1 1960 173 EPIGENETIC AGING IN CHILDREN FROM A SMALL-SCALE FARMING SOCIETY IN THE CONGO BASIN: ASSOCIATIONS WITH CHILD GROWTH AND FAMILY CONFLICT. DEVELOPMENTAL ENVIRONMENTS INFLUENCE INDIVIDUALS' LONG-TERM HEALTH TRAJECTORIES, AND THERE IS INCREASING EMPHASIS ON UNDERSTANDING THE BIOLOGICAL PATHWAYS THROUGH WHICH THIS OCCURS. EPIGENETIC AGING EVALUATES DNA METHYLATION AT A SUITE OF DISTINCT CPG SITES IN THE GENOME, AND EPIGENETIC AGE ACCELERATION (EAA) IS LINKED TO HEIGHTENED CHRONIC MORBIDITY AND MORTALITY RISKS IN ADULTS. CONSEQUENTLY, EAA PROVIDES INSIGHTS ON TRAJECTORIES OF BIOLOGICAL AGING, WHICH EARLY LIFE EXPERIENCES MAY HELP SHAPE. HOWEVER, FEW STUDIES HAVE MEASURED CORRELATES OF CHILDREN'S EPIGENETIC AGING, ESPECIALLY OUTSIDE OF THE U.S. AND EUROPE. IN PARTICULAR, LITTLE IS KNOWN ABOUT HOW CHILDREN'S GROWTH AND DEVELOPMENT RELATE TO EAA IN ECOLOGIES IN WHICH ENERGETIC AND PATHOGENIC STRESSORS ARE COMMONPLACE. WE STUDIED EAA FROM DRIED BLOOD SPOTS AMONG BONDONGO CHILDREN (N = 54) RESIDING IN A SMALL-SCALE, FISHER-FARMER SOCIETY IN A REMOTE REGION OF THE REPUBLIC OF THE CONGO. HERE, INFECTIOUS DISEASE BURDENS AND THEIR RESULTANT ENERGY DEMANDS ARE HIGH. CHILDREN WHO WERE HEAVIER FOR HEIGHT OR TALLER FOR AGE, RESPECTIVELY, EXHIBITED GREATER EAA, INCLUDING INTRINSIC EAA, WHICH IS CONSIDERED TO MEASURE EAA INTERNAL TO CELLS. FURTHERMORE, WE FOUND THAT CHILDREN IN FAMILIES WITH MORE CONFLICT BETWEEN PARENTS HAD GREATER INTRINSIC EAA. THESE RESULTS SUGGEST THAT IN CONTEXTS IN WHICH LIMITED ENERGY MUST BE ALLOCATED TO COMPETING DEMANDS, MORE INVESTMENT IN GROWTH MAY COINCIDE WITH GREATER EAA, WHICH PARALLELS FINDINGS IN EUROPEAN CHILDREN WHO DO NOT FACE SIMILAR ENERGETIC CONSTRAINTS. OUR FINDINGS ALSO INDICATE THAT ASSOCIATIONS BETWEEN ADVERSE FAMILY ENVIRONMENTS AND GREATER INTRINSIC EAA WERE NONETHELESS OBSERVABLE BUT ONLY AFTER ADJUSTMENT FOR COVARIATES RELEVANT TO THE ENERGETICALLY AND IMMUNOLOGICALLY DEMANDING NATURE OF THE LOCAL ECOLOGY. 2020 2 1776 46 ECONOMIC HARDSHIP AND BIOLOGICAL WEATHERING: THE EPIGENETICS OF AGING IN A U.S. SAMPLE OF BLACK WOMEN. BACKGROUND: PAST RESEARCH HAS LINKED LOW SOCIO-ECONOMIC STATUS (SES) TO INFLAMMATION, METABOLIC DYSREGULATION, AND VARIOUS CHRONIC AND AGE-RELATED DISEASES SUCH AS TYPE 2 DIABETES, CORONARY HEART DISEASE, STROKE, AND DEMENTIA. THESE STUDIES SUGGEST THAT THE CHALLENGES AND ADVERSITIES ASSOCIATED WITH LOW SES MAY RESULT IN PREMATURE AGING AND INCREASED RISK OF MORBIDITY AND MORTALITY. OBJECTIVE: BUILDING UPON THIS RESEARCH, THE PRESENT STUDY INVESTIGATES VARIOUS AVENUES WHEREBY LOW INCOME MIGHT ACCELERATE BIOLOGICAL AGING. METHODS: STRUCTURAL EQUATION MODELING AND LONGITUDINAL DATA FROM A SAMPLE OF 100 BLACK, MIDDLE-AGED WOMEN RESIDING IN THE UNITED STATES WAS USED TO INVESTIGATE THE EFFECT OF INCOME ON A RECENTLY DEVELOPED EPIGENETIC MEASURE OF BIOLOGICAL AGING. THIS MEASURE CAN BE USED AS A "BIOLOGICAL CLOCK" TO ASSESS, AT ANY POINT DURING ADULTHOOD, THE EXTENT TO WHICH AN INDIVIDUAL IS EXPERIENCING ACCELERATED OR DECELERATED BIOLOGICAL AGING. RESULTS: LOW INCOME DISPLAYED A ROBUST ASSOCIATION WITH ACCELERATED AGING THAT WAS UNAFFECTED AFTER CONTROLLING FOR OTHER SES-RELATED FACTORS SUCH AS EDUCATION, MARITAL STATUS, AND CHILDHOOD ADVERSITY. FURTHER, OUR ANALYSES INDICATED THAT THE ASSOCIATION BETWEEN INCOME AND BIOLOGICAL AGING WAS NOT EXPLAINED BY HEALTH-RELATED BEHAVIORS SUCH AS DIET, EXERCISE, SMOKING, ALCOHOL CONSUMPTION, OR HAVING HEALTH INSURANCE. RATHER, IN LARGE MEASURE, IT WAS FINANCIAL PRESSURE (DIFFICULTY PAYING BILLS, BUYING NECESSITIES, OR MEETING DAILY EXPENSES) THAT ACCOUNTED FOR THE ASSOCIATION BETWEEN LOW INCOME AND ACCELERATED AGING. CONCLUSIONS: THESE FINDINGS SUPPORT THE VIEW THAT CHRONIC FINANCIAL PRESSURES ASSOCIATED WITH LOW INCOME EXERT A WEATHERING EFFECT THAT RESULTS IN PREMATURE AGING. 2016 3 1780 40 EDUCATION AND LIFESTYLE FACTORS ARE ASSOCIATED WITH DNA METHYLATION CLOCKS IN OLDER AFRICAN AMERICANS. DNA METHYLATION (DNAM) CLOCKS ARE IMPORTANT BIOMARKERS OF CELLULAR AGING AND ARE ASSOCIATED WITH A VARIETY OF AGE-RELATED CHRONIC DISEASES AND ALL-CAUSE MORTALITY. EXAMINING THE RELATIONSHIP BETWEEN EDUCATION AND LIFESTYLE RISK FACTORS FOR AGE-RELATED DISEASES AND MULTIPLE DNAM CLOCKS CAN INCREASE THE UNDERSTANDING OF HOW RISK FACTORS CONTRIBUTE TO AGING AT THE CELLULAR LEVEL. THIS STUDY EXPLORED THE ASSOCIATION BETWEEN EDUCATION OR LIFESTYLE RISK FACTORS FOR AGE-RELATED DISEASES AND THE ACCELERATION OF FOUR DNAM CLOCKS, INCLUDING INTRINSIC (IEAA) AND EXTRINSIC EPIGENETIC AGE ACCELERATION (EEAA), PHENOAGE ACCELERATION (PHENOAA), AND GRIMAGE ACCELERATION (GRIMAA) IN THE AFRICAN AMERICAN PARTICIPANTS OF THE GENETIC EPIDEMIOLOGY NETWORK OF ARTERIOPATHY. WE PERFORMED BOTH CROSS-SECTIONAL AND LONGITUDINAL ANALYSES. IN CROSS-SECTIONAL ANALYSES, GENDER, EDUCATION, BMI, SMOKING, AND ALCOHOL CONSUMPTION WERE ALL INDEPENDENTLY ASSOCIATED WITH GRIMAA, WHEREAS ONLY SOME OF THEM WERE ASSOCIATED WITH OTHER CLOCKS. THE EFFECT OF SMOKING AND EDUCATION ON GRIMAA VARIED BY GENDER. LONGITUDINAL ANALYSES SUGGEST THAT AGE AND BMI CONTINUED TO INCREASE GRIMAA, AND THAT AGE AND CURRENT SMOKING CONTINUED TO INCREASE PHENOAA AFTER CONTROLLING DNAM CLOCKS AT BASELINE. IN CONCLUSION, EDUCATION AND COMMON LIFESTYLE RISK FACTORS WERE ASSOCIATED WITH MULTIPLE DNAM CLOCKS. HOWEVER, THE ASSOCIATION WITH EACH RISK FACTOR VARIED BY CLOCK, WHICH SUGGESTS THAT DIFFERENT CLOCKS MAY CAPTURE ADVERSE EFFECTS FROM DIFFERENT ENVIRONMENTAL STIMULI. 2019 4 1746 33 EARLY LIFE ADVERSITY, PUBERTAL TIMING, AND EPIGENETIC AGE ACCELERATION IN ADULTHOOD. BACKGROUND: GIVEN ASSOCIATIONS LINKING EARLY LIFE ADVERSITY, PUBERTAL TIMING, AND BIOLOGICAL AGING, WE EXAMINED THE DIRECT AND INDIRECT EFFECTS OF EARLY LIFE TRAUMA ON ADULT BIOLOGICAL AGING (VIA AGE OF MENARCHE). METHODS: PARTICIPANTS WERE PREMENOPAUSAL WOMEN (N = 183). PATH MODELS EVALUATED WHETHER EARLY LIFE TRAUMA PREDICTED EARLY PUBERTAL TIMING AND THEREBY, ADULT EPIGENETIC AGE ACCELERATION (INDEXED VIA FOUR EPIGENETIC CLOCKS: HORVATH DNAM AGE, HANNUM DNAM AGE, DNAM PHENOAGE, AND DNAM GRIMAGE). SECONDARY ANALYSES EXPLORED THE EFFECTS OF TYPE OF TRAUMA (ABUSE AND NEGLECT) AND ADULT CHRONIC STRESS STATUS (CAREGIVER OF CHILD WITH AUTISM AND NON-CAREGIVER). RESULTS: EARLY LIFE TRAUMA AND EARLIER AGE AT MENARCHE INDEPENDENTLY PREDICTED ACCELERATED AGING BASED ON ONE OF THE FOUR EPIGENETIC CLOCKS, DNAM GRIMAGE, THOUGH EARLY LIFE TRAUMA WAS NOT ASSOCIATED WITH AGE OF MENARCHE. CHILDHOOD ABUSE, BUT NOT NEGLECT, PREDICTED FASTER EPIGENETIC AGING; RESULTS DID NOT DIFFER BY CHRONIC STRESS STATUS. CONCLUSIONS: EARLY TRAUMA AND EARLY MENARCHE APPEAR TO EXERT INDEPENDENT EFFECTS ON DNAM GRIMAGE, WHICH HAS BEEN SHOWN TO BE THE STRONGEST EPIGENETIC PREDICTOR OF MORTALITY RISK. THIS STUDY IDENTIFIES A POTENTIAL CORRELATE OR DETERMINANT OF ACCELERATED EPIGENETIC AGING-MENARCHEAL AGE. FUTURE RESEARCH SHOULD ADDRESS THE LIMITATIONS OF THIS STUDY BY USING RACIALLY DIVERSE SAMPLES. 2021 5 5395 48 REDUCED EPIGENETIC AGE IN OLDER ADULTS WITH HIGH SENSE OF PURPOSE IN LIFE. PSYCHOSOCIAL RISK FACTORS HAVE BEEN LINKED WITH ACCELERATED EPIGENETIC AGING, BUT LITTLE IS KNOWN ABOUT WHETHER PSYCHOSOCIAL RESILIENCE FACTORS (EG, SENSE OF PURPOSE IN LIFE) MIGHT REDUCE EPIGENETIC AGE ACCELERATION. IN THIS STUDY, WE TESTED IF OLDER ADULTS WHO EXPERIENCE HIGH LEVELS OF PURPOSE MIGHT SHOW REDUCED EPIGENETIC AGE ACCELERATION. WE EVALUATED THE RELATIONSHIP BETWEEN PURPOSE AND EPIGENETIC AGE ACCELERATION AS MEASURED BY 13 DNA METHYLATION (DNAM) "EPIGENETIC CLOCKS" ASSESSED IN 1 572 OLDER ADULTS FROM THE HEALTH AND RETIREMENT STUDY (MEAN AGE 70 YEARS). WE QUANTIFIED THE TOTAL ASSOCIATION BETWEEN PURPOSE AND DNAM AGE ACCELERATION AS WELL AS THE EXTENT TO WHICH THAT TOTAL ASSOCIATION MIGHT BE ATTRIBUTABLE TO DEMOGRAPHIC FACTORS, CHRONIC DISEASE, OTHER PSYCHOSOCIAL VARIABLES (EG, POSITIVE AFFECT), AND HEALTH-RELATED BEHAVIORS (HEAVY DRINKING, SMOKING, PHYSICAL ACTIVITY, AND BODY MASS INDEX [BMI]). PURPOSE IN LIFE WAS ASSOCIATED WITH REDUCED EPIGENETIC AGE ACCELERATION ACROSS 4 "SECOND-GENERATION" DNAM CLOCKS OPTIMIZED FOR PREDICTING HEALTH AND LONGEVITY (FALSE DISCOVERY RATE [FDR] Q < 0.0001: PHENOAGE, GRIMAGE, ZHANG EPIGENETIC MORTALITY INDEX; FDR Q < 0.05: DUNEDINPOAM). THESE ASSOCIATIONS WERE INDEPENDENT OF DEMOGRAPHIC AND PSYCHOSOCIAL FACTORS, BUT SUBSTANTIALLY ATTENUATED AFTER ADJUSTING FOR HEALTH-RELATED BEHAVIORS (DRINKING, SMOKING, PHYSICAL ACTIVITY, AND BMI). PURPOSE SHOWED NO SIGNIFICANT ASSOCIATION WITH 9 "FIRST-GENERATION" DNAM EPIGENETIC CLOCKS TRAINED ON CHRONOLOGICAL AGE. OLDER ADULTS WITH GREATER PURPOSE IN LIFE SHOW "YOUNGER" DNAM EPIGENETIC AGE ACCELERATION. THESE RESULTS MAY BE DUE IN PART TO ASSOCIATED DIFFERENCES IN HEALTH-RELATED BEHAVIORS. RESULTS SUGGEST NEW OPPORTUNITIES TO REDUCE BIOLOGICAL AGE ACCELERATION BY ENHANCING PURPOSE AND ITS BEHAVIORAL SEQUELAE IN LATE ADULTHOOD. 2023 6 2150 43 EPIGENETIC MEASURES OF AGEING PREDICT THE PREVALENCE AND INCIDENCE OF LEADING CAUSES OF DEATH AND DISEASE BURDEN. BACKGROUND: INDIVIDUALS OF THE SAME CHRONOLOGICAL AGE DISPLAY DIFFERENT RATES OF BIOLOGICAL AGEING. A NUMBER OF MEASURES OF BIOLOGICAL AGE HAVE BEEN PROPOSED WHICH HARNESS AGE-RELATED CHANGES IN DNA METHYLATION PROFILES. THESE MEASURES INCLUDE FIVE 'EPIGENETIC CLOCKS' WHICH PROVIDE AN INDEX OF HOW MUCH AN INDIVIDUAL'S BIOLOGICAL AGE DIFFERS FROM THEIR CHRONOLOGICAL AGE AT THE TIME OF MEASUREMENT. THE FIVE CLOCKS ENCOMPASS METHYLATION-BASED PREDICTORS OF CHRONOLOGICAL AGE (HORVATHAGE, HANNUMAGE), ALL-CAUSE MORTALITY (DNAM PHENOAGE, DNAM GRIMAGE) AND TELOMERE LENGTH (DNAM TELOMERE LENGTH). A SIXTH EPIGENETIC MEASURE OF AGEING DIFFERS FROM THESE CLOCKS IN THAT IT ACTS AS A SPEEDOMETER PROVIDING A SINGLE TIME-POINT MEASUREMENT OF THE PACE OF AN INDIVIDUAL'S BIOLOGICAL AGEING. THIS MEASURE OF AGEING IS TERMED DUNEDINPOAM. IN THIS STUDY, WE TEST THE ASSOCIATION BETWEEN THESE SIX EPIGENETIC MEASURES OF AGEING AND THE PREVALENCE AND INCIDENCE OF THE LEADING CAUSES OF DISEASE BURDEN AND MORTALITY IN HIGH-INCOME COUNTRIES (N 2500 G) CONTROL PARTICIPANTS. METHODS: BUCCAL CELLS WERE COLLECTED FROM 45 ELBW SURVIVORS AND 49 NBW CONTROL PARTICIPANTS AT 30 TO 35 YEARS OF AGE. EPIGENETIC AGE WAS CALCULATED FROM THE WEIGHTED AVERAGE OF DNA METHYLATION AT 353 CYTOSINE-PHOSPHATE-GUANINE SEQUENCE WITHIN DNA SITES, BY USING THE ILLUMINA INFINIUM HUMAN METHYLATION EPIC 850K BEADCHIP ARRAY. RESULTS: BEFORE AND AFTER STATISTICALLY ADJUSTING FOR NEUROSENSORY IMPAIRMENT AND THE PRESENCE OF CHRONIC HEALTH CONDITIONS, A SIGNIFICANT SEX BY BIRTH WEIGHT GROUP INTERACTION WAS OBSERVED IN THE 353-SITE EPIGENETIC-CLOCK ASSAY (P = .03), WHEREBY ELBW MEN HAD A SIGNIFICANTLY OLDER EPIGENETIC AGE THAN NBW MEN (4.6 YEARS; P = .01). WOMEN BORN AT ELBW WERE NOT FOUND TO BE EPIGENETICALLY OLDER THAN THEIR NBW PEERS. CONCLUSIONS: THE RESULTS OF THIS STUDY SUGGEST THAT PRENATAL EXPOSURES MAY PLAY AN IMPORTANT ROLE IN AGING, AND THAT MEN BORN PRETERM MAY EXPERIENCE ACCELERATED AGING RELATIVE TO THEIR PEERS. WE FURTHER HIGHLIGHT THE NEED TO MONITOR AND PROMOTE THE HEALTH OF PRETERM SURVIVORS, WITH A PARTICULAR FOCUS ON HEALTHY AGING ACROSS THE LIFE SPAN. 2021 18 178 39 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 19 4010 35 LOW MATERNAL ADHERENCE TO A MEDITERRANEAN DIET IS ASSOCIATED WITH INCREASE IN METHYLATION AT THE MEG3-IG DIFFERENTIALLY METHYLATED REGION IN FEMALE INFANTS. DIET IS DICTATED BY THE SURROUNDING ENVIRONMENT, AS FOOD ACCESS AND AVAILABILITY MAY CHANGE DEPENDING ON WHERE ONE LIVES. MATERNAL DIET DURING PREGNANCY IS AN IMPORTANT PART OF THE IN UTERO ENVIRONMENT, AND MAY AFFECT THE EPIGENOME. STUDIES LOOKING AT OVERALL DIET PATTERN IN RELATION TO DNA METHYLATION HAVE BEEN LACKING. THE MEDITERRANEAN DIET IS KNOWN FOR ITS HEALTH BENEFITS, INCLUDING DECREASED INFLAMMATION, WEIGHT LOSS, AND MANAGEMENT OF CHRONIC DISEASES. THIS STUDY ASSESSES THE ASSOCIATION BETWEEN MATERNAL ADHERENCE TO A MEDITERRANEAN DIET PATTERN DURING PREGNANCY AND INFANT DNA METHYLATION AT BIRTH. MEDITERRANEAN DIET ADHERENCE IN EARLY PREGNANCY WAS MEASURED IN 390 WOMEN ENROLLED IN THE NEWBORN EPIGENETIC STUDY, AND DNA METHYLATION WAS ASSESSED IN THEIR INFANTS AT BIRTH. MULTINOMIAL LOGISTIC REGRESSION WAS USED TO ASSESS THE ASSOCIATION BETWEEN ADHERENCE TO A MEDITERRANEAN DIET AND INFANT METHYLATION AT THE MEG3, MEG3-IG, PLEIOMORPHIC ADENOMA GENE-LIKE 1, INSULIN-LIKE GROWTH FACTOR 2 GENE, H19, MESODERM-SPECIFIC TRANSCRIPT, NEURONATIN, PATERNALLY EXPRESSED GENE 3, SARCOGLYCAN AND PATERNALLY EXPRESSED GENE 10 REGIONS, MEASURED BY PYROSEQUENCING. INFANTS OF MOTHERS WITH A LOW ADHERENCE TO A MEDITERRANEAN DIET HAD A GREATER ODDS OF HYPO-METHYLATION AT THE MEG3-IG DIFFERENTIALLY METHYLATED REGION (DMR). SEX-STRATIFIED MODELS SHOWED THAT THIS ASSOCIATION WAS PRESENT IN GIRLS ONLY. THIS STUDY PROVIDES EARLY EVIDENCE ON THE ASSOCIATION BETWEEN OVERALL DIET PATTERN AND METHYLATION AT THE 9 DMRS INCLUDED IN THIS STUDY, AND SUGGESTS THAT MATERNAL DIET CAN HAVE A SEX-SPECIFIC IMPACT ON INFANT DNA METHYLATION AT SPECIFIC IMPRINTED DMRS. 2017 20 1516 44 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