PROSPECTIVE ASSOCIATIONS BETWEEN NEIGHBORHOOD ENVIRONMENTS AND PHYSICAL ACTIVITY AND WEIGHT STATUS ACROSS AGE GROUPS: SECONDARY ANALYSES COMBINING 5 NIH STUDIES - PROJECT SUMMARY/ABSTRACT PHYSICAL INACTIVITY IS A LEADING RISK FACTOR FOR OBESITY AND CARDIOVASCULAR DISEASE ACROSS AGE GROUPS. NUMEROUS STUDIES ACROSS THE LIFESPAN HAVE FOUND CROSS-SECTIONAL ASSOCIATIONS INDICATING NEIGHBORHOOD ENVIRONMENT FEATURES (E.G., WALKABILITY) ARE FAVORABLY RELATED TO BOTH PHYSICAL ACTIVITY AND BMI/WEIGHT STATUS. THOUGH THERE WAS EVIDENCE FROM PROSPECTIVE STUDIES SUPPORTING WHAT HAS BEEN FOUND IN CROSS-SECTIONAL STUDIES, IMPORTANT GAPS REMAIN. MANY PROSPECTIVE STUDIES DID NOT ALLOW FOR INTERPRETATION OF THE MAGNITUDE OF CHANGES IN OUTCOMES, HAVE FOCUSED ON A SINGLE AGE GROUP, AND INCLUDED SHORT DURATIONS OF FOLLOW-UP, PRECLUDING EXAMINATION OF LONG-TERM IMPACT OF NEIGHBORHOOD ENVIRONMENTS ON DEVELOPMENT OF REGULAR PA HABITS AND WEIGHT STATUS ACROSS THE LIFESPAN. THIS PROPOSED STUDY ADDRESSES THESE LIMITATIONS BY EFFICIENTLY LEVERAGING EXISTING DATA FROM 5 EXISTING NIH-FUNDED STUDIES TO INVESTIGATE PROSPECTIVE ASSOCIATIONS BETWEEN NEIGHBORHOOD ENVIRONMENT FEATURES AND PHYSICAL ACTIVITY IN 4 AGE GROUPS (CHILDREN, ADOLESCENTS, ADULTS, AND OLDER ADULTS). A KEY INNOVATION IS THE ABILITY TO EXAMINE SIMILARITIES AND DIFFERENCES IN ENVIRONMENT-HEALTH ASSOCIATIONS ACROSS THE LIFESPAN. EACH EXISTING STUDY INVOLVES CROSS-SECTIONAL DATA BUT THE SHARED PARTICIPANTS AND MEASURES ACROSS STUDIES ALLOWS FOR THE INVESTIGATION OF LONG-TERM PROSPECTIVE ASSOCIATIONS OVER TWO ASSESSMENT TIME POINTS 5-15 YEARS APART. WE WILL INVESTIGATE IN 1083 PARTICIPANTS WHETHER AND HOW BASELINE NEIGHBORHOOD ENVIRONMENT FEATURES (USING GIS-BASED AND REPORTED MEASURES) AND CHANGES IN REPORTED NEIGHBORHOOD ENVIRONMENT FEATURES OVER TIME RELATE TO CHANGES IN PARTICIPANTS' ACCELEROMETER-DERIVED TOTAL PHYSICAL ACTIVITY, SELF-REPORTED PHYSICAL ACTIVITY FOR TRANSPORT AND LEISURE, AND WEIGHT STATUS. THE GIS-BASED MEASURES ARE BASED ON BEST PRACTICES IN NEIGHBORHOOD WALKABILITY RESEARCH AND INCLUDE RESIDENTIAL DENSITY, LAND USE MIX, STREET CONNECTIVITY, RETAIL FLOOR AREA RATION, AND A WALKABILITY INDEX, AS WELL AS PARK DENSITY (PLAYABILITY) AND TRANSIT DENSITY (TRANSITABILITY). THE SELF-REPORT MEASURES CAPTURE ADDITIONAL WIDELY USED CONSTRUCTS SUCH AS PEDESTRIAN FACILITIES, CRIME SAFETY, TRAFFIC SAFETY, AND AESTHETICS. THE AGE GROUPS CAPTURED INVOLVE CRITICAL TRANSITION TIME POINTS (E.G., INTO ADOLESCENCE, YOUNG ADULTHOOD, AND RETIREMENT) WHEN UNDERSTANDING PREDICTORS OF CHANGES IN PHYSICAL ACTIVITY ARE PARTICULARLY IMPORTANT. THE ANALYTIC APPROACHES USED WILL IDENTIFY WHETHER ASSOCIATIONS DIFFER ACROSS AGE GROUPS, SEX, RACE/ETHNICITY, AND EDUCATION STATUS. THE FINDINGS WILL BE CRITICAL IN STRENGTHENING THE EVIDENCE BASE ON NEIGHBORHOOD ENVIRONMENT IMPACTS ON HEALTH TO BETTER GUIDE POLICY AND PRACTICE AROUND CARDIOVASCULAR DISEASE PREVENTION AND CONTROL. RESULTS WILL BE WIDELY COMMUNICATED TO RESEARCHERS AS WELL AS PRACTICE AND POLICY AUDIENCES.