Short-Term Exposure of PM2.5 and Epigenetic Aging: A Quasi-Experimental Study

Chemical and climatic environmental exposures and epigenetic aging: A systematic review

Epigenetic aging biomarkers are used for evaluating morbidity and mortality, monitoring therapies, and direct-to-consumer testing. However, the influence of environmental exposures on epigenetic age acceleration (EAA), also known as epigenetic age deviation, has not been systematically evaluated. In this systematic review, we synthesized findings from human epidemiologic studies on chemical and climatic environmental exposures, particularly air pollution, chemicals, metals, climate, and cigarette smoke, and EAA. A total of 102 studies analyzing epigenetic data from over 180,000 subjects were evaluated. Overall, studies in each exposure category frequently included adult participants, used a variety of epigenetic clocks, analyzed whole blood samples, and had a low risk of bias. Exposure to air pollution (15/19 of studies; 79%), cigarette smoke (53/66; 80%), and synthetic and occupational chemicals (5/8; 63%) were notably associated with increased EAA. Results for essential and non-essential metal exposure were more equivocal: 7/13 studies (54%) reported increased EAA. One study reported increased EAA with greater temperature exposure. In summary, we identified environmental exposures, such as air pollution and cigarette smoke, that were strongly associated with increased EAA. Further research is needed with larger and more diverse samples and high-quality exposure assessment.

Prolonged Exposure to Environmental Levels of Haloacetamides Exacerbates Cellular Senescence: Phenotypic and Mechanistic Insights

Disinfection byproducts (DBPs), such as haloacetamides (HAMs), have been associated with adverse health outcomes, including bladder cancer. The potential for DBPs to exacerbate cellular senescence, thereby linking exposure to health impacts, remains underexplored. In this study, MRC-5 cells were exposed to HAMs at concentrations of 2, 5, and 8 μg/L for 30 days to simulate long-term exposure to levels found in drinking water. All six tested HAMs significantly increased the cellular senescence degree and enriched the cellular senescence pathway at the proteomic-wide level. Specifically, HAMs upregulated microRNA-24 expression, which increased p16 mRNA levels and decreased p16 protein levels, thereby activating oncogene-induced senescence pathways. Additionally, HAMs were found to covalently bind to TNRC6A, activating the p53/p21 pathway. Principal component analysis highlighted the critical role of functional groups in activating senescence, and the interaction between HAMs and TNRC6A could extend to at least 27 other amide-containing DBPs. Prolonged exposure to HAMs at environmentally relevant levels notably exacerbates cellular senescence, shedding light on a commonly overlooked phenomenon. Given the widespread presence of DBPs in drinking water and their continuous exposure in humans, their role in cellular senescence represents an ongoing public health concern.

Early-life smoking, cardiovascular disease risk, and the mediating role of DNA methylation biomarkers of aging

BACKGROUND

Early-life smoking is linked to biological aging and chronic diseases, yet its specific relationship with cardiovascular disease (CVD) risk and the role of DNA methylation biomarkers of aging as potential mediators of that relationship remain underexplored.

METHODS

In this study, we analyzed data from 2345 participants in the National Health and Nutrition Examination Survey (NHANES; 1999-2002). Early-life smoking status was assessed on the basis of the age of smoking initiation (ASI) and categorized into three smoking initiation periods (SIPs): childhood (5-14 years), adolescence/adulthood (> 14 years), and never smoked. DNA methylation biomarkers of aging (DNAm PhenoAge, DunedinPoAm, HorvathTelo) were measured, and CVD outcomes were determined via self-reported, physician-confirmed diagnoses. Multivariate logistic regression and causal mediation analyses were performed to assess the associations between SIP and CVD outcomes and explore the mediating effects of DNA methylation biomarkers on those associations.

RESULTS

Earlier smoking initiation was more strongly associated with an increased risk of developing CVD, with childhood smoking showing the highest risk (OR = 1.95, 95% CI: 1.15-3.29; P = 0.013). Furthermore, DNA methylation biomarkers of aging were independently associated with increased CVD risk (1-year increase in DNAm PhenoAge: OR = 1.03, 95% CI: 1.01-1.05, P < 0.001; 0.1-unit increase in DunedinPoAm: OR = 1.19, 95% CI: 1.00-1.40, P < 0.05; 1-kb increase in HorvathTelo: OR = 0.57, 95% CI: 0.34-0.96, P < 0.05). Subgroup analysis revealed that the association between early-life smoking status and the risk of developing CVD was stronger among individuals without household smoking exposure (P for interaction = 0.035). Moreover, compared with early-life smoking status, later smoking initiation status was correlated with delayed epigenetic aging, as indicated by lower DNAm PhenoAge (β=-0.02, 95% CI: -0.03--0.01, P < 0.01), slower DunedinPoAm (β=-0.01, 95% CI: -0.01--0.01, P < 0.001), and longer HorvathTelo (β = 0.01, 95% CI: 0.01-0.01, P < 0.001). Mediation analysis revealed that DNAm PhenoAge significantly mediated the relationship between early-life smoking status and CVD risk, accounting for 6% of the total effect (ASI: ACME=-0.000100, P = 0.010; SIP: ACME = 0.004796, P = 0.022).

CONCLUSION

Early-life smoking status is associated with significantly increased CVD risk. DNAm PhenoAge partially mediates this relationship, suggesting its potential as a target for prevention. Moreover, these findings highlight the need for early smoking prevention to reduce CVD risk.

Beyond the outdoors: indoor air quality guidelines and standards - challenges, inequalities, and the path forward

In the last few decades, indoor air quality (IAQ) has become a major threat to public health. It is the fifth leading cause of premature death globally. It has been estimated that people spend ∼90 % of their time in an indoor environment. Consequently, IAQ has significant health effects. Although IAQ-related standards and guidelines, policies, and monitoring plans have been developed in a few countries, there remain several global inequalities and challenges. This review paper aims to comprehensively synthesize the current status of widely accepted IAQ guidelines and standards. It analyzes their global implementation and effectiveness to offer insights into challenges and disparities in IAQ policies and practices. However, the complexity of domestic environments and the diversity of international standards impede effective implementation. This manuscript evaluates international, national, and regional IAQ guidelines, emphasizing similarities and differences. In addition, it highlights knowledge gaps and challenges, urging the international scientific community, policymakers, and stakeholders to collaborate to advance IAQ standards and guidelines. The analysis evaluates the efficacy of guidelines, identifies deficiencies, and offers recommendations for the future of domestic air quality standards.

Pollutant emissions and environmental advantages of heating peanut oil by using commercial induction cooktop: A comparative analysis with traditional natural gas stoves

Commercial induction cooktops are increasingly gaining popularity in residential households and business restaurants. However, little is known about the specific environmental benefits of induction cooking compared to conventional gas cooking. This study used two heating methods to heat peanut oil to achieve the same heating effect, and compared particulate matter, volatile organic compounds (VOCs), ozone precursors, and total carbon emissions generated during the heating process using various detection devices. Utilising an induction cooktop will result in a 27.3% reduction in the overall emission of VOC after 15 min of heating, indicating that using an induction cooktop has an advantage in terms of ozone formation potential, cutting OFPs by 23.6%. Using induction cooktops also reduces 26.8% in PM2.5 emissions, 63.3% in CH4 emissions, 100% in CO2 direct emissions, and 94.4% in CO emissions, owing to the varied heating techniques employed. Considering indirect emissions, such as energy usage, the utilization of induction cooktops will reduce total carbon emissions by an equivalent of 11.4%. The reasons for these advantages are partly due to the additional COX and CH4 generated by natural gas combustion, and on the other hand, the concentration and particle size differences of particulate matter may be due to the fact that compared to natural gas stoves, induction cooktops have a more uniform and concentrated heat utilization rate, resulting in lower ambient temperatures around the pot and suppressing the production of some pollutants. These findings suggest that replacing conventional natural gas stoves with commercial induction cooktops has significant advantages in terms of reduction of gaseous pollutant emissions as well as environmental impacts such as carbon neutrality.

Accelerated aging as a mediator of the association between co-exposure to multiple air pollutants and risk of chronic kidney disease

BACKGROUND

The association between co-exposure to multiple air pollutants and the occurrence of chronic kidney disease (CKD) was not well-established, and the mediating role of accelerated aging in this association remained uncertain.

METHODS

Using a cohort of 313,908 participants without CKD at baseline from the UK Biobank, we examined the potential association between co-exposure to multiple air pollutants, including PM2.5, PM10, PM2.5-10, NO2 and NOx, and the incidence of CKD by calculating an air pollution score. Mediation analyses were performed to examine the mediating role of accelerated aging (PhenoAgeAccel or KDM-BioAgeAccel) in this association.

RESULTS

During the median follow-up time of 12.9 years, 11,117 participants developed CKD. The results showed that per interquartile range (IQR) increment in air pollution score led to an approximately 9.0 % (6.6-11.4 %) elevated risk of occurring CKD. Compared to the first quartile (Q1) of air pollution score, those in the highest quartile (Q4) had a 21.2 % (14.8-27.9 %) higher risk of developing CKD (Ptrend<0.001). Mediation analyses suggested that PhenoAgeAccel and KDM-BioAgeAccel significantly mediated 1.5 % and 5.7 % of the association between air pollution score and incident CKD, respectively.

CONCLUSION

Co-exposure to multiple air pollutants could increase the risk of developing CKD, with accelerated aging serving as a partial mechanism in the relationship between air pollution and CKD. These findings highlight the importance of reducing air pollution, and suggest a possible mechanism from air pollution to CKD through accelerated aging.

Association between wildfire-related PM2.5 and epigenetic aging: A twin and family study in Australia

Wildfire-related PM2.5 has been associated with various adverse health outcomes, but its association with epigenetic aging remains unclear. This study examined the association between wildfire-related PM2.5 exposure and epigenetic aging using DNA methylation data from a twin and family study. With a within-sibship analysis, we found that each 1 µg/m3 increase in annual wildfire-related PM2.5 was associated with a 0.25-year (95 % CI: 0.04, 0.47) increase in GrimAge1 acceleration and a 0.36-year (95 % CI: 0.12, 0.59) increase in GrimAge2 acceleration. Subgroup analyses found that participants aged ≥ 60 years, those with a history of current or former smoking and alcohol consumption, and those living in rural regions exhibited more pronounced epigenetic age acceleration. These findings suggest that wildfire smoke could accelerate biological aging, particularly in vulnerable populations, posing a significant challenge to healthy aging.

Exploring the progress and challenges of ultrasonic technology in environmental remediation

Amidst escalating environmental pollution due to accelerated industrialization and urbanization, there is an acute demand for effective and sustainable environmental remediation strategies. Ultrasonic technology, recognized for its green and efficient characteristics, has gained significant prominence in mitigating environmental pollution in aquatic, soil, and atmospheric ecosystems. The review provides a comprehensive analysis of the role of ultrasonic treatment in wastewater treatment, air quality improvement, and soil remediation. We systematically evaluate existing research to assess the effectiveness of ultrasonic technology in degrading pollutants and its potential for large-scale deployment. The review also examines the challenges associated with ultrasonic remediation, including optimizing operational parameters, enhancing energy transfer efficiency, and understanding the unique degradation mechanisms for various pollutants. Furthermore, we discuss environmental and safety considerations, along with the economic implications related to equipment costs and energy consumption. This review aims to contribute to the advancement of ultrasonic technology in environmental remediation by presenting a forward-looking perspective, aligning with the goals of environmental protection and sustainable development.

Moderate BMI accumulation modified associations between blood benzene, toluene, ethylbenzene and xylene (BTEX) and phenotypic aging: mediating roles of inflammation and oxidative stress

The associations between blood benzene, toluene, ethylbenzene, and xylenes (BTEX) and biological aging among general adults remain elusive. The present study comprised 5780 participants from the National Health and Nutrition Examination Survey 1999-2010. A novel measure of biological aging, phenotypic age acceleration (PhenoAge.Accel), derived from biochemical markers was calculated. Weighted generalized linear regression and weighted quantile sum regression (WQS) were utilized to assess the associations between BTEX components and mixed exposure, and PhenoAge.Accel. The mediating roles of systemic immune-inflammation index (SII) and oxidative stress indicators (serum bilirubin and gamma-glutamyl transferase), along with the modifying effects of body mass index (BMI) were also examined. In the single-exposure model, the highest quantile of blood benzene (b = 0.89, 95%CI: 0.58 to 1.20), toluene (b = 0.87, 95%CI: 0.52 to 1.20), and ethylbenzene (b = 0.80, 95%CI: 0.46 to 1.10) was positively associated with PhenoAge.Accel compared to quantile 1. Mixed-exposure analyses revealed a consistent positive association between BTEX mixed exposure and PhenoAge.Accel (b = 0.88, 95%CI: 0.56 to 1.20), primarily driven by benzene (92.78%). The association between BTEX and PhenoAge.Accel was found to be partially mediated by inflammation and oxidative stress indicators (ranging from 3.2% to 13.7%). Additionally, BMI negatively modified the association between BTEX mixed exposure and PhenoAge.Accel, with a threshold identified at 36.2 kg/m^2. Furthermore, BMI negatively moderated the direct effect of BTEX mixed exposure on PhenoAge.Accel in moderated mediation models, while positively modified the link between SII and PhenoAge.Accel in the indirect path (binteraction = 0.04, 95%CI: 0.01 to 0.06). Overall, BTEX mixed exposure was associated with PhenoAge.Accel among US adults, with benzene may have reported most contribution, and inflammation and oxidative damage processes may partially explain this underlying mechanism. The study also highlighted the potential benefits of appropriate BMI increased. Additional large-scale cohort studies and experiments were necessary to substantiate these findings.

Particulate matter 2.5 accelerates aging: Exploring cellular senescence and age-related diseases

Exposure to Particulate matter 2.5 (PM2.5) accelerates aging, causing declines in tissue and organ function, and leading to diseases such as cardiovascular, neurodegenerative, and musculoskeletal disorders. PM2.5 is a major environmental pollutant and an exogenous pathogen in air pollution that is now recognized as an accelerator of human aging and a predisposing factor for several age-related diseases. In this paper, we seek to elucidate the mechanisms by which PM2.5 induces cellular senescence, such as genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, and mitochondrial dysfunction, and age-related diseases. Our goal is to increase awareness among researchers within the field of the toxicity of environmental pollutants and to advocate for personal and public health initiatives to curb their production and enhance population protection. Through these endeavors, we aim to promote longevity and health in older adults.

Bronchial cell epigenetic aging in a human experimental study of short-term diesel and ozone exposures

Blood-based, observational, and cross-sectional epidemiological studies suggest that air pollutant exposures alter biological aging. In a single-blinded randomized crossover human experiment of 17 volunteers, we examined the effect of randomized 2-h controlled air pollution exposures on respiratory tissue epigenetic aging. Bronchial epithelial cell DNA methylation 24 h post-exposure was measured using the HumanMethylation450K BeadChip, and there was a minimum 2-week washout period between exposures. All 17 volunteers were exposed to ozone, but only 13 were exposed to diesel exhaust. Horvath DNAmAge [Pearson coefficient (r) = 0.64; median absolute error (MAE) = 2.7 years], GrimAge (r = 0.81; MAE = 13 years), and DNAm Telomere Length (DNAmTL) (r = -0.65) were strongly correlated with chronological age in this tissue. Compared to clean air, ozone exposure was associated with longer DNAmTL (median difference 0.11 kb, Fisher's exact P-value = .036). This randomized trial suggests a weak relationship of ozone exposure with DNAmTL in target respiratory cells. Still, causal relationships with long-term exposures need to be evaluated.

Epigenetic Aging and Racialized, Economic, and Environmental Injustice: NIMHD Social Epigenomics Program

Importance

Epigenetic age acceleration is associated with exposure to social and economic adversity and may increase the risk of premature morbidity and mortality. However, no studies have included measures of structural racism, and few have compared estimates within or across the first and second generation of epigenetic clocks.

Objective

To determine whether epigenetic age acceleration is positively associated with exposures to diverse measures of racialized, economic, and environmental injustice measured at different levels and time periods.

Design, Setting, and Participants

This cross-sectional study used data from the My Body My Story (MBMS) study between August 8, 2008, and December 31, 2010, and examination 5 of the Multi-Ethnic Atherosclerosis Study (MESA) from April 1, 2010, to February 29, 2012. In the MBMS, DNA extraction was performed in 2021; linkage of structural measures to the MBMS and MESA, in 2022. US-born individuals were randomly selected from 4 community health centers in Boston, Massachusetts (MBMS), and 4 field sites in Baltimore, Maryland; Forsyth County, North Carolina; New York City, New York; and St Paul, Minnesota (MESA). Data were analyzed from November 13, 2021, to August 31, 2023.

Main Outcomes and Measures

Ten epigenetic clocks (6 first-generation and 4 second-generation), computed using DNA methylation data (DNAm) from blood spots (MBMS) and purified monocytes (MESA).

Results

The US-born study population included 293 MBMS participants (109 men [37.2%], 184 women [62.8%]; mean [SD] age, 49.0 [8.0] years) with 224 Black non-Hispanic and 69 White non-Hispanic participants and 975 MESA participants (492 men [50.5%], 483 women [49.5%]; mean [SD] age, 70.0 [9.3] years) with 229 Black non-Hispanic, 191 Hispanic, and 555 White non-Hispanic participants. Of these, 140 (11.0%) exhibited accelerated aging for all 5 clocks whose estimates are interpretable on the age (years) scale. Among Black non-Hispanic MBMS participants, epigenetic age acceleration was associated with being born in a Jim Crow state by 0.14 (95% CI, 0.003-0.27) SDs and with birth state conservatism by 0.06 (95% CI, 0.01-0.12) SDs, pooling across all clocks. Low parental educational level was associated with epigenetic age acceleration, pooling across all clocks, for both Black non-Hispanic (0.24 [95% CI, 0.08-0.39] SDs) and White non-Hispanic (0.27 [95% CI, 0.03-0.51] SDs) MBMS participants. Adult impoverishment was positively associated with the pooled second-generation clocks among the MESA participants (Black non-Hispanic, 0.06 [95% CI, 0.01-0.12] SDs; Hispanic, 0.07 [95% CI, 0.01-0.14] SDs; White non-Hispanic, 0.05 [95% CI, 0.01-0.08] SDs).

Conclusions and Relevance

The findings of this cross-sectional study of MBMS and MESA participants suggest that epigenetic age acceleration was associated with racialized and economic injustice, potentially contributing to well-documented inequities in premature mortality. Future research should test the hypothesis that epigenetic accelerated aging may be one of the biological mechanisms underlying the well-documented elevated risk of premature morbidity and mortality among social groups subjected to racialized and economic injustice.

Short-Term PM2.5 Exposure and DNA Methylation Changes of Circadian Rhythm Genes: Evidence from Two Experimental Studies

The circadian rhythm regulates many crucial physiological processes, impacting human aging and aging-related outcomes. Observational evidence links circadian rhythm disturbance to PM2.5 exposure, yet the underlying DNA methylation mechanisms remain unclear due to limited PM2.5-dominated experimental settings. Therefore, we investigated the associations between short-term PM2.5 exposure and DNA methylation changes of 1188 CpG candidates across circadian genes among 32 young adults in the FDU study, with the validation in 26 individuals from the PKU study. Further mediation analyses tested whether DNA methylation of circadian genes could mediate the influence of PM2.5 on aging measured by three epigenetic ages: DNAmGrimAge, DunedinPoAm, and the mortality risk score. We identified three CpG sites associated with personal PM2.5 exposure: cg01248361 (CSNK2A2), cg17728065 (RORA), and cg22513396 (PRKAG2). Acute effects of PM2.5 on the three loci could be mediated by several circulating biomarkers, including MDA and EGF, with up to ∼30% of mediated proportions. Three loci further showed varying potentials in mediating the aging acceleration effect of PM2.5. Locus cg17728065 is the key site exhibiting a robust mediating effect (7.54-12.52%) on PM2.5-induced aging acceleration. Our findings demonstrated that PM2.5, even short-term peaks, could leave imprints on human aging via inducing aberrant temporal fluctuation in circadian homeostasis captured by DNA methylation profiles.

Air pollution exposure, accelerated biological aging, and increased thyroid dysfunction risk: Evidence from a nationwide prospective study

BACKGROUND

Long-term air pollution exposure is a major health concern, yet its associations with thyroid dysfunction (hyperthyroidism and hypothyroidism) and biological aging remain unclear. We aimed to determine the association of long-term air pollution exposure with thyroid dysfunction and to investigate the potential roles of biological aging.

METHODS

A prospective cohort study was conducted on 432,340 participants with available data on air pollutants including particulate matter (PM2.5, PM10, and PM2.5-10), nitrogen dioxide (NO2), and nitric oxide (NO) from the UK Biobank. An air pollution score was calculated using principal component analysis to reflect joint exposure to these pollutants. Biological aging was assessed using the Klemera-Doubal method biological age and the phenotypic age algorithms. The associations of individual and joint air pollutants with thyroid dysfunction were estimated using the Cox proportional hazards regression model. The roles of biological aging were explored using interaction and mediation analyses.

RESULTS

During a median follow-up of 12.41 years, 1,721 (0.40 %) and 9,296 (2.15 %) participants developed hyperthyroidism and hypothyroidism, respectively. All air pollutants were observed to be significantly associated with an increased risk of incident hypothyroidism, while PM2.5, PM10, and NO2 were observed to be significantly associated with an increased risk of incident hyperthyroidism. The hazard ratios (HRs) for hyperthyroidism and hypothyroidism were 1.15 (95 % confidence interval: 1.00-1.32) and 1.15 (1.08-1.22) for individuals in the highest quartile compared with those in the lowest quartile of air pollution score, respectively. Additionally, we noticed that individuals with higher pollutant levels and biologically older generally had a higher risk of incident thyroid dysfunction. Moreover, accelerated biological aging partially mediated 1.9 %-9.4 % of air pollution-associated thyroid dysfunction.

CONCLUSIONS

Despite the possible underestimation of incident thyroid dysfunction, long-term air pollution exposure may increase the risk of incident thyroid dysfunction, particularly in biologically older participants, with biological aging potentially involved in the mechanisms.

Whole-body aging mediates the association between exposure to volatile organic compounds and osteoarthritis among U.S. middle-to-old-aged adults

BACKGROUND

Humans are constantly exposed to various volatile organic compounds (VOCs) because of their widespread sources and characteristic of easy evaporation. Existing evidence regarding the association between VOC exposure and osteoarthritis (OA) risk is limited.

PURPOSE

This study aimed to investigate the associations between individual urinary VOC metabolites (VOCMs) and the VOCM mixture, representing internal exposure levels of VOCs, with prevalent OA risk and to explore the mediating effect of aging and oxidative stress (OS) in these associations.

METHODS

Data from the National Health and Nutrition Examination Surveys 2005-2020 were analyzed. Weighted generalized linear regression was employed to explore the associations between individual VOCMs and OA risk, as well as aging and OS biomarkers. A five-repeated ten-fold cross-validation elastic net model was used to identify critical VOCMs for the weight quantile sum (WQS) analysis, which was performed to explore the VOCM mixture and OA risk association. Parallel and serial mediation analyses were conducted to identify the potential mediators and mediation pathways.

RESULTS

This study included 6578 American adults aged ≥40 years, among whom 1052 (16.0 %) individuals reported prevalent OA. Urinary levels of N-acetyl-S-(benzyl)-L-cysteine, mandelic acid and phenylglyoxylic acid were positively associated with OA risk. Eleven VOCMs with nonzero coefficients were identified and included in the WQS analysis, and results revealed an average increase of 24.4 % in OA risk (OR = 1.244, 95 % CI: 1.041, 1.486) per one-quantile increment in the VOCM mixture. Two aging biomarkers, phenotypic age and biological age, parallelly mediated the association between the VOCM mixture and OA risk, with mediation effect proportions of 9.0 % and 16.4 %, respectively.

CONCLUSIONS

Exposure to VOCs is associated with an increased OA risk in middle-to-old aged American adults. The mediating effect of aging contributes to the association between co-exposure to VOCs and OA risk. Further prospective studies are required to substantiate these findings.

Epigenetic aging & embodying injustice: US My Body My Story and Multi-Ethnic Atherosclerosis Study

Importance

Epigenetic accelerated aging is associated with exposure to social and economic adversity and may increase risk of premature morbidity and mortality. However, no studies have included measures of structural racism and few have compared estimates within or across the 1st and 2nd generation of epigenetic clocks (the latter additionally trained on phenotypic data).

Objective

To determine if accelerated epigenetic aging is associated with exposures to diverse measures of racialized, economic, and environmental injustice measured at different levels and time periods.

Design

Cross-sectional My Body My Story Study (MBMS; US, 2008-2010) and Exam 5 Multi-Ethnic Atherosclerosis Study (MESA; US, 2010-2012). MBMS DNA extraction: 2021; linkage of structural measures to MBMS and MESA: 2022.

Setting

MBMS recruited a random sample of US-born Black non-Hispanic (BNH) and white non-Hispanic (WNH) participants from 4 community health centers in Boston, MA. The MESA Exam 5 epigenetic component included 975 randomly selected US-born BNH, WNH, and Hispanic participants from four field sites: Baltimore, MD; Forsyth County, NC; New York City, NY; St. Paul, MN.

Participants

US-born persons (MBMS: 224 BNH, 69 WNH; MESA: 229 BNH, 555 WNH, 191 Hispanic).

Main outcome and measures

10 epigenetic clocks (six 1st generation; four 2nd generation), computed using DNA methylation data (DNAm) from blood spots (MBMS; N = 293) and purified monocytes (MESA; N = 975).

Results

Among Black non-Hispanic MBMS participants, epigenetic age acceleration was associated with being born in a Jim Crow state by 0.14 standard deviations (95% confidence interval [CI] 0.00, 0.27) and with birth state conservatism (0.06, 95% CI 0.00, 0.05), pooling across all clocks, as was low parental education for both Black non-Hispanic and white non-Hispanic MBMS participants (respectively: 0.24, 95% CI 0.08, 0.39, and 0.27, 95% CI 0.03, 0.51. Adult impoverishment was positively associated with the pooled 2nd generation clocks among the MESA participants (Black non-Hispanic: 0.06, 95% CI 0.01, 0.12; white non-Hispanic: 0.05, 95% CI 0.01, 0.08; Hispanic: 0.07, 95% CI 0.01, 0.14).

Conclusions and Relevance

Epigenetic accelerated aging may be one of the biological mechanisms linking exposure to racialized and economic injustice to well-documented inequities in premature morbidity and mortality.

Methylomic, Proteomic, and Metabolomic Correlates of Traffic-Related Air Pollution in the Context of Cardiorespiratory Health: A Systematic Review, Pathway Analysis, and Network Analysis

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead to cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease and highlight contemporary challenges and opportunities associated with such efforts.

Climate Change and New Challenges for Rural Communities: Particulate Matter Matters

Climate change presents multiple challenges to rural communities. Here, we investigated the toxicological potential of the six types of particulate matter most common to rural Arkansas: soil, road, and agricultural dusts, pollen, traffic exhaust, and particles from biomass burning in human small airway epithelial cells (SAECs). Biomass burning and agricultural dust demonstrated the most potent toxicological responses, exhibited as significant (p < 0.05) up-regulation of HMOX1 (oxidative stress) and TNFα (inflammatory response) genes as well as epigenetic alterations (altered expression of DNA methyltransferases DNMT1, DNMT3A, and DNMT3B, enzymatic activity, and DNA methylation of alpha satellite elements) that were evident at both 24 h and 72 h of exposure. We further demonstrate evidence of aridification in the state of Arkansas and the presence of winds capable of transporting agricultural dust- and biomass burning-associated particles far beyond their origination. Partnerships in the form of citizen science projects may provide important solutions to prevent and mitigate the negative effects of the rapidly evolving climate and improve the well-being of rural communities. Furthermore, the identification of the most toxic types of particulate matter could inform local policies related to agriculture, biomass burning, and dust control.

Methylomic, proteomic, and metabolomic correlates of traffic-related air pollution: A systematic review, pathway analysis, and network analysis relating traffic-related air pollution to subclinical and clinical cardiorespiratory outcomes

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease, and highlight contemporary challenges and opportunities associated with such efforts.

The effect of polyphenols on DNA methylation-assessed biological age attenuation: the DIRECT PLUS randomized controlled trial

BACKGROUND

Epigenetic age is an estimator of biological age based on DNA methylation; its discrepancy from chronologic age warrants further investigation. We recently reported that greater polyphenol intake benefitted ectopic fats, brain function, and gut microbiota profile, corresponding with elevated urine polyphenols. The effect of polyphenol-rich dietary interventions on biological aging is yet to be determined.

METHODS

We calculated different biological aging epigenetic clocks of different generations (Horvath2013, Hannum2013, Li2018, Horvath skin and blood2018, PhenoAge2018, PCGrimAge2022), their corresponding age and intrinsic age accelerations, and DunedinPACE, all based on DNA methylation (Illumina EPIC array; pre-specified secondary outcome) for 256 participants with abdominal obesity or dyslipidemia, before and after the 18-month DIRECT PLUS randomized controlled trial. Three interventions were assigned: healthy dietary guidelines, a Mediterranean (MED) diet, and a polyphenol-rich, low-red/processed meat Green-MED diet. Both MED groups consumed 28 g walnuts/day (+ 440 mg/day polyphenols). The Green-MED group consumed green tea (3-4 cups/day) and Mankai (Wolffia globosa strain) 500-ml green shake (+ 800 mg/day polyphenols). Adherence to the Green-MED diet was assessed by questionnaire and urine polyphenols metabolomics (high-performance liquid chromatography quadrupole time of flight).

RESULTS

Baseline chronological age (51.3 ± 10.6 years) was significantly correlated with all methylation age (mAge) clocks with correlations ranging from 0.83 to 0.95; p < 2.2e - 16 for all. While all interventions did not differ in terms of changes between mAge clocks, greater Green-Med diet adherence was associated with a lower 18-month relative change (i.e., greater mAge attenuation) in Li and Hannum mAge (beta =  - 0.41, p = 0.004 and beta =  - 0.38, p = 0.03, respectively; multivariate models). Greater Li mAge attenuation (multivariate models adjusted for age, sex, baseline mAge, and weight loss) was mostly affected by higher intake of Mankai (beta =  - 1.8; p = 0.061) and green tea (beta =  - 1.57; p = 0.0016) and corresponded with elevated urine polyphenols: hydroxytyrosol, tyrosol, and urolithin C (p < 0.05 for all) and urolithin A (p = 0.08), highly common in green plants. Overall, participants undergoing either MED-style diet had ~ 8.9 months favorable difference between the observed and expected Li mAge at the end of the intervention (p = 0.02).

CONCLUSIONS

This study showed that MED and green-MED diets with increased polyphenols intake, such as green tea and Mankai, are inversely associated with biological aging. To the best of our knowledge, this is the first clinical trial to indicate a potential link between polyphenol intake, urine polyphenols, and biological aging.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03020186.

Household air pollution and epigenetic aging in Xuanwei, China

BACKGROUND

Household air pollution (HAP) from indoor combustion of solid fuel is a global health burden linked to lung cancer. In Xuanwei, China, lung cancer rate for nonsmoking women is among the highest in the world and largely attributed to high levels of polycyclic aromatic hydrocarbons (PAHs) that are produced from combustion of smoky (bituminous) coal used for cooking and heating. Epigenetic age acceleration (EAA), a DNA methylation-based biomarker of aging, has been shown to be highly correlated with biological processes underlying the susceptibility of age-related diseases. We aim to assess the association between HAP exposure and EAA.

METHODS

We analyzed data from 106 never-smoking women from Xuanwei, China. Information on fuel type was collected using a questionnaire, and validated exposure models were used to predict levels of 43 HAP constituents. Exposure clusters were identified using hierarchical clustering. EAA was derived for five epigenetic clocks defined as the residuals resulting from regressing each clock on chronological age. We used generalized estimating equations to test associations between exposure clusters derived from predicted levels of HAP exposure, ambient 5-methylchrysene (5-MC), a PAH previously found to be associated with risk of lung cancer, and EAA, while accounting for repeated-measurements and confounders.

RESULTS

We observed an increase in GrimAge EAA for clusters with 31 and 33 PAHs reflecting current (β = 0.77 y per standard deviation (SD) increase, 95 % CI:0.36,1.19) and childhood (β = 0.92 y per SD, 95 % CI:0.40,1.45) exposure, respectively. 5-MC (ng/m3-year) was found to be associated with GrimAge EAA for current (β = 0.15 y, 95 % CI:0.05,0.25) and childhood (β = 0.30 y, 95 % CI:0.13,0.47) exposure.

CONCLUSIONS

Our findings suggest that exposure to PAHs from indoor smoky coal combustion, particularly 5-MC, is associated with GrimAge EAA, a biomarker of mortality.

Vascular Ageing: Mechanisms, Risk Factors, and Treatment Strategies

Ageing constitutes the biggest risk factor for poor health and adversely affects the integrity and function of all the cells, tissues, and organs in the human body. Vascular ageing, characterised by vascular stiffness, endothelial dysfunction, increased oxidative stress, chronic low-grade inflammation, and early-stage atherosclerosis, may trigger or exacerbate the development of age-related vascular diseases, which each year contribute to more than 3.8 million deaths in Europe alone and necessitate a better understanding of the mechanisms involved. To this end, a large number of recent preclinical and clinical studies have focused on the exponential accumulation of senescent cells in the vascular system and paid particular attention to the specific roles of senescence-associated secretory phenotype, proteostasis dysfunction, age-mediated modulation of certain microRNA (miRNAs), and the contribution of other major vascular risk factors, notably diabetes, hypertension, or smoking, to vascular ageing in the elderly. The data generated paved the way for the development of various senotherapeutic interventions, ranging from the application of synthetic or natural senolytics and senomorphics to attempt to modify lifestyle, control diet, and restrict calorie intake. However, specific guidelines, considering the severity and characteristics of vascular ageing, need to be established before widespread use of these agents. This review briefly discusses the molecular and cellular mechanisms of vascular ageing and summarises the efficacy of widely studied senotherapeutics in the context of vascular ageing.

Associations of stress and stress-related psychiatric disorders with GrimAge acceleration: review and suggestions for future work

The notion of "biological aging" as distinct from chronological aging has been of increasing interest in psychiatry, and many studies have explored associations of stress and psychiatric illness with accelerated biological aging. The "epigenetic clocks" are one avenue of this research, wherein "biological age" is estimated using DNA methylation data from specific CpG dinucleotide sites within the human genome. Many iterations of the epigenetic clocks have been developed, but the GrimAge clock continues to stand out for its ability to predict morbidity and mortality. Several studies have now explored associations of stress, PTSD, and MDD with GrimAge acceleration (GrimAA). While stress, PTSD, and MDD are distinct psychiatric entities, they may share common mechanisms underlying accelerated biological aging. Yet, no one has offered a review of the evidence on associations of stress and stress-related psychopathology with GrimAA. In this review, we identify nine publications on associations of stress, PTSD, and MDD with GrimAA. We find that results are mixed both within and across each of these exposures. However, we also find that analytic methods - and specifically, the choice of covariates - vary widely between studies. To address this, we draw upon popular methods from the field of clinical epidemiology to offer (1) a systematic framework for covariate selection, and (2) an approach to results reporting that facilitates analytic consensus. Although covariate selection will differ by the research question, we encourage researchers to consider adjustment for tobacco, alcohol use, physical activity, race, sex, adult socioeconomic status, medical comorbidity, and blood cell composition.