Background: A strong association of serum 25-hydroxyvitamin-D levels (25(OH)D) with all-cause mortality has been shown previously and 25(OH)D could be a useful aging marker. Methods: The analysis was performed in a population-based, cohort study from Germany with 9,940 participants, aged 50-74 years at baseline. A general linear model was used to assess associations of 25(OH)D levels with chronological age and the aging markers leukocyte telomere length (LTL), epigenetic age acceleration, and 8-isoprostane levels. A multivariate Cox regression model was applied to explore the independent and combined associations of these biomarkers with all-cause mortality (2,204 deaths occurred during a median follow-up of 14.3 years). Results: On average, study participants lost 2.9 nmol/L 25(OH)D each 10 years of age. Increasing 25(OH)D levels were significantly associated with decreasing levels of 8-isoprostane levels but neither with LTL nor epigenetic age acceleration. The association of 25(OH)D quartiles with mortality was almost unchanged after adjusting for all aging markers (1.6-fold increased mortality in bottom quartile compared with top quartile). All aging markers were independent mortality predictors and subjects with unfavorable values for 4, 3, 2, and 1 aging marker(s) had 4.3-, 2.9-, 2.2, and 1.4-fold increased mortality, respectively. Conclusions: The 25(OH)D level can be regarded as an aging marker because it is linearly associated with age and an independent mortality predictor. Mechanisms linking vitamin D to healthy aging are unique and can neither be fully explained by aging of the epigenome, loss of telomeres, or antioxidative effects of vitamin D metabolites.

DNA methylation may play a critical role in aging and age-related diseases. DNA methylation phenotypic age (DNAmPhenoAge) is a new aging biomarker and predictor of chronic disease risk. While smoking is a strong risk factor for chronic diseases and influences methylation, its influence on DNAmPhenoAge is unknown. We investigated associations of self-reported and epigenetic smoking indicators with DNAmPhenoAge acceleration in a longitudinal aging study in eastern Massachusetts. DNA methylation was measured in whole blood samples from multiple visits for 692 male participants in the Veterans Affairs Normative Aging Study during 1999-2013. Acceleration was defined using residuals from linear regression of the DNAmPhenoAge on the chronological age. Cumulative smoking (pack-years) was significantly associated with DNAmPhenoAge acceleration, whereas self-reported smoking status was not. We observed significant validated associations between smoking-related loci and DNAmPhenoAge acceleration for 52 CpG sites, where 18 were hypomethylated and 34 were hypermethylated, mapped to 16 genes. The AHRR gene had the most loci (N = 8) among the 16 genes. We generated a smoking aging index based on these 52 loci, which showed positive significant associations with DNAmPhenoAge acceleration. These epigenetic biomarkers may help to predict age-related risks driven by smoking.

Oxidative stress (OS) has been found to be related to accelerated aging and many aging-related health outcomes. Recently, an epigenetic "mortality risk score" (MS) based on whole blood DNA methylation at 10 mortality-related CpG sites has been demonstrated to be associated with all-cause mortality. This study aimed to address the association between OS and MS, and to assess and compare their performance in the prediction of all-cause mortality. For 1448 participants aged 50-75 of the German ESTHER cohort study, the MS was derived from the DNA methylation profiles measured by Illumina HumanMethylation450K Beadchip and the levels of two urinary OS markers, 8-isoprostane (8-iso) and oxidized guanine/guanosine [including 8-hydroxy-2'-deoxyguanosine (8-oxo)], were measured by ELISA kits. Associations between OS markers and the MS were evaluated by linear and ordinal logistic regression models, and their associations with all-cause mortality were examined by Cox regression models. Both OS markers were associated with the MS at baseline. The 8-iso levels and MS, but not 8-oxo levels, were associated with all-cause mortality during a median follow-up of 15.1 years. Fully-adjusted hazard ratios (95% CI) were 1.56 (1.13-2.16) for the 4th quartile of 8-iso levels compared with the 1st, 1.71 (1.27-2.29) and 2.92 (2.03-4.18) for the moderate and high MS defined by 2-5 and > 5 CpG sites with aberrant methylation compared with a MS of 0-1, respectively. After controlling for 8-iso levels, the hazard ratios of MS remained essentially unchanged while the association of 8-iso levels with mortality was attenuated. This study demonstrates that OS is highly associated with the epigenetic MS, and the latter at the same time has a higher predictive value for all-cause mortality.

{BACKGROUND: Whole-body and thoracic ionizing radiation exposure are both associated with the development of renal dysfunction. However, whether low-level environmental radiation from air pollution affects renal function remains unknown. OBJECTIVES: We investigated the association of particle radioactivity (PR) with renal function defined by the estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) in the Normative Aging Study. METHODS: This longitudinal analysis included 2491 medical visits from 809 white males enrolled between 1999 and 2013. The eGFR was calculated using the CKD-EPI and MDRD equations, and CKD cases were identified as those with an eGFR <60mL/min/1.73m(2). Gross beta activity measured by five monitors of the U.S. Environmental Protection Agency's RadNet monitoring network was utilized to represent PR. RESULTS: Ambient PR levels from 1 to 28days prior to clinical visit demonstrated robust negative associations with both forms of eGFR, but not with the increased odds of CKD. An interquartile range higher 28-day average ambient PR level was significantly associated with 0.83-mL/min/1.73m(2) lower eGFR estimated by the CKD-EPI equation (95% confidence interval: -1.46, -0.20

BACKGROUND: A 'mortality risk score' (MS) based on ten prominent mortality-related cytosine-phosphate-guanine (CpG) sites was previously associated with all-cause mortality, but has not been verified externally. We aimed to validate the association of MS with mortality and to compare MS with three aging biomarkers: telomere length (TL), DNA methylation age (DNAmAge) and phenotypic age (DNAmPhenoAge) to explore whether MS can serve as a reliable measure of biological aging and mortality. METHODS: Among 534 males aged 55-85 years from the US Normative Aging Study, the MS, DNAmAge and DNAmPhenoAge were derived from blood DNA methylation profiles from the Illumina HumanMethylation450 BeadChip, and TL was measured by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: A total of 147 participants died during a median follow-up of 9.4 years. The MS showed strong associations with all-cause, cardiovascular disease (CVD) and cancer mortality. After controlling for all potential covariates, participants with high MS (>5 CpG sites with aberrant methylation) had almost 4-fold all-cause mortality (hazard ratio: 3.84, 95% confidence interval: 1.92-7.67) compared with participants with a low MS (0-1 CpG site with aberrant methylation). Similar patterns were observed with respect to CVD and cancer mortality. MS was associated with TL and DNAmPhenoAge acceleration but not with DNAmAge acceleration. Although the MS and DNAmPhenoAge acceleration were independently associated with all-cause mortality, the former exhibited a higher predictive accuracy of mortality than the latter. CONCLUSIONS: MS has the potential to be a prominent predictor of mortality that could enhance survival prediction in clinical settings.

BACKGROUND: Exploring the associations of air pollution and weather variables with blood leukocyte distribution is critical to understand the impacts of environmental exposures on the human immune system. OBJECTIVES: As previous analyses have been mainly based on data from cell counters, which might not be feasible in epidemiologic studies including large populations of long-stored blood samples, we aimed to expand the understanding of this topic by employing the leukocyte distribution estimated by DNA methylation profiles. METHODS: We measured DNA methylation profiles in blood samples using Illumina HumanMethylation450 BeadChip from 1519 visits of 774 Caucasian males participating in the Normative Aging Study. Leukocyte distribution was estimated using Houseman's and Horvath's algorithms. Data on air pollution exposure, temperature, and relative humidity within 28days before each blood draw was obtained. RESULTS: After fully adjusting for potential covariates, PM2.5, black carbon, particle number, carbon monoxide, nitrogen dioxide, sulfur dioxide, temperature, and relative humidity were associated with the proportions of at least one subtype of leukocytes. Particularly, an interquartile range-higher 28-day average exposure of PM2.5 was associated with 0.147-, 0.054- and 0.101-unit lower proportions (z-scored) of plasma cells, naive CD8+ T cells, and natural killers, respectively, and 0.059- and 0.161-unit higher proportions (z-scored) of naive CD4+ T cells and CD8+ T cells, respectively. CONCLUSIONS: Our study suggests that short-term air pollution exposure, temperature, and relative humidity are associated with leukocyte distribution. Our study further provides a successful attempt to use epigenetic patterns to assess the influences of environmental exposures on human immune profiles.