1 4249 140 METHYLATION-BASED BIOLOGICAL AGE AND BREAST CANCER RISK. BACKGROUND: AGE IS ONE OF THE STRONGEST PREDICTORS OF CANCER, CHRONIC DISEASE, AND MORTALITY, BUT BIOLOGICAL RESPONSES TO AGING DIFFER AMONG PEOPLE. EPIGENETIC DNA MODIFICATIONS HAVE BEEN USED TO ESTIMATE "BIOLOGICAL AGE," WHICH MAY BE A USEFUL PREDICTOR OF DISEASE RISK. WE TESTED THIS HYPOTHESIS FOR BREAST CANCER. METHODS: USING A CASE-COHORT APPROACH, WE MEASURED BASELINE BLOOD DNA METHYLATION OF 2764 WOMEN ENROLLED IN THE SISTER STUDY, 1566 OF WHOM SUBSEQUENTLY DEVELOPED BREAST CANCER AFTER AN AVERAGE OF 6 YEARS. USING THREE PREVIOUSLY ESTABLISHED METHYLATION-BASED "CLOCKS" (HANNUM, HORVATH, AND LEVINE), WE DEFINED BIOLOGICAL AGE ACCELERATION FOR EACH WOMAN BY COMPARING HER ESTIMATED BIOLOGICAL AGE WITH HER CHRONOLOGICAL AGE. HAZARD RATIOS AND 95% CONFIDENCE INTERVALS FOR BREAST CANCER RISK WERE ESTIMATED USING COX REGRESSION MODELS. ALL STATISTICAL TESTS WERE TWO-SIDED. RESULTS: EACH OF THE THREE CLOCKS SHOWED THAT BIOLOGICAL AGE ACCELERATION WAS STATISTICALLY SIGNIFICANTLY ASSOCIATED WITH INCREASED RISK OF DEVELOPING BREAST CANCER (5-YEAR AGE ACCELERATION, HANNUM'S CLOCK: HAZARD RATIO [HR] = 1.10, 95% CONFIDENCE INTERVAL [CI] = 1.00 TO 1.21, P = .04; HORVATH'S CLOCK: HR = 1.08, 95% CI = 1.00 TO 1.17, P = .04; LEVINE'S CLOCK: HR = 1.15, 95% CI = 1.07 TO 1.23, P < .001). FOR LEVINE'S CLOCK, EACH 5-YEAR ACCELERATION IN BIOLOGICAL AGE CORRESPONDED WITH A 15% INCREASE IN BREAST CANCER RISK. ALTHOUGH BIOLOGICAL AGE MAY ACCELERATE WITH MENOPAUSAL TRANSITION, AGE ACCELERATION IN PREMENOPAUSAL WOMEN INDEPENDENTLY PREDICTED BREAST CANCER. CASE-ONLY ANALYSIS SUGGESTED THAT, AMONG WOMEN WHO DEVELOP BREAST CANCER, INCREASED AGE ACCELERATION IS ASSOCIATED WITH INVASIVE CANCER (ODDS RATIO FOR INVASIVE = 1.09, 95% CI = 0.98 TO 1.22, P = .10). CONCLUSIONS: DNA METHYLATION-BASED MEASURES OF BIOLOGICAL AGE MAY BE IMPORTANT PREDICTORS OF BREAST CANCER RISK. 2019 2 525 46 ASSOCIATIONS OF BODY COMPOSITION AND PHYSICAL ACTIVITY LEVEL WITH MULTIPLE MEASURES OF EPIGENETIC AGE ACCELERATION. EPIGENETIC CLOCKS USE DNA METHYLATION TO ESTIMATE BIOLOGICAL AGE. WHETHER BODY COMPOSITION AND PHYSICAL ACTIVITY ARE ASSOCIATED WITH THESE CLOCKS IS NOT WELL UNDERSTOOD. USING BLOOD SAMPLES COLLECTED AT ENROLLMENT (2003-2009) FROM 2,758 WOMEN IN THE US NATIONWIDE SISTER STUDY, WE CALCULATED 6 EPIGENETIC AGE ACCELERATION METRICS USING 4 EPIGENETIC CLOCKS (HANNUM, HORVATH, PHENOAGE, GRIMAGE). RECREATIONAL PHYSICAL ACTIVITY WAS SELF-REPORTED, AND ADIPOSITY MEASURES WERE ASSESSED BY TRAINED MEDICAL EXAMINERS (BODY MASS INDEX (BMI), WAIST-TO-HIP RATIO (WTH), WAIST CIRCUMFERENCE). IN CROSS-SECTIONAL ANALYSES, ALL ADIPOSITY MEASURES WERE ASSOCIATED WITH EPIGENETIC AGE ACCELERATION. THE STRONGEST ASSOCIATION WAS FOR BMI AND PHENOAGE, A MEASURE OF BIOLOGICAL AGE THAT CORRELATES WITH CHRONIC DISEASE (BMI OF >/=35.0 VS. 18.5-24.9, BETA = 3.15 YEARS, 95% CONFIDENCE INTERVAL (CI): 2.41, 3.90; P FOR TREND < 0.001). IN A MUTUAL-ADJUSTMENT MODEL, BOTH WERE ASSOCIATED WITH PHENOAGE AGE ACCELERATION (BMI OF >/=35.0 VS. 18.5-24.9, BETA = 2.69 YEARS, 95% CI: 1.90, 3.48; P FOR TREND < 0.001; QUARTILE 4 VS.1 WTH, BETA = 1.00 YEARS, 95% CI: 0.34, 1.65; P FOR TREND < 0.008). AFTER ADJUSTMENT, PHYSICAL ACTIVITY WAS ASSOCIATED ONLY WITH GRIMAGE (QUARTILE 4 VS. 1, BETA = -0.42 YEARS, 95% CI: -0.70, -0.14; P FOR TREND = 0.001). PHYSICAL ACTIVITY ATTENUATED THE WAIST CIRCUMFERENCE ASSOCIATIONS WITH PHENOAGE AND GRIMAGE. EXCESS ADIPOSITY WAS ASSOCIATED WITH EPIGENETIC AGE ACCELERATION; PHYSICAL ACTIVITY MIGHT ATTENUATE ASSOCIATIONS WITH WAIST CIRCUMFERENCE. 2021 3 1955 61 EPIGENETIC AGE ACCELERATION PREDICTS CANCER, CARDIOVASCULAR, AND ALL-CAUSE MORTALITY IN A GERMAN CASE COHORT. BACKGROUND: PREVIOUS STUDIES HAVE DEVELOPED MODELS PREDICTING METHYLATION AGE FROM DNA METHYLATION IN BLOOD AND OTHER TISSUES (EPIGENETIC CLOCK) AND SUGGESTED THE DIFFERENCE BETWEEN DNA METHYLATION AND CHRONOLOGICAL AGES AS A MARKER OF HEALTHY AGING. THE GOAL OF THIS STUDY WAS TO CONFIRM AND EXPAND SUCH OBSERVATIONS BY INVESTIGATING WHETHER DIFFERENT CONCEPTS OF THE EPIGENETIC CLOCKS IN A POPULATION-BASED COHORT ARE ASSOCIATED WITH CANCER, CARDIOVASCULAR, AND ALL-CAUSE MORTALITY. RESULTS: DNA METHYLATION AGE WAS ESTIMATED IN A COHORT OF 1863 OLDER PEOPLE, AND THE DIFFERENCE BETWEEN AGE PREDICTED BY DNA METHYLATION AND CHRONOLOGICAL AGE (DELTAAGE) WAS CALCULATED. A CASE-COHORT DESIGN AND WEIGHTED PROPORTIONAL COX HAZARD MODELS WERE USED TO ESTIMATE ASSOCIATIONS OF DELTAAGE WITH CANCER, CARDIOVASCULAR, AND ALL-CAUSE MORTALITY. HAZARD RATIOS FOR DELTAAGE (PER 5 YEARS) CALCULATED USING THE EPIGENETIC CLOCK DEVELOPED BY HORVATH WERE 1.23 (95 % CI 1.10-1.38) FOR ALL-CAUSE MORTALITY, 1.22 (95 % CI 1.03-1.45) FOR CANCER MORTALITY, AND 1.19 (95 % CI 0.98-1.43) FOR CARDIOVASCULAR MORTALITY AFTER ADJUSTMENT FOR BATCH EFFECTS, AGE, SEX, EDUCATIONAL LEVEL, HISTORY OF CHRONIC DISEASES, HYPERTENSION, SMOKING STATUS, BODY MASS INDEX, AND LEUCOCYTE DISTRIBUTION. ASSOCIATIONS WERE SIMILAR BUT WEAKER FOR DELTAAGE CALCULATED USING THE EPIGENETIC CLOCK DEVELOPED BY HANNUM. CONCLUSIONS: THESE RESULTS SHOW THAT AGE ACCELERATION IN TERMS OF THE DIFFERENCE BETWEEN AGE PREDICTED BY DNA METHYLATION AND CHRONOLOGICAL AGE IS AN INDEPENDENT PREDICTOR OF ALL-CAUSE AND CAUSE-SPECIFIC MORTALITY AND MAY BE USEFUL AS A GENERAL MARKER OF HEALTHY AGING. 2016 4 1956 51 EPIGENETIC AGE IN PERIPHERAL BLOOD AMONG CHILDREN, ADOLESCENT, AND ADULT SURVIVORS OF CHILDHOOD CANCER. IMPORTANCE: CERTAIN CANCER THERAPIES ARE RISK FACTORS FOR EPIGENETIC AGE ACCELERATION (EAA) AMONG SURVIVORS OF CHILDHOOD CANCER, AND EAA IS ASSOCIATED WITH CHRONIC HEALTH CONDITIONS (CHCS). HOWEVER, SMALL NUMBERS OF YOUNGER SURVIVORS (AGED <20 YEARS) PREVIOUSLY EVALUATED HAVE LIMITED THE ABILITY TO CALCULATE EAA AMONG THIS AGE GROUP. OBJECTIVE: TO EVALUATE THE CHANGE RATE OF EPIGENETIC AGE (EA) AND EAA IN YOUNGER COMPARED WITH OLDER SURVIVORS AND THE POSSIBLE ASSOCIATION OF EAA WITH EARLY-ONSET OBESITY (AGED <20 YEARS), SEVERITY/BURDEN OF CHCS, AND LATE MORTALITY (>5 YEARS FROM CANCER DIAGNOSIS). DESIGN, SETTING, AND PARTICIPANTS: STUDY PARTICIPANTS WERE FROM THE ST JUDE LIFETIME COHORT, INITIATED IN 2007 WITH ONGOING FOLLOW-UP. THE PRESENT STUDY WAS CONDUCTED FROM APRIL 17, 2022, TO MARCH 23, 2023. SURVIVORS IN THIS COHORT OF EUROPEAN ANCESTRY WITH DNA METHYLATION DATA WERE INCLUDED. CROSS-SECTIONAL ANNUAL CHANGES IN EA AND EAA WERE COMPARED ACROSS 5 DIFFERENT CHRONOLOGIC AGE GROUPS: AGE 0 TO 9 (CHILDREN), 10 TO 19 (ADOLESCENTS), 20 TO 34 (YOUNGER ADULTS), 35 TO 49 (MIDDLE-AGED ADULTS), AND GREATER THAN OR EQUAL TO 50 (OLDER ADULTS) YEARS. LOGISTIC REGRESSION EVALUATED THE ASSOCIATION BETWEEN EAA AND EARLY-ONSET OBESITY OR SEVERITY/BURDEN OF CHCS. COX PROPORTIONAL HAZARDS REGRESSION ASSESSED THE ASSOCIATION BETWEEN EAA AND LATE MORTALITY. MAIN OUTCOMES AND MEASURES: EARLY-ONSET OBESITY, SEVERITY/BURDEN OF CHCS (GRADED USING THE COMMON TERMINOLOGY CRITERIA FOR ADVERSE EVENTS (GRADE 1, MILD; 2, MODERATE; 3, SEVERE/DISABLING; 4, LIFE-THREATENING) AND WERE COMBINED INTO HIGH VS LOW SEVERITY/BURDEN BASED ON FREQUENCY AND GRADE), AND LATE MORTALITY WERE THE OUTCOMES BASED ON FOLLOW-UP UNTIL APRIL 2020. EXPANDED DNA METHYLATION PROFILING INCREASED THE NUMBER OF SURVIVORS YOUNGER THAN 20 YEARS (N = 690). EPIGENETIC AGE WAS CALCULATED PRIMARILY USING THE LEVINE CLOCK, AND EAA WAS DERIVED FROM LEAST SQUARES REGRESSION OF EA AGAINST CHRONOLOGIC AGE AND WAS STANDARDIZED TO A Z SCORE (LEVINE EEA). RESULTS: AMONG 2846 PARTICIPANTS (MEDIAN AGE, 30.3 [IQR, 9.3-41.5] YEARS; 53% MALES), THE CROSS-SECTIONAL ANNUAL CHANGE IN EA_LEVINE WAS HIGHER IN CHILDREN (1.63 YEARS) AND ADOLESCENTS (1.14 YEARS), AND THE ADJUSTED LEAST-SQUARES MEAN OF LEVINE EEA WAS LOWER IN CHILDREN (-0.22 YEARS) AND OLDER ADULTS (-1.70 YEARS). EACH 1-SD INCREASE IN LEVINE EEA WAS ASSOCIATED WITH INCREASED RISK OF DEVELOPING EARLY-ONSET OBESITY (ODDS RATIO [OR], 1.46; 95% CI, 1.19-1.78), HIGH SEVERITY/BURDEN OF CHCS (OR, 1.13; 95% CI, 1.03-1.24), AND LATE MORTALITY (HAZARD RATIO, 1.75; 95% CI, 1.35-2.26). CONCLUSIONS AND RELEVANCE: THE FINDINGS OF THIS STUDY SUGGEST THAT EAA MEASURED IN CHILDREN AND ADOLESCENT SURVIVORS OF CHILDHOOD CANCER IS ASSOCIATED WITH EARLY-ONSET OBESITY, SEVERITY/BURDEN OF ALL CHCS, AND LATE MORTALITY. EVALUATING EAA MAY HELP IDENTIFY SURVIVORS OF CHILDHOOD CANCER AT INCREASED RISK FOR EARLY-ONSET OBESITY, MORBIDITY IN GENERAL, AND MORTALITY. 2023 5 173 37 ACCELERATED AGING IN BIPOLAR DISORDERS: AN EXPLORATORY STUDY OF SIX EPIGENETIC CLOCKS. BIPOLAR DISORDER (BD) IS A CHRONIC AND SEVERE PSYCHIATRIC DISORDER ASSOCIATED WITH SIGNIFICANT MEDICAL MORBIDITY AND REDUCED LIFE EXPECTANCY. IN THIS STUDY, WE ASSESSED ACCELERATED EPIGENETIC AGING IN INDIVIDUALS WITH BD USING VARIOUS DNA METHYLATION (DNAM)-BASED MARKERS. FOR THIS PURPOSE, WE USED FIVE EPIGENETIC CLOCKS (HORVATH, HANNUM, EN, PHENOAGE, AND GRIMAGE) AND A DNAM-BASED TELOMERE LENGTH CLOCK (DNAMTL). DNAM PROFILES WERE OBTAINED USING INFINIUM METHYLATIONEPIC ARRAYS FROM WHOLE-BLOOD SAMPLES OF 184 INDIVIDUALS WITH BD. WE ALSO ESTIMATED BLOOD CELL COUNTS BASED ON DNAM LEVELS FOR ADJUSTMENT. SIGNIFICANT CORRELATIONS BETWEEN CHRONOLOGICAL AGE AND EACH EPIGENETIC AGE ESTIMATED USING THE SIX DIFFERENT CLOCKS WERE OBSERVED. FOLLOWING ADJUSTMENT FOR BLOOD CELL COUNTS, WE FOUND THAT THE SIX EPIGENETIC AGEACCELS (AGE ACCELERATIONS) WERE SIGNIFICANTLY ASSOCIATED WITH THE BODY MASS INDEX. GRIMAGE AGEACCEL WAS SIGNIFICANTLY ASSOCIATED WITH MALE SEX, SMOKING STATUS AND CHILDHOOD MALTREATMENT. DNAMTL AGEACCEL WAS SIGNIFICANTLY ASSOCIATED WITH SMOKING STATUS. OVERALL, THIS STUDY SHOWED THAT DISTINCT EPIGENETIC CLOCKS ARE SENSITIVE TO DIFFERENT ASPECTS OF AGING PROCESS IN BD. FURTHER INVESTIGATIONS WITH COMPREHENSIVE EPIGENETIC CLOCK ANALYSES AND LARGE SAMPLES ARE REQUIRED TO CONFIRM OUR FINDINGS OF POTENTIAL DETERMINANTS OF AN ACCELERATED EPIGENETIC AGING IN BD. 2023 6 2150 46 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 450 000 CPG SITES IN 40 NON-SMOKING WOMEN (AGE 40-80) DIFFERENTIALLY EXPOSED TO ENVIRONMENTAL CD FROM THAILAND. BASED ON SPECIFIC GRAVITY ADJUSTED URINARY CD, WE CLASSIFIED THEM AS HIGH (HE) AND LOW (LE) EXPOSED AND AGE-MATCHED WITHIN 5 YEARS. URINARY CD WAS DEFINED AS BELOW 2 MICROG/L IN THE LE GROUP. WE PREDICTED EPIGENETIC AGE (DNAM-AGE) USING TWO PUBLISHED METHODS BY HORVATH AND HANNUM AND EXAMINED THE DIFFERENCE BETWEEN EPIGENETIC AGE AND CHRONOLOGIC AGE (DELTAAGE). WE ASSESSED DIFFERENCES BY CD EXPOSURE USING LINEAR MIXED MODELS ADJUSTED FOR ESTIMATED WHITE BLOOD CELL PROPORTIONS, BMI, AND URINARY CREATININE. WE IDENTIFIED 213 AGE-ASSOCIATED CPG SITES IN OUR POPULATION (P < 10(-4)). COUNTERINTUITIVELY, THE MEAN DELTAAGE WAS SMALLER IN HE VS. LE (HANNUM: 3.6 VS. 7.6 YEARS, P = 0.0093; HORVATH: 2.4 VS. 4.5 YEARS, P = 0.1308). THE CD EXPOSED GROUP WAS ASSOCIATED WITH CHANGES IN METHYLATION (P < 0.05) AT 12, 8, AND 20 AGE-ASSOCIATED SITES IDENTIFIED IN OUR POPULATION, HANNUM, AND HORVATH. FROM THE RESULTS OF THIS PILOT STUDY, ELEVATED CD EXPOSURE IS ASSOCIATED WITH METHYLATION CHANGES AT AGE-ASSOCIATED SITES AND SMALLER DIFFERENCES BETWEEN DNAM-AGE AND CHRONOLOGIC AGE, IN CONTRAST TO EXPECTED AGE-ACCELERATING EFFECTS. CD MAY MODIFY EPIGENETIC AGING, AND BIOMARKERS OF AGING WARRANT FURTHER INVESTIGATION WHEN EXAMINING CD AND ITS RELATIONSHIP WITH CHRONIC DISEASE AND MORTALITY. 2017 18 2044 42 EPIGENETIC CLOCK ANALYSIS OF BLOOD SAMPLES IN DRUG-NAIVE FIRST-EPISODE SCHIZOPHRENIA PATIENTS. BACKGROUND: SCHIZOPHRENIA (SCZ) IS A SEVERE AND CHRONIC PSYCHIATRIC DISORDER WITH PREMATURE AGE-RELATED PHYSIOLOGICAL CHANGES. HOWEVER, NUMEROUS PREVIOUS STUDIES EXAMINED THE EPIGENETIC AGE ACCELERATION IN SCZ PATIENTS AND YIELDED INCONCLUSIVE RESULTS. IN THIS STUDY, WE PROPOSE TO EXPLORE THE EPIGENETIC AGE ACCELERATION IN DRUG-NAIVE FIRST-EPISODE SCZ (FSCZ) PATIENTS AND INVESTIGATE WHETHER EPIGENETIC AGE ACCELERATION IS ASSOCIATED WITH ANTIPSYCHOTIC TREATMENT, PSYCHOTIC SYMPTOMS, COGNITION, AND SUBCORTICAL VOLUMES. METHODS: WE ASSESSED THE EPIGENETIC AGE IN 38 DRUG-NAIVE FSCZ PATIENTS AND 38 HEALTHY CONTROLS BY USING THREE INDEPENDENT CLOCKS, INCLUDING HORVATH, HANNUM AND LEVINE ALGORITHMS. THE EPIGENETIC AGE MEASUREMENTS IN SCZ PATIENTS WERE REPEATED AFTER RECEIVING 8 WEEKS RISPERIDONE MONOTHERAPY. RESULTS: OUR FINDINGS SHOWED SIGNIFICANTLY POSITIVE CORRELATIONS BETWEEN EPIGENETIC AGES ASSESSED BY THREE CLOCKS AND CHRONOLOGICAL AGE IN BOTH FSCZ PATIENTS AND HEALTHY CONTROLS. COMPARED WITH HEALTHY CONTROLS, DRUG-NAIVE FSCZ PATIENTS HAVE A SIGNIFICANT EPIGENETIC AGE DECELERATION IN HORVATH CLOCK (P = 0.01), BUT NOT IN HANNUM CLOCK (P = 0.07) AND LEVINE CLOCK (P = 0.43). THE EPIGENETIC AGES OF HANNUM CLOCK (P = 0.002) AND LEVINE CLOCK (P = 0.01) WERE SIGNIFICANTLY ACCELERATED IN SCZ PATIENTS AFTER 8-WEEK RISPERIDONE TREATMENT. HOWEVER, NO SIGNIFICANT ASSOCIATIONS BETWEEN EPIGENETIC AGE ACCELERATION AND PSYCHOTIC SYMPTOMS, COGNITIVE FUNCTION, AS WELL AS SUBCORTICAL VOLUMES WERE OBSERVED IN FSCZ PATIENTS. CONCLUSION: THESE RESULTS DEMONSTRATE THAT DISTINCT EPIGENETIC CLOCKS ARE SENSITIVE TO DIFFERENT ASPECTS OF AGING PROCESS. FURTHER INVESTIGATIONS WITH COMPREHENSIVE EPIGENETIC CLOCK ANALYSES AND LARGE SAMPLES ARE REQUIRED TO CONFIRM OUR FINDINGS. 2023 19 1514 55 DNA METHYLATION AND THE EPIGENETIC CLOCK IN RELATION TO PHYSICAL FRAILTY IN OLDER PEOPLE: THE LOTHIAN BIRTH COHORT 1936. BACKGROUND: THE BIOLOGICAL MECHANISMS UNDERLYING FRAILTY IN OLDER PEOPLE ARE POORLY UNDERSTOOD. THERE IS SOME EVIDENCE TO SUGGEST THAT DNA METHYLATION PATTERNS MAY BE ALTERED IN FRAIL INDIVIDUALS. METHODS: PARTICIPANTS WERE 791 PEOPLE AGED 70 YEARS FROM THE LOTHIAN BIRTH COHORT 1936. DNA METHYLATION WAS MEASURED IN WHOLE BLOOD. BIOLOGICAL AGE WAS ESTIMATED USING TWO MEASURES OF DNA METHYLATION-BASED AGE ACCELERATION-EXTRINSIC AND INTRINSIC EPIGENETIC AGE ACCELERATION. WE CARRIED OUT AN EPIGENOME-WIDE ASSOCIATION STUDY OF PHYSICAL FRAILTY, AS DEFINED BY THE FRIED PHENOTYPE. MULTINOMIAL LOGISTIC REGRESSION WAS USED TO CALCULATE RELATIVE RISK RATIOS FOR BEING PHYSICALLY FRAIL OR PRE-FRAIL ACCORDING TO EPIGENETIC AGE ACCELERATION. RESULTS: THERE WAS A SINGLE SIGNIFICANT (P = 1.16 X 10-7) ASSOCIATION IN THE EPIGENOME-WIDE ASSOCIATION STUDY COMPARING FRAIL VERSUS NOT FRAIL. THE SAME CPG WAS NOT SIGNIFICANT WHEN COMPARING PRE-FRAIL VERSUS NOT FRAIL. GREATER EXTRINSIC EPIGENETIC AGE ACCELERATION WAS ASSOCIATED WITH AN INCREASED RISK OF BEING PHYSICALLY FRAIL, BUT NOT OF BEING PRE-FRAIL. FOR A YEAR INCREASE IN EXTRINSIC EPIGENETIC AGE ACCELERATION, AGE- AND SEX-ADJUSTED RELATIVE RISK RATIOS (95% CI) FOR BEING PHYSICALLY FRAIL OR PRE-FRAIL WERE 1.06 (1.02, 1.10) AND 1.02 (1.00, 1.04), RESPECTIVELY. AFTER FURTHER ADJUSTMENT FOR SMOKING AND CHRONIC DISEASE, THE ASSOCIATION WITH PHYSICAL FRAILTY REMAINED SIGNIFICANT. INTRINSIC EPIGENETIC AGE ACCELERATION WAS NOT ASSOCIATED WITH PHYSICAL FRAILTY STATUS. CONCLUSIONS: PEOPLE WHO ARE BIOLOGICALLY OLDER, AS INDEXED BY GREATER EXTRINSIC EPIGENETIC AGE ACCELERATION, ARE MORE LIKELY TO BE PHYSICALLY FRAIL. FUTURE RESEARCH WILL NEED TO INVESTIGATE WHETHER EPIGENETIC AGE ACCELERATION PLAYS A CAUSAL ROLE IN THE ONSET OF PHYSICAL FRAILTY. 2018 20 3579 46 IMPACT OF PATERNAL EDUCATION ON EPIGENETIC AGEING IN ADOLESCENCE AND MID-ADULTHOOD: A MULTI-COHORT STUDY IN THE USA AND MEXICO. BACKGROUND: BOTH PARENTAL AND NEIGHBOURHOOD SOCIO-ECONOMIC STATUS (SES) ARE LINKED TO POORER HEALTH INDEPENDENTLY OF PERSONAL SES MEASURES, BUT THE BIOLOGICAL MECHANISMS ARE UNCLEAR. OUR OBJECTIVE WAS TO EXAMINE THESE INFLUENCES VIA EPIGENETIC AGE ACCELERATION (EAA)-THE DISCREPANCY BETWEEN CHRONOLOGICAL AND EPIGENETIC AGES. METHODS: WE EXAMINED THREE USA-BASED [CORONARY ARTERY RISK DISEASE IN ADULTS (CARDIA) STUDY, FRAGILE FAMILIES AND CHILD WELLBEING STUDY (FFCWS) AND PROGRAMMING RESEARCH IN OBESITY, GROWTH, ENVIRONMENT AND SOCIAL STRESSORS (PROGRESS)] AND ONE MEXICO-BASED (PROJECT VIVA) COHORT. DNA METHYLATION WAS MEASURED USING ILLUMINA ARRAYS, PERSONAL/PARENTAL SES BY QUESTIONNAIRE AND NEIGHBOURHOOD DISADVANTAGE FROM GEOCODED ADDRESS. IN CARDIA, WE EXAMINED THE MOST STRONGLY ASSOCIATED PERSONAL, PARENTAL AND NEIGHBOURHOOD SES MEASURES WITH EAA (HANNUM'S METHOD) AT STUDY YEARS 15 AND 20 SEPARATELY AND COMBINED USING A GENERALIZED ESTIMATING EQUATION (GEE) AND COMPARED WITH OTHER EAA MEASURES (HORVATH'S EAA, PHENOAGE AND GRIMAGE CALCULATORS, AND DUNEDINPOAM). RESULTS: EAA WAS ASSOCIATED WITH PATERNAL EDUCATION IN CARDIA [GEES: BETASOME COLLEGE = -1.01 YEARS (-1.91, -0.11) AND BETA