Telomere length and epigenetic clocks as markers of cellular aging: a comparative study.

Telomere length (TL) and DNA methylation-based epigenetic clocks are markers of biological age, but the relationship between the two is not fully understood. Here, we used multivariable regression models to evaluate the relationships between leukocyte TL (LTL; measured by qPCR [n = 635] or flow FISH [n = 144]) and five epigenetic clocks (Hannum, DNAmAge pan-tissue, PhenoAge, SkinBlood, or GrimAge clocks), or their epigenetic age acceleration measures in healthy adults (age 19-61 years). LTL showed statistically significant negative correlations with all clocks (qPCR: r = - 0.26 to - 0.32; flow FISH: r = - 0.34 to - 0.49; p < 0.001 for all). Yet, models adjusted for age, sex, and race revealed significant associations between three of five clocks (PhenoAge, GrimAge, and Hannum clocks) and LTL by flow FISH (p < 0.01 for all) or qPCR (p < 0.001 for all). Significant associations between age acceleration measures for the same three clocks and qPCR or flow FISH TL were also found (p < 0.01 for all). Additionally, LTL (by qPCR or flow FISH) showed significant associations with extrinsic epigenetic age acceleration (EEAA: p < 0.0001 for both), but not intrinsic epigenetic age acceleration (IEAA; p > 0.05 for both). In conclusion, the relationships between LTL and epigenetic clocks were limited to clocks reflecting phenotypic age. The observed association between LTL and EEAA reflects the ability of both measures to detect immunosenescence. The observed modest correlations between LTL and epigenetic clocks highlight a possible benefit from incorporating both measures in understanding disease etiology and prognosis.

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.

Cardiac Rehabilitation Programs for Cancer Survivors: A Scoping Review.

PURPOSE OF REVIEW: Participation in cardiac rehabilitation is associated with improved quality of life and physical functioning and may be an effective strategy to assist in the recovery from cancer. We conducted a scoping review to identify studies that enrolled cancer survivors into cardiac rehabilitation programs. RECENT FINDINGS: We identified nine studies that included 662 cancer survivors. Five studies integrated cancer survivors and cardiac patients into the same sessions, three studies developed cancer-only rehabilitation sessions, and one study did not report details on the rehabilitation sessions. On average, more than 60% of enrolled cancer survivors completed the rehabilitation programs and many health and psychosocial outcomes improved after rehabilitation. SUMMARY: Cardiac rehabilitation appears to be acceptable and favorably impacts many health and psychosocial outcomes among cancer survivors. Future research should consider randomized controlled trial study designs, enrolling diverse survivor populations, and using a set of core physical function and psychosocial outcomes.

Strategies to Promote Physical Activity During Pregnancy: A Systematic Review of Intervention Evidence.

Physical activity during pregnancy has been associated with significant health benefits, however most women in the United States do not meet current guidelines. This systematic review evaluates evidence for interventions to improve physical activity during pregnancy in order to identify best practices and inform future research. Electronic databases (PubMed, CINAHL, SportDISCUS, Embase, ERIC, Psych Info and ISI Web of Science) were searched in July 2011 for peer-reviewed journal articles. Studies were included if they were English-language randomized control trials that measured the efficacy of an intervention targeted to pregnant women and designed to change physical activity as a primary or secondary outcome. Out of 777 studies identified through the systematic search, nine interventions were identified for inclusion by multiple reviewers. Data was abstracted using an abstraction form modeled after the "Guide to Community Preventive Services." Of the nine interventions included in the review, three reported statistically significant positive results for physical activity. While interventions included a variety of strategies and techniques, none were uniquely associated with positive outcomes. Overall this review suggests that little is known about the efficacy of interventions for physical activity during pregnancy. We provide several recommendations for future research and intervention design.

Review of self-reported physical activity assessments for pregnancy: summary of the evidence for validity and reliability.

BACKGROUND: Epidemiological studies and surveillance systems of pregnant women often rely on collection of physical activity through self-report. This systematic review identified and summarised self-reported physical activity assessments with evidence for validity and reliability among pregnant women. METHODS: Peer-reviewed articles published through 2011 were included if they assessed validity and/or reliability of an interviewer- or self-administered physical activity questionnaire or diary among pregnant women. RESULTS: We identified 15 studies, including 12 studies that assessed questionnaires and 4 studies that assessed diaries, conducted in Australia, Finland, Norway, the U.K., the U.S. and Vietnam. For questionnaires, 92% (11/12) assessed mode, all assessed frequency and/or duration and 58% (7/12) collected information on perceived intensity. All but one study (92%) assessed validity of the questionnaires. Questionnaires compared with objective measures (accelerometers, pedometers) ranged from slight to fair agreement, while comparison with other self-reported measures ranged from substantial to almost perfect agreement. Five studies (42%) assessed test-retest reliability of the questionnaires, ranging from substantial to almost perfect agreement. The four studies on diaries were all assessed for validity against objective measures, ranging from slight to substantial agreement. CONCLUSIONS: Selection of valid and reliable physical activity measures that collect information on dose (type, frequency, duration, intensity) is recommended to increase precision and accuracy in detecting associations of physical activity with maternal and fetal outcomes.