Physical activity, sedentary behavior, and leukocyte telomere length in women

Physical Performance and Telomere Length in Older Adults

BACKGROUND

The aging population prompts studying risk factors and markers to predict healthy aging. Telomere length is a promising candidate for assessing various age-related traits.

AIM OF THE STUDY

To investigate the association between physical performance and telomere length.

METHODS

We enrolled 323 older Mexican adults from the "Cohort of Obesity, Sarcopenia, and Frailty of Older Mexican Adults" affiliated with the Instituto Mexicano del Seguro Social and assessed their physical performance using the Short Physical Performance Battery, dividing participants into low (≤7) and high (>7) groups. Absolute telomere length was determined by qPCR, and individuals were classified into short (≤4.22 kb) and long (>4.22 kb) groups. We calculated the mean and adjusted mean, considering sex and age, among others, with 95% CI. We estimated the effect size between physical performance and telomere length using Cohen's d for unequal group sizes and calculated the odds ratio for physical performance based on telomere length.

RESULTS

Participants with low physical performance had significantly shorter telomeres (mean 4.14.44.7 kb, adjusted mean 3.54.04.5 kb, p <0.001), while those with high physical performance exhibited longer telomeres (mean 5.55.75.9 kb, adjusted mean 4.75.35.8 kb, p <0.001), with a medium-to-high telomere length effect size (d = 0.762). The odds of low physical activity increased 2.13.66.1-fold per kb of telomere attrition (adjOR 1.73.36.3, p <0.001).

CONCLUSION

Decreased physical function is associated with shorter telomere length. Absolute telomere length presents a promising biomarker for distinguishing between healthy and unhealthy aging, warranting further investigation.

Association of Obesity with Telomere Length in Human Sperm

Background: Telomere attrition and mitochondrial dysfunction are two fundamental aspects of aging. Calorie restriction (CR) is the best strategy to postpone aging since it can enhance telomere attrition, boost antioxidant capacity, and lower the generation of reactive oxygen species (ROS). Since ROS is produced by mitochondria and can readily travel to cell nuclei, it is thought to be a crucial molecule for information transfer between mitochondria and cell nuclei. Important variables that affect the quality and functionality of sperm and may affect male reproductive health and fertility include telomere length, mitochondrial content, and the ratio of mitochondrial DNA (mtDNA) to nuclear DNA (nDNA). Telomere damage results from mitochondrial failure, whereas nuclear DNA remains unaffected. This research aims to investigate potential associations between these three variables and how they might relate to body mass index. Methods: Data were collected from 82 men who underwent IVF/ICSI at the University Hospital of Ioannina's IVF Unit in the Obstetrics and Gynecology Department. Evaluations included sperm morphology, sperm count, sperm motility, and participant history. To address this, male participants who were categorized into three body mass index (ΒΜΙ) groups-normal, overweight, and obese-had their sperm samples tested. Results: For both the normal and overweight groups, our results show a negative connection between relative telomere length and ΒΜI. As an illustration of a potential connection between mitochondrial health and telomere maintenance, a positive correlation was found for the obese group. Only the obese group's results were statistically significant (p < 0.05). More evidence that longer telomeres are associated with lower mitochondrial content can be found in the negative connection between telomere length and mitochondrial content in both the normal and overweight groups. However, the obese group showed a positive association. The data did not reach statistical significance for any of the three groups. These associations may affect sperm quality since telomere length and mitochondrial concentration are indicators of cellular integrity and health. Moreover, the ratio of mtDNA to nDNA was positively correlated with the relative telomere lengths of the obese group, but negatively correlated with the normal and overweight groups. In every group that was studied, the results were not statistically significant. According to this, male fertility may be negatively impacted by an imbalance in the copy number of the mitochondrial genome compared to the nuclear DNA in sperm. Conclusions: Essentially, the goal of our work is to determine whether mitochondria and telomere length in human sperm interact. Understanding these connections may aid in the explanation of some male infertility causes and possibly contribute to the creation of new treatment modalities for problems pertaining to reproductive health. The functional implications of these connections and their applications in therapeutic settings require further investigation.

The association of leukocyte telomere length with exceptional longevity among older women

The association of leukocyte telomere length (LTL) with survival to late life with intact mobility has not been adequately studied. This prospective cohort study consisted of 1451 postmenopausal women from a Women's Health Initiative ancillary study, who were eligible, because of birth year, to survive to age 90 as of March 6, 2021. LTL was measured by Southern blot at baseline (1993-1998). Associations between LTL and survival to age 90 were evaluated using logistic regression models adjusted for socio-demographic characteristics, health factors, and lifestyle factors. Multinominal logistic regression was utilized to examine associations of LTL with survival to age 90 with or without intact mobility. Mediation analysis examined the extent to which incident coronary heart disease and stroke-mediated the association between LTL and longevity. Overall, 76.7% of women were White, and 23.3% were Black; average age at baseline was 70.4±3.5 years. Relative to death before age 90, the odds of survival to age 90 were 60% higher (OR, 1.60; 95% CI, 1.28-2.01), the odds of survival to age 90 with mobility limitation were 72% higher (OR, 1.72; 95% CI, 1.33-2.21), and the odds of survival to age 90 with intact mobility were 44% higher (OR, 1.44; 95% CI, 1.06-1.95) for every one kilobase longer LTL. Absence of CHD, stroke, or CHD/stroke mediated the association of LTL with survival to age 90 by 11.1%, 37.4%, and 31.3%, respectively; however, these findings were not significant. Longer LTL was associated with higher odds of survival to age 90 among older women.

Association between modifiable lifestyle factors and telomere length: a univariable and multivariable Mendelian randomization study

BACKGROUND

Telomere length has long been recognized as a valuable biomarker of aging and is inversely correlated with chronological age. Various lifestyle factors have been implicated in telomere shortening or preservation; however, the association between lifestyle factors and telomere length remains controversial. To address this issue, we conducted a Mendelian randomization (MR) analysis to investigate the potential causal associations between multiple lifestyle factors and telomere length.

METHODS

Independent genetic variants strongly associated with lifestyle factors (tobacco smoking, sleep duration, insomnia, and physical activity) were selected as instrumental variables from corresponding genome-wide association studies (GWASs). Summary-level data for telomere length was obtained from a GWAS comprising 472,174 European ancestries. Univariable and multivariable MR analyses were performed to assess the relationships.

RESULTS

The genetic liability to lifetime smoking was robustly associated with shorter telomere length (odd ratio [OR]: 0.882; 95% confidence interval [CI]: 0.847-0.918). Genetically predicted insomnia was also linked to shorter telomere length (OR: 0.972; 95% CI: 0.959-0.985), while no significant association was observed between sleep duration and telomere length. Furthermore, a suggestive association was found between moderate-to-vigorous physical activity and longer telomere length (OR: 1.680; 95% CI: 1.115-2.531). In multivariable MR analyses, adjusting for potential mediators such as body mass index, type 2 diabetes, alcohol consumption, and alcohol use disorder, the associations of lifetime smoking and insomnia with telomere length remained robust.

CONCLUSION

Our findings suggest that smoking and insomnia may contribute to telomere shortening, while physical activity may play a role in telomere length maintenance. These findings underscore the importance of managing positive risk factors and adopting a healthy lifestyle to promote telomere health.

Differential Effects of Very-Low-Volume Exercise Modalities on Telomere Length, Inflammation, and Cardiometabolic Health in Obese Metabolic Syndrome Patients: A Subanalysis from Two Randomized Controlled Trials

Oxidative stress (OS) and inflammation are features of metabolic syndrome (MetS) that can contribute to the shortening of telomere length (TL), a marker of cellular ageing. Research indicates that exercise can positively influence MetS-associated conditions and TL. However, the effects of low-volume exercise types on TL are still unknown. We investigated the impact of very-low-volume high-intensity interval training (LV-HIIT), one-set resistance training (1-RT), and whole-body electromyostimulation (WB-EMS) on TL, inflammation, and cardiometabolic indices in 167 MetS patients. Data were derived from two randomized controlled trials where patients were allocated to an exercise group (2 sessions/week, for 12 weeks) or a control group. All groups received standard-care nutritional weight loss counselling. TL was determined as the T/S ratio (telomere to single-copy gene amount). All groups significantly reduced body weight (p < 0.05), but the T/S-ratio (p < 0.001) only increased with LV-HIIT. OS-related inflammatory markers (C-reactive protein, interleukin-6, and lipopolysaccharide-binding protein) only decreased (p < 0.05) following LV-HIIT. The MetS severity z-score improved with LV-HIIT (p < 0.001) and 1-RT (p = 0.014) but not with WB-EMS. In conclusion, very-low-volume exercise modalities have differential effects on telomeres, inflammation, and cardiometabolic health. Only LV-HIIT but not strength-based low-volume exercise increased TL in MetS patients, presumably due to superior effects on OS-related inflammatory markers.

Time Spent Jogging/Running and Biological Aging in 4458 U.S. Adults: An NHANES Investigation

Telomere length is a good index of cellular aging. Longer telomeres are predictive of longer life, and healthy lifestyles are associated with longer telomeres. This study explored the relationship between time spent jogging or running each week and leukocyte telomere length (LTL) in 4458 randomly selected U.S. adults. The association was studied using data collected by the National Health and Nutrition Examination Survey (NHANES), and a cross-sectional design. Total weekly jog/run time was calculated from survey responses. From the minute totals, three categories were formed: <10 min/week, 10-74 min/week, and ≥75 min/week. Adults in the third category met the U.S. guidelines. Data were analyzed using one-way ANOVA. Partial correlation was used to adjust for differences in potential mediating factors, including demographic and lifestyle/medical factors. In the total sample, after adjusting for all the potential covariates, mean LTL significantly differed across the three jog/run categories (F = 4.1, p = 0.0272). Specifically, adults who met the guidelines via jogging and/or running had significantly longer telomeres than adults who performed no jogging/running. Adults in the middle category did not differ from the other two categories. A minimum of 75 min of jogging/running weekly is predictive of longer telomeres when compared to adults who do not jog or run regularly.

Effects of Cardiorespiratory Fitness on Cardiovascular Disease Risk Factors and Telomere Length by Age and Obesity

Background

This study investigates differences in telomere length according to obesity, cardiovascular disease (CVD) risk factors, and fitness level in South Korean males.

Methods

The subjects of this study were males in their 10s to 50s (n=249). We measured obesity indices, CVD risk factors, leukocyte telomere length (LTL), and cardiorespiratory fitness (CRF). Correlation and regression analyses were performed to analyze the data.

Results

Measurement of participants' obesity indices, CVD risk factors, and maximum oxygen intake and analyzing their correlations with LTL revealed that LTL and CRF decreased with age and the levels and numbers of obesity indices and CVD risk factors increased. The LTL showed differences according to whether subjects exhibited obesity or dyslipidemia and by CRF level. When all the variables that influence the LTL were adjusted, the LTL became shorter as the age and low-density lipoprotein cholesterol (LDL-C) level increased, and it became longer as the maximum rate of oxygen utilization (VO2max) increased. When the age and CVD risk factors that influence the LTL were adjusted according to obesity and CRF for the obese group, the LTL became shorter as the age and LDL-C level increased (P<0.01), and it became longer as VO2max increased (P<0.01).

Conclusion

We found that obesity influenced the LTL by increasing the levels of CVD risk factors and decreasing CRF, whereas maintaining high CRF could alleviate the effects of obesity and CVD risk factors according to age while maintaining and influencing the elongation of LTL.

Cell Survival, Death, and Proliferation in Senescent and Cancer Cells: the Role of (Poly)phenols

Cellular senescence has long been considered a permanent state of cell cycle arrest occurring in proliferating cells subject to different stressors, used as a cellular defense mechanism from acquiring potentially harmful genetic faults. However, recent studies highlight that senescent cells might also alter the local tissue environment and concur to chronic inflammation and cancer risk by secreting inflammatory and matrix remodeling factors, acquiring a senescence-associated secretory phenotype (SASP). Indeed, during aging and age-related diseases, senescent cells amass in mammalian tissues, likely contributing to the inevitable loss of tissue function as we age. Cellular senescence has thus become one potential target to tackle age-associated diseases as well as cancer development. One important aspect characterizing senescent cells is their telomere length. Telomeres shorten as a consequence of multiple cellular replications, gradually leading to permanent cell cycle arrest, known as replicative senescence. Interestingly, in the large majority of cancer cells, a senescence escape strategy is used and telomere length is maintained by telomerase, thus favoring cancer initiation and tumor survival. There is growing evidence showing how (poly)phenols can impact telomere maintenance through different molecular mechanisms depending on dose and cell phenotypes. Although normally, (poly)phenols maintain telomere length and support telomerase activity, in cancer cells this activity is negatively modulated, thus accelerating telomere attrition and promoting cancer cell death. Some (poly)phenols have also been shown to exert senolytic activity, thus suggesting both antiaging (directly eliminating senescent cells) and anticancer (indirectly, via SASP inhibition) potentials. In this review, we analyze selective (poly)phenol mechanisms in senescent and cancer cells to discriminate between in vitro and in vivo evidence and human applications considering (poly)phenol bioavailability, the influence of the gut microbiota, and their dose-response effects.

Sedentary Behaviour and Telomere Length Shortening during Early Childhood: Evidence from the Multicentre Prospective INMA Cohort Study

Sedentary behaviour (SB) may be related to telomere length (TL) attrition due to a possible pro-inflammatory effect. This study examined the association between parent-reported sedentary behaviour (SB) and leukocyte TL at the age of 4 and telomere tracking from 4 to 8 years. In the Spanish birth cohort Infancia y Medio Ambiente (INMA) project, we analysed data from children who attended follow-up visits at age 4 (n = 669) and 8 (n = 530). Multiple robust regression models were used to explore the associations between mean daily hours of SB (screen time, other sedentary activities, and total SB) at 4 years categorised into tertiles and TL at 4 years and difference in TL rank between age 4 and 8, respectively. At the age of 4, the results showed that children with the highest screen time (1.6-5.0 h/day) had a shorter TL of -3.9% (95% CI: -7.4, -0.4; p = 0.03) compared with children in the lowest tertile (0.0-1.0 h/day). Between 4 and 8 years, a higher screen time (highest tertile group vs. lowest tertile) was associated with a decrease in the LTL rank of -1.9% (95% CI: -3.8, -0.1; p = 0.03) from 4 to 8 years. Children exposed to a higher screen time at 4 years were more prone to have shorter TL at 4 and between 4 and 8 years of age. This study supports the potential negative effect of SB during childhood on cellular longevity.

Sedentary behavior and the risk of stroke: A systematic review and dose-response meta-analysis

BACKGROUND AND AIMS

The sedentary behavior in people's daily life has continued to increase in recent years, causing many studies to focus on its relationship with diseases. Several studies have shown that sedentary behavior is an independent risk factor for cardiovascular disease and metabolic disease. Therefore, we performed a meta-analysis to assess the association between sedentary behavior and the risk of stroke.

METHODS AND RESULTS

Two independent investigators searched for prospective cohort studies on the association between sedentary behavior and stroke risk, published before February 2022. We pooled adjusted effect size and performed the dose-response analysis by random-effect model. Seven studies with 677,614 participants and 15,135 stroke events during a median follow-up of 12.2 years were included. The pooled hazard ratio (HR) of stroke was 1.16 (95% confidence interval [CI]: 1.09-1.24) with no significant heterogeneity (I2 = 0.0%, p for heterogeneity = 0.983). In dose-response analysis, a nonlinear association between sedentary behavior and stroke risk was discovered. Stroke risk began to increase when sedentary time exceeded 3.7 h/d (HR, 1.01; 95% CI, 0.97-1.05). And when reached 11 h/d, a significantly increased risk of stroke was observed (HR, 1.21; 95% CI 1.12-1.31).

CONCLUSION

A nonlinear association was found in the dose-response analysis, with increased risk only when sedentary time exceeded a certain level. Further research is needed to explain the biological mechanisms by which sedentary time above a certain threshold significantly increases stroke risk. (PROSPERO registration number: CRD42022311544).

Physical Activity on Telomere Length as a Biomarker for Aging: A Systematic Review

Background

Overall life expectancy continues to rise, approaching 80 years of age in several developed countries. However, healthy life expectancy lags far behind, which has, in turn, contributed to increasing costs in healthcare. One way to improve health and attenuate the socio-economic impact of an aging population is to increase overall fitness through physical activity. Telomere attrition or shortening is a well-known molecular marker in aging. As such, several studies have focused on whether exercise influences health and aging through telomere biology. This systematic review examines the recent literature on the effect of physical activity on telomere length (TL) and/or telomerase activity as molecular markers of aging.

Methods

A focused search was performed in the databases PubMed and Web of Science for retrieving relevant articles over the past ten years. The search contained the following keywords: exercise, sport, physical activity, fitness, sedentary, physical inactivity, telomere, telomere length, t/s ratio, and telomerase. PRISMA guidelines for systematic reviews were observed.

Results

A total of 43 articles were identified and categorized into randomized controlled trials (RCT), observational or interventional studies. RCTs (n = 8) showed inconsistent findings of increased TL length with physical activity in, e.g. obese, post-menopausal women. In comparison with a predominantly sedentary lifestyle, observational studies (n = 27) showed significantly longer TL with exercise of moderate to vigorous intensity; however, there was no consensus on the duration and type of physical activity and training modality. Interventional studies (n = 8) also showed similar findings of significantly longer TL prior to exercise intervention; however, these studies had smaller numbers of enrolled participants (mostly of high-performance athletes), and the physical activities covered a range of exercise intensities and duration. Amongst the selected studies, aerobic training of moderate to vigorous intensity is most prevalent. For telomere biology analysis, TL was determined mainly from leukocytes using qPCR. In some cases, especially in RCT and interventional studies, different sample types such as saliva, sperm, and muscle biopsies were analyzed; different leukocyte cell types and potential genetic markers in regulating telomere biology were also investigated.

Conclusions

Taken together, physical activity with regular aerobic training of moderate to vigorous intensity appears to help preserve TL. However, the optimal intensity, duration of physical activity, as well as type of exercise still need to be further elucidated. Along with TL or telomerase activity, participants’ fitness level, the type of physical activity, and training modality should be assessed at different time points in future studies, with the plan for long-term follow-up. Reducing the amount of sedentary behavior may have a positive effect of preserving and increasing TL. Further molecular characterization of telomere biology in different cell types and tissues is required in order to draw definitive causal conclusions on how physical activity affects TL and aging.

Association of Dietary Magnesium Intake With Leukocyte Telomere Length in United States Middle-Aged and Elderly Adults

Aim

Magnesium supplementation may extend the life span; however, the biological mechanism is still unknown. Leukocyte telomere length (LTL) is a marker of cell aging and biological health in humans. Data concerning whether magnesium supplementation can maintain telomere length, thus prolonging life are limited. We aimed to investigate the association between dietary magnesium intake and LTL in United States middle-aged and elderly adults.

Methods

A total of 4,039 United States adults aged ≥ 45 years from National Health and Nutrition Examination Survey (1999–2002). Dietary magnesium intake was collected by a trained interviewer using 24-h dietary recall method and LTL was obtained using the quantitative polymerase chain reaction method. Multiple linear regression analysis was performed to evaluate the crude and adjusted association of dietary magnesium intake with LTL.

Results

The overall mean (SD) of LTL was 5.6 (0.6) kp. After adjusting potential confounders, every 1 mg increase in log-transformed dietary magnesium intake was associated with 0.20 kp (95% confidence intervals: 0.05–0.34) longer LTL. Participants with the highest tertile (≥299 mg) of dietary magnesium intake had statistically significant longer LTL (β = 0.07, P = 0.038) compared with the lowest tertile (&lt;198 mg), with significant linear trends across tertiles. Moreover, the association between dietary magnesium intake and LTL was significantly stronger in participants with higher levels of education (≥high school compared with &lt; high school, P for interaction = 0.002). E-value analysis suggested robustness to unmeasured confounding.

Conclusion

Our findings showed that increased dietary magnesium intake was associated with longer LTL, which suggested that magnesium was conducive to a longer life expectancy.

Influences of Long-Term Exercise and High-Fat Diet on Age-Related Telomere Shortening in Rats

(1) Obesity and exercise are believed to modify age-related telomere shortening by regulating telomerase and shelterins. Existing studies are inconsistent and limited to peripheral blood mononuclear cells (PBMCs) and selected solid tissues. (2) Female Sprague Dawley (SD) rats received either standard diet (ND) or high-fat diet (HFD). For 10 months, half of the animals from both diet groups performed 30 min running at 30 cm/s on five consecutive days followed by two days of rest (exeND, exeHFD). The remaining animals served as sedentary controls (coND, coHFD). Relative telomere length (RTL) and mRNA expression of telomerase (TERT) and the shelterins TERF-1 and TERF-2 were mapped in PBMCs and nine solid tissues. (3) At study end, coND and coHFD animals showed comparable RTL in most tissues with no systematic differences in TERT, TERF-1 and TERF-2 expression. Only visceral fat of coHFD animals showed reduced RTL and lower expression of TERT, TERF-1 and TERF-2. Exercise had heterogeneous effects on RTL in exeND and exeHFD animals with longer telomeres in aorta and large intestine, but shorter telomeres in PBMCs and liver. Telomere-regulating genes showed inconsistent expression patterns. (4) In conclusion, regular exercise or HFD cannot systematically modify RTL by regulating the expression of telomerase and shelterins.

The Impact of Exercise on Telomere Length, DNA Methylation and Metabolic Footprints

Aging as a major risk factor influences the probability of developing cancer, cardiovascular disease and diabetes, amongst others. The underlying mechanisms of disease are still not fully understood, but research suggests that delaying the aging process could ameliorate these pathologies. A key biological process in aging is cellular senescence which is associated with several stressors such as telomere shortening or enhanced DNA methylation. Telomere length as well as DNA methylation levels can be used as biological age predictors which are able to detect excessive acceleration or deceleration of aging. Analytical methods examining aging are often not suitable, expensive, time-consuming or require a high level of technical expertise. Therefore, research focusses on combining analytical methods which have the potential to simultaneously analyse epigenetic, genomic as well as metabolic changes.

Effect of Physical Activity, Smoking, and Sleep on Telomere Length: A Systematic Review of Observational and Intervention Studies

Aging is a risk factor for several pathologies, restricting one’s health span, and promoting chronic diseases (e.g., cardiovascular and neurodegenerative diseases), as well as cancer. Telomeres are regions of repetitive DNA located at chromosomal ends. Telomere length has been inversely associated with chronological age and has been considered, for a long time, a good biomarker of aging. Several lifestyle factors have been linked with telomere shortening or maintenance. However, the consistency of results is hampered by some methodological issues, including study design, sample size, measurement approaches, and population characteristics, among others. Therefore, we aimed to systematically review the current literature on the effects of three relevant lifestyle factors on telomere length in human adults: physical activity, smoking, and sleep. We conducted a qualitative systematic review of observational and intervention studies using the Preferred Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The systematic literature search covered articles published in MEDLINE and EMBASE databases (from 2010 to 2020). A total of 1400 studies were identified; 83 were included after quality control. Although fewer sedentary activities, optimal sleep habits, and non- or ex-smoker status have been associated with less telomere shortening, several methodological issues were detected, including the need for more targeted interventions and standardized protocols to better understand how physical activity and sleep can impact telomere length and aging. We discuss the main findings and current limitations to gain more insights into the influence of these lifestyle factors on the healthy aging process.

Effects of Physical Exercise on Cognition and Telomere Length in Healthy Older Women

BACKGROUND

Physical exercise is an effective measure for preventing the onset of cognitive decline and has a direct influence on the aging process. The purpose of this study was to assess the effect of a 6-month physical exercise program on cognition and telomere length in adults over 65 years of age.

METHOD

Seventy-four healthy women were separated into two groups: 41 were included in the intervention group (IG) (72.70 ± 4.127 years and 8.18 ± 1.551 years of education) and 33 in the control group (CG) (71.21 ± 4.127 years and 8.42 ± 2.562). The participants included within the IG carried out three sessions of physical exercise per week for six months. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), the Stroop test and the Trail Making Test (TMT). Saliva samples were taken and analyzed and relative telomere length was calculated. Those conducting the analysis were blind to the group to which the participants had been assigned.

RESULTS

An improvement was observed in global cognitive function, in both attentional and executive functions, in the group of adults doing physical exercise as compared to the control group. Six months after the physical exercise program had finished, relative telomere length was found to have increased in the participants in the intervention group.

CONCLUSION

Physical exercise programs can lead to an improvement in both cognitive functions and telomere length.

Land use mix and leukocyte telomere length in Mexican Americans

It has been well-known that built environment features influence the risk of chronic diseases. However, the existing data of its relationship with telomere length, a biomarker of biological aging, is still limited, with no study available for Mexican Americans. This study investigates the relationship between several factors of the built environment with leukocyte telomere length among 5508 Mexican American adults enrolled in Mano-A-Mano, the Mexican American Cohort Study (MACS). Based on the quartile levels of telomere length, the study population was categorized into four groups, from the lowest (1st quartile) to the highest telomere length group (4th quartile). For individual built environment factors, their levels did not differ significantly across four groups. However, in the multinominal logistic regression analysis, increased Rundle’s land use mixture (LUM) and Frank’s LUM were found statistically significantly associated with increased odds of having high levels of telomere length (Rundle’s LUM: 2nd quartile: Odds ratio (OR) 1.26, 95% Confidence interval (CI) 1.07, 1.48; 3rd quartile: OR 1.25, 95% CI 1.06, 1.46; 4th quartile: OR 1.19, 95% CI 1.01, 1.41; Frank’s LUM: 2nd quartile: OR 1.34, 95% CI 1.02, 2.63; 3rd quartile: OR 1.55, 95% CI 1.04, 2.91; 4th quartile: OR 1.36, 95% CI 1.05, 2.72, respectively). The associations for Rundle’s LUM remained significant after further adjusting other non-redundant built environment factors. Finally, in stratified analysis, we found the association between Rundle’s LUM and telomere length was more evident among younger individuals (< 38 years old), women, and those with obesity, born in Mexico, having low levels of physical activity, and having low levels of acculturation than their relative counterparts. In summary, our results indicate that land use mixture may impact telomere length in leukocytes in Mexican Americans.

Regular, Intense Exercise Training as a Healthy Aging Lifestyle Strategy: Preventing DNA Damage, Telomere Shortening and Adverse DNA Methylation Changes Over a Lifetime

Exercise training is one of the few therapeutic interventions that improves health span by delaying the onset of age-related diseases and preventing early death. The length of telomeres, the 5'-TTAGGG n -3' tandem repeats at the ends of mammalian chromosomes, is one of the main indicators of biological age. Telomeres undergo shortening with each cellular division. This subsequently leads to alterations in the expression of several genes that encode vital proteins with critical functions in many tissues throughout the body, and ultimately impacts cardiovascular, immune and muscle physiology. The sub-telomeric DNA is comprised of heavily methylated, heterochromatin. Methylation and histone acetylation are two of the most well-studied examples of the epigenetic modifications that occur on histone proteins. DNA methylation is the type of epigenetic modification that alters gene expression without modifying gene sequence. Although diet, genetic predisposition and a healthy lifestyle seem to alter DNA methylation and telomere length (TL), recent evidence suggests that training status or physical fitness are some of the major factors that control DNA structural modifications. In fact, TL is positively associated with cardiorespiratory fitness, physical activity level (sedentary, active, moderately trained, or elite) and training intensity, but is shorter in over-trained athletes. Similarly, somatic cells are vulnerable to exercise-induced epigenetic modification, including DNA methylation. Exercise-training load, however, depends on intensity and volume (duration and frequency). Training load-dependent responses in genomic profiles could underpin the discordant physiological and physical responses to exercise. In the current review, we will discuss the role of various forms of exercise training in the regulation of DNA damage, TL and DNA methylation status in humans, to provide an update on the influence exercise training has on biological aging.

Systematic Review of Studies on Telomere Length in Patients with Multiple Sclerosis

Telomeres are protective cap structures at the end of chromosomes that are essential for maintaining genomic stability. Accelerated telomere shortening is related to premature cellular senescence. Shortened telomere lengths (TL) have been implicated in the pathogenesis of various chronic immune-mediated and neurological diseases. We aimed to systematically review the current literature on the association of TL as a measure of biological age and multiple sclerosis (MS). A comprehensive literature search was conducted to identify original studies that presented data on TL in samples from persons with MS. Quantitative and qualitative information was extracted from the articles to summarize and compare the studies. A total of 51 articles were screened, and 7 of them were included in this review. In 6 studies, average TL were analyzed in peripheral blood cells, whereas in one study, bone marrow-derived cells were used. Four of the studies reported significantly shorter leukocyte TL in at least one MS subtype in comparison to healthy controls (p=0.003 in meta-analysis). Shorter telomeres in patients with MS were found to be associated, independently of age, with greater disability, lower brain volume, increased relapse rate and more rapid conversion from relapsing to progressive MS. However, it remains unclear how telomere attrition in MS may be linked to oxidative stress, inflammation and age-related disease processes. Despite few studies in this field, there is substantial evidence on the association of TL and MS. Variability in TL appears to reflect heterogeneity in clinical presentation and course. Further investigations in large and well-characterized cohorts are warranted. More detailed studies on TL of individual chromosomes in specific cell types may help to gain new insights into the pathomechanisms of MS.

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.

Omega-3 supplementation and stress reactivity of cellular aging biomarkers: an ancillary substudy of a randomized, controlled trial in midlife adults

Higher levels of omega-3 track with longer telomeres, lower inflammation, and blunted sympathetic and cardiovascular stress reactivity. Whether omega-3 supplementation alters the stress responsivity of telomerase, cortisol, and inflammation is unknown. This randomized, controlled trial examined the impact of omega-3 supplementation on cellular aging-related biomarkers following a laboratory speech stressor. In total, 138 sedentary, overweight, middle-aged participants (n = 93 women, n = 45 men) received either 2.5 g/d of omega-3, 1.25 g/d of omega-3, or a placebo for 4 months. Before and after the trial, participants underwent the Trier Social Stress Test. Saliva and blood samples were collected once before and repeatedly after the stressor to measure salivary cortisol, telomerase in peripheral blood lymphocytes, and serum anti-inflammatory (interleukin-10; IL-10) and pro-inflammatory (interleukin-6; IL-6, interleukin-12, tumor necrosis factor-alpha) cytokines. Adjusting for pre-supplementation reactivity, age, sagittal abdominal diameter, and sex, omega-3 supplementation altered telomerase (p = 0.05) and IL-10 (p = 0.05) stress reactivity; both supplementation groups were protected from the placebo group's 24% and 26% post-stress declines in the geometric means of telomerase and IL-10, respectively. Omega-3 also reduced overall cortisol (p = 0.03) and IL-6 (p = 0.03) throughout the stressor; the 2.5 g/d group had 19% and 33% lower overall cortisol levels and IL-6 geometric mean levels, respectively, compared to the placebo group. By lowering overall inflammation and cortisol levels during stress and boosting repair mechanisms during recovery, omega-3 may slow accelerated aging and reduce depression risk. ClinicalTrials.gov identifier: NCT00385723.

Age and Sport Intensity-Dependent Changes in Cytokines and Telomere Length in Elite Athletes

Exercise-associated immune response plays a crucial role in the aging process. The aim of this study is to investigate the effect of sport intensity on cytokine levels, oxidative stress markers and telomere length in aging elite athletes. In this study, 80 blood samples from consenting elite athletes were collected for anti-doping analysis at an anti-doping laboratory in Italy (FMSI). Participants were divided into three groups according to their sport intensity: low-intensity skills and power sports (LI, n = 18); moderate-intensity mixed soccer players (MI, n = 31); and high-intensity endurance sports (HI, n = 31). Participants were also divided into two age groups: less than 25 (n = 45) and above 25 years old (n = 35). Serum levels of 10 pro and anti-inflammatory cytokines and two antioxidant enzymes were compared in age and sport intensity groups and telomere lengths were measured in their respective blood samples. Tumor necrosis factor-alpha (TNF-α) was the only cytokine showing significantly higher concentration in older athletes, regardless of sport intensity. Interleukin (IL)-10 increased significantly in HI regardless of age group, whereas IL-6 concentration was higher in the older HI athletes. IL-8 showed a significant interaction with sport intensity in different age groups. Overall, significant positive correlations among levels of IL-6, IL-10, IL-8 and TNF-α were identified. The antioxidant catalase activity was positively correlated with levels of TNF-α. Telomere length increased significantly with sport intensity, especially in the younger group. HI had longer telomeres and higher levels of pro- and anti-inflammatory cytokines, suggesting less aging in HI compared to low and moderate counterparts in association with heightened immune response. Investigation of the functional significance of these associations on the health and performance of elite athletes is warranted.

Telomere length and its relationships with lifestyle and behavioural factors: variations by sex and race/ethnicity

BACKGROUND

Adherence to healthy lifestyles/behaviours promotes healthy ageing. However, little is known about whether age, sex and/or race/ethnicity moderate associations of lifestyle/behavioural factors with relative telomere length (RTL), a potential biomarker of ageing.

METHODS

We included 749 midlife to older non-Hispanic White (n = 254), Black (n = 248) and Hispanic (n = 247) US participants [mean (standard deviation) age = 69.3 (7.2) years; women: 50.5%]. We extracted genomic DNA from peripheral leucocytes. RTL was assayed using real-time quantitative polymerase chain reaction. Multivariable regression was used to examine associations between lifestyle/behavioural exposures (i.e. physical activity, alcohol consumption, smoking and depression) with RTL.

RESULTS

Increasing chronological age was associated with shorter RTL (P < 0.01). Higher physical activity was associated with longer RTL (P-trend = 0.03); daily versus never/rare alcohol consumption and 30+ versus <5 smoking pack-year were associated with shorter RTLs (P-trend = 0.02). Associations varied significantly by sex and race/ethnicity. The association between physical activity and longer RTL appeared strongest among non-Hispanic Whites (P-interaction = 0.01). Compared to men, women had stronger associations between heavy smoking and shorter RTLs (P-interaction = 0.03). Light/moderate alcohol consumption (monthly/weekly) was associated with longer RTL among non-Hispanic Whites, while daily consumption was related to shorter RTLs among Blacks and Hispanics (P-interactions < 0.01). Associations of daily alcohol and heavy smoking with shorter RTLs were particularly apparent among Black women.

CONCLUSION

We observed novel variations by sex and race/ethnicity in associations between lifestyle/behavioural factors and RTL. Further work is needed to replicate these findings and to address potential public health implications for modifying strategies by sex or across racial/ethnic groups to optimise lifestyles/behaviours for healthy ageing.

Mediterranean-Type Dietary Pattern and Physical Activity: The Winning Combination to Counteract the Rising Burden of Non-Communicable Diseases (NCDs)

Non-communicable diseases (NCDs) (mainly cardiovascular diseases, cancers, chronic respiratory diseases and type 2 diabetes) are the main causes of death worldwide. Their burden is expected to rise in the future, especially in less developed economies and among the poor spread across middle- and high-income countries. Indeed, the treatment and prevention of these pathologies constitute a crucial challenge for public health. The major non-communicable diseases share four modifiable behavioral risk factors: unhealthy diet, physical inactivity, tobacco usage and excess of alcohol consumption. Therefore, the adoption of healthy lifestyles, which include not excessive alcohol intake, no smoking, a healthy diet and regular physical activity, represents a crucial and economical strategy to counteract the global NCDs burden. This review summarizes the latest evidence demonstrating that Mediterranean-type dietary pattern and physical activity are, alone and in combination, key interventions to both prevent and control the rise of NCDs.

Telomere length as a function of age at population level parallels human survival curves

Telomeres are subject to age related shortening which can be accelerated by oxidative stress and inflammation. Many studies have reported an inverse correlation between telomere length and survival, but such inverse correlation has not been always confirmed in different populations. We analyzed the trend of Leukocyte Telomere Length (LTL) as a function of age in a cohort of 516 subjects aged 65-106 years from Southern Italy. The trend of LTL obtained was quite similar to demographic survival curves reported with data of western societies. We observed a decrease of LTL after 70 years of age and then an increase after 92 years, in agreement with the sharp decrease of survival after 70 years of age and its increase after 90 years, due to the deceleration of mortality at old ages. Our data suggest that a generalized LTL attrition after 70 years of age, associated to organismal decline, affects most of the population. Such generalized attrition may exacerbate senescence in these subjects, predisposing them to high mortality risk. Conversely, the subjects with better physical conditions, experience a lower attrition and, consequently, a delayed senescence, contributing to the deceleration of mortality which has been observed among very old subjects in modern societies.

Advanced paternal age and risk of cancer in offspring

Many risk factors of cancer have been established, but the contribution of paternal age in this regard remains largely unexplored. To further understand the etiology of cancer, we investigated the relationship between paternal age and cancer incidence using PLCO cohort. Cox proportional hazards models were performed to assess the association between paternal age and the risk of cancers. During follow-up time (median 11.5 years), 18,753 primary cancers occurred. Paternal age was associated with reduced risk of cancers of the female genitalia (HR, 0.79; 95%CI, 0.66-0.94; P = 0.008) as well as cancers of the respiratory and intrathoracic organs (HR, 0.78; 95%CI, 0.63-0.97; P = 0.026). The association was stronger for lung cancer (HR, 0.67; 95%CI, 0.52-0.86; P = 0.002). The subgroup analysis suggested that age, gender, smoking and BMI were related to the decreased cancer incidence of the respiratory and intrathoracic organs, lung and the female genitalia. Positive linear associations were observed between paternal age and cancer incidence of the female genitalia, respiratory and intrathoracic organs and the lungs. These findings indicate that advanced paternal age is an independent protective factor against various cancers in offspring.

Neighborhood social environment and changes in leukocyte telomere length: The Multi-Ethnic Study of Atherosclerosis (MESA)

Given limited research on the impact of neighborhood environments on accelerated biological aging, we examined whether changes in neighborhood socioeconomic and social conditions were associated with change in leukocyte telomere length using 10 years of longitudinal data from the Multi-Ethnic Study of Atherosclerosis (years 2000-2011; N = 1031; mean age = 61, SD = 9.4). Leukocyte telomere length change was corrected for regression to the mean and neighborhood was defined as census tract. Neighborhood socioeconomic indicators (factor-based score of income, education, occupation, and wealth of neighborhood) and neighborhood social environment indicators (aesthetic quality, social cohesion, safety) were obtained from the U.S Census/American Community Survey and via study questionnaire, respectively. Results of linear mixed-effects models showed that independent of individual sociodemographic characteristics, each unit of improvement in neighborhood socioeconomic status was associated with slower telomere length attrition over 10-years (β = 0.002; 95% Confidence Interval (CI): 0.0001, 0.004); whereas each unit of increase in safety (β = -0.043; 95% CI: -0.069, -0.016) and overall neighborhood social environment score (β = -0.005; 95% CI: -0.009, -0.0004) were associated with more pronounced telomere attrition, after additionally adjusting for neighborhood socioeconomic status. This study provides support for considerations of the broader social and socioeconomic contexts in relation to biological aging. Future research should explore potential psychosocial mechanisms underlying these associations using longitudinal study designs with repeated observations.

Association between favourable changes in objectively measured physical activity and telomere length after a lifestyle intervention in pediatric patients with abdominal obesity

The purpose of this study was to assess the effect of physical activity (PA) changes, measured by accelerometry, on telomere length (TL) in pediatric patients with abdominal obesity after a lifestyle intervention. One hundred and twenty-one children (7-16 years old) with abdominal obesity were randomized to the intervention (a moderately hypocaloric Mediterranean diet) or the usual care group (standard pediatric recommendations) for 22 months (a 2 month intensive phase and a subsequent 20 month follow-up). Both groups were encouraged to accumulate an extra 200 min/week of PA. TL was measured by MMqPCR. Data were analyzed in 102 subjects after 2 months and 64 subjects at the first 10 months of follow-up. Light PA level decreased in both groups after 12 months of intervention. At month 2, moderate to vigorous PA (MVPA) increased in the intervention group (+5.4 min/day, p = 0.035) and so did sedentary time in the usual care group (+49.7 min/day, p = 0.010). TL changes were positively associated (p < 0.050) with metabolic equivalents (METs), MVPA level, and number of steps, and were inversely associated with sedentary and light PA levels in the intervention group after the intensive phase. In conclusion, favourable changes in PA levels in the intensive phase of a lifestyle intervention could contribute to TL maintenance in a pediatric population with abdominal obesity. Novelty Changes in physical activity levels had a direct effect on telomere length, a biomarker of cellular aging and oxidative stress. PA advice based on The American College of Sports Medicine included in this intervention is easy to implement in primary care.

Physical activity, a modulator of aging through effects on telomere biology

Aging is a complex process that is not well understood but involves finite changes at the genetic and epigenetic level. Physical activity is a well-documented modulator of the physiological process of aging. It has been suggested that the beneficial health effects of regular exercise are at least partly mediated through its effects on telomeres and associated regulatory pathways. Telomeres, the region of repetitive nucleotide sequences functioning as a "cap" at the chromosomal ends, play an important role to protect genomic DNA from degradation. Telomeres of dividing cells progressively shorten with age. Leucocyte telomere length (TL) has been associated with age-related diseases. Epidemiologic evidence indicates a strong relationship between physical activity and TL. In addition, TL has also been shown to predict all-cause and cardiovascular mortality. Experimental studies support a functional link between aerobic exercise and telomere preservation through activation of telomerase, an enzyme that adds nucleotides to the telomeric ends. However, unresolved questions regarding exercise modalities, pathomechanistic aspects and analytical issues limit the interpretability of available data. This review provides an overview about the current knowledge in the area of telomere biology, aging and physical activity. Finally, the capabilities and limitations of available analytical methods are addressed.

Impact of Nutrition on Telomere Health: Systematic Review of Observational Cohort Studies and Randomized Clinical Trials

Diet, physical activity, and other lifestyle factors have been implicated in the pathophysiology of several chronic diseases, but also in a lower total mortality and longer life expectancy. One of the mechanisms in which diet can reduce the risk of disease is with regard to its impact on telomeres. Telomere length (TL) is highly correlated to chronological age and metabolic status. Individuals with shorter telomeres are at higher risk of chronic diseases and mortality. Diet may influence TL by several mechanisms such as regulating oxidative stress and inflammation or modulating epigenetic reactions. The present systematic review aims to examine the results from epidemiologic and clinical trials conducted in humans evaluating the role of nutrients, food groups, and dietary patterns on TL. We also discuss the possible mechanisms of action that influence this process, with the perspective that TL could be a novel biomarker indicating the risk of metabolic disturbances and age-related diseases. The available evidence suggests that some antioxidant nutrients, the consumption of fruits and vegetables, and Mediterranean diet are mainly associated with longer telomeres. However, most of the evidence is based on high heterogenic observational studies and very few randomized clinical trials (RCTs). Therefore, the associations summarized in the present review need to be confirmed with larger prospective cohort studies and better-designed RCTs.

Leukocyte Telomere Length and Its Interaction with Germline Variation in Telomere-Related Genes in Relation to Pancreatic Adenocarcinoma Risk

BACKGROUND

Leukocyte telomere length (LTL) has been associated with risk of multiple cancers, but its association with pancreatic ductal adenocarcinoma (PDAC) is unclear. We therefore investigated the association between peripheral blood LTL and PDAC risk, and examined effect modification by candidate SNPs previously reported to be associated with variation in LTL.

METHODS

A case-control study of 1,460 PDAC cases and 1,459 frequency-matched controls was performed using biospecimens and data from the Mayo Clinic Biospecimen Resource for Pancreas Research. Quantitative PCR was used to measure LTL and categorized into tertiles based on sex-specific control distribution. Eleven telomere-related SNPs also were genotyped. Logistic regression was used to calculate ORs and 95% confidence intervals (CI).

RESULTS

Shorter peripheral blood LTL was associated with a higher risk of PDAC (OR_T1vsT3 = 1.26, 95% CI = 1.03-1.54, P _trend = 0.02; OR_continuous = 1.14, 95% CI = 1.02-1.28), but the association was restricted to cases with treatment-naïve blood samples (OR_T1vsT3 = 1.51, 95% CI = 1.16-1.96, P _trend = 0.002; OR_continuous = 1.25, 95% CI = 1.08-1.45) and not cases whose blood samples were collected after initiation of cancer therapy (OR_T1vsT3 = 1.10, 95% CI = 0.87-1.39, P _trend = 0.42; OR_continuous = 1.08, 95% CI = 0.94-1.23). Three SNPs (TERC-rs10936599, ACYP2-rs11125529, and TERC-rs1317082) were each associated with interindividual variation in LTL among controls, but there was no evidence of effect modification by these SNPs.

CONCLUSIONS

Treatment-naïve short LTL is associated with a higher risk of PDAC, and the association does not differ by germline variation in the candidate telomere-related SNPs examined.

IMPACT

Peripheral blood LTL might serve as a molecular marker for risk modeling to identify persons at high risk of PDAC.

Clark C, Celka R. A Review of Exercise as Medicine in Cardiovascular Disease: Pathology and Mechanism

BACKGROUND

Physical inactivity and resultant lower energy expenditure contribute unequivocally to cardiovascular diseases, such as coronary artery disease and stroke, which are considered major causes of disability and mortality worldwide.

AIM

The aim of the study was to investigate the influence of physical activity (PA) and exercise on different aspects of health - genetics, endothelium function, blood pressure, lipid concentrations, glucose intolerance, thrombosis, and self - satisfaction. Materials and.

METHODS

In this article, we conducted a narrative review of the influence PA and exercise have on the cardiovascular system, risk factors of cardiovascular diseases, searching the online databases; Web of Science, PubMed and Google Scholar, and, subsequently, discuss possible mechanisms of this action.

RESULTS AND DISCUSSION

Based on our narrative review of literature, discussed the effects of PA on telomere length, nitric oxide synthesis, thrombosis risk, blood pressure, serum glucose, cholesterol and triglycerides levels, and indicated possible mechanisms by which physical training may lead to improvement in chronic cardiovascular diseases.

CONCLUSION

PA is effective for the improvement of exercise tolerance, lipid concentrations, blood pressure, it may also reduce the serum glucose level and risk of thrombosis, thus should be advocated concomitant to, or in some cases instead of, traditional drug-therapy.

The impact of depression and anxiety treatment on biological aging and metabolic stress: study protocol of the MOod treatment with antidepressants or running (MOTAR) study

BACKGROUND

Depressive and anxiety disorders have shown to be associated to premature or advanced biological aging and consequently to adversely impact somatic health. Treatments with antidepressant medication or running therapy are both found to be effective for many but not all patients with mood and anxiety disorders. These interventions may, however, work through different pathophysiological mechanisms and could differ in their impact on biological aging and somatic health. This study protocol describes the design of an unique intervention study that examines whether both treatments are similarly effective in reducing or reversing biological aging (primary outcome), psychiatric status, metabolic stress and neurobiological indicators (secondary outcomes).

METHODS

The MOod Treatment with Antidepressants or Running (MOTAR) study will recruit a total of 160 patients with a current major depressive and/or anxiety disorder in a mental health care setting. Patients will receive a 16-week treatment with either antidepressant medication or running therapy (3 times/week). Patients will undergo the treatment of their preference and a subsample will be randomized (1:1) to overcome preference bias. An additional no-disease-no-treatment group of 60 healthy controls without lifetime psychopathology, will be included as comparison group for primary and secondary outcomes at baseline. Assessments are done at week 0 for patients and controls, and at week 16 and week 52 for patients only, including written questionnaires, a psychiatric and medical examination, blood, urine and saliva collection and a cycle ergometer test, to gather information about biological aging (telomere length and telomerase activity), mental health (depression and anxiety disorder characteristics), general fitness, metabolic stress-related biomarkers (inflammation, metabolic syndrome, cortisol) and genetic determinants. In addition, neurobiological alterations in brain processes will be assessed using structural and functional Magnetic Resonance Imaging (MRI) in a subsample of at least 25 patients per treatment arm and in all controls.

DISCUSSION

This intervention study aims to provide a better understanding of the impact of antidepressant medication and running therapy on biological aging, metabolic stress and neurobiological indicators in patients with depressive and anxiety disorders in order to guide a more personalized medicine treatment.

TRIAL REGISTRATION

Trialregister.nl Number of identification: NTR3460, May 2012.

Association between leukocyte telomere length and the risk of pancreatic cancer: Findings from a prospective study

INTRODUCTION

Telomeres and telomerase play important role in maintaining chromosome integrity and genomic stability. Recent epidemiologic data showed inconsistent findings which suggested that both short and long leukocyte telomeres could be associated with increased risk of pancreatic cancer. We prospectively examined the association between telomere length and pancreatic cancer risk in a population-based cohort study.

METHODS

The Singapore Chinese Health Study recruited 63,257 Chinese aged 45 to 74 years from 1993 to 1998 in Singapore. Relative telomere length in peripheral blood leukocytes was quantified using a validated monochrome multiplex quantitative polymerase chain reaction method in 26,540 participants, including 116 participants who later developed pancreatic cancer after an average of 13 years of follow-up. Cox proportional hazard regression method was used to calculate hazard ratio (HR) and its 95% confidence interval (CI) of pancreatic cancer risk associated with telomere length, with adjustment for confounding factors.

RESULTS

Longer telomeres were significantly associated with higher risk of pancreatic cancer (Ptrend = 0.02). Compared with lowest quartile, subjects with highest quartile of telomere length had an HR of 2.18 (95% CI: 1.25-3.80) for developing pancreatic cancer. In stratified analysis, this association remained among pancreatic adenocarcinoma patients but not among pancreatic non-adenocarcinoma patients. In continuous scale, the HRs and 95% CIs were 3.08 (1.17-8.11) for adenocarcinoma patients and 1.47 (0.43-5.06) for non-adenocarcinoma patients. The HRs and 95% CIs of the highest quartile of telomere length, compared with the lowest quartile, for adenocarcinoma and non-adenocarcinoma were 2.50 (1.22-5.13) and 1.63 (0.66-4.03), respectively. The length of follow-up from the collection of blood for the measurement of telomere length to the diagnosis of cancer (median = 8.0, range: from 5.0 months to 16.2 years) had no significant impact on the association between telomere length and pancreatic cancer risk.

CONCLUSIONS

The present study demonstrates that longer telomeres are associated with increased risk of overall pancreatic cancer.

Hazardous air pollutants and telomere length in the Sister Study

BACKGROUND

Telomeres are vital for genomic integrity and telomere length has been linked to many adverse health outcomes. Some hazardous air pollutants, or air toxics, increase oxidative stress and inflammation, two possible determinants of shortened telomere length. No studies have examined air toxic-telomere length associations in a non-occupational setting.

METHODS

This study included 731 Sister Study participants (enrolled 2003-2007) who were randomly selected to assess telomere length in baseline blood samples. Multiplex qPCR was used to determine telomere to single copy gene (T/S) ratios. Census tract concentration estimates of 29 air toxics from the 2005 National Air Toxics Assessment were linked to baseline residential addresses. Air toxics were classified into tertile-based categories of the exposure. Multivariable linear regression was used to estimate β coefficients and 95% confidence intervals (CI) in single pollutant models. Multipollutant groups were identified with regression trees.

RESULTS

The average T/S ratio was 1.24. Benzidine (T3vsT1 β= -0.08; 95% CI: -0.14, -0.01) and 1,4-dioxane (T3vsT1 β= -0.06; 95% CI: -0.13, 0.00) in particular, as well as carbon tetrachloride, chloroprene, ethylene dibromide, and propylene dichloride, were associated with shorter relative telomere length. Benzidine (p=0.02) and 1,4-dioxane (p=0.06) demonstrated some evidence of a monotonic trend. The regression tree identified age, BMI, physical activity, ethylene oxide, acrylonitrile, ethylidene dichloride, propylene dichloride, and styrene in multipollutant groups related to telomere length.

CONCLUSIONS

In this first study of air toxics and telomere length in a non-occupational setting, several air toxics, particularly 1,4-dioxane and benzidine, were associated with shorter relative telomere length.

Helicobacter pylori infection, serum pepsinogens as markers of atrophic gastritis, and leukocyte telomere length: a population-based study

Background

Persistent infections that induce prolonged inflammation might negatively affect the leukocyte telomere length (LTL); however, the role in LTL of Helicobacter pylori (H. pylori) infection, which persistently colonizes the stomach, remains unknown.

The study objective was to examine associations of sero-prevalence of H. pylori immunoglobulin G (IgG) antibody and serum pepsinogens (PGs), as markers of atrophic gastritis, with LTL.

A cross-sectional study was performed among 934 Arab residents of East Jerusalem, aged 27–78 years, randomly selected from Israel’s national population registry. Sera were tested for H. pylori IgG and PG levels by ELISA. LTL was measured by southern blots. Multiple linear regression models were fitted to adjust for sociodemographic and lifestyle factors.

Results

LTL decreased significantly with age (p < 0.001) and was shorter in men than women (p = 0.032). The mean LTL was longer in H. pylori sero-positive persons than negative ones: mean difference 0.13 kb (95% CI 0.02, 0.24), p = 0.016. Participants with atrophic gastritis (PGI < 30 μg/L or a PGI: PGII < 3.0) had shorter LTL than did those without: mean difference − 0.18 (95% CI − 0.32, − 0.04). The difference was of larger magnitude between persons who had past H. pylori infection (sero-negative to H. pylori IgG antibody) and atrophic gastritis, compared to those who were H. pylori sero-negative and did not have atrophic gastritis: mean difference − 0.32 kb (95% CI − 0.55, − 0.10). This association remained significant after adjustment for age, sex, and religiosity: beta coefficient − 0.21 kb (95% CI − 0.41, − 0.001), p = 0.049. The results were similar after further adjustment for lifestyle factors. In bivariate analysis, mean LTL was longer in physically active persons than non-active ones, and shorter in persons with than without obesity; however, these differences were diminished and were not significant in the multivariable model.

Conclusions

H. pylori IgG sero-positivity per se was not related to reduced LTL. However, persons with past H. pylori infection (i.e., lacking H. pylori IgG serum antibody) and with serological evidence of atrophic gastritis, had a significantly shorter LTL than did those without atrophic gastritis.

Electronic supplementary material

The online version of this article (10.1186/s40246-019-0217-3) contains supplementary material, which is available to authorized users.

How Does Obesity and Physical Activity Affect Aging?: Focused on Telomere as a Biomarker of Aging

Obesity is known to continuously increase systemic inflammation and oxidative stress, leading to shorter telomere length. However, research regarding the correlation between physical activity, exercise, obesity, and telomere length is not consistent. Therefore, this review aims to summarize the effects of obesity, physical activity, and exercise on telomere length. Our search for effects of obesity, physical activity, and exercise, on telomeres was conducted using three computerized databases: Medline, PubMed, and EBSCO. Keywords in the search were “physical activity, exercise and obesity,” “physical activity, exercise and telomere,” and “obesity and telomere.” Improving chronic inflammation and oxidative stress levels can prevent telomere attrition due to obesity. In addition, differences in the anti-aging effects of physical activity and exercise are shown in the post-middle-age period, when telomere length changes, rather than in past exercise habits. Maintaining high cardiorespiratory fitness levels through regular exercise and physical activity in the post-middle-age period minimizes obesity-related diseases and helps maintain telomere length, which is an index of cell senescence.

Telomeres, Telomerase and Ageing

Telomeres are specialised structures at the end of linear chromosomes. They consist of tandem repeats of the hexanucleotide sequence TTAGGG, as well as a protein complex called shelterin. Together, they form a protective loop structure against chromosome fusion and degradation. Shortening or damage to telomeres and opening of the loop induce an uncapped state that triggers a DNA damage response resulting in senescence or apoptosis.Average telomere length, usually measured in human blood lymphocytes, was thought to be a biomarker for ageing, survival and mortality. However, it becomes obvious that regulation of telomere length is very complex and involves multiple processes. For example, the "end replication problem" during DNA replication as well as oxidative stress are responsible for the shortening of telomeres. In contrast, telomerase activity can potentially counteract telomere shortening when it is able to access and interact with telomeres. However, while highly active during development and in cancer cells, the enzyme is down-regulated in most human somatic cells with a few exceptions such as human lymphocytes. In addition, telomeres can be transcribed, and the transcription products called TERRA are involved in telomere length regulation.Thus, telomere length and their integrity are regulated at many different levels, and we only start to understand this process under conditions of increased oxidative stress, inflammation and during diseases as well as the ageing process.This chapter aims to describe our current state of knowledge on telomeres and telomerase and their regulation in order to better understand their role for the ageing process.

Physical activity is not related to risk of early menopause in a large prospective study

STUDY QUESTION

Is physical activity associated with incident early menopause?

SUMMARY ANSWER

Physical activity is not associated with incident early menopause.

WHAT IS KNOWN ALREADY

Lifestyle factors such as physical activity may influence menopause timing, but results from prior research are inconsistent.

STUDY DESIGN, SIZE, DURATION

We evaluated the association between physical activity and the occurrence of early natural menopause in a prospective cohort study, the Nurses' Health Study II. Women were followed prospectively from 1989 to 2011.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Our analysis included 107 275 women who were premenopausal at baseline. Menopause status was self-reported biennially. Time per week participating in specific activities was reported approximately every 4 years and used to calculate metabolic task hours per week (MET h/week). We used Cox proportional hazards model to evaluate the association between physical activity and incidence of natural menopause before age 45 years while controlling for potential confounding factors.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 2 786 study members who experienced menopause before the age of 45. After adjustment for age, smoking and other factors, we observed no association between adulthood physical activity and early menopause. For example, compared to women reporting <3 MET h/week, the hazard ratio for women in the highest category (≥42 MET h/week) of cumulatively-averaged total physical activity was 0.89 (95% confidence interval: 0.76-1.04; P-trend: 0.26). Neither moderate nor strenuous activity in adolescence and young adulthood were related to risk. The relation of physical activity and early menopause did not vary across strata of body mass index or smoking status.

LIMITATIONS, REASONS FOR CAUTION

Physical activity and menopausal status were self-reported, but repeated assessment of physical activity and prospective report of menopause status likely reduce the potential for non-differential misclassification. While the majority of our study participants were white, it is unlikely that the physiological relation of activity and early menopause varies by ethnicity.

WIDER IMPLICATIONS OF THE FINDINGS

Findings from our large prospective study do not support an important association between physical activity and early menopause.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by UM1CA176726 and R01HD078517 from the National Institutes of Health, Department of Health and Human Services. No competing interests are declared.

TRIAL REGISTRATION NUMBER

N/A.

Relative Telomere Length in Blood Leukocytes of Patients with Anterior Cruciate Ligament Injury: A Pilot Study

Introduction: Anterior cruciate ligament (ACL) tear is the most common knee ligament injury, especially in athletes. The objective of this study was to investigate relative telomere length (RTL) in blood leukocytes of patients with ACL injury compared with that of controls.

Materials and Methods: A total of 187 subjects were invited to participate in this study. Ninety-two patients with clinically diagnosed ACL rupture were enrolled. Ninety-five age and gender-matched healthy controls were also recruited. Blood leukocyte RTL were analysed using quantitative real-time polymerase chain reaction.

Results: Patients with ACL rupture had significantly longer relative telomere length than healthy controls (P=0.002). The patients with ACL rupture were classified into two groups according to the sport history of patients which are contact sports and non-contact sports. RTL in patients with non-contact sports was significantly greater than those with contact sports (P=0.006). Moreover, RTL was inversely correlated with body mass index of patients with ACL injury (r=-0.34, P=0.001). Logistic regression analysis indicated that long RTL was associated with a higher risk of ACL rupture.

Conclusion: The present study showed that subjects with ACL rupture had significantly greater telomere length compared with their age and gender-matched controls. This finding may result from the increases in physical activity and overexpression of telomerase which acts as a protective mechanism against ACL injury. RTL in blood leukocytes is associated with a risk of ACL rupture.

Serum Level of Total Lipids and Telomere Length in the Male Population: A Cross-Sectional Study

Telomeres contain TTAGGG (T; Thymine, A; Adenine and G; Guanine) repetitive sequences and are placed at the end of human chromosomes. Telomere dysfunction is implicated in some age-related and chronic diseases, but its association with total serum lipids and obesity is unknown. Our objective was to determine influenced of total serum lipids on leukocyte telomere lengths (TLs). Participants were selected by cluster sampling from 22 districts of Tehran. The questionnaires were completed by 500 subjects and after the initial assessment in terms of lifestyle, nutrition, home, and job, 300 healthy people, aged 25-40 years were finally selected. TLs and serum level of total lipids were measured by quantitative real-time PCR and the Phillips method, respectively. The average telomere length (T/S) and total lipids were 1.05 ± 0.3 mg/dl and 643.3 ± 70.8 mg/dl, respectively. We found that a one unit difference in the following parameters were associated with kilo base pair differences in TL: Age -0.0002 (95% CI [-0.0022, -0.0018]), BMI -0.0019 (95% CI [-0.0003, -0.0034]), TC 0.0001 (95% CI [-0.0006, -0.0007]), TG -0.0010 (95% CI [-0.0015, -0.0004]), PL 0.0001 (95% CI [-0.0005, -0.0007]), and TSL -0.0003 (95% CI [-0.0008, 0.0001]). Spearman correlation analysis revealed an inverse relationship between TC (R = -0.53; 95% CI [-0.61, -0.44]), TG (R = -0.50; 95% CI [-0.58, -0.41]), PL (R = -0.46; 95% CI [-0.54-0.36]), and TSL (R = -0.63; 95% CI [-0.69, -0.56]) with T/S. Our research suggests that the inverse relationship was found between TL and weight, BMI, age, and TSL which were associated with obesity. High serum lipids concentration may be associated with systemic inflammation and atherosclerosis and may lead to oxidative stress, resulting in telomere shortening.

Sedentary time, metabolic abnormalities, and all-cause mortality after myocardial infarction: A mediation analysis

BACKGROUND

Sedentary time was associated with myocardial infarction (MI) and metabolic diseases in previous studies.

PURPOSE

To investigate whether sedentary time measured before disease onset was associated with all-cause mortality among MI survivors and whether the sedentary time-mortality association was mediated by physical activity status and metabolic phenotypes.

METHODS

In this prospective community-based cohort including 101,510 Chinese adults, we used sedentary time, evaluated at 2006 (baseline), to predict further all-cause mortality among individuals who then developed new onset MI from 2006 to December 2013 ( n = 989). The post-MI mortality was ascertained after the first non-fatal MI until December 2014. We assessed the mediating effects of physical inactivity and metabolic factors on the sedentary time-mortality association.

RESULTS

During 7 years follow up, 180 deaths occurred among these participants with incident MI. Prolonged sedentary time was associated with a higher risk of mortality among MI survivors. The adjusted hazard ratio (HR) of mortality for sedentary time 4-8 hours/day versus <4 hours/day, was 1.62 (95% confidence interval (CI) 1.14-2.31). A high amount of sedentary time (>4 hours/day) and inactive physical activity had an increased risk of all-cause mortality (HR: 2.74, 95% CI 1.34-5.60), relative to those with sedentary time ≤4 hours/day and moderate/vigorous physical activity. Physical inactivity and metabolic factors mediated a small proportion (≤9.2 % for all) of the total association between sedentary time and post-MI mortality.

CONCLUSION

High sedentary time was significantly associated with all-cause mortality among MI survivors, independent of physical activity status and metabolic abnormalities.

Diet Quality Indices and Leukocyte Telomere Length Among Healthy US Adults: Data From the National Health and Nutrition Examination Survey, 1999-2002

Aging is the biggest risk factor for the development of chronic diseases. Telomere length may represent one important mechanism by which dietary intake influences risk of age-related diseases; however, it is unknown which diet pattern is most strongly related to telomere length. We compared the relationships between 4 evidence-based diet quality indices and leukocyte telomere length in a nationally representative sample of healthy adults, and the extent to which these associations differed between men and women. Data on 4,758 adults aged 20-65 years with no prior diagnosis of major chronic disease were obtained from the 1999-2002 cycles of the National Health and Nutrition Examination Survey. Diet was assessed using one 24-hour dietary recall. After adjustment for sociodemographic and health characteristics, comparison of the top and bottom quintiles showed that higher Healthy Eating Index 2010 scores (β = 0.065, 95% confidence interval (CI): 0.018, 0.112; P-trend = 0.007), Alternate Healthy Eating Index 2010 scores (β = 0.054, 95% CI: 0.010, 0.097; P-trend = 0.007), Mediterranean Diet scores (β = 0.058, 95% CI: 0.017, 0.098; P-trend = 0.008), and Dietary Approaches to Stop Hypertension (DASH) scores (β = 0.052, 95% CI: 0.014, 0.090; P-trend = 0.007) were each associated with longer telomere length in women. These results may provide insight into the complex associations between optimal nutrition and longevity. Further investigation is needed to understand why associations were not observed in men.

Effect of a 12-month exercise intervention on leukocyte telomere length: Results from the ALPHA Trial

BACKGROUND

Short telomeres may indicate a higher risk of cancer and other chronic diseases. Some observational studies show positive associations between leukocyte telomere length (LTL) and physical activity levels. We hypothesized, therefore, that exercise may be one strategy for slowing telomere attrition.

METHODS

We conducted an ancillary analysis of blood from a year-long, two-centred, two-armed (1:1) randomized controlled trial of aerobic exercise versus usual inactivity. The analysis included 212 physically inactive, disease-free, non-smoking, postmenopausal women (n = 99 exercisers, n = 113 controls) in Alberta, Canada (2003-2006). The exercise prescription was aerobic exercise five days/week (supervised three days/week), 45 min/session, achieving 70-80% heart rate reserve. Baseline and 12-month LTL were analyzed using quantitative real-time polymerase chain reactions (qPCR). The primary statistical analysis was intention-to-treat, comparing the ratio of mean LTLs (12-months:baseline) for exercisers versus controls from a general linear model. Secondary analyses included a per-protocol analysis (≥90% adherence) and analyses stratified by baseline LTL, age, body mass index, and fitness level, respectively.

RESULTS

Participants were overweight at baseline (mean BMI = 29 kg/m²). The primary analysis showed no evidence that LTL change differed between groups (12-month mean LTL change for the exercise group: -13% (95% CI: -32%, 11%) versus controls: -8% (95%CI: -27%, 15%); treatment effect ratio (TER, Exercise/Control) = 0.95 (95% CI: 0.68, 1.32). Per-protocol results were similar (TER = 0.87, 95% CI: 0.59, 1.30). In stratified models, TERs ranged from 0.68 to 1.35 across strata and P-interaction > 0.05).

CONCLUSION

We found no evidence to suggest that one year of aerobic exercise alters telomere attrition significantly in healthy postmenopausal women.

Prospective association of depression and phobic anxiety with changes in telomere lengths over 11 years

BACKGROUND

Although depression and anxiety have been associated with shorter telomeres in cross-sectional studies, the data regarding the prospective relations of depression and anxiety to accelerated telomere length shortening are limited and findings are mixed. We prospectively examined relations of baseline depression and phobic anxiety to subsequent 11-year change in relative leukocyte telomere lengths (LTLs).

METHODS

We selected 1,250 women from a subcohort of the Nurses' Health Study who provided blood specimens at both blood collections (1989-1990 and 2000-2001). Depression was defined by self-reported regular antidepressant use or presence of severe depressive symptoms; anxiety symptoms were assessed using the Crown-Crisp Experiential Index. Using quantitative real-time polymerase chain reaction assay, LTLs were measured as the copy number ratio of telomere repeat to a single control gene. Changes in LTLs were defined in three ways: absolute change, symmetrized percent change, and decile shift.

RESULTS

Overall, there were no statistically significant associations of depression or phobic anxiety to subsequent 11-year LTL shortening, despite a point estimates in the direction of greater telomere shortening among participants with versus without depression, across all three metrics of telomere change. The strongest predictor of LTL change was baseline telomere length, and regression-to-the-mean was observed.

CONCLUSION

Baseline depression and phobic anxiety were not significantly associated with 11-year attrition in LTLs among 1,250 mid-life and older women. However, a suggestion of depression and greater subsequent LTL attrition, while not statistically significant, may warrant further inquiry, particularly in prospective studies with larger sample sizes and broader windows of the lifespan.

Prospective association between major depressive disorder and leukocyte telomere length over two years

BACKGROUND

Reduced leukocyte telomere length (LTL) has been found to be associated with multiple common age-related diseases, including heart disease, diabetes, and cancer. A link has also been suggested between shortened LTL and major depressive disorder (MDD), suggesting that MDD may be a disease of accelerated aging. This prospective, longitudinal study examined the association between depression diagnosis at baseline and change in LTL over two years in a well-characterized sample of N = 117 adults with or without MDD at baseline, using rigorous entry criteria.

METHODS

Participants aged 18-70 were assessed with validated instruments by trained, doctoral-level clinician raters at baseline and at two-year follow-up, and blood samples were obtained at both visits. LTL was assayed under identical methods using quantitative polymerase chain reaction (qPCR). The effect of an MDD diagnosis at baseline on change in LTL over two years was examined via hierarchical mixed models, which included potential confounders.

RESULTS

Individuals with MDD at baseline had greater LTL shortening over two years than individuals without MDD (p = 0.03), even after controlling for differences in age, sex, and body mass index (BMI). In the sub-sample of individuals with MDD diagnoses at baseline, no significant associations between LTL change and symptom severity or duration were found.

CONCLUSION

A baseline diagnosis of MDD prospectively predicted LTL shortening over two years. Our results provide further support for MDD as a disease associated with accelerated aging in a well-characterized sample using validated, clinician-rated measures.

Physical activity and telomere length: Impact of aging and potential mechanisms of action

Telomeres protect the integrity of information-carrying DNA by serving as caps on the terminal portions of chromosomes. Telomere length decreases with aging, and this contributes to cell senescence. Recent evidence supports that telomere length of leukocytes and skeletal muscle cells may be positively associated with healthy living and inversely correlated with the risk of several age-related diseases, including cancer, cardiovascular disease, obesity, diabetes, chronic pain, and stress. In observational studies, higher levels of physical activity or exercise are related to longer telomere lengths in various populations, and athletes tend to have longer telomere lengths than non-athletes. This relationship is particularly evident in older individuals, suggesting a role of physical activity in combating the typical age-induced decrements in telomere length. To date, a small number of exercise interventions have been executed to examine the potential influence of chronic exercise on telomere length, but these studies have not fully established such relationship. Several potential mechanisms through which physical activity or exercise could affect telomere length are discussed, including changes in telomerase activity, oxidative stress, inflammation, and decreased skeletal muscle satellite cell content. Future research is needed to mechanistically examine the effects of various modalities of exercise on telomere length in middle-aged and older adults, as well as in specific clinical populations.

State of the Science: Using Telomeres as Biomarkers During the First 1,000 Days of Life

Telomere biology shows promise as an integrative biomarker of exposures and increased occurrence of chronic disease and early mortality. This integrative review examined the state of the science regarding toxicokinetic risks and maternal factors in humans and in vivo models that are correlated with telomere length during the first 1,000 days of life. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses framework assisted in guiding this integrative by aiding researchers in identifying, selecting, and critically appraising the literature. Ovid MEDLINE, CINAHL, Cochrane Systematic Reviews, Web of Science, and SCOPUS databases were searched. The initial search yielded a total of 381 published articles. Full-text screening resulted in 19 articles retained for review (14 quasi-experimental studies and five experimental studies). Findings suggest a relationship between toxicokinetic exposures creating inflammation or oxidative stress (i.e., smoking) and maternal health conditions such as sleep apnea to shorter telomere length in children below 2 years old.

Leukocyte Telomere Length and Pancreatic Cancer Risk: Updated Epidemiologic Review

Many risk factors have been firmly established for pancreatic cancer (PC), but the molecular processes by which known risk factors influence susceptibility to PC are not clear. There has been a recent upsurge of interest in the role of telomere length (TL), the protective DNA sequence repeats at chromosome ends, in pancreatic carcinogenesis. Given this heightened interest, we performed an in-depth, focused, and up-to-date review of the epidemiological evidence linking leukocyte TL (LTL) with PC risk. We searched MEDLINE, Embase, and the Cochrane Library databases for all published studies on LTL and PC risk, up to May 2017. Five studies were identified for review: 4 nested case-control studies and 1 retrospective case-control study. Two studies found opposite associations between LTL and PC risk: 1 found a dose-response positive association and the other found a dose-response inverse association. Two studies also found a "U-shaped" association, whereas another reported a weak nonlinear relationship. We offer potential reasons for the conflicting findings including variation in study design, biospecimen characteristics, and differences in interlaboratory measurements of TL. Future studies should carefully control for risk factors of PC that are associated also with telomere attrition and investigate the role of genetic variation in TL maintenance.