1 5100 137 POLYCHLORINATED BIPHENYLS (PCBS) ALTER DNA METHYLATION AND GENOMIC INTEGRITY OF SHEEP FETAL CELLS IN A SIMPLIFIED IN VITRO MODEL OF PREGNANCY EXPOSURE. POLYCHLORINATED BIPHENYLS (PCBS) ARE PERSISTENT ORGANIC POLLUTANTS UBIQUITOUSLY DETECTABLE IN THE ENVIRONMENT AND IN THE FOOD CHAIN. PRENATAL EXPOSURE TO PCBS NEGATIVELY AFFECTS FETAL DEVELOPMENT AND PRODUCES LONG-TERM DETRIMENTAL EFFECTS ON CHILD HEALTH. THE PRESENT STUDY SOUGHT TO EVALUATE THE CYTOTOXIC AND GENOTOXIC EFFECTS OF CHRONIC PCB EXPOSURE ON FETAL CELLS DURING PREGNANCY. TO THIS AIM, SHEEP EMBRYONIC FIBROBLASTS (SEF) AND AMNIOCYTES (SA) WERE CULTURED IN VITRO IN THE PRESENCE OF LOW DOSES OF PCBS FOR A PERIOD OF 120DAYS, COMPARABLE TO THE FULL TERM OF OVINE PREGNANCY. CELLULAR PROLIFERATION RATES, GLOBAL DNA METHYLATION, CHROMOSOME INTEGRITY, AND MARKERS OF DNA DAMAGE WERE EVALUATED AT DIFFERENT TIME POINTS. MOREOVER, SEF TREATED WITH PCBS FOR 60DAYS WERE LEFT UNTREATED FOR ONE FURTHER MONTH AND THEN EXAMINED IN ORDER TO EVALUATE THE REVERSIBILITY OF PCB-INDUCED EPIGENETIC DEFECTS. PCB-TREATED SEF WERE MORE SENSITIVE THAN SA TREATED WITH PCBS, IN TERMS OF LOW CELL PROLIFERATION, AND INCREASED DNA DAMAGE AND GLOBAL DNA METHYLATION, WHICH WERE STILL DETECTABLE AFTER INTERRUPTION OF PCB TREATMENT. THESE DATA INDICATE THAT CHRONIC EXPOSURE OF FETAL CELLS TO PCBS CAUSES PERMANENT GENOMIC AND EPIGENETIC INSTABILITY, WHICH MAY INFLUENCE BOTH PRENATAL AND POST-NATAL GROWTH UP TO ADULTHOOD. OUR IN VITRO MODEL OFFER A SIMPLE AND CONTROLLED MEANS OF STUDYING THE EFFECTS OF DIFFERENT CONTAMINANTS ON FETAL CELLS - ONE THAT COULD SET THE STAGE FOR TARGETED IN VIVO STUDIES. 2018 2 508 33 ASSOCIATION OF LOW-DOSE EXPOSURE TO PERSISTENT ORGANIC POLLUTANTS WITH E-CADHERIN PROMOTER METHYLATION IN HEALTHY KOREANS. BACKGROUND: PERSISTENT ORGANIC POLLUTANTS (POPS), DESPITE THEIR CONSIDERABLY LOW LEVELS IN HUMANS, ARE AN INCREASING CONCERN FOR THE GENERAL POPULATIONS GIVEN THEIR VARIOUS ADVERSE HEALTH PROBLEMS, INCLUDING METABOLIC AND CARCINOGENIC EFFECTS. DNA METHYLATION DEREGULATION IS THOUGHT TO BE A KEY MECHANISM IN THE DEVELOPMENT OF HUMAN CHRONIC DISEASES INCLUDING CANCER. METHODS: IN AN ATTEMPT TO IDENTIFY BIOMARKERS MONITORING LOW-DOSE EXPOSURE AND HAZARD, WE EXPLORED WHETHER ORGANOCHLORINE PESTICIDES (OCPS) AND POLYCHLORINATED BIPHENYLS (PCBS) MAY INFLUENCE THE METHYLATION OF TUMOUR SUPPRESSOR GENE E-CADHERIN (CDH1) USING PERIPHERAL BLOOD CELLS FROM 364 HEALTHY KOREAN SUBJECTS. RESULTS: CDH1 METHYLATION WAS OBSERVED IN 78.3% OF STUDY SUBJECTS. SERUM CONCENTRATIONS OF OCPS OR PCBS COMPOUNDS WERE HIGHER IN CDH1 METHYLATION-POSITIVE SUBJECTS THAN IN METHYLATION-NEGATIVE ONES. AFTER ADJUSTING FOR VARIOUS COVARIATES, THE ODDS RATIO OF CDH1 METHYLATION OF THE SUMMARY MEASURE OF PCBS WERE 1.0, 2.5 (95% CONFIDENCE INTERVAL: 1.2-5.3), 3.6 (1.6-8.1), 3.6 (1.4-8.6), AND 2.5 (1.1-5.7) ACROSS QUINTILES OF PCBS (P(TREND) = 0.01). THE VALUES OF OCPS WERE 1.0, 0.9, 1.2, 2.4 (1.0-5.9), AND 1.7 (P(TREND) = 0.05). CONCLUSIONS: IN THIS EXPLORATORY STUDY WITH A SMALL SAMPLE, CDH1 METHYLATION MIGHT BE SERVED AS THE EPIGENETIC BIOMARKER ASSOCIATED WITH POPS EXPOSURE AND ADVERSE HEALTH EFFECT. 2018 3 2698 36 EXAMINING MULTI- AND TRANSGENERATIONAL BEHAVIORAL AND MOLECULAR ALTERATIONS RESULTING FROM PARENTAL EXPOSURE TO AN ENVIRONMENTAL PCB AND PBDE MIXTURE. POLYCHLORINATED BIPHENYLS (PCBS) AND POLYBROMINATED DIPHENYL ETHERS (PBDES) ARE PERSISTENT ORGANIC POLLUTANTS EXTENSIVELY USED DURING THE 20(TH) CENTURY AND STILL PRESENT IN AQUATIC ENVIRONMENTS DESPITE THEIR BAN. EFFECTS OF EXPOSURE TO THESE COMPOUNDS OVER GENERATIONS ARE POORLY DOCUMENTED. THEREFORE, OUR AIMS WERE TO CHARACTERIZE BEHAVIORAL RESPONSES AND UNDERLYING MOLECULAR MECHANISMS IN ZEBRAFISH EXPOSED TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PCBS AND PBDES AS WELL AS IN FOUR UNEXPOSED OFFSPRING GENERATIONS. ZEBRAFISH (F0) WERE CHRONICALLY EXPOSED FROM THE FIRST MEAL ONWARD TO A DIET SPIKED WITH A MIXTURE CONTAINING 22 PCB AND 7 PBDE CONGENERS IN PROPORTIONS AND CONCENTRATIONS REFLECTING ENVIRONMENTAL SITUATIONS (SIGMAPCBS = 1991 AND SIGMAPBDES = 411 NG/G). FOUR OFFSPRING GENERATIONS (F1 TO F4) WERE OBTAINED FROM THIS F0 AND WERE NOT FURTHER EXPOSED. BEHAVIOR WAS ASSESSED AT BOTH LARVAL AND ADULT STAGES. MECHANISMS RELATED TO BEHAVIORAL DEFECTS (HABENULA MATURATION AND C-FOS TRANSCRIPTION) AND METHYLATION (DNMTS TRANSCRIPTION) WERE MONITORED IN LARVAE. EXPOSED ADULT F0 AS WELL AS F1 AND F3 ADULTS DISPLAYED NO BEHAVIORAL CHANGE WHILE F2 EXPRESSED ANXIETY-LIKE BEHAVIOR. LARVAL BEHAVIOR WAS ALSO DISRUPTED, I.E. HYPERACTIVE AFTER LIGHT TO DARK TRANSITION IN F1 OR HYPOACTIVE IN F2, F3 AND F4. BEHAVIORAL DISRUPTIONS MAY BE RELATED TO DEFECT IN HABENULA MATURATION (OBSERVED IN F1) AND CHANGE IN C-FOS TRANSCRIPTION (OBSERVED IN F1 AND F2). TRANSCRIPTION OF THE GENE ENCODING DNA METHYLTRANSFERASE (DNMT3BA) WAS ALSO MODIFIED IN ALL GENERATIONS. OUR RESULTS LEAD US TO HYPOTHESIZE THAT CHRONIC DIETARY EXPOSURE TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PCB AND PBDE TRIGGERS MULTIGENERATIONAL AND TRANSGENERATIONAL MOLECULAR AND BEHAVIORAL DISRUPTIONS IN A VERTEBRATE MODEL. 2019 4 3505 29 IDENTIFICATION OF SEX-SPECIFIC DNA METHYLATION CHANGES DRIVEN BY SPECIFIC CHEMICALS IN CORD BLOOD IN A FAROESE BIRTH COHORT. FAROE ISLANDERS CONSUME MARINE FOODS CONTAMINATED WITH METHYLMERCURY (MEHG), POLYCHLORINATED BIPHENYLS (PCBS), AND OTHER TOXICANTS ASSOCIATED WITH CHRONIC DISEASE RISKS. DIFFERENTIAL DNA METHYLATION AT SPECIFIC CPG SITES IN CORD BLOOD MAY SERVE AS A SURROGATE BIOMARKER OF HEALTH IMPACTS FROM CHEMICAL EXPOSURES. WE AIMED TO IDENTIFY KEY ENVIRONMENTAL CHEMICALS IN CORD BLOOD ASSOCIATED WITH DNA METHYLATION CHANGES IN A POPULATION WITH ELEVATED EXPOSURE TO CHEMICAL MIXTURES. WE STUDIED 72 PARTICIPANTS OF A FAROESE BIRTH COHORT RECRUITED BETWEEN 1986 AND 1987 AND FOLLOWED UNTIL ADULTHOOD. THE CORD BLOOD DNA METHYLOME WAS PROFILED USING INFINIUM HUMANMETHYLATION450 BEADCHIPS. WE DETERMINED THE ASSOCIATIONS OF CPG SITE CHANGES WITH CONCENTRATIONS OF MEHG, MAJOR PCBS, OTHER ORGANOCHLORINE COMPOUNDS [HEXACHLOROBENZENE (HCB), P,P'-DICHLORODIPHENYLDICHLOROETHYLENE (P,P'-DDE) AND P,P'-DICHLORODIPHENYLTRICHLOROETHANE], AND PERFLUOROALKYL SUBSTANCES. IN A COMBINED SEX ANALYSIS, AMONG THE 16 CHEMICALS STUDIED, PCB CONGENER 105 (CB-105) EXPOSURE WAS ASSOCIATED WITH THE MAJORITY OF DIFFERENTIALLY METHYLATED CPG SITES (214 OUT OF A TOTAL OF 250). IN FEMALE-ONLY ANALYSIS, ONLY 73 CB-105 ASSOCIATED CPG SITES WERE DETECTED, 44 OF WHICH WERE MAPPED TO GENES IN THE ELAV1-ASSOCIATED CANCER NETWORK. IN MALES-ONLY, METHYLATION CHANGES WERE SEEN FOR PERFLUOROOCTANE SULFONATE, HCB, AND P,P'-DDE IN 10,598, 1,238, AND 1,473 CPG SITES, RESPECTIVELY, 15% OF WHICH WERE ENRICHED IN CYTOBANDS OF THE X-CHROMOSOME ASSOCIATED WITH NEUROLOGICAL DISORDERS. IN THIS MULTIPLE-POLLUTANT AND GENOME-WIDE STUDY, WE IDENTIFIED KEY EPIGENETIC TOXICANTS. THE SIGNIFICANT ENRICHMENT OF SPECIFIC X-CHROMOSOME SITES IN MALES IMPLIES POTENTIAL SEX-SPECIFIC EPIGENOME RESPONSES TO PRENATAL CHEMICAL EXPOSURES. 2018 5 1588 33 DNA METHYLATION PROFILING IMPLICATES EXPOSURE TO PCBS IN THE PATHOGENESIS OF B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA. OBJECTIVES: TO CHARACTERIZE THE IMPACT OF PCB EXPOSURE ON DNA METHYLATION IN PERIPHERAL BLOOD LEUCOCYTES AND TO EVALUATE THE CORRESPONDING CHANGES IN RELATION TO POSSIBLE HEALTH EFFECTS, WITH A FOCUS ON B-CELL LYMPHOMA. METHODS: WE CONDUCTED AN EPIGENOME-WIDE ASSOCIATION STUDY ON 611 ADULTS FREE OF DIAGNOSED DISEASE, LIVING IN ITALY AND SWEDEN, IN WHOM WE ALSO MEASURED PLASMA CONCENTRATIONS OF 6 PCB CONGENERS, DDE AND HEXACHLOROBENZENE. RESULTS: WE IDENTIFIED 650 CPG SITES WHOSE METHYLATION CORRELATES STRONGLY (FDR < 0.01) WITH PLASMA CONCENTRATIONS OF AT LEAST ONE PCB CONGENER. STRONGER EFFECTS WERE OBSERVED IN MALES AND IN SWEDEN. THIS EPIGENETIC EXPOSURE PROFILE SHOWS EXTENSIVE AND HIGHLY STATISTICALLY SIGNIFICANT OVERLAPS WITH PUBLISHED PROFILES ASSOCIATED WITH THE RISK OF FUTURE B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) AS WELL AS WITH CLINICAL CLL (38 AND 28 CPG SITES, RESPECTIVELY). FOR ALL THESE SITES, THE METHYLATION CHANGES WERE IN THE SAME DIRECTION FOR INCREASING EXPOSURE AND FOR HIGHER DISEASE RISK OR CLINICAL DISEASE STATUS, SUGGESTING AN ETIOLOGICAL LINK BETWEEN EXPOSURE AND CLL. MEDIATION ANALYSIS REINFORCED THE SUGGESTION OF A CAUSAL LINK BETWEEN EXPOSURE, CHANGES IN DNA METHYLATION AND DISEASE. DISEASE CONNECTIVITY ANALYSIS IDENTIFIED MULTIPLE ADDITIONAL DISEASES ASSOCIATED WITH DIFFERENTIALLY METHYLATED GENES, INCLUDING MELANOMA FOR WHICH AN ETIOLOGICAL LINK WITH PCB EXPOSURE IS ESTABLISHED, AS WELL AS DEVELOPMENTAL AND NEUROLOGICAL DISEASES FOR WHICH THERE IS CORRESPONDING EPIDEMIOLOGICAL EVIDENCE. DIFFERENTIALLY METHYLATED GENES INCLUDE MANY HOMEOBOX GENES, SUGGESTING THAT PCBS TARGET STEM CELLS. FURTHERMORE, NUMEROUS POLYCOMB PROTEIN TARGET GENES WERE HYPERMETHYLATED WITH INCREASING EXPOSURE, AN EFFECT KNOWN TO CONSTITUTE AN EARLY MARKER OF CARCINOGENESIS. CONCLUSIONS: THIS STUDY PROVIDES MECHANISTIC EVIDENCE IN SUPPORT OF A LINK BETWEEN EXPOSURE TO PCBS AND THE ETIOLOGY OF CLL AND UNDERLINES THE UTILITY OF OMIC PROFILING IN THE EVALUATION OF THE POTENTIAL TOXICITY OF ENVIRONMENTAL CHEMICALS. 2019 6 3267 22 HEPATOCELLULAR CARCINOMA AND POSSIBLE CHEMICAL AND BIOLOGICAL CAUSES: A REVIEW. THE DEVELOPMENT OF HEPATOCELLULAR CARCINOMA (HCC) IS A MULTISTEP PROCESS. IN HCC, PROGRESSIVE AND MORPHOLOGICALLY DISTINCT PRENEOPLASTIC LESIONS/ALTERATIONS ASSOCIATED WITH CHRONIC LIVER INJURY, INFLAMMATION, HEPATOCELLULAR DEGENERATION/REGENERATION, NECROSIS, AND SMALL-CELL DYSPLASIA CAN BE OBSERVED. THE INCIDENCE OF HCC EXHIBITS REGIONAL AND ETHNIC DIFFERENCES. SEVERAL CYTOTOXIC AND DNA-DAMAGING CHEMICALS ARE SUGGESTED TO BE THE UNDERLYING CAUSES OF HCC-FOR EXAMPLE, ACRYLAMIDE, PERFLUOROOCTANOIC ACID (PFOA), POLYCHLORINATED BIPHENYLS (PCBS), BENZO(A)PYRENE (BAP), PERFLUORINATED CHEMICALS (PFCS), VINYL CHLORIDE MONOMER (VCM), AND DIETARY CONTAMINANTS (AFLATOXINS, OCHRATOXINS). ALSO SUGGESTED ARE SUBSTANCES OF ABUSE (ALCOHOL) AND BIOLOGICAL AGENTS, SUCH AS HEPATITIS B AND C AND HUMAN IMMUNODEFICIENCY VIRUS 1 (HIV-1). THESE CAN ACT THROUGH GENETIC AND/OR EPIGENETIC MECHANISMS. THIS REVIEW WILL SHORTLY ADDRESS THE GENETIC AND EPIGENETIC MECHANISMS OF HCC AND FOCUS ON CYTOTOXIC AND DNA-DAMAGING CHEMICALS AND BIOLOGICAL AGENTS, EXPOSURE TO WHICH ARE SUGGESTED TO LEAD TO HCC INITIATION, PROMOTION, AND/OR PROGRESSION. 2017 7 3063 30 GENOME-WIDE DNA METHYLATION AND LONG-TERM AMBIENT AIR POLLUTION EXPOSURE IN KOREAN ADULTS. BACKGROUND: AMBIENT AIR POLLUTION IS ASSOCIATED WITH NUMEROUS ADVERSE HEALTH OUTCOMES, BUT THE UNDERLYING MECHANISMS ARE NOT WELL UNDERSTOOD; EPIGENETIC EFFECTS INCLUDING ALTERED DNA METHYLATION COULD PLAY A ROLE. TO EVALUATE ASSOCIATIONS OF LONG-TERM AIR POLLUTION EXPOSURE WITH DNA METHYLATION IN BLOOD, WE CONDUCTED AN EPIGENOME-WIDE ASSOCIATION STUDY IN A KOREAN CHRONIC OBSTRUCTIVE PULMONARY DISEASE COHORT (N = 100 INCLUDING 60 CASES) USING ILLUMINA'S INFINIUM HUMANMETHYLATION450K BEADCHIP. ANNUAL AVERAGE CONCENTRATIONS OF PARTICULATE MATTER 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 10 713 29 CADMIUM EXPOSURE AND AGE-ASSOCIATED DNA METHYLATION CHANGES IN NON-SMOKING WOMEN FROM NORTHERN THAILAND. DNA METHYLATION CHANGES WITH AGE, AND MAY SERVE AS A BIOMARKER OF AGING. CADMIUM (CD) MODIFIES CELLULAR PROCESSES THAT PROMOTE AGING AND DISRUPTS METHYLATION GLOBALLY. WHETHER CD MODIFIES AGING PROCESSES BY INFLUENCING ESTABLISHMENT OF AGE-ASSOCIATED METHYLATION MARKS IS CURRENTLY UNKNOWN. IN THIS PILOT STUDY, WE CHARACTERIZED METHYLATION PROFILES IN > 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 11 2690 30 EVOLUTION OF DOHAD: THE IMPACT OF ENVIRONMENTAL HEALTH SCIENCES. ENVIRONMENTAL EXPOSURES HAVE A SIGNIFICANT INFLUENCE ON THE CHRONIC HEALTH CONDITIONS PLAGUING CHILDREN AND ADULTS. ALTHOUGH THE DEVELOPMENTAL ORIGINS OF HEALTH AND DISEASE (DOHAD) PARADIGM HISTORICALLY HAS FOCUSED ON NUTRITION, AN EXPANDING BODY OF RESEARCH SPECIFICALLY COMMUNICATES THE EFFECTS OF CHEMICAL EXPOSURES ON EARLY-LIFE DEVELOPMENT AND THE PROPAGATION OF NON-COMMUNICABLE DISEASE ACROSS THE LIFESPAN. THIS PAPER PROVIDES AN OVERVIEW OF 20 YEARS OF RESEARCH EFFORTS AIMED AT IDENTIFYING CRITICAL WINDOWS OF SUSCEPTIBILITY TO ENVIRONMENTAL EXPOSURES AND THE SIGNALING CHANGES AND EPIGENETIC INFLUENCES ASSOCIATED WITH DISEASE PROGRESSION. DOHAD GRANTS FUNDED BY THE NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES (NIEHS) IN 1991, 2001 AND 2011 ARE IDENTIFIED BY GRANT-ANALYSIS SOFTWARE, AND EACH PORTFOLIO IS ANALYZED FOR EXPOSURES, DISEASE ENDPOINTS, WINDOWS OF EXPOSURE, STUDY DESIGN AND IMPACT ON THE FIELD BASED ON PUBLICATION DATA. RESULTS SHOW THAT THE 1991 AND 2001 PORTFOLIOS COMPRISED METALS, PCBS AND AIR POLLUTANTS; HOWEVER, BY 2011, THE PORTFOLIO HAS EVOLVED TO INCLUDE OR EXPAND THE VARIETY OF ENDOCRINE DISRUPTORS, PESTICIDES/PERSISTENT ORGANIC POLLUTANTS AND METALS. AN ASSORTMENT OF BRAIN-HEALTH ENDPOINTS IS MOST TARGETED ACROSS THE PORTFOLIOS, WHEREAS REPRODUCTION AND CANCER INCREASE STEADILY OVER THE SAME TIME PERIOD, AND NEW ENDPOINTS LIKE OBESITY ARE INTRODUCED BY 2011. WITH MOUNTING EVIDENCE CONNECTING EARLY-LIFE EXPOSURES TO LATER-LIFE DISEASE, WE CONCLUDE THAT IT IS CRITICAL TO EXPAND THE ORIGINAL DOHAD CONCEPT TO INCLUDE ENVIRONMENTAL CHEMICAL EXPOSURES, AND TO CONTINUE A RESEARCH AGENDA THAT EMPHASIZES DEFINING SENSITIVE WINDOWS OF EXPOSURE AND THE MECHANISMS THAT CAUSE DISEASE. 2015 12 5463 30 RESIDENTIAL PM(2.5) EXPOSURE AND THE NASAL METHYLOME IN CHILDREN. RATIONALE: PM(2.5-)INDUCED ADVERSE EFFECTS ON RESPIRATORY HEALTH MAY BE DRIVEN BY EPIGENETIC MODIFICATIONS IN AIRWAY CELLS. THE POTENTIAL IMPACT OF EXPOSURE DURATION ON EPIGENETIC ALTERATIONS IN THE AIRWAYS IS NOT YET KNOWN. OBJECTIVES: WE AIMED TO STUDY ASSOCIATIONS OF FINE PARTICULATE MATTER PM(2.5) EXPOSURE WITH DNA METHYLATION IN NASAL CELLS. METHODS: WE CONDUCTED NASAL EPIGENOME-WIDE ASSOCIATION ANALYSES WITHIN 503 CHILDREN FROM PROJECT VIVA (MEAN AGE 12.9 Y), AND EXAMINED VARIOUS EXPOSURE DURATIONS (1-DAY, 1-WEEK, 1-MONTH, 3-MONTHS AND 1-YEAR) PRIOR TO NASAL SAMPLING. WE USED RESIDENTIAL ADDRESSES TO ESTIMATE AVERAGE DAILY PM(2.5) AT 1 KM RESOLUTION. WE COLLECTED NASAL SWABS FROM THE ANTERIOR NARES AND MEASURED DNA METHYLATION (DNAM) USING THE ILLUMINA METHYLATIONEPIC BEADCHIP. WE TESTED 719,075 HIGH QUALITY AUTOSOMAL CPGS USING CPG-BY-CPG AND REGIONAL DNAM ANALYSES CONTROLLING FOR MULTIPLE COMPARISONS, AND ADJUSTED FOR MATERNAL EDUCATION, HOUSEHOLD SMOKERS, CHILD SEX, RACE/ETHNICITY, BMI Z-SCORE, AGE, SEASON AT SAMPLE COLLECTION AND CELL-TYPE HETEROGENEITY. WE FURTHER CORRECTED FOR BIAS AND GENOMIC INFLATION. WE TESTED FOR REPLICATION IN A COHORT FROM THE NETHERLANDS (PIAMA). RESULTS: IN ADJUSTED ANALYSES, WE FOUND 362 CPGS ASSOCIATED WITH 1-YEAR PM(2.5) (FDR < 0.05), 20 CPGS PASSING BONFERRONI CORRECTION (P < 7.0X10(-8)) AND 10 DIFFERENTIALLY METHYLATED REGIONS (DMRS). IN 445 PIAMA PARTICIPANTS (MEAN AGE 16.3 YEARS) 11 OF 203 AVAILABLE CPGS REPLICATED AT P < 0.05. WE OBSERVED DIFFERENTIAL DNAM AT/NEAR GENES IMPLICATED IN CELL CYCLE, IMMUNE AND INFLAMMATORY RESPONSES. THERE WERE NO CPGS OR REGIONS ASSOCIATED WITH PM(2.5) LEVELS AT 1-DAY, 1-WEEK, OR 1-MONTH PRIOR TO SAMPLE COLLECTION, ALTHOUGH 2 CPGS WERE ASSOCIATED WITH PAST 3-MONTH PM(2.5). CONCLUSION: WE OBSERVED WIDE-SPREAD DNAM VARIABILITY ASSOCIATED WITH AVERAGE PAST YEAR PM(2.5) EXPOSURE BUT WE DID NOT DETECT ASSOCIATIONS WITH SHORTER-TERM EXPOSURE. OUR RESULTS SUGGEST THAT NASAL DNAM MARKS REFLECT CHRONIC AIR POLLUTION EXPOSURE. 2021 13 6491 30 TRAFFIC-DERIVED PARTICULATE MATTER EXPOSURE AND HISTONE H3 MODIFICATION: A REPEATED MEASURES STUDY. BACKGROUND: AIRBORNE PARTICULATE MATTER (PM) MAY INDUCE EPIGENETIC CHANGES THAT POTENTIALLY LEAD TO CHRONIC DISEASES. HISTONE MODIFICATIONS REGULATE GENE EXPRESSION BY INFLUENCING CHROMATIN STRUCTURE THAT CAN CHANGE GENE EXPRESSION STATUS. WE EVALUATED WHETHER TRAFFIC-DERIVED PM EXPOSURE IS ASSOCIATED WITH FOUR TYPES OF ENVIRONMENTALLY INDUCIBLE GLOBAL HISTONE H3 MODIFICATIONS. METHODS: THE BEIJING TRUCK DRIVER AIR POLLUTION STUDY INCLUDED 60 TRUCK DRIVERS AND 60 OFFICE WORKERS EXAMINED TWICE, 1-2 WEEKS APART, FOR AMBIENT PM(10) (BOTH DAY-OF AND 14-DAY AVERAGE EXPOSURES), PERSONAL PM(2.5), BLACK CARBON (BC), AND ELEMENTAL COMPONENTS (POTASSIUM, SULFUR, IRON, SILICON, ALUMINUM, ZINC, CALCIUM, AND TITANIUM). FOR BOTH PM(10) MEASURES, WE OBTAINED HOURLY AMBIENT PM(10) DATA FOR THE STUDY PERIOD FROM THE BEIJING MUNICIPAL ENVIRONMENTAL BUREAU'S 27 REPRESENTATIVELY DISTRIBUTED MONITORING STATIONS. WE THEN CALCULATED A 24H AVERAGE FOR EACH EXAMINATION DAY AND A MOVING AVERAGE OF AMBIENT PM(10) MEASURED IN THE 14 DAYS PRIOR TO EACH EXAMINATION. EXAMINATIONS MEASURED GLOBAL LEVELS OF H3 LYSINE 9 ACETYLATION (H3K9AC), H3 LYSINE 9 TRI-METHYLATION (H3K9ME3), H3 LYSINE 27 TRI-METHYLATION (H3K27ME3), AND H3 LYSINE 36 TRI-METHYLATION (H3K36ME3) IN BLOOD LEUKOCYTES COLLECTED AFTER WORK. WE USED ADJUSTED LINEAR MIXED-EFFECT MODELS TO EXAMINE PERCENT CHANGES IN HISTONE MODIFICATIONS PER EACH MUG/M(3) INCREASE IN PM EXPOSURE. RESULTS: IN ALL PARTICIPANTS EACH MUG/M(3) INCREASE IN 14-DAY AVERAGE AMBIENT PM(10) EXPOSURE WAS ASSOCIATED WITH LOWER H3K27ME3 (BETA=-1.1%, 95% CI: -1.6, -0.6) AND H3K36ME3 LEVELS (BETA=-0.8%, 95% CI: -1.4, -0.1). OCCUPATION-STRATIFIED ANALYSES SHOWED ASSOCIATIONS BETWEEN BC AND BOTH H3K9AC AND H3K36ME3 THAT WERE STRONGER IN OFFICE WORKERS (BETA=4.6%, 95% CI: 0.9, 8.4; AND BETA=4.1%, 95% CI: 1.3; 7.0 RESPECTIVELY) THAN IN TRUCK DRIVERS (BETA=0.1%, 95% CI: -1.3, 1.5; AND BETA=0.9%, 95% CI: -0.9, 2.7, RESPECTIVELY; BOTH P(INTERACTION) <0.05). SEX-STRATIFIED ANALYSES SHOWED ASSOCIATIONS BETWEEN EXAMINATION-DAY PM(10) AND H3K9AC, AND BETWEEN BC AND H3K9ME3, WERE STRONGER IN WOMEN (BETA=10.7%, 95% CI: 5.4, 16.2; AND BETA=7.5%, 95% CI: 1.2, 14.2, RESPECTIVELY) THAN IN MEN (BETA=1.4%, 95% CI: -0.9, 3.7; AND BETA=0.9%, 95% CI: -0.9, 2.7, RESPECTIVELY; BOTH P(INTERACTION) <0.05). WE OBSERVED NO ASSOCIATIONS BETWEEN PERSONAL PM(2.5) OR ELEMENTAL COMPONENTS AND HISTONE MODIFICATIONS. CONCLUSIONS: OUR RESULTS SUGGEST A POSSIBLE ROLE OF GLOBAL HISTONE H3 MODIFICATIONS IN EFFECTS OF TRAFFIC-DERIVED PM EXPOSURES, PARTICULARLY BC EXPOSURE. FUTURE STUDIES SHOULD ASSESS THE ROLES OF THESE MODIFICATIONS IN HUMAN DISEASES AND AS POTENTIAL MEDIATORS OF AIR POLLUTION-INDUCED DISEASE, IN PARTICULAR BC EXPOSURE. 2017 14 502 26 ASSOCIATION OF ARSENIC EXPOSURE WITH WHOLE BLOOD DNA METHYLATION: AN EPIGENOME-WIDE STUDY OF BANGLADESHI ADULTS. BACKGROUND: ARSENIC EXPOSURE AFFECTS [FORMULA: SEE TEXT] PEOPLE WORLDWIDE, INCLUDING [FORMULA: SEE TEXT] IN BANGLADESH. ARSENIC EXPOSURE INCREASES THE RISK OF CANCER AND OTHER CHRONIC DISEASES, AND ONE POTENTIAL MECHANISM OF ARSENIC TOXICITY IS EPIGENETIC DYSREGULATION. OBJECTIVE: WE ASSESSED ASSOCIATIONS BETWEEN ARSENIC EXPOSURE AND GENOME-WIDE DNA METHYLATION MEASURED AT BASELINE AMONG 396 BANGLADESHI ADULTS PARTICIPATING IN THE HEALTH EFFECTS OF ARSENIC LONGITUDINAL STUDY (HEALS) WHO WERE EXPOSED BY DRINKING NATURALLY CONTAMINATED WELL WATER. METHODS: METHYLATION IN WHOLE BLOOD DNA WAS MEASURED AT [FORMULA: SEE TEXT] USING THE ILLUMINA INFINIUMMETHYLATIONEPIC (EPIC) ARRAY. TO ASSESS ASSOCIATIONS BETWEEN ARSENIC EXPOSURE AND CPG METHYLATION, WE USED LINEAR REGRESSION MODELS ADJUSTED FOR COVARIATES AND SURROGATE VARIABLES (SVS) (CAPTURING UNKNOWN TECHNICAL AND BIOLOGIC FACTORS). WE ATTEMPTED REPLICATION AND CONDUCTED A META-ANALYSIS USING AN INDEPENDENT DATASET OF [FORMULA: SEE TEXT] FROM 400 BANGLADESHI INDIVIDUALS WITH ARSENICAL SKIN LESIONS. RESULTS: WE IDENTIFIED 34 CPGS ASSOCIATED WITH [FORMULA: SEE TEXT] CREATININE-ADJUSTED URINARY ARSENIC [[FORMULA: SEE TEXT]]. SIXTEEN OF THESE CPGS ANNOTATED TO THE [FORMULA: SEE TEXT] ARRAY, AND 10 ASSOCIATIONS WERE REPLICATED ([FORMULA: SEE TEXT]). THE TOP TWO CPGS ANNOTATED UPSTREAM OF THE ABR GENE (CG01912040, CG10003262 ). ALL URINARY ARSENIC-ASSOCIATED CPGS WERE ALSO ASSOCIATED WITH ARSENIC CONCENTRATION MEASURED IN DRINKING WATER ([FORMULA: SEE TEXT]). META-ANALYSIS ([FORMULA: SEE TEXT] SAMPLES) IDENTIFIED 221 URINARY ARSENIC-ASSOCIATED CPGS ([FORMULA: SEE TEXT]). THE ARSENIC-ASSOCIATED CPGS FROM THE META-ANALYSIS WERE ENRICHED IN NON-CPG ISLANDS AND SHORES ([FORMULA: SEE TEXT]) AND DEPLETED IN PROMOTER REGIONS ([FORMULA: SEE TEXT]). AMONG THE ARSENIC-ASSOCIATED CPGS ([FORMULA: SEE TEXT]), WE OBSERVED SIGNIFICANT ENRICHMENT OF GENES ANNOTATING TO THE REACTIVE OXYGEN SPECIES PATHWAY, INFLAMMATORY RESPONSE, AND TUMOR NECROSIS FACTOR [FORMULA: SEE TEXT] ([FORMULA: SEE TEXT]) SIGNALING VIA NUCLEAR FACTOR KAPPA-B ([FORMULA: SEE TEXT]) HALLMARKS ([FORMULA: SEE TEXT]). CONCLUSIONS: THE NOVEL AND REPLICABLE ASSOCIATIONS BETWEEN ARSENIC EXPOSURE AND DNA METHYLATION AT SPECIFIC CPGS OBSERVED IN THIS WORK SUGGEST THAT EPIGENETIC ALTERATIONS SHOULD BE FURTHER INVESTIGATED AS POTENTIAL MEDIATORS IN ARSENIC TOXICITY AND AS BIOMARKERS OF EXPOSURE AND EFFECT IN EXPOSED POPULATIONS. HTTPS://DOI.ORG/10.1289/EHP3849. 2019 15 4090 29 MATERNAL PRE-PREGNANCY BMI, OFFSPRING EPIGENOME-WIDE DNA METHYLATION, AND CHILDHOOD OBESITY: FINDINGS FROM THE BOSTON BIRTH COHORT. BACKGROUND: MATERNAL PRE-PREGNANCY OBESITY IS AN ESTABLISHED RISK FACTOR FOR CHILDHOOD OBESITY. INVESTIGATING EPIGENETIC ALTERATIONS INDUCED BY MATERNAL OBESITY DURING FETAL DEVELOPMENT COULD GAIN MECHANISTIC INSIGHT INTO THE DEVELOPMENTAL ORIGINS OF CHILDHOOD OBESITY. WHILE OBESITY DISPROPORTIONATELY AFFECTS UNDERREPRESENTED RACIAL AND ETHNIC MOTHERS AND CHILDREN IN THE USA, FEW STUDIES INVESTIGATED THE ROLE OF PRENATAL EPIGENETIC PROGRAMMING IN INTERGENERATIONAL OBESITY OF THESE HIGH-RISK POPULATIONS. METHODS: THIS STUDY INCLUDED 903 MOTHER-CHILD PAIRS FROM THE BOSTON BIRTH COHORT, A PREDOMINANTLY URBAN, LOW-INCOME MINORITY BIRTH COHORT. MOTHER-INFANT DYADS WERE ENROLLED AT BIRTH AND THE CHILDREN WERE FOLLOWED PROSPECTIVELY TO AGE 18 YEARS. INFINIUM METHYLATION EPIC BEADCHIP WAS USED TO MEASURE EPIGENOME-WIDE METHYLATION LEVEL OF CORD BLOOD. WE PERFORMED AN EPIGENOME-WIDE ASSOCIATION STUDY OF MATERNAL PRE-PREGNANCY BODY MASS INDEX (BMI) AND CORD BLOOD DNA METHYLATION (DNAM). TO QUANTIFY THE DEGREE TO WHICH CORD BLOOD DNAM MEDIATES THE MATERNAL BMI-CHILDHOOD OBESITY, WE FURTHER INVESTIGATED WHETHER MATERNAL BMI-ASSOCIATED DNAM SITES IMPACT BIRTHWEIGHT OR CHILDHOOD OVERWEIGHT OR OBESITY (OWO) FROM AGE 1 TO AGE 18 AND PERFORMED CORRESPONDING MEDIATION ANALYSES. RESULTS: THE STUDY SAMPLE CONTAINED 52.8% MATERNAL PRE-PREGNANCY OWO AND 63.2% OFFSPRING OWO AT AGE 1-18 YEARS. MATERNAL BMI WAS ASSOCIATED WITH CORD BLOOD DNAM AT 8 CPG SITES (GENOME-WIDE FALSE DISCOVERY RATE [FDR] < 0.05). AFTER ACCOUNTING FOR THE POSSIBLE INTERPLAY OF MATERNAL BMI AND SMOKING, 481 CPG SITES WERE DISCOVERED FOR ASSOCIATION WITH MATERNAL BMI. AMONG THEM 123 CPGS WERE ASSOCIATED WITH CHILDHOOD OWO, RANGING FROM 42% DECREASE TO 87% INCREASE IN OWO RISK FOR EACH SD INCREASE IN DNAM. A TOTAL OF 14 IDENTIFIED CPG SITES SHOWED A SIGNIFICANT MEDIATION EFFECT ON THE MATERNAL BMI-CHILD OWO ASSOCIATION (FDR < 0.05), WITH MEDIATING PROPORTION RANGING FROM 3.99% TO 25.21%. SEVERAL OF THESE 14 CPGS WERE MAPPED TO GENES IN ASSOCIATION WITH ENERGY BALANCE AND METABOLISM (AKAP7) AND ADULTHOOD METABOLIC SYNDROME (CAMK2B). CONCLUSIONS: THIS PROSPECTIVE BIRTH COHORT STUDY IN A HIGH-RISK YET UNDERSTUDIED US POPULATION FOUND THAT MATERNAL PRE-PREGNANCY OWO SIGNIFICANTLY ALTERED DNAM IN NEWBORN CORD BLOOD AND PROVIDED SUGGESTIVE EVIDENCE OF EPIGENETIC INVOLVEMENT IN THE INTERGENERATIONAL RISK OF OBESITY. 2023 16 490 28 ASSESSING THE IMPACT OF ARSENIC METABOLISM EFFICIENCY ON DNA METHYLATION USING MENDELIAN RANDOMIZATION. BACKGROUND: ARSENIC EXPOSURE AFFECTS >100 MILLION PEOPLE GLOBALLY AND INCREASES RISK FOR CHRONIC DISEASES. ONE POSSIBLE TOXICITY MECHANISM IS EPIGENETIC MODIFICATION. PREVIOUS EPIGENOME-WIDE ASSOCIATION STUDIES (EWAS) HAVE IDENTIFIED ASSOCIATIONS BETWEEN ARSENIC EXPOSURE AND CPG-SPECIFIC DNA METHYLATION. TO PROVIDE ADDITIONAL EVIDENCE THAT OBSERVED ASSOCIATIONS REPRESENT CAUSAL RELATIONSHIPS, WE EXAMINE THE ASSOCIATION BETWEEN GENETIC DETERMINANTS OF ARSENIC METABOLISM EFFICIENCY (PERCENT DIMETHYLARSINIC ACID, DMA%, IN URINE) AND DNA METHYLATION AMONG INDIVIDUALS FROM THE HEALTH EFFECTS OF ARSENIC LONGITUDINAL STUDY (N = 379) AND BANGLADESH VITAMIN E AND SELENIUM TRIAL (N = 393). METHODS: WE USED MULTIVARIATE LINEAR MODELS TO ASSESS THE ASSOCIATION OF METHYLATION AT 221 ARSENIC-ASSOCIATED CPGS WITH DMA% AND MEASURES OF GENETICALLY PREDICTED DMA% DERIVED FROM THREE SNPS (RS9527, RS11191527, AND RS61735836). WE ALSO CONDUCTED TWO-SAMPLE MENDELIAN RANDOMIZATION ANALYSES TO ESTIMATE THE ASSOCIATION BETWEEN ARSENIC METABOLISM EFFICIENCY AND CPG METHYLATION. RESULTS: AMONG THE ASSOCIATIONS BETWEEN DMA% AND METHYLATION AT EACH OF 221 CPGS, 64% WERE DIRECTIONALLY CONSISTENT WITH ASSOCIATIONS OBSERVED BETWEEN ARSENIC EXPOSURE AND THE 221 CPGS FROM A PRIOR EWAS. SIMILARLY, AMONG THE ASSOCIATIONS BETWEEN GENETICALLY PREDICTED DMA% AND EACH CPG, 62% WERE DIRECTIONALLY CONSISTENT WITH THE PRIOR EWAS RESULTS. TWO-SAMPLE MENDELIAN RANDOMIZATION ANALYSES PRODUCED SIMILAR CONCLUSIONS. CONCLUSION: OUR FINDINGS SUPPORT THE HYPOTHESIS THAT ARSENIC EXPOSURE EFFECTS DNA METHYLATION AT SPECIFIC CPGS IN WHOLE BLOOD. OUR NOVEL APPROACH FOR ASSESSING THE IMPACT OF ARSENIC EXPOSURE ON DNA METHYLATION REQUIRES LARGER SAMPLES IN ORDER TO DRAW MORE ROBUST CONCLUSIONS FOR SPECIFIC CPG SITES. 2020 17 935 27 CHRONIC LOW-DOSE EXPOSURE TO XENOESTROGEN AMBIENT AIR POLLUTANTS AND BREAST CANCER RISK: XENAIR PROTOCOL FOR A CASE-CONTROL STUDY NESTED WITHIN THE FRENCH E3N COHORT. BACKGROUND: BREAST CANCER IS THE MOST FREQUENT CANCER IN WOMEN IN INDUSTRIALIZED COUNTRIES. LIFESTYLE AND ENVIRONMENTAL FACTORS, PARTICULARLY ENDOCRINE-DISRUPTING POLLUTANTS, HAVE BEEN SUGGESTED TO PLAY A ROLE IN BREAST CANCER RISK. CURRENT EPIDEMIOLOGICAL STUDIES, ALTHOUGH NOT FULLY CONSISTENT, SUGGEST A POSITIVE ASSOCIATION OF BREAST CANCER RISK WITH EXPOSURE TO SEVERAL INTERNATIONAL AGENCY FOR RESEARCH ON CANCER GROUP 1 AIR-POLLUTANT CARCINOGENS, SUCH AS PARTICULATE MATTER, POLYCHLORINATED BIPHENYLS (PCB), DIOXINS, BENZO[A]PYRENE (BAP), AND CADMIUM. HOWEVER, EPIDEMIOLOGICAL STUDIES REMAIN SCARCE AND INCONSISTENT. IT HAS BEEN PROPOSED THAT THE MENOPAUSAL STATUS COULD MODIFY THE RELATIONSHIP BETWEEN POLLUTANTS AND BREAST CANCER AND THAT THE ASSOCIATION VARIES WITH HORMONE RECEPTOR STATUS. OBJECTIVE: THE XENAIR PROJECT WILL INVESTIGATE THE ASSOCIATION OF BREAST CANCER RISK (OVERALL AND BY HORMONE RECEPTOR STATUS) WITH CHRONIC EXPOSURE TO SELECTED AIR POLLUTANTS, INCLUDING PARTICULATE MATTER, NITROGEN DIOXIDE (NO2), OZONE (O3), BAP, DIOXINS, PCB-153, AND CADMIUM. METHODS: OUR RESEARCH IS BASED ON A CASE-CONTROL STUDY NESTED WITHIN THE FRENCH NATIONAL E3N COHORT OF 5222 INVASIVE BREAST CANCER CASES IDENTIFIED DURING FOLLOW-UP FROM 1990 TO 2011, AND 5222 MATCHED CONTROLS. A QUESTIONNAIRE WAS SENT TO ALL PARTICIPANTS TO COLLECT THEIR LIFETIME RESIDENTIAL ADDRESSES AND INFORMATION ON INDOOR POLLUTION. WE WILL ASSESS THESE EXPOSURES USING COMPLEMENTARY MODELS OF LAND-USE REGRESSION, ATMOSPHERIC DISPERSION, AND REGIONAL CHEMISTRY-TRANSPORT (CHIMERE) MODELS, VIA A GEOGRAPHIC INFORMATION SYSTEM. ASSOCIATIONS WITH BREAST CANCER RISK WILL BE MODELED USING CONDITIONAL LOGISTIC REGRESSION MODELS. WE WILL ALSO STUDY THE IMPACT OF EXPOSURE ON DNA METHYLATION AND INTERACTIONS WITH GENETIC POLYMORPHISMS. APPROPRIATE STATISTICAL METHODS, INCLUDING BAYESIAN MODELING, PRINCIPAL COMPONENT ANALYSIS, AND CLUSTER ANALYSIS, WILL BE USED TO ASSESS THE IMPACT OF MULTIPOLLUTANT EXPOSURE. THE FRACTION OF BREAST CANCER CASES ATTRIBUTABLE TO AIR POLLUTION WILL BE ESTIMATED. RESULTS: THE XENAIR PROJECT WILL CONTRIBUTE TO CURRENT KNOWLEDGE ON THE HEALTH EFFECTS OF AIR POLLUTION AND IDENTIFY AND UNDERSTAND ENVIRONMENTAL MODIFIABLE RISK FACTORS RELATED TO BREAST CANCER RISK. CONCLUSIONS: THE RESULTS WILL PROVIDE RELEVANT EVIDENCE TO GOVERNMENTS AND POLICY-MAKERS TO IMPROVE EFFECTIVE PUBLIC HEALTH PREVENTION STRATEGIES ON AIR POLLUTION. THE XENAIR DATASET CAN BE USED IN FUTURE EFFORTS TO STUDY THE EFFECTS OF EXPOSURE TO AIR POLLUTION ASSOCIATED WITH OTHER CHRONIC CONDITIONS. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/15167. 2020 18 5683 29 SHORTER TELOMERE LENGTH IN PERIPHERAL BLOOD LYMPHOCYTES OF WORKERS EXPOSED TO POLYCYCLIC AROMATIC HYDROCARBONS. SHORTER TELOMERE LENGTH (TL) IN PERIPHERAL BLOOD LYMPHOCYTES (PBLS) IS PREDICTIVE OF LUNG CANCER RISK. POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) ARE ESTABLISHED LUNG CARCINOGENS THAT CAUSE CHROMOSOME INSTABILITY. WHETHER PAH EXPOSURE AND ITS MOLECULAR EFFECTS ARE LINKED WITH SHORTER TL HAS NEVER BEEN EVALUATED. IN THE PRESENT STUDY, WE INVESTIGATED THE EFFECT OF CHRONIC EXPOSURE TO PAHS ON TL MEASURED IN PBLS OF POLISH MALE NON-CURRENT SMOKING COKEOVEN WORKERS AND MATCHED CONTROLS. PAH EXPOSURE AND MOLECULAR EFFECTS WERE CHARACTERIZED USING MEASURES OF INTERNAL DOSE (URINARY 1-PYRENOL), EFFECTIVE DOSE [ANTI-BENZO[A]PYRENE DIOLEPOXIDE (ANTI-BPDE)-DNA ADDUCT], GENETIC INSTABILITY (MICRONUCLEI, MN) AND DNA METHYLATION [P53 PROMOTER AND ALU AND LONG INTERSPERSED NUCLEAR ELEMENT-1 (LINE-1) REPETITIVE ELEMENTS, AS SURROGATE MEASURES OF GLOBAL METHYLATION] IN PBLS. TL WAS MEASURED BY REAL-TIME POLYMERASE CHAIN REACTION. COKEOVEN WORKERS WERE HEAVILY EXPOSED TO PAHS (79% EXCEEDED THE URINARY 1-PYRENOL BIOLOGICAL EXPOSURE INDEX) AND EXHIBITED LOWER TL (P = 0.038) THAN CONTROLS, AS WELL AS HIGHER LEVELS OF GENETIC AND CHROMOSOMAL ALTERATIONS [I.E. ANTI-BPDE-DNA ADDUCT AND MN (P < 0.0001)] AND EPIGENETIC CHANGES [I.E. P53 GENE-SPECIFIC PROMOTER AND GLOBAL METHYLATION (P