1 1956 211 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 2 5757 41 SOCIOECONOMIC STATUS, KNEE PAIN, AND EPIGENETIC AGING IN COMMUNITY-DWELLING MIDDLE-TO-OLDER AGE ADULTS. CHRONIC MUSCULOSKELETAL PAIN IS OFTEN ASSOCIATED WITH LOWER SOCIOECONOMIC STATUS (SES). SES CORRELATES WITH PSYCHOLOGICAL AND ENVIRONMENTAL CONDITIONS THAT COULD CONTRIBUTE TO THE DISPROPORTIONATE BURDEN OF CHRONIC STRESS. CHRONIC STRESS CAN INDUCE CHANGES IN GLOBAL DNA METHYLATION AND GENE EXPRESSION, WHICH INCREASES RISK OF CHRONIC PAIN. WE AIMED TO EXPLORE THE ASSOCIATION OF EPIGENETIC AGING AND SES IN MIDDLE-TO-OLDER AGE INDIVIDUALS WITH VARYING DEGREES OF KNEE PAIN. PARTICIPANTS COMPLETED SELF-REPORTED PAIN, A BLOOD DRAW, AND ANSWERED DEMOGRAPHIC QUESTIONS PERTAINING TO SES. WE USED AN EPIGENETIC CLOCK PREVIOUSLY ASSOCIATED WITH KNEE PAIN (DNAMGRIMAGE) AND THE SUBSEQUENT DIFFERENCE OF PREDICTED EPIGENETIC AGE (DNAMGRIMAGE-DIFF). OVERALL, THE MEAN DNAMGRIMAGE WAS 60.3 (+/-7.6), AND THE AVERAGE DNAMGRIMAGE-DIFF WAS 2.4 YEARS (+/-5.6 YEARS). THOSE EXPERIENCING HIGH-IMPACT PAIN EARNED LESS INCOME AND HAD LOWER EDUCATION LEVELS COMPARED TO BOTH LOW-IMPACT AND NO PAIN GROUPS. DIFFERENCES IN DNAMGRIMAGE-DIFF ACROSS PAIN GROUPS WERE FOUND, WHEREBY INDIVIDUALS WITH HIGH-IMPACT PAIN HAD ACCELERATED EPIGENETIC AGING ( APPROXIMATELY 5 YEARS) COMPARED TO LOW-IMPACT PAIN AND NO PAIN CONTROL GROUPS (BOTH APPROXIMATELY 1 YEAR). OUR MAIN FINDING WAS THAT EPIGENETIC AGING MEDIATED THE ASSOCIATIONS OF INCOME AND EDUCATION WITH PAIN IMPACT, AS SUCH THE RELATIONSHIP BETWEEN SES AND PAIN OUTCOMES MAY OCCUR THROUGH POTENTIAL INTERACTIONS WITH THE EPIGENOME REFLECTIVE OF ACCELERATED CELLULAR AGING. PERSPECTIVE: SOCIOECONOMIC STATUS (SES) HAS PREVIOUSLY BEEN IMPLICATED IN THE PAIN EXPERIENCE. THE PRESENT MANUSCRIPT AIMS TO PRESENT A POTENTIAL SOCIAL-BIOLOGICAL LINK BETWEEN SES AND PAIN VIA ACCELERATED EPIGENETIC AGING. 2023 3 2150 47 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