title: Sedentary behavior and subclinical atherosclerosis in African Americans: cross-sectional analysis of the Jackson heart study.
abstract: BACKGROUND
  Previous studies have reported conflicting results as to whether an association exists between sedentary time and cardiovascular disease (CVD) risk among African Americans. These studies, however, were limited by lack of consideration of sedentary behavior in leisure versus non-leisure settings. To elucidate this relation, we investigated the associations of television (TV) viewing time and occupational sitting with carotid intima-media thickness (CIMT), a subclinical atherosclerosis measure, in a community-based sample of African Americans.
  
  
  METHODS
  We studied 3410 participants from the Jackson Heart Study, a single-site, community-based study of African Americans residing in Jackson, MS. CIMT was assessed by ultrasonography and represented mean far-wall thickness across right and left sides of the common carotid artery. TV viewing time, a measure of leisure sedentary behavior, and occupational sitting, a measure of non-leisure sedentary behavior, were assessed by questionnaire.
  
  
  RESULTS
  In a multivariable regression model that included physical activity and CVD risk factors, longer TV viewing time (2-4 h/day and >4 h/day) was associated with greater CIMT (adjusted mean ± SE difference from referent [<2 h/day] of 0.009 ± 0.008 mm for 2-4 h/day, and 0.028 ± 0.009 mm for >4 h/day; P-trend =0.001). In contrast, more frequent occupational sitting ('sometimes' and 'often/always') was associated with lower CIMT (adjusted mean ± SE difference from referent ['never/seldom']:-0.021 ± 0.009 mm for 'sometimes', and-0.018 ± 0.008 mm for 'often/always'; P-trend = 0.042).
  
  
  CONCLUSIONS
  Longer TV viewing time was associated with greater CIMT, while occupational sitting was associated with lower CIMT. These findings suggest the role of sedentary behaviors in the pathogenesis of CVD among African Americans may vary by whether individuals engage in leisure versus non-leisure sedentary behaviors.
authors.affiliation: Department of Medicine, Center for Behavioral Cardiovascular Health, Columbia University Medical Center, 622 West 168th Street, PH9-319, New York, NY, 10032, USA. kd2442@columbia.edu.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Diaz
authors.affiliation: Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA. jnbooth@uab.edu.
authors.forename: John N
authors.initials: JN
authors.lastname: Booth
authors.affiliation: Center of Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson, MS, USA. sseals@umc.edu.
authors.forename: Samantha R
authors.initials: SR
authors.lastname: Seals
authors.affiliation: School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ, USA. Steven.Hooker@asu.edu.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Hooker
authors.affiliation: Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA. msims2@umc.edu.
authors.forename: Mario
authors.initials: M
authors.lastname: Sims
authors.affiliation: South Central Mental Illness, Research, and Clinical Center and Little Rock Geriatric Research, Education, and Clinical Center, Little Rock, AR, USA. Patricia.Dubbert@va.gov.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Dubbert
authors.affiliation: Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA. pmunter@uab.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
authors.affiliation: Department of Medicine, Center for Behavioral Cardiovascular Health, Columbia University Medical Center, 622 West 168th Street, PH9-319, New York, NY, 10032, USA. ds2231@cumc.columbia.edu.
authors.forename: Daichi
authors.initials: D
authors.lastname: Shimbo
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D050197:Atherosclerosis / Q000453:epidemiology*; D059168:Carotid Intima-Media Thickness; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008922:Mississippi / Q000453:epidemiology; D057185:Sedentary Behavior / Q000208:ethnology*