Department of Physical Therapy, University of Delaware, Newark, DE, USA.
Department of Medicine, Section of Rheumatology, Boston University School of Medicine, Boston, MA, USA.
Osteoarthritis Cartilage. 2023 Aug;31(8):1091-1100. doi: 10.1016/j.joca.2022.12.012. Epub 2023 Feb 21.
There is continued debate as to how engaging in physical activity (PA), including moderate-to-vigorous PA (MVPA), light PA (LPA), and sedentary time (SED), affects one's risk for knee osteoarthritis (OA). Traditional regression methods do not account for the codependence of these categories of PA, whereby when one category increases, the others must decrease. Thus, we used compositional data analysis (CoDA) to examine time spent in each category of PA, or PA composition, and its association with loss of knee joint space width (JSW), a common indicator of knee OA progression.
We performed a secondary analysis of data from a subset of participants in the Osteoarthritis Initiative. These participants had minute-by-minute activity data collected over 7 days at baseline; we then categorized each minute as MVPA, LPA, or SED. Our exposure, PA composition, represented min/day spent in each category. Our outcome, medial JSW loss, was the difference in medial tibiofemoral JSW from baseline to 2 years later. We employed CoDA, using an isometric log-ratio transformation, to examine the association of PA composition with medial JSW loss over 2 years, adjusting for potential confounders.
We included 969 participants (age: 64.5 years, 56% female, body mass index [BMI]: 28.8 kg/m). Mean PA composition was: MVPA 9.1 min/day, LPA 278 min/day, SED 690 min/day. Per adjusted regression models, higher MVPA was not associated with greater medial JSW loss (β = -0.0005, P = 0.97), nor was LPA (β = 0.06, P = 0.27) or SED (β = -0.06, P = 0.21).
Using CoDA, PA composition was not associated with medial JSW loss over 2 years.
关于进行身体活动（PA），包括中等到剧烈的 PA（MVPA）、轻度 PA（LPA）和久坐时间（SED），如何影响人们患膝骨关节炎（OA）的风险，仍存在持续的争论。传统的回归方法没有考虑到这些 PA 类别的相互依存性，即当一个类别增加时，其他类别必须减少。因此，我们使用成分数据分析（CoDA）来检查每个 PA 类别的时间分配，即 PA 组成，及其与膝关节间隙宽度（JSW）丧失的关系，JSW 丧失是 OA 进展的一个常见指标。
我们对 Osteoarthritis Initiative 参与者的一个子集中的数据进行了二次分析。这些参与者在基线时有 7 天的每分钟活动数据；然后我们将每一分钟分为 MVPA、LPA 或 SED。我们的暴露因素，PA 组成，代表每天在每个类别中花费的分钟数。我们的结果，内侧 JSW 丧失，是从基线到 2 年后内侧胫股 JSW 的差异。我们使用 CoDA，使用等比对数变换，来检查 PA 组成与 2 年内内侧 JSW 丧失的关联，同时调整了潜在的混杂因素。
我们纳入了 969 名参与者（年龄：64.5 岁，56%为女性，体重指数 [BMI]：28.8kg/m2）。PA 组成的平均值为：MVPA 9.1 分钟/天，LPA 278 分钟/天，SED 690 分钟/天。根据调整后的回归模型，较高的 MVPA 与较大的内侧 JSW 丧失无关（β=-0.0005，P=0.97），LPA 也无关（β=0.06，P=0.27）或 SED 无关（β=-0.06，P=0.21）。
使用 CoDA，PA 组成在 2 年内与内侧 JSW 丧失无关。
