We describe 10-year changes in accelerometer-determined physical activity (PA) and sedentary time in a midlife cohort of the Coronary Artery Risk Development in Young Adults Study, within and by race and sex groups. Participants (n = 962) wore the accelerometer with valid wear (≥4 of 7 days, ≥10 hours per day) at baseline (2005-2006; ages 38-50 years) and 10-year follow-up (2015-2016; ages 48-60 years). Data were calibrated to account for accelerometer model differences. Participants (mean age = 45.0 (standard deviation, 3.5) years at baseline) had reduced accelerometer counts overall (mean = -'65.5 (standard error (SE), 10.2) counts per minute/day), and within race and sex groups (all P < 0.001). Sedentary time increased overall (mean = 37.9 (SE, 3.7) minutes/day) and within race and sex groups, whereas light-intensity PA (mean = -'30.6 (SE, 2.7) minutes/day) and moderate-to vigorous-intensity PA (mean = -'7.5 (SE, 0.8) minutes/day) declined overall and within race and sex groups (all P < 0.001). Significant differences in 10-year change estimates were noted by race and sex groups for accelerometer counts, sedentary time, and moderate-to vigorous-intensity PA bouts; black men had the greatest reductions in PA compared with other groups. PA declines during midlife were characterized by reductions in light-intensity PA with increases in sedentary time, which may have important health consequences. Targeted efforts are needed to preserve PA, regardless of intensity level, across midlife.
Bibliographical noteFunding Information:
The Coronary Artery Risk Development in Young Adults (CARDIA) Study is supported by contracts HHSN268201300025C, HHSN268201300026C, HHSN268201300027C, HHSN268201300028C, HHSN268201300029C, and HHSN268200900041C from the National Heart, Lung, and Blood Institute (NHLBI), the Intramural Research Program of the National Institute on Aging (NIA), and an intra-agency agreement between the NIA and NHLBI (AG0005). Additional support for this work was provided by the CARDIA Fitness Study (grant R01 HL078972 to B.S. and S.S.) and CARDIA Activity Study (grant R56 HL125423 to K.P.G., B.S., S.S.). We thank the CARDIA Study participants. Conflict of interest: none declared.
© Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2018.
- cohort study
- diverse sample