Age‐related DNA damage is regarded as one of the possible explanations of aging. Although a generalized idea about the accumulation of DNA damage with age exists, results found in the literature are inconsistent. To better understand the question of age‐related DNA damage in humans and to identify possible moderator variables, a metaanalysis was conducted. Electronic databases and bibliographies for studies published since 2004 were searched. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for age‐related DNA damage were calculated in a random‐effects model. A total of 76 correlations from 36 studies with 4676 participants were included. Based on our analysis, a correlation between age and DNA damage was found (r=0.230, p=0.000; 95% confidence interval=0.111‐0.342). The test for heterogeneity of variance indicates that the study´s results are significantly high (Q (75)=1754.831, p=0.000). Moderator variables such as smoking habits, technique used, and the tissue/sample analyzed, are shown to influence age‐related DNA damage (p=0.026; p=0.000; p=0.000, respectively). Nevertheless, sex did not show any influence on this relation (p=0.114). In conclusion, this meta‐analysis showed an association between age and DNA damage in humans. It was also found that smoking habits, the technique used, and tissue/sample analyzed, are important moderator variables in age‐related DNA damage.

Ginkgo biloba L. leaf extracts and herbal infusions are used worldwide due to the health benefits that are attributed to its use, including anti-neoplastic, anti-aging, neuro-protection, antioxidant and others. The aim of this study was to evaluate the effect of an aqueous Ginkgo biloba extract on HepG2 cell viability, genotoxicity and DNA protection against paraquat-induced oxidative damage. Exposure to paraquat (PQ), over 24 h incubation at 1.0 and 1.5 µM, did not significantly reduce cell viability but induced concentration and time-dependent oxidative DNA damage. Ginkgo biloba leaf extract produced dose-dependent cytotoxicity (IC₅₀ = 540.8 ± 40.5 µg/mL at 24 h exposure), and short incubations (1 h) produced basal and oxidative DNA damage (>750 and 1500 µg/mL, respectively). However, lower concentrations (e.g., 75 µg/mL) of Ginkgo biloba leaf extract were not cytotoxic and reduced basal DNA damage, indicating a protective effect at incubations up to 4 h. On the other hand, longer incubations (24 h) induced oxidative DNA damage. Co-incubation of HepG2 cells for 4 h, with G. biloba leaf extract (75 µg/mL) and PQ (1.0 or 1.5 µM) significantly reduced PQ-induced oxidative DNA damage. In conclusion, the consumption of Ginkgo biloba leaf extract for long periods at high doses/concentrations is potentially toxic; however, low doses protect the cells against basal oxidative damage and against environmentally derived toxicants that induce oxidative DNA damage.

The use of preclinical models to investigate antitumor effects of exercise on breast tumor (BT) development and progression are critical. However, published results have not been quantitatively summarized or examined for potential exercise-moderating variables. We conducted this review to summarize and quantify the effect-size of exercise on BT outcomes in preclinical studies. A literature search was performed in MEDLINE, PubMed, Web of Science and System for Information on Grey Literature in Europe (SIGLE) databases. Risk of bias was assessed using SYRCLE’s RoB tool. A total of 116 correlations were performed to analyze 28 preclinical studies published through December 2016, which included 2,085 animals and 51 exercise programs. Positive effects of small, medium and large magnitude were observed in tumor incidence, growth and multiplicity, respectively. In the tumor microenvironment, positive effects of large magnitude were also observed in proliferation and apoptosis but not in angiogenesis. Moderator variables correlated with higher intervention effects were identified along with a considerable heterogeneity in exercise protocols that precluded us from clearly perceiving the benefits of exercise exposure. In conclusion, exercise performed under specific conditions benefits BT outcomes. Preclinical studies with exercise designs mimicking exercise exposure that can be used in clinical contexts are needed.