conclusions:

Weight-loss and comprehensive lifestyle intervention strategies show encouraging impacts in delaying telomere shortening. More rigorous studies targeting populations at different age stages through life span are needed.

Measuring biological aging in humans: A quest

The global population of individuals over the age of 65 is growing at an unprecedented rate and is expected to reach 1.6 billion by 2050. Most older individuals are affected by multiple chronic diseases, leading to complex drug treatments and increased risk of physical and cognitive disability. Improving or preserving the health and quality of life of these individuals is challenging due to a lack of well-established clinical guidelines. Physicians are often forced to engage in cycles of "trial and error" that are centered on palliative treatment of symptoms rather than the root cause, often resulting in dubious outcomes. Recently, geroscience challenged this view, proposing that the underlying biological mechanisms of aging are central to the global increase in susceptibility to disease and disability that occurs with aging. In fact, strong correlations have recently been revealed between health dimensions and phenotypes that are typical of aging, especially with autophagy, mitochondrial function, cellular senescence, and DNA methylation. Current research focuses on measuring the pace of aging to identify individuals who are "aging faster" to test and develop interventions that could prevent or delay the progression of multimorbidity and disability with aging. Understanding how the underlying biological mechanisms of aging connect to and impact longitudinal changes in health trajectories offers a unique opportunity to identify resilience mechanisms, their dynamic changes, and their impact on stress responses. Harnessing how to evoke and control resilience mechanisms in individuals with successful aging could lead to writing a new chapter in human medicine.

Shortened Leukocyte Telomere Length Associates with an Increased Prevalence of Chronic Health Conditions among Survivors of Childhood Cancer: A Report from the St. Jude Lifetime Cohort

PURPOSE

We aimed to analyze and compare leukocyte telomere length (LTL) and age-dependent LTL attrition between childhood cancer survivors and noncancer controls, and to evaluate the associations of LTL with treatment exposures, chronic health conditions (CHC), and health behaviors among survivors.

EXPERIMENTAL DESIGN

We included 2,427 survivors and 293 noncancer controls of European ancestry, drawn from the participants in St. Jude Lifetime Cohort Study (SJLIFE), a retrospective hospital-based study with prospective follow-up (2007-2016). Common nonneoplastic CHCs (59 types) and subsequent malignant neoplasms (5 types) were clinically assessed. LTL was measured with whole-genome sequencing data.

RESULTS

After adjusting for age at DNA sampling, gender, genetic risk score based on 9 SNPs known to be associated with telomere length, and eigenvectors, LTL among survivors was significantly shorter both overall [adjusted mean (AM) = 6.20 kb; SE = 0.03 kb] and across diagnoses than controls (AM = 6.69 kb; SE = 0.07 kb). Among survivors, specific treatment exposures associated with shorter LTL included chest or abdominal irradiation, glucocorticoid, and vincristine chemotherapies. Significant negative associations of LTL with 14 different CHCs, and a positive association with subsequent thyroid cancer occurring out of irradiation field were identified. Health behaviors were significantly associated with LTL among survivors aged 18 to 35 years (P _trend = 0.03).

CONCLUSIONS

LTL is significantly shorter among childhood cancer survivors than noncancer controls, and is associated with CHCs and health behaviors, suggesting LTL as an aging biomarker may be a potential mechanistic target for future intervention studies designed to prevent or delay onset of CHCs in childhood cancer survivors.See related commentary by Walsh, p. 2281.

The effects of short-term combined exercise training on telomere length in obese women: a prospective, interventional study

Background

Telomere length is inversely associated with the senescence and aging process. Parallelly, obesity can promote telomere shortening. Evidence suggests that physical activity may promote telomere elongation.

Objective

This study’s objective is to evaluate the effects of combined exercise training on telomere length in obese women.

Design and Methods

Twenty pre-menopausal women (BMI 30–40 kg/m², 20–40 years) submitted to combined training (strength and aerobic exercises), but only 13 finished the protocol. Each exercise session lasted 55 min/day, three times a week, throughout 8 weeks. Anthropometric data, body composition, physical performance (Vo_2max), and 8-h fasting blood samples were taken before and after 8 weeks of training. Leukocyte DNA was extracted for telomere length by RT-qPCR reaction, using the 2^−ΔΔCt methodology.

Results

After the training intervention, significant differences (p < 0.05) were observed in telomere length (respectively before and after, 1.03 ± 0.04 to 1.07 ± 0.04 T/S ratio), fat-free mass (46 ± 7 to 48 ± 5 kg), Vo_2max (35 ± 3 to 38 ± 3 ml/kg/min), and waist circumference (96 ± 8 to 90 ± 6 cm). In addition, an inverse correlation between waist circumference and telomere length was found, before (r = − 0.536, p = 0.017) and after (r = − 0.655, p = 0.015) exercise training.

Conclusion

Combined exercise promoted leukocyte telomere elongation in obese women. Besides, the data suggested that greater waist circumference may predict shorter telomere length.

Clinical Trial Registration

ClinicalTrails.gov, NCT03119350. Retrospectively registered on 18 April 2017

Childhood obesity and leucocyte telomere length

BACKGROUND

Obesity in adulthood is associated with decreased leucocyte telomere length (LTL), which is associated with cardiovascular disease and diabetes mellitus type 2. The aim of our study was to investigate whether increased body mass index (BMI) is associated with decreased LTL in children and adolescents, and to identify other risk factors of shorter LTL in this population.

MATERIALS AND METHODS

A cross-sectional study was conducted among 919 Greek children aged 9-13 years (The Healthy Growth Study). Participants were classified as obese (n = 124), overweight (n = 276) or of normal BMI (n = 519). LTL was determined by monochrome multiplex quantitative real-time polymerase chain reaction. Univariate and multivariable linear regression analyses were applied to determine the predictive factors of LTL.

RESULTS

Both overweight and obese children had significantly shorter LTL than their normal-BMI counterparts. Following adjustment for age, sex, total daily energy intake and average weekly physical activity (average total steps per day), increasing weight category was inversely associated with LTL in children and adolescents (β: -0.110 ± 0.035; P = .002).

CONCLUSION

Overweight and obesity in childhood and adolescence are associated with shorter LTL, even following adjustment for potential confounding effects. Therefore, the increased BMI in childhood and adolescence may be associated with accelerated biological ageing and may have an adverse impact on future health in adulthood.

Telomere length and lung function in a population-based cohort of children and mid-life adults

OBJECTIVE

Telomere length is associated with poorer lung health in older adults, possibly from cumulative risk factor exposure, but data are lacking in pediatric and population-based cohorts. We examined associations of telomere length with lung function in children and mid-life adults.

METHODS

Data were drawn from a population-based cross-sectional study of 11 to 12 year-olds and mid-life adults. Lung function was assessed by spirometric FEV₁ , FVC, FEV ₁ /FVC ratio, and MMEF _25-75 . Telomere length was measured by quantitative polymerase chain reaction from blood and expressed as the amount of telomeric genomic DNA to the beta-globin gene (T/S ratio). Associations of telomere length with spirometric parameters were tested by linear and logistic regression models, adjusting for potential confounders of sex, age, body mass index, socioeconomic position, physical activity, inflammation, asthma, pubertal status, and smoking.

RESULTS

Mean T/S ratio was 1.09 (n = 1206; SD 0.55) in children and 0.81 (n = 1343; SD 0.38) in adults. In adults, for every additional unit in T/S ratio, FEV ₁ /FVC and MMEF _25-75 z-scores were higher (β 0.21 [95% confidence interval, CI; 0.06-0.36] and 0.23 [95% CI; 0.08-0.38], respectively), and the likelihood of being in the lowest quartile for FEV ₁ /FVC and MMEF _25-75 z-scores was lower (odds ratios 0.59 [95% CI, 0.39-0.89] and 0.64 [95% CI, 0.41-0.99], respectively). No evidence of association was seen for adult FEV ₁ or FVC, or any childhood spirometric index after adjustments.

CONCLUSION

Shorter telomere length showed moderate associations with poorer airflow parameters, but not vital capacity (lung volume) in mid-life adults. However, there was no convincing evidence of associations in children.

Suppression effect of body weight on the association between cigarette smoking and telomere length: the Bogalusa Heart Study

This study aimed to dissect the direct effect of smoking and its indirect effect through body mass index (BMI) on leukocyte telomere length (LTL) and to distinguish the mediation and suppression effects of BMI. The study cohort included 1,037 adults (729 Whites and 308 African Americans; 42.1% males; mean age: 40.3 years) with LTL measurements by Southern blotting. General third variable models were used to distinguish the mediation and suppression effects of BMI on the smoking-LTL association. After adjusting for age, race, sex and alcohol drinking, the total effect of smoking on LTL was significant (standardized regression coefficient, β= -0.061, p=0.034) without BMI included in the model. With additional adjustment for BMI, the indirect effect of smoking on LTL through BMI was estimated at β= 0.011 (p=0.023), and the direct effect of smoking on LTL was strengthened to β= -0.072 (p=0.012). The results were similar when pack-years of smoking was used. The effect parameters did not differ significantly between race and sex groups. These results suggest that BMI has a suppression effect, not a mediation effect, on the smoking-LTL association, which potentially contributes to previous inconsistencies in the effect of smoking on LTL.

The Dietary Inflammatory Index® and Alternative Healthy Eating Index 2010 in relation to leucocyte telomere length in postmenopausal women: a cross-sectional study

Telomeres are nucleoprotein complexes that form the ends of eukaryotic chromosomes where they protect DNA from genomic instability, prevent end-to-end fusion and limit cellular replicative capabilities. Increased telomere attrition rates, and relatively shorter telomere length, is associated with genomic instability and has been linked with several chronic diseases, malignancies and reduced longevity. Telomeric DNA is highly susceptible to oxidative damage and dietary habits may make an impact on telomere attrition rates through the mediation of oxidative stress and chronic inflammation. The aim of this study was to examine the association between leucocyte telomere length (LTL) with both the Dietary Inflammatory Index^® 2014 (DII^®) and the Alternative Healthy Eating Index 2010 (AHEI-2010). This is a cross-sectional analysis using baseline data from 263 postmenopausal women from the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial, in Calgary and Edmonton, Alberta, Canada. No statistically significant association was detected between LTL z-score and the AHEI-2010 (P = 0·20) or DII^® (P = 0·91) in multivariable adjusted models. An exploratory analysis of AHEI-2010 and DII^® parameters and LTL revealed anthocyanidin intake was associated with LTL (P < 0·01); however, this association was non-significant after a Bonferroni correction was applied (P = 0·27). No effect modification by age, smoking history, or recreational physical activity was detected for either relationship. Increased dietary antioxidant and decreased oxidant intake were not associated with LTL in this analysis.

Milk Fat Intake and Telomere Length in U.S. Women and Men: The Role of the Milk Fat Fraction

The associations between milk intake frequency and milk fat consumption and telomere length, an index of biological aging, were studied using an NHANES sample of 5,834 U.S. adults and a cross-sectional design. The milk consumption variables were assessed with the NHANES Diet Behavior and Nutrition questionnaire. The quantitative polymerase chain reaction method was used to measure leukocyte telomere length. Results showed that milk consumption frequency was not related to telomere length; however, there was a strong association between milk fat intake and telomere length. With the sample delimited to milk drinkers only, milk fat intake was linearly and inversely related to telomere length, after adjusting for the covariates (F = 8.6, P = 0.0066). For each 1 percentage point increase in milk fat consumed (e.g., 1% to 2%), adults had more than 4 years of additional biological aging. With milk fat intake divided into 5 categories (i.e., milk abstainers, nonfat, 1%, 2%, and full-fat milk), mean telomere lengths differed across the categories (F = 4.1, P = 0.0093). The mean telomere difference between the extremes of milk fat intake (nonfat vs. full-fat) was 145 base pairs, representing years of additional biological aging for full-fat milk consumers. Effect modification testing indicated that the milk fat and cellular aging association may be partly due to saturated fat intake differences across the milk fat groups. When the sample was delimited to adults reporting only high total saturated fat intake (tertile 3), the milk fat and telomere relationship was strong. However, when the sample was restricted to adults reporting only low saturated fat consumption (tertile 1), there was no relationship between milk fat intake and telomere length. Overall, the findings highlight an association of increased biological aging in U.S. adults who consumed high-fat milk. The results support the latest Dietary Guidelines for Americans (2015–2020), which recommend consumption of low-fat milk, but not high-fat milk, as part of a healthy diet.

Telomere regulation: lessons learnt from mice and men, potential opportunities in horses

Telomeres are genetically conserved nucleoprotein complexes located at the ends of chromosomes that preserve genomic stability. In large mammals, somatic cell telomeres shorten with age, owing to the end replication problem and lack of telomere-lengthening events (e.g. telomerase and ALT activity). Therefore, telomere length reflects cellular replicative reserve and mitotic potential. Environmental insults can accelerate telomere attrition in response to cell division and DNA damage. As such, telomere shortening is considered one of the major hallmarks of ageing. Much effort has been dedicated to understanding the environmental perturbations that accelerate telomere attrition and therapeutic strategies to preserve or extend telomeres. As telomere dynamics seem to reflect cumulative cellular stress, telomere length could serve as a biomarker of animal welfare. The assessment of telomere dynamics (i.e. rate of shortening) in conjunction with telomere-regulating genes and telomerase activity in racehorses could monitor long-term animal health, yet it could also provide some unique opportunities to address particular limitations with the use of other animal models in telomere research. Considering the ongoing efforts to optimise the health and welfare of equine athletes, the purpose of this review is to discuss the potential utility of assessing telomere length in Thoroughbred racehorses. A brief review of telomere biology in large and small mammals will be provided, followed by discussion on the biological implications of telomere length and environmental (e.g. lifestyle) factors that accelerate or attenuate telomere attrition. Finally, the utility of quantifying telomere dynamics in horses will be offered with directions for future research.

Controlling for baseline telomere length biases estimates of the rate of telomere attrition

Longitudinal studies have sought to establish whether environmental exposures such as smoking accelerate the attrition of individuals' telomeres over time. These studies typically control for baseline telomere length (TL) by including it as a covariate in statistical models. However, baseline TL also differs between smokers and non-smokers, and telomere attrition is spuriously linked to baseline TL via measurement error and regression to the mean. Using simulated datasets, we show that controlling for baseline TL overestimates the true effect of smoking on telomere attrition. This bias increases with increasing telomere measurement error and increasing difference in baseline TL between smokers and non-smokers. Using a meta-analysis of longitudinal datasets, we show that as predicted, the estimated difference in telomere attrition between smokers and non-smokers is greater when statistical models control for baseline TL than when they do not, and the size of the discrepancy is positively correlated with measurement error. The bias we describe is not specific to smoking and also applies to other exposures. We conclude that to avoid invalid inference, models of telomere attrition should not control for baseline TL by including it as a covariate. Many claims of accelerated telomere attrition in individuals exposed to adversity need to be re-assessed.