%0 Journal Article %A Christian M. Lo Cascio %A Carrie P. Aaron %A John H.M. Austin %A Mark V. Avdalovic %A Alan G. Bertoni %A Vincent S. Fan %A Eric A. Hoffman %A Steven M. Kawut %A Gina Lovasi %A Mirja Quante %A Susan Redline %A Joseph E. Schwartz %A R. Graham Barr %T Late-breaking abstract: Daytime motor activity and emphysema on CT: The multi-ethnic study of atherosclerosis (MESA) lung and sleep studies %D 2014 %J European Respiratory Journal %P 1391 %V 44 %N Suppl 58 %X Rationale: Emphysema is characterized by decrease in activity. Little is known about daytime activity and emphysema on computed tomography (CT) independent of COPD on spirometry. We hypothesize that greater percent emphysema is associated with lower daytime activity among participants with and without COPD.Methods: MESA enrolled participants aged 45-84 years, without clinical cardiovascular disease in 2000-02. MESA Lung measured percent emphysema, defined as % voxels with an attenuation < -950 HU, on full-lung CT scans for 3202 participants in 2010-12. MESA Sleep measured actimetry in 1466 participants. Daily activity was examined using the total activity counts/24h over 7 days. Multivariate linear regression was used to adjust for age, sex, race/ethnicity, education, height, weight, smoking, FEV1/FVC, scanner, hypertension and cholesterol.Results: Among 1513 participants (age 69±9 years, 52% ever-smokers, 8% with COPD), the mean maximal daily activity counts were 276000±106000. An increase of 1 log% emphysema was associated with an 7643 count decrease in activity (P=0.03) in the fully adjusted model (∼50 kcal active energy expenditure / 1 SD difference in log% emphysema1). Findings among participants without COPD were similar (-8651 / log% emphysema; P=0.01). Results were not modified by smoking status (Pint =0.6) or obesity (Pint =0.3).Conclusions: Percent emphysema on CT was independently associated with reduced daytime activity measured by actimetry in this multiethnic general-population sample including in participants without COPD.Funding: NIH/NHLBI, R01-HL077612, R01-HL093081, N01-HC95159-HC95169, UL1-TR000040, EPA RD831697011Rabinovich. ERJ. Nov 2013;42(5). %U