Diaz Keith M, Booth John N, Seals Samantha R, Hooker Steven P, Sims Mario, Dubbert Patricia M, Muntner Paul, Shimbo Daichi
Department of Medicine, Center for Behavioral Cardiovascular Health, Columbia University Medical Center, 622 West 168th Street, PH9-319, New York, NY, 10032, USA.
Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA.
Int J Behav Nutr Phys Act. 2016 Mar 1;13:31. doi: 10.1186/s12966-016-0349-y.
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.
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.
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).
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.
以往研究对于非裔美国人久坐时间与心血管疾病（CVD）风险之间是否存在关联给出了相互矛盾的结果。然而，这些研究存在局限性，未考虑休闲与非休闲环境下的久坐行为。为阐明这种关系，我们在一个基于社区的非裔美国人样本中，研究了看电视时间和职业性久坐与颈动脉内膜中层厚度（CIMT，一种亚临床动脉粥样硬化指标）之间的关联。
我们研究了来自杰克逊心脏研究的3410名参与者，该研究是一项针对居住在密西西比州杰克逊市的非裔美国人的单中心社区研究。通过超声检查评估CIMT，其代表颈总动脉左右两侧远壁的平均厚度。看电视时间（一种休闲久坐行为指标）和职业性久坐（一种非休闲久坐行为指标）通过问卷调查进行评估。
在一个包含身体活动和CVD风险因素的多变量回归模型中，较长的看电视时间（每天2 - 4小时和>4小时）与更大的CIMT相关（与参照组[每天<2小时]相比，每天2 - 4小时的调整后均值±标准误差异为0.009±0.008毫米，每天>4小时为0.028±0.009毫米；P趋势=0.001）。相比之下，更频繁的职业性久坐（“有时”和“经常/总是”）与更低的CIMT相关（与参照组[“从不/很少”]相比的调整后均值±标准误差异：“有时”为 - 0.021±0.009毫米，“经常/总是”为 - 0.018±0.008毫米；P趋势=0.042）。
较长的看电视时间与更大的CIMT相关，而职业性久坐与更低的CIMT相关。这些发现表明，非裔美国人中久坐行为在CVD发病机制中的作用可能因个体从事的是休闲还是非休闲久坐行为而有所不同。
