1 2411 117 EPIGENETIC SCORES FOR THE CIRCULATING PROTEOME AS TOOLS FOR DISEASE PREDICTION. PROTEIN BIOMARKERS HAVE BEEN IDENTIFIED ACROSS MANY AGE-RELATED MORBIDITIES. HOWEVER, CHARACTERISING EPIGENETIC INFLUENCES COULD FURTHER INFORM DISEASE PREDICTIONS. HERE, WE LEVERAGE EPIGENOME-WIDE DATA TO STUDY LINKS BETWEEN THE DNA METHYLATION (DNAM) SIGNATURES OF THE CIRCULATING PROTEOME AND INCIDENT DISEASES. USING DATA FROM FOUR COHORTS, WE TRAINED AND TESTED EPIGENETIC SCORES (EPISCORES) FOR 953 PLASMA PROTEINS, IDENTIFYING 109 SCORES THAT EXPLAINED BETWEEN 1% AND 58% OF THE VARIANCE IN PROTEIN LEVELS AFTER ADJUSTING FOR KNOWN PROTEIN QUANTITATIVE TRAIT LOCI (PQTL) GENETIC EFFECTS. BY PROJECTING THESE EPISCORES INTO AN INDEPENDENT SAMPLE (GENERATION SCOTLAND; N = 9537) AND RELATING THEM TO INCIDENT MORBIDITIES OVER A FOLLOW-UP OF 14 YEARS, WE UNCOVERED 137 EPISCORE-DISEASE ASSOCIATIONS. THESE ASSOCIATIONS WERE LARGELY INDEPENDENT OF IMMUNE CELL PROPORTIONS, COMMON LIFESTYLE AND HEALTH FACTORS, AND BIOLOGICAL AGING. NOTABLY, WE FOUND THAT OUR DIABETES-ASSOCIATED EPISCORES HIGHLIGHTED PREVIOUS TOP BIOMARKER ASSOCIATIONS FROM PROTEOME-WIDE ASSESSMENTS OF DIABETES. THESE EPISCORES FOR PROTEIN LEVELS CAN THEREFORE BE A VALUABLE RESOURCE FOR DISEASE PREDICTION AND RISK STRATIFICATION. 2022 2 1516 36 DNA METHYLATION AS A BIOMARKER OF AGING IN EPIDEMIOLOGIC STUDIES. CANCER IS LARGELY AN AGING DISEASE. ACCELERATED BIOLOGICAL AGING MAY BE THE STRONGEST PREDICTOR OF CANCER AND OTHER CHRONIC DISEASE RISKS. IN THE ABSENCE OF RELIABLE AND QUANTIFIABLE BIOMARKERS OF AGING TO DATE, IT HAS LONG BEEN OBSERVED THAT TUMORIGENESIS SHARES DISTINCT EPIGENETIC ALTERATIONS WITH THE AGING PROCESS. RECENTLY, EPIGENETIC AGE ESTIMATES HAVE BEEN DEVELOPED BASED ON THE AVAILABILITY OF GENOME-WIDE DNA METHYLATION PROFILES, BY APPLYING IN THE PREDICTION FORMULA THE METHYLATION LEVEL AT A SUBSET OF HIGHLY PREDICTIVE METHYLATION SITES, CALLED EPIGENETIC CLOCK. THESE DNA METHYLATION AGE ESTIMATES HAVE PRODUCED REMARKABLY STRONG CORRELATIONS WITH CHRONOLOGICAL AGE, WITH A SMALL DEVIATION AND HIGH REPRODUCIBILITY ACROSS DIFFERENT AGE GROUPS AND STUDY POPULATIONS. MOREOVER, AN INCREASING NUMBER OF EPIDEMIOLOGIC STUDIES HAVE DEMONSTRATED AN INDEPENDENT ASSOCIATION OF DNA METHYLATION AGE OR THE EXTENT OF ACCELERATION WITH MORTALITY AND VARIOUS AGING-RELATED CONDITIONS, EVEN AFTER ACCOUNTING FOR DIFFERENCES IN CHRONOLOGICAL AGE AND OTHER RISK FACTORS. ALTHOUGH EPIGENETIC PROFILES ARE KNOWN TO BE TISSUE-SPECIFIC, BOTH TARGET TISSUE- AND MULTIPLE TISSUE-DERIVED ESTIMATES APPEAR TO PERFORM WELL TO CAPTURE WHAT IS THOUGHT TO BE THE CUMULATIVE EPIGENETIC DRIFT THAT REPRESENTS A MULTIFACTORIAL DEGENERATIVE PROCESS ACROSS TISSUES AND ORGANISMS. FURTHER REFINEMENT OF THE EPIGENETIC AGE ESTIMATES IS ANTICIPATED OVER TIME TO ACCOMMODATE A BETTER TECHNOLOGICAL COVERAGE OF THE METHYLOME AND A BETTER UNDERSTANDING OF THE BIOLOGY UNDERLYING PREDICTIVE REGIONS. EPIDEMIOLOGIC PRINCIPLES WILL REMAIN CRITICAL FOR THE EVALUATION OF RESEARCH FINDINGS INVOLVING, FOR EXAMPLE, DIFFERENT STUDY POPULATIONS, DESIGN, FOLLOW-UP TIME, AND QUALITY OF COVARIATE DATA. OVERALL, THE EPIGENETIC AGE ESTIMATES ARE AN EXCITING DEVELOPMENT WITH USEFUL IMPLICATIONS FOR BIOMEDICAL RESEARCH OF HEALTHY AGING AND DISEASE PREVENTION AND CONTROL. 2018 3 1599 36 DNA METHYLATION SIGNATURE OF CHILDHOOD CHRONIC PHYSICAL AGGRESSION IN T CELLS OF BOTH MEN AND WOMEN. BACKGROUND: HIGH FREQUENCY OF PHYSICAL AGGRESSION IS THE CENTRAL FEATURE OF SEVERE CONDUCT DISORDER AND IS ASSOCIATED WITH A WIDE RANGE OF SOCIAL, MENTAL AND PHYSICAL HEALTH PROBLEMS. WE HAVE PREVIOUSLY TESTED THE HYPOTHESIS THAT DIFFERENTIAL DNA METHYLATION SIGNATURES IN PERIPHERAL T CELLS ARE ASSOCIATED WITH A CHRONIC AGGRESSION TRAJECTORY IN MALES. DESPITE THE FACT THAT SEX DIFFERENCES APPEAR TO PLAY A PIVOTAL ROLE IN DETERMINING THE DEVELOPMENT, MAGNITUDE AND FREQUENCY OF AGGRESSION, MOST OF PREVIOUS STUDIES FOCUSED ON MALES, SO LITTLE IS KNOWN ABOUT FEMALE CHRONIC PHYSICAL AGGRESSION. WE THEREFORE TESTED HERE WHETHER OR NOT THERE IS A SIGNATURE OF PHYSICAL AGGRESSION IN FEMALE DNA METHYLATION AND, IF THERE IS, HOW IT RELATES TO THE SIGNATURE OBSERVED IN MALES. METHODOLOGY/PRINCIPAL FINDINGS: METHYLATION PROFILES WERE CREATED USING THE METHOD OF METHYLATED DNA IMMUNOPRECIPITATION (MEDIP) FOLLOWED BY MICROARRAY HYBRIDIZATION AND STATISTICAL AND BIOINFORMATIC ANALYSES ON T CELL DNA OBTAINED FROM ADULT WOMEN WHO WERE FOUND TO BE ON A CHRONIC PHYSICAL AGGRESSION TRAJECTORY (CPA) BETWEEN 6 AND 12 YEARS OF AGE COMPARED TO WOMEN WHO FOLLOWED A NORMAL PHYSICAL AGGRESSION TRAJECTORY. WE CONFIRMED THE EXISTENCE OF A WELL-DEFINED, GENOME-WIDE SIGNATURE OF DNA METHYLATION ASSOCIATED WITH CHRONIC PHYSICAL AGGRESSION IN THE PERIPHERAL T CELLS OF ADULT FEMALES THAT INCLUDES MANY OF THE GENES SIMILARLY ASSOCIATED WITH PHYSICAL AGGRESSION IN THE SAME CELL TYPES OF ADULT MALES. CONCLUSIONS: THIS STUDY IN A SMALL NUMBER OF WOMEN PRESENTS PRELIMINARY EVIDENCE FOR A GENOME-WIDE VARIATION IN PROMOTER DNA METHYLATION THAT ASSOCIATES WITH CPA IN WOMEN THAT WARRANT LARGER STUDIES FOR FURTHER VERIFICATION. A SIGNIFICANT PROPORTION OF THESE ASSOCIATIONS WERE PREVIOUSLY OBSERVED IN MEN WITH CPA SUPPORTING THE HYPOTHESIS THAT THE EPIGENETIC SIGNATURE OF EARLY LIFE AGGRESSION IN FEMALES IS COMPOSED OF A COMPONENT SPECIFIC TO FEMALES AND ANOTHER COMMON TO BOTH MALES AND FEMALES. 2014 4 287 27 AGING AND CHRONIC SUN EXPOSURE CAUSE DISTINCT EPIGENETIC CHANGES IN HUMAN SKIN. EPIGENETIC CHANGES ARE WIDELY CONSIDERED TO PLAY AN IMPORTANT ROLE IN AGING, BUT EXPERIMENTAL EVIDENCE TO SUPPORT THIS HYPOTHESIS HAS BEEN SCARCE. WE HAVE USED ARRAY-BASED ANALYSIS TO DETERMINE GENOME-SCALE DNA METHYLATION PATTERNS FROM HUMAN SKIN SAMPLES AND TO INVESTIGATE THE EFFECTS OF AGING, CHRONIC SUN EXPOSURE, AND TISSUE VARIATION. OUR RESULTS REVEAL A HIGH DEGREE OF TISSUE SPECIFICITY IN THE METHYLATION PATTERNS AND ALSO SHOWED VERY LITTLE INTERINDIVIDUAL VARIATION WITHIN TISSUES. DATA STRATIFICATION BY AGE REVEALED THAT DNA FROM OLDER INDIVIDUALS WAS CHARACTERIZED BY A SPECIFIC HYPERMETHYLATION PATTERN AFFECTING LESS THAN 1% OF THE MARKERS ANALYZED. INTERESTINGLY, STRATIFICATION BY SUN EXPOSURE PRODUCED A FUNDAMENTALLY DIFFERENT PATTERN WITH A SIGNIFICANT TREND TOWARDS HYPOMETHYLATION. OUR RESULTS THUS IDENTIFY DEFINED AGE-RELATED DNA METHYLATION CHANGES AND SUGGEST THAT THESE ALTERATIONS MIGHT CONTRIBUTE TO THE PHENOTYPIC CHANGES ASSOCIATED WITH SKIN AGING. 2010 5 6311 34 THE RELATION BETWEEN DNA METHYLATION PATTERNS AND SERUM CYTOKINE LEVELS IN COMMUNITY-DWELLING ADULTS: A PRELIMINARY STUDY. BACKGROUND: THE LEVELS OF CIRCULATING CYTOKINES FLUCTUATE WITH AGE, ACUTE ILLNESS, AND CHRONIC DISEASE, AND ARE PREDICTIVE OF MORTALITY; THIS IS ALSO TRUE FOR PATTERNS OF DNA (CPG) METHYLATION. GIVEN THAT IMMUNE CELLS ARE PARTICULARLY SENSITIVE TO CHANGES IN THE CONCENTRATION OF CYTOKINES IN THEIR MICROENVIRONMENT, WE HYPOTHESIZED THAT SERUM LEVELS OF TNF, IL-6, IL-8 AND IL-10 WOULD CORRELATE WITH GENOME-WIDE ALTERATIONS IN THE DNA METHYLATION LEVELS OF BLOOD LEUKOCYTES. TO TEST THIS, WE EVALUATED COMMUNITY-DWELLING ADULTS (N = 14; 48-78 YEARS OLD) RECRUITED TO A PILOT STUDY FOR THE CANADIAN LONGITUDINAL STUDY ON AGING (CLSA), EXAMINING DNA METHYLATION PATTERNS IN PERIPHERAL BLOOD MONONUCLEAR CELLS USING THE ILLUMINA HUMANMETHYLATION 450 K BEADCHIP. RESULTS: WE SHOW THAT, APART FROM AGE, SERUM IL-10 LEVELS EXHIBITED THE MOST SUBSTANTIAL ASSOCIATION TO DNA METHYLATION PATTERNS, FOLLOWED BY TNF, IL-6 AND IL-8. FURTHERMORE, WHILE THE LEVELS OF THESE CYTOKINES WERE HIGHER IN ELDERLY ADULTS, NO ASSOCIATIONS WITH EPIGENETIC ACCELERATED AGING, DERIVED USING THE EPIGENETIC CLOCK, WERE OBSERVED. CONCLUSIONS: AS A PRELIMINARY STUDY WITH A SMALL SAMPLE SIZE, THE CONCLUSIONS DRAWN FROM THIS WORK MUST BE VIEWED WITH CAUTION; HOWEVER, OUR OBSERVATIONS ARE ENCOURAGING AND CERTAINLY WARRANT MORE SUITABLY POWERED STUDIES OF THIS RELATIONSHIP. 2017 6 1583 28 DNA METHYLATION PROFILES OF BLOOD CELLS ARE DISTINCT BETWEEN EARLY-ONSET OBESE AND CONTROL INDIVIDUALS. OBESITY IS A HIGHLY PREVALENT, CHRONIC DISORDER THAT HAS BEEN INCREASING IN INCIDENCE IN YOUNG PATIENTS. BOTH EPIGENETIC AND GENETIC ABERRATIONS MAY PLAY A ROLE IN THE PATHOGENESIS OF OBESITY. THEREFORE, IN-DEPTH EPIGENOMIC AND GENOMIC ANALYSES WILL ADVANCE OUR UNDERSTANDING OF THE DETAILED MOLECULAR MECHANISMS UNDERLYING OBESITY AND AID IN THE SELECTION OF POTENTIAL BIOMARKERS FOR OBESITY IN YOUTH. HERE, WE PERFORMED MICROARRAY-BASED DNA METHYLATION AND GENE EXPRESSION PROFILING OF PERIPHERAL WHITE BLOOD CELLS OBTAINED FROM SIX YOUNG, OBESE INDIVIDUALS AND SIX HEALTHY CONTROLS. WE OBSERVED THAT THE HIERARCHICAL CLUSTERING OF DNA METHYLATION, BUT NOT GENE EXPRESSION, CLEARLY SEGREGATES THE OBESE INDIVIDUALS FROM THE CONTROLS, SUGGESTING THAT THE METABOLIC DISTURBANCE THAT OCCURS AS A RESULT OF OBESITY AT A YOUNG AGE MAY AFFECT THE DNA METHYLATION OF PERIPHERAL BLOOD CELLS WITHOUT ACCOMPANYING TRANSCRIPTIONAL CHANGES. TO EXAMINE THE GENOME-WIDE DIFFERENCES IN THE DNA METHYLATION PROFILES OF YOUNG OBESE AND CONTROL INDIVIDUALS, WE IDENTIFIED DIFFERENTIALLY METHYLATED CPG SITES AND INVESTIGATED THEIR GENOMIC AND EPIGENOMIC CONTEXTS. THE ABERRANT DNA METHYLATION PATTERNS IN OBESE INDIVIDUALS CAN BE SUMMARIZED AS RELATIVE GAINS AND LOSSES OF DNA METHYLATION IN GENE PROMOTERS AND GENE BODIES, RESPECTIVELY. WE ALSO OBSERVED THAT THE CPG ISLANDS OF OBESE INDIVIDUALS ARE MORE SUSCEPTIBLE TO DNA METHYLATION COMPARED TO CONTROLS. OUR PILOT STUDY SUGGESTS THAT THE GENOME-WIDE ABERRANT DNA METHYLATION PATTERNS OF OBESE INDIVIDUALS MAY ADVANCE NOT ONLY OUR UNDERSTANDING OF THE EPIGENOMIC PATHOGENESIS BUT ALSO EARLY SCREENING OF OBESITY IN YOUTH. 2017 7 5748 34 SOCIAL AND PHYSICAL ENVIRONMENTS EARLY IN DEVELOPMENT PREDICT DNA METHYLATION OF INFLAMMATORY GENES IN YOUNG ADULTHOOD. CHRONIC INFLAMMATION CONTRIBUTES TO A WIDE RANGE OF HUMAN DISEASES, AND ENVIRONMENTS IN INFANCY AND CHILDHOOD ARE IMPORTANT DETERMINANTS OF INFLAMMATORY PHENOTYPES. THE UNDERLYING BIOLOGICAL MECHANISMS CONNECTING EARLY ENVIRONMENTS WITH THE REGULATION OF INFLAMMATION IN ADULTHOOD ARE NOT KNOWN, BUT EPIGENETIC PROCESSES ARE PLAUSIBLE CANDIDATES. WE TESTED THE HYPOTHESIS THAT PATTERNS OF DNA METHYLATION (DNAM) IN INFLAMMATORY GENES IN YOUNG ADULTHOOD WOULD BE PREDICTED BY EARLY LIFE NUTRITIONAL, MICROBIAL, AND PSYCHOSOCIAL EXPOSURES PREVIOUSLY ASSOCIATED WITH LEVELS OF INFLAMMATION. DATA COME FROM A POPULATION-BASED LONGITUDINAL BIRTH COHORT STUDY IN METROPOLITAN CEBU, THE PHILIPPINES, AND DNAM WAS CHARACTERIZED IN WHOLE BLOOD SAMPLES FROM 494 PARTICIPANTS (AGE 20-22 Y). ANALYSES FOCUSED ON PROBES IN 114 TARGET GENES INVOLVED IN THE REGULATION OF INFLAMMATION, AND WE IDENTIFIED 10 SITES ACROSS NINE GENES WHERE THE LEVEL OF DNAM WAS SIGNIFICANTLY PREDICTED BY THE FOLLOWING VARIABLES: HOUSEHOLD SOCIOECONOMIC STATUS IN CHILDHOOD, EXTENDED ABSENCE OF A PARENT IN CHILDHOOD, EXPOSURE TO ANIMAL FECES IN INFANCY, BIRTH IN THE DRY SEASON, OR DURATION OF EXCLUSIVE BREASTFEEDING. TO EVALUATE THE BIOLOGICAL SIGNIFICANCE OF THESE SITES, WE TESTED FOR ASSOCIATIONS WITH A PANEL OF INFLAMMATORY BIOMARKERS MEASURED IN PLASMA OBTAINED AT THE SAME AGE AS DNAM ASSESSMENT. THREE SITES PREDICTED ELEVATED INFLAMMATION, AND ONE SITE PREDICTED LOWER INFLAMMATION, CONSISTENT WITH THE INTERPRETATION THAT LEVELS OF DNAM AT THESE SITES ARE FUNCTIONALLY RELEVANT. THIS PATTERN OF RESULTS POINTS TOWARD DNAM AS A POTENTIALLY IMPORTANT BIOLOGICAL MECHANISM THROUGH WHICH DEVELOPMENTAL ENVIRONMENTS SHAPE INFLAMMATORY PHENOTYPES ACROSS THE LIFE COURSE. 2017 8 70 29 A METHOD TO DETECT DIFFERENTIALLY METHYLATED LOCI WITH NEXT-GENERATION SEQUENCING. EPIGENETIC CHANGES, ESPECIALLY DNA METHYLATION AT CPG LOCI HAVE IMPORTANT IMPLICATIONS IN CANCER AND OTHER COMPLEX DISEASES. WITH THE DEVELOPMENT OF NEXT-GENERATION SEQUENCING (NGS), IT IS FEASIBLE TO GENERATE DATA TO INTERROGATE THE DIFFERENCE IN METHYLATION STATUS FOR GENOME-WIDE LOCI USING CASE-CONTROL DESIGN. HOWEVER, A PROPER AND EFFICIENT STATISTICAL TEST IS LACKING. THERE ARE SEVERAL CHALLENGES. FIRST, UNLIKE METHYLATION EXPERIMENTS USING MICROARRAYS, WHERE THERE IS ONE MEASURE OF METHYLATION FOR ONE INDIVIDUAL AT A PARTICULAR CPG SITE, HERE WE HAVE THE COUNTS OF METHYLATION ALLELE AND UNMETHYLATION ALLELE FOR EACH INDIVIDUAL. SECOND, DUE TO THE NATURE OF SAMPLE PREPARATION, THE MEASURED METHYLATION REFLECTS THE METHYLATION STATUS OF A MIXTURE OF CELLS INVOLVED IN SAMPLE PREPARATION. THEREFORE, THE UNDERLYING DISTRIBUTION OF THE MEASURED METHYLATION LEVEL IS UNKNOWN, AND A ROBUST TEST IS MORE DESIRABLE THAN PARAMETRIC APPROACH. THIRD, CURRENTLY NGS MEASURES METHYLATION AT OVER 2 MILLION CPG SITES. ANY STATISTICAL TESTS HAVE TO BE COMPUTATIONALLY EFFICIENT IN ORDER TO BE APPLIED TO THE NGS DATA. TAKING THESE CHALLENGES INTO ACCOUNT, WE PROPOSE A TEST FOR DIFFERENTIAL METHYLATION BASED ON CLUSTERED DATA ANALYSIS BY MODELING THE METHYLATION COUNTS. WE PERFORMED SIMULATIONS TO SHOW THAT IT IS ROBUST UNDER SEVERAL DISTRIBUTIONS FOR THE MEASURED METHYLATION LEVELS. IT HAS GOOD POWER AND IS COMPUTATIONALLY EFFICIENT. FINALLY, WE APPLY THE TEST TO OUR NGS DATA ON CHRONIC LYMPHOCYTIC LEUKEMIA. THE RESULTS INDICATE THAT IT IS A PROMISING AND PRACTICAL TEST. 2013 9 1585 29 DNA METHYLATION PROFILING IDENTIFIES EPIGENETIC DIFFERENCES BETWEEN DIABETES PATIENTS WITH ESRD AND DIABETES PATIENTS WITHOUT NEPHROPATHY. WE IDENTIFIED POTENTIAL EPIGENETIC BIOMARKERS FOR CHRONIC KIDNEY DISEASE PROGRESSION BY COMPARING SITE-SPECIFIC DNA METHYLATION LEVELS IN MORE THAN 14,000 GENES BETWEEN AFRICAN AMERICAN AND HISPANIC DIABETES PATIENTS WITH END STAGE RENAL DISEASE (ESRD) AND DIABETES PATIENTS WITHOUT NEPHROPATHY. WE IDENTIFIED 187 GENES THAT ARE DIFFERENTIALLY METHYLATED BETWEEN THE TWO GROUPS ON AT LEAST TWO CPG SITES IN EACH GENE IN DNA EXTRACTED FROM SALIVA. OF THE 187 GENES WHOSE MEAN METHYLATION LEVELS DIFFERED BETWEEN THE TWO GROUPS, 39 GENES, OR CLOSELY RELATED GENE FAMILY MEMBERS, HAVE BEEN REPORTED TO BE INVOLVED IN KIDNEY DEVELOPMENT OR DIABETIC NEPHROPATHY, PER SE, OR HAVE BEEN ASSOCIATED WITH DIALYSIS-INDUCED CHANGES IN GENE EXPRESSION IN PERIPHERAL BLOOD CELLS. THE FACT THAT SUCH A SUBSTANTIAL FRACTION (21%) OF THE 187 CANDIDATE GENES HAVE BEEN IMPLICATED PREVIOUSLY THROUGH GENOME ASSOCIATION OR TRANSCRIPTION PROFILING STUDIES SUGGESTS STRONGLY THAT THE DNA METHYLATION DIFFERENCES WE OBSERVE ARE ASSOCIATED WITH DISEASE PREDISPOSITION AND/OR TREATMENT. THE FACT THAT THESE NEPHROPATHY AND/OR DIALYSIS-ASSOCIATED DIFFERENCES BETWEEN PATIENTS WERE IDENTIFIED IN DNA EXTRACTED FROM SALIVA OFFERS PROOF-OF-PRINCIPLE THAT INTER-INDIVIDUAL EPIGENETIC DIFFERENCES MAY PROVE USEFUL AS PREDICTIVE BIOMARKERS OF DISEASE SUSCEPTIBILITY. 2011 10 1705 35 DYNAMICS OF SMOKING-INDUCED GENOME-WIDE METHYLATION CHANGES WITH TIME SINCE SMOKING CESSATION. SEVERAL STUDIES HAVE RECENTLY IDENTIFIED STRONG EPIGENETIC SIGNALS RELATED TO TOBACCO SMOKING. HOWEVER, AN ASPECT THAT DID NOT RECEIVE MUCH ATTENTION IS THE EVOLUTION OF EPIGENETIC CHANGES WITH TIME SINCE SMOKING CESSATION. WE CONDUCTED A SERIES OF EPIGENOME-WIDE ASSOCIATION STUDIES TO CAPTURE THE DYNAMICS OF SMOKING-INDUCED EPIGENETIC CHANGES AFTER SMOKING CESSATION, USING GENOME-WIDE METHYLATION PROFILES OBTAINED FROM BLOOD SAMPLES IN 745 WOMEN FROM 2 EUROPEAN POPULATIONS. TWO DISTINCT CLASSES OF CPG SITES WERE IDENTIFIED: SITES WHOSE METHYLATION REVERTS TO LEVELS TYPICAL OF NEVER SMOKERS WITHIN DECADES AFTER SMOKING CESSATION, AND SITES REMAINING DIFFERENTIALLY METHYLATED, EVEN MORE THAN 35 YEARS AFTER SMOKING CESSATION. OUR RESULTS SUGGEST THAT THE DYNAMICS OF METHYLATION CHANGES FOLLOWING SMOKING CESSATION ARE DRIVEN BY A DIFFERENTIAL AND SITE-SPECIFIC MAGNITUDE OF THE SMOKING-INDUCED ALTERATIONS (WITH PERSISTENT SITES BEING MOST AFFECTED) IRRESPECTIVE OF THE INTENSITY AND DURATION OF SMOKING. ANALYSES OF THE LINK BETWEEN METHYLATION AND EXPRESSION LEVELS REVEALED THAT METHYLATION PREDOMINANTLY AND REMOTELY DOWN-REGULATES GENE EXPRESSION. AMONG GENES WHOSE EXPRESSION WAS ASSOCIATED WITH OUR CANDIDATE CPG SITES, LRRN3 APPEARED TO BE PARTICULARLY INTERESTING AS IT WAS ONE OF THE FEW GENES WHOSE METHYLATION AND EXPRESSION WERE DIRECTLY ASSOCIATED, AND THE ONLY GENE IN WHICH BOTH METHYLATION AND GENE EXPRESSION WERE FOUND ASSOCIATED WITH SMOKING. OUR STUDY HIGHLIGHTS PERSISTENT EPIGENETIC MARKERS OF SMOKING, WHICH CAN POTENTIALLY BE DETECTED DECADES AFTER CESSATION. SUCH HISTORICAL SIGNATURES ARE PROMISING BIOMARKERS TO REFINE INDIVIDUAL RISK PROFILING OF SMOKING-INDUCED CHRONIC DISEASE SUCH AS LUNG CANCER. 2015 11 6027 22 THE BLOOD DNA METHYLATION CLOCK GRIMAGE IS A ROBUST SURROGATE FOR AIRWAY EPITHELIA AGING. ONE KEY FEATURE OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS THAT ITS PREVALENCE INCREASES EXPONENTIALLY WITH AGE. DNA METHYLATION CLOCKS HAVE BECOME POWERFUL BIOMARKERS TO DETECT ACCELERATED AGING IN A VARIETY OF DISEASES AND CAN HELP PROGNOSE OUTCOMES IN SEVERE COPD. THIS STUDY INVESTIGATED WHICH DNA METHYLATION CLOCK COULD BEST REFLECT AIRWAY EPIGENETIC AGE WHEN USED IN MORE ACCESSIBLE BLOOD SAMPLES. OUR ANALYSES SHOWED THAT OUT OF SIX DNA METHYLATION CLOCKS INVESTIGATED, DNAMGRIMAGE DEMONSTRATED THE STRONGEST CORRELATION AND THE SMALLEST DIFFERENCE BETWEEN THE AIRWAY EPITHELIUM AND BLOOD. OUR FINDINGS SUGGESTS THAT BLOOD DNAMGRIMAGE ACCURATELY REFLECTS AIRWAY EPIGENETIC AGE OF INDIVIDUALS AND THAT ITS ELEVATION IS HIGHLY ASSOCIATED WITH COPD. 2022 12 2922 32 GENE-SPECIFIC DNA METHYLATION ASSOCIATION WITH SERUM LEVELS OF C-REACTIVE PROTEIN IN AFRICAN AMERICANS. A MORE THOROUGH UNDERSTANDING OF THE DIFFERENCES IN DNA METHYLATION (DNAM) PROFILES IN POPULATIONS MAY HOLD PROMISE FOR IDENTIFYING MOLECULAR MECHANISMS THROUGH WHICH GENETIC AND ENVIRONMENTAL FACTORS JOINTLY CONTRIBUTE TO HUMAN DISEASES. INFLAMMATION IS A KEY MOLECULAR MECHANISM UNDERLYING SEVERAL CHRONIC DISEASES INCLUDING CARDIOVASCULAR DISEASE, AND IT AFFECTS DNAM PROFILE ON BOTH GLOBAL AND LOCUS-SPECIFIC LEVELS. TO UNDERSTAND THE IMPACT OF INFLAMMATION ON THE DNAM OF THE HUMAN GENOME, WE INVESTIGATED DNAM PROFILES OF PERIPHERAL BLOOD LEUKOCYTES FROM 966 AFRICAN AMERICAN PARTICIPANTS IN THE GENETIC EPIDEMIOLOGY NETWORK OF ARTERIOPATHY (GENOA) STUDY. BY TESTING THE ASSOCIATION OF DNAM SITES ON CPG ISLANDS OF OVER 14,000 GENES WITH C-REACTIVE PROTEIN (CRP), AN INFLAMMATORY BIOMARKER OF CARDIOVASCULAR DISEASE, WE IDENTIFIED 257 DNAM SITES IN 240 GENES SIGNIFICANTLY ASSOCIATED WITH SERUM LEVELS OF CRP ADJUSTED FOR AGE, SEX, BODY MASS INDEX AND SMOKING STATUS, AND CORRECTED FOR MULTIPLE TESTING. OF THE SIGNIFICANTLY ASSOCIATED DNAM SITES, 80.5% WERE HYPOMETHYLATED WITH HIGHER CRP LEVELS. THE MOST SIGNIFICANT GENE ONTOLOGY TERMS ENRICHED IN THE GENES ASSOCIATED WITH THE CRP LEVELS WERE IMMUNE SYSTEM PROCESS, IMMUNE RESPONSE, DEFENSE RESPONSE, RESPONSE TO STIMULUS, AND RESPONSE TO STRESS, WHICH ARE ALL LINKED TO THE FUNCTIONS OF LEUKOCYTES. WHILE THE CRP-ASSOCIATED DNAM MAY BE CELL-TYPE SPECIFIC, UNDERSTANDING THE DNAM ASSOCIATION WITH CRP IN PERIPHERAL BLOOD LEUKOCYTES OF MULTI-ETHNIC POPULATIONS CAN ASSIST IN UNVEILING THE MOLECULAR MECHANISM OF HOW THE PROCESS OF INFLAMMATION AFFECTS THE RISKS OF DEVELOPING COMMON DISEASE THROUGH EPIGENETIC MODIFICATIONS. 2013 13 4255 26 METHYLOME-WIDE ANALYSIS OF CHRONIC HIV INFECTION REVEALS FIVE-YEAR INCREASE IN BIOLOGICAL AGE AND EPIGENETIC TARGETING OF HLA. HIV-INFECTED INDIVIDUALS ARE LIVING LONGER ON ANTIRETROVIRAL THERAPY, BUT MANY PATIENTS DISPLAY SIGNS THAT IN SOME WAYS RESEMBLE PREMATURE AGING. TO INVESTIGATE AND QUANTIFY THE IMPACT OF CHRONIC HIV INFECTION ON AGING, WE REPORT A GLOBAL ANALYSIS OF THE WHOLE-BLOOD DNA METHYLOMES OF 137 HIV+ INDIVIDUALS UNDER SUSTAINED THERAPY ALONG WITH 44 MATCHED HIV- INDIVIDUALS. FIRST, WE DEVELOP AND VALIDATE EPIGENETIC MODELS OF AGING THAT ARE INDEPENDENT OF BLOOD CELL COMPOSITION. USING THESE MODELS, WE FIND THAT BOTH CHRONIC AND RECENT HIV INFECTION LEAD TO AN AVERAGE AGING ADVANCEMENT OF 4.9 YEARS, INCREASING EXPECTED MORTALITY RISK BY 19%. IN ADDITION, SUSTAINED INFECTION RESULTS IN GLOBAL DEREGULATION OF THE METHYLOME ACROSS >80,000 CPGS AND SPECIFIC HYPOMETHYLATION OF THE REGION ENCODING THE HUMAN LEUKOCYTE ANTIGEN LOCUS (HLA). WE FIND THAT DECREASED HLA METHYLATION IS PREDICTIVE OF LOWER CD4 / CD8 T CELL RATIO, LINKING MOLECULAR AGING, EPIGENETIC REGULATION, AND DISEASE PROGRESSION. 2016 14 667 47 BLOOD-BASED EPIGENOME-WIDE ANALYSES OF 19 COMMON DISEASE STATES: A LONGITUDINAL, POPULATION-BASED LINKED COHORT STUDY OF 18,413 SCOTTISH INDIVIDUALS. BACKGROUND: DNA METHYLATION IS A DYNAMIC EPIGENETIC MECHANISM THAT OCCURS AT CYTOSINE-PHOSPHATE-GUANINE DINUCLEOTIDE (CPG) SITES. EPIGENOME-WIDE ASSOCIATION STUDIES (EWAS) INVESTIGATE THE STRENGTH OF ASSOCIATION BETWEEN METHYLATION AT INDIVIDUAL CPG SITES AND HEALTH OUTCOMES. ALTHOUGH BLOOD METHYLATION MAY ACT AS A PERIPHERAL MARKER OF COMMON DISEASE STATES, PREVIOUS EWAS HAVE TYPICALLY FOCUSED ONLY ON INDIVIDUAL CONDITIONS AND HAVE HAD LIMITED POWER TO DISCOVER DISEASE-ASSOCIATED LOCI. THIS STUDY EXAMINED THE ASSOCIATION OF BLOOD DNA METHYLATION WITH THE PREVALENCE OF 14 DISEASE STATES AND THE INCIDENCE OF 19 DISEASE STATES IN A SINGLE POPULATION OF OVER 18,000 SCOTTISH INDIVIDUALS. METHODS AND FINDINGS: DNA METHYLATION WAS ASSAYED AT 752,722 CPG SITES IN WHOLE-BLOOD SAMPLES FROM 18,413 VOLUNTEERS IN THE FAMILY-STRUCTURED, POPULATION-BASED COHORT STUDY GENERATION SCOTLAND (AGE RANGE 18 TO 99 YEARS). EWAS TESTED FOR CROSS-SECTIONAL ASSOCIATIONS BETWEEN BASELINE CPG METHYLATION AND 14 PREVALENT DISEASE STATES, AND FOR LONGITUDINAL ASSOCIATIONS BETWEEN BASELINE CPG METHYLATION AND 19 INCIDENT DISEASE STATES. PREVALENT CASES WERE SELF-REPORTED ON HEALTH QUESTIONNAIRES AT THE BASELINE. INCIDENT CASES WERE IDENTIFIED USING LINKAGE TO SCOTTISH PRIMARY (READ 2) AND SECONDARY (ICD-10) CARE RECORDS, AND THE CENSORING DATE WAS SET TO OCTOBER 2020. THE MEAN TIME-TO-DIAGNOSIS RANGED FROM 5.0 YEARS (FOR CHRONIC PAIN) TO 11.7 YEARS (FOR CORONAVIRUS DISEASE 2019 (COVID-19) HOSPITALISATION). THE 19 DISEASE STATES CONSIDERED IN THIS STUDY WERE SELECTED IF THEY WERE PRESENT ON THE WORLD HEALTH ORGANISATION'S 10 LEADING CAUSES OF DEATH AND DISEASE BURDEN OR INCLUDED IN BASELINE SELF-REPORT QUESTIONNAIRES. EWAS MODELS WERE ADJUSTED FOR AGE AT METHYLATION TYPING, SEX, ESTIMATED WHITE BLOOD CELL COMPOSITION, POPULATION STRUCTURE, AND 5 COMMON LIFESTYLE RISK FACTORS. A STRUCTURED LITERATURE REVIEW WAS ALSO CONDUCTED TO IDENTIFY EXISTING EWAS FOR ALL 19 DISEASE STATES TESTED. THE MEDLINE, EMBASE, WEB OF SCIENCE, AND PREPRINT SERVERS WERE SEARCHED TO RETRIEVE RELEVANT ARTICLES INDEXED AS OF MARCH 27, 2023. FIFTY-FOUR OF APPROXIMATELY 2,000 INDEXED ARTICLES MET OUR INCLUSION CRITERIA: ASSAYED BLOOD-BASED DNA METHYLATION, HAD >20 INDIVIDUALS IN EACH COMPARISON GROUP, AND EXAMINED ONE OF THE 19 CONDITIONS CONSIDERED. FIRST, WE ASSESSED WHETHER THE ASSOCIATIONS IDENTIFIED IN OUR STUDY WERE REPORTED IN PREVIOUS STUDIES. WE IDENTIFIED 69 ASSOCIATIONS BETWEEN CPGS AND THE PREVALENCE OF 4 CONDITIONS, OF WHICH 58 WERE NEWLY DESCRIBED. THE CONDITIONS WERE BREAST CANCER, CHRONIC KIDNEY DISEASE, ISCHEMIC HEART DISEASE, AND TYPE 2 DIABETES MELLITUS. WE ALSO UNCOVERED 64 CPGS THAT ASSOCIATED WITH THE INCIDENCE OF 2 DISEASE STATES (COPD AND TYPE 2 DIABETES), OF WHICH 56 WERE NOT REPORTED IN THE SURVEYED LITERATURE. SECOND, WE ASSESSED REPLICATION ACROSS EXISTING STUDIES, WHICH WAS DEFINED AS THE REPORTING OF AT LEAST 1 COMMON SITE IN >2 STUDIES THAT EXAMINED THE SAME CONDITION. ONLY 6/19 DISEASE STATES HAD EVIDENCE OF SUCH REPLICATION. THE LIMITATIONS OF THIS STUDY INCLUDE THE NONCONSIDERATION OF MEDICATION DATA AND A POTENTIAL LACK OF GENERALIZABILITY TO INDIVIDUALS THAT ARE NOT OF SCOTTISH AND EUROPEAN ANCESTRY. CONCLUSIONS: WE DISCOVERED OVER 100 ASSOCIATIONS BETWEEN BLOOD METHYLATION SITES AND COMMON DISEASE STATES, INDEPENDENTLY OF MAJOR CONFOUNDING RISK FACTORS, AND A NEED FOR GREATER STANDARDISATION AMONG EWAS ON HUMAN DISEASE. 2023 15 5884 33 SYSTEMIC INFLAMMATION AND BIOLOGICAL AGING IN THE HEALTH AND RETIREMENT STUDY. CHRONIC, LOW-LEVEL SYSTEMIC INFLAMMATION ASSOCIATED WITH AGING, OR INFLAMMAGING, IS A RISK FACTOR FOR SEVERAL CHRONIC DISEASES AND MORTALITY. USING DATA FROM THE HEALTH AND RETIREMENT STUDY, WE GENERATED A CONTINUOUS LATENT VARIABLE FOR SYSTEMIC INFLAMMATION FROM SEVEN MEASURED INDICATORS OF INFLAMMATION AND EXAMINED ASSOCIATIONS WITH ANOTHER BIOMARKER OF BIOLOGICAL AGING, DNA METHYLATION AGE ACCELERATION MEASURED BY EPIGENETIC CLOCKS, AND 4-YEAR MORTALITY (N = 3,113). WE FOUND THAT GREATER SYSTEMIC INFLAMMATION WAS POSITIVELY ASSOCIATED WITH DNA METHYLATION AGE ACCELERATION FOR 10 OF THE 13 EPIGENETIC CLOCKS, AFTER ADJUSTMENT FOR SOCIODEMOGRAPHICS AND CHRONIC DISEASE RISK FACTORS. THE LATENT VARIABLE FOR SYSTEMIC INFLAMMATION WAS ASSOCIATED WITH 4-YEAR MORTALITY INDEPENDENT OF DNA METHYLATION AGE ACCELERATION AND WAS A BETTER PREDICTOR OF 4-YEAR MORTALITY THAN ANY OF THE EPIGENETIC CLOCKS EXAMINED, AS WELL AS MORTALITY RISK FACTORS, INCLUDING OBESITY AND MULTIMORBIDITY. INFLAMMAGING AND DNA METHYLATION AGE ACCELERATION MAY REPRESENT DIFFERENT BIOLOGICAL PROCESSES CONTRIBUTING TO MORTALITY RISK. LEVERAGING MULTIPLE MEASURED INFLAMMATION MARKERS TO CAPTURE INFLAMMAGING IS IMPORTANT FOR BIOLOGY OF AGING RESEARCH. 2023 16 178 30 ACCELERATED EPIGENETIC AGING AS A RISK FACTOR FOR CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND DECREASED LUNG FUNCTION IN TWO PROSPECTIVE COHORT STUDIES. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A FREQUENT DIAGNOSIS IN OLDER INDIVIDUALS AND CONTRIBUTOR TO GLOBAL MORBIDITY AND MORTALITY. GIVEN THE LINK BETWEEN LUNG DISEASE AND AGING, WE NEED TO UNDERSTAND HOW MOLECULAR INDICATORS OF AGING RELATE TO LUNG FUNCTION AND DISEASE. USING DATA FROM THE POPULATION-BASED KORA (COOPERATIVE HEALTH RESEARCH IN THE REGION OF AUGSBURG) SURVEYS, WE ASSOCIATED BASELINE EPIGENETIC (DNA METHYLATION) AGE ACCELERATION WITH INCIDENT COPD AND LUNG FUNCTION. MODELS WERE ADJUSTED FOR AGE, SEX, SMOKING, HEIGHT, WEIGHT, AND BASELINE LUNG DISEASE AS APPROPRIATE. ASSOCIATIONS WERE REPLICATED IN THE NORMATIVE AGING STUDY. OF 770 KORA PARTICIPANTS, 131 DEVELOPED INCIDENT COPD OVER 7 YEARS. BASELINE ACCELERATED EPIGENETIC AGING WAS SIGNIFICANTLY ASSOCIATED WITH INCIDENT COPD. THE CHANGE IN AGE ACCELERATION (FOLLOW-UP - BASELINE) WAS MORE STRONGLY ASSOCIATED WITH COPD THAN BASELINE AGING ALONE. THE ASSOCIATION BETWEEN THE CHANGE IN AGE ACCELERATION BETWEEN BASELINE AND FOLLOW-UP AND INCIDENT COPD REPLICATED IN THE NORMATIVE AGING STUDY. ASSOCIATIONS WITH SPIROMETRIC LUNG FUNCTION PARAMETERS WERE WEAKER THAN THOSE WITH COPD, BUT A META-ANALYSIS OF BOTH COHORTS PROVIDE SUGGESTIVE EVIDENCE OF ASSOCIATIONS. ACCELERATED EPIGENETIC AGING, BOTH BASELINE MEASURES AND CHANGES OVER TIME, MAY BE A RISK FACTOR FOR COPD AND REDUCED LUNG FUNCTION. 2020 17 3555 27 IMPACT OF AGE, ANTIRETROVIRAL THERAPY, AND CANCER ON EPIGENETIC AGING IN PEOPLE LIVING WITH HIV. BACKGROUND: PREMATURE AGING HAS BEEN IDENTIFIED AS A GLOBAL RISK FACTOR FOR CANCER. CAUSES OF PREMATURE AGING ARE MULTIFACTORIAL, INCLUDING INFLAMMATION, INFECTION, CHRONIC STRESS, AND LIFESTYLE FACTORS. METHOD: WE EVALUATED WHETHER PREMATURE AGING IN PEOPLE LIVING WITH HIV (PLWH) WAS ASSOCIATED WITH ANTIRETROVIRAL THERAPY (ART) OR THE DIAGNOSIS OF CANCER. WE USED WELL-ESTABLISHED DNA METHYLATION PATTERNS TO ASSESS PREMATURE AGING, USING HORVATH ET AL., IN INDIVIDUALS WITH HIV LOCATED IN CLEVELAND, OHIO AND COMPARED THESE TO STANDARDIZED DATASETS OF US HISTORICAL BLOOD SAMPLES. SOME OF THE PLWH DEVELOPED CANCER OVER TIME. RESULTS: WE FOUND THAT DNA METHYLATION ANALYSIS IDENTIFIED ACCELERATED AGING IN PLWH WHEREAS ART THERAPY MITIGATED THE ADVANCEMENT OF DNA METHYLATION AGE. A VARIETY OF CANCERS WERE OBSERVED IN THIS POPULATION, BUT A CANCER DIAGNOSIS WAS NOT SIGNIFICANTLY ASSOCIATED WITH MORE ADVANCED DNA METHYLATION AGE. CONCLUSION: WE FIND THAT THE AGE ACCELERATION DETECTED IN PLWH IS MITIGATED BY ART THERAPY AND IS NOT FURTHER ACCELERATED BY A DIAGNOSIS OF CANCER. 2023 18 2920 33 GENE-SET ANALYSIS IS SEVERELY BIASED WHEN APPLIED TO GENOME-WIDE METHYLATION DATA. MOTIVATION: DNA METHYLATION IS AN EPIGENETIC MARK THAT CAN STABLY REPRESS GENE EXPRESSION. BECAUSE OF ITS BIOLOGICAL AND CLINICAL SIGNIFICANCE, SEVERAL METHODS HAVE BEEN DEVELOPED TO COMPARE GENOME-WIDE PATTERNS OF METHYLATION BETWEEN GROUPS OF SAMPLES. THE APPLICATION OF GENE SET ANALYSIS TO IDENTIFY RELEVANT GROUPS OF GENES THAT ARE ENRICHED FOR DIFFERENTIALLY METHYLATED GENES IS OFTEN A MAJOR COMPONENT OF THE ANALYSIS OF THESE DATA. THIS CAN BE USED, FOR EXAMPLE, TO IDENTIFY PROCESSES OR PATHWAYS THAT ARE PERTURBED IN DISEASE DEVELOPMENT. WE SHOW THAT GENE-SET ANALYSIS, AS IT IS TYPICALLY APPLIED TO GENOME-WIDE METHYLATION ASSAYS, IS SEVERELY BIASED AS A RESULT OF DIFFERENCES IN THE NUMBERS OF CPG SITES ASSOCIATED WITH DIFFERENT CLASSES OF GENES AND GENE PROMOTERS. RESULTS: WE DEMONSTRATE THIS BIAS USING PUBLISHED DATA FROM A STUDY OF DIFFERENTIAL CPG ISLAND METHYLATION IN LUNG CANCER AND A DATASET WE GENERATED TO STUDY METHYLATION CHANGES IN PATIENTS WITH LONG-STANDING ULCERATIVE COLITIS. WE SHOW THAT SEVERAL OF THE GENE SETS THAT SEEM ENRICHED WOULD ALSO BE IDENTIFIED WITH RANDOMIZED DATA. WE SUGGEST TWO EXISTING APPROACHES THAT CAN BE ADAPTED TO CORRECT THE BIAS. ACCOUNTING FOR THE BIAS IN THE LUNG CANCER AND ULCERATIVE COLITIS DATASETS PROVIDES NOVEL BIOLOGICAL INSIGHTS INTO THE ROLE OF METHYLATION IN CANCER DEVELOPMENT AND CHRONIC INFLAMMATION, RESPECTIVELY. OUR RESULTS HAVE SIGNIFICANT IMPLICATIONS FOR MANY PREVIOUS GENOME-WIDE METHYLATION STUDIES THAT HAVE DRAWN CONCLUSIONS ON THE BASIS OF SUCH STRONGLY BIASED ANALYSIS. CONTACT: CATHAL.SEOIGHE@NUIGALWAY.IE SUPPLEMENTARY INFORMATION: SUPPLEMENTARY DATA ARE AVAILABLE AT BIOINFORMATICS ONLINE. 2013 19 6112 33 THE EPIGENETIC CLOCK AS A PREDICTOR OF DISEASE AND MORTALITY RISK: A SYSTEMATIC REVIEW AND META-ANALYSIS. BACKGROUND: AGEING IS ONE OF THE PRINCIPAL RISK FACTORS FOR MANY CHRONIC DISEASES. HOWEVER, THERE IS CONSIDERABLE BETWEEN-PERSON VARIATION IN THE RATE OF AGEING AND INDIVIDUAL DIFFERENCES IN THEIR SUSCEPTIBILITY TO DISEASE AND DEATH. EPIGENETIC MECHANISMS MAY PLAY A ROLE IN HUMAN AGEING, AND DNA METHYLATION AGE BIOMARKERS MAY BE GOOD PREDICTORS OF AGE-RELATED DISEASES AND MORTALITY RISK. THE AIMS OF THIS SYSTEMATIC REVIEW WERE TO IDENTIFY AND SYNTHESISE THE EVIDENCE FOR AN ASSOCIATION BETWEEN PERIPHERALLY MEASURED DNA METHYLATION AGE AND LONGEVITY, AGE-RELATED DISEASE, AND MORTALITY RISK. METHODS: A SYSTEMATIC SEARCH WAS CONDUCTED IN LINE WITH THE PREFERRED REPORTING ITEMS FOR SYSTEMATIC REVIEWS AND META-ANALYSES (PRISMA) GUIDELINES. USING RELEVANT SEARCH TERMS, MEDLINE, EMBASE, COCHRANE CENTRAL REGISTER OF CONTROLLED TRIALS, AND PSYCHINFO DATABASES WERE SEARCHED TO IDENTIFY ARTICLES MEETING THE INCLUSION CRITERIA. STUDIES WERE ASSESSED FOR BIAS USING JOANNA BRIGGS INSTITUTE CRITICAL APPRAISAL CHECKLISTS. DATA WAS EXTRACTED FROM STUDIES MEASURING AGE ACCELERATION AS A PREDICTOR OF AGE-RELATED DISEASES, MORTALITY OR LONGEVITY, AND THE FINDINGS FOR SIMILAR OUTCOMES COMPARED. USING REVIEW MANAGER 5.3 SOFTWARE, TWO META-ANALYSES (ONE PER EPIGENETIC CLOCK) WERE CONDUCTED ON STUDIES MEASURING ALL-CAUSE MORTALITY. RESULTS: TWENTY-THREE RELEVANT ARTICLES WERE IDENTIFIED, INCLUDING A TOTAL OF 41,607 PARTICIPANTS. FOUR STUDIES FOCUSED ON AGEING AND LONGEVITY, 11 ON AGE-RELATED DISEASE (CANCER, CARDIOVASCULAR DISEASE, AND DEMENTIA), AND 11 ON MORTALITY. THERE WAS SOME, ALTHOUGH INCONSISTENT, EVIDENCE FOR AN ASSOCIATION BETWEEN INCREASED DNA METHYLATION AGE AND RISK OF DISEASE. META-ANALYSES INDICATED THAT EACH 5-YEAR INCREASE IN DNA METHYLATION AGE WAS ASSOCIATED AN 8 TO 15% INCREASED RISK OF MORTALITY. CONCLUSION: DUE TO THE SMALL NUMBER OF STUDIES AND HETEROGENEITY IN STUDY DESIGN AND OUTCOMES, THE ASSOCIATION BETWEEN DNA METHYLATION AGE AND AGE-RELATED DISEASE AND LONGEVITY IS INCONCLUSIVE. INCREASED EPIGENETIC AGE WAS ASSOCIATED WITH MORTALITY RISK, BUT POSITIVE PUBLICATION BIAS NEEDS TO BE CONSIDERED. FURTHER RESEARCH IS NEEDED TO DETERMINE THE EXTENT TO WHICH DNA METHYLATION AGE CAN BE USED AS A CLINICAL BIOMARKER. 2019 20 3652 32 INDIVIDUAL DNA METHYLATION PATTERN SHIFTS IN NANOPARTICLES-EXPOSED WORKERS ANALYZED IN FOUR CONSECUTIVE YEARS. A DNA METHYLATION PATTERN REPRESENTS AN ORIGINAL PLAN OF THE FUNCTION SETTINGS OF INDIVIDUAL CELLS AND TISSUES. THE BASIC STRATEGIES OF ITS DEVELOPMENT AND CHANGES DURING THE HUMAN LIFETIME ARE KNOWN, BUT THE DETAILS RELATED TO ITS MODIFICATION OVER THE YEARS ON AN INDIVIDUAL BASIS HAVE NOT YET BEEN STUDIED. MOREOVER, CURRENT EVIDENCE SHOWS THAT ENVIRONMENTAL EXPOSURE COULD GENERATE CHANGES IN DNA METHYLATION SETTINGS AND, SUBSEQUENTLY, THE FUNCTION OF GENES. IN THIS STUDY, WE ANALYZED THE EFFECT OF CHRONIC EXPOSURE TO NANOPARTICLES (NP) IN OCCUPATIONALLY EXPOSED WORKERS REPEATEDLY SAMPLED IN FOUR CONSECUTIVE YEARS (2016-2019). A DETAILED METHYLATION PATTERN ANALYSIS OF 14 PERSONS (10 EXPOSED AND 4 CONTROLS) WAS PERFORMED ON AN INDIVIDUAL BASIS. A MICROARRAY-BASED APPROACH USING CHIPS, ALLOWING THE ASSESSMENT OF MORE THAN 850 K CPG LOCI, WAS USED. INDIVIDUAL DNA METHYLATION PATTERNS WERE COMPARED BY PRINCIPAL COMPONENT ANALYSIS (PCA). THE RESULTS SHOW THE SHIFT IN DNA METHYLATION PATTERNS IN INDIVIDUAL YEARS IN ALL THE EXPOSED AND CONTROL SUBJECTS. THE OVERALL RANGE OF DIFFERENCES VARIED BETWEEN THE YEARS IN INDIVIDUAL PERSONS. THE DIFFERENCES BETWEEN THE FIRST AND LAST YEAR OF EXAMINATION (A THREE-YEAR TIME PERIOD) SEEM TO BE CONSISTENTLY GREATER IN THE NP-EXPOSED SUBJECTS IN COMPARISON WITH THE CONTROLS. THE SELECTED 14 MOST DIFFERENTLY METHYLATED CG LOCI WERE RELATIVELY STABLE IN THE CHRONICALLY EXPOSED SUBJECTS. IN SUMMARY, THE SPECIFIC TYPE OF LONG-TERM EXPOSURE CAN CONTRIBUTE TO THE FIXING OF RELEVANT EPIGENETIC CHANGES RELATED TO A SPECIFIC ENVIRONMENT AS, E.G., NP INHALATION. 2021