Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
JAMA Intern Med. 2024 Jul 1;184(7):718-725. doi: 10.1001/jamainternmed.2024.0892.
Current US physical activity (PA) guidelines prescribe moderate to vigorous PA (MVPA) time of at least 150 minutes per week for health. An analogous step-based recommendation has not been issued due to insufficient evidence.
To examine the associations of MVPA time and step counts with all-cause mortality and cardiovascular disease (CVD).
DESIGN, SETTING, AND PARTICIPANTS: This cohort study analyzed data from an ongoing follow-up study of surviving participants of the Women's Health Study, a randomized clinical trial conducted from 1992 to 2004 in the US to evaluate use of low-dose aspirin and vitamin E for preventing cancer and CVD. Participants were 62 years or older who were free from CVD and cancer, completed annual questionnaires, and agreed to measure their PA with an accelerometer as part of a 2011-2015 ancillary study. Participants were followed up through December 31, 2022.
Time spent in MVPA and step counts, measured with an accelerometer for 7 consecutive days.
The associations of MVPA time and step counts with all-cause mortality and CVD (composite of myocardial infarction, stroke, and CVD mortality) adjusted for confounders. Cox proportional hazards regression models, restricted mean survival time differences, and area under the receiver operating characteristic curve (AUC) were used to evaluate the associations.
A total of 14 399 women (mean [SD] age, 71.8 [5.6] years) were included. The median (IQR) MVPA time and step counts were 62 (20-149) minutes per week and 5183 (3691-7001) steps per day, respectively. During a median (IQR) follow-up of 9.0 (8.0-9.9) years, the hazard ratios (HR) per SD for all-cause mortality were 0.82 (95% CI, 0.75-0.90) for MVPA time and 0.74 (95% CI, 0.69-0.80) for step counts. Greater MVPA time and step counts (top 3 quartiles vs bottom quartile) were associated with a longer period free from death: 2.22 (95% CI, 1.58-2.85) months and 2.36 (95% CI, 1.73-2.99) months at 9 years follow-up, respectively. The AUCs for all-cause mortality from MVPA time and step counts were similar: 0.55 (95% CI, 0.52-0.57) for both metrics. Similar associations of these 2 metrics with CVD were observed.
Results of this study suggest that among females 62 years or older, MVPA time and step counts were qualitatively similar in their associations with all-cause mortality and CVD. Step count-based goals should be considered for future guidelines along with time-based goals, allowing for the accommodation of personal preferences.
目前美国的身体活动（PA）指南规定，每周至少进行 150 分钟的中等至剧烈 PA（MVPA），以促进健康。由于证据不足，尚未发布类似的基于步数的建议。
研究 MVPA 时间和步数与全因死亡率和心血管疾病（CVD）的相关性。
设计、地点和参与者：本队列研究分析了正在进行的女性健康研究参与者后续研究的数据，该研究是一项在美国进行的随机临床试验，于 1992 年至 2004 年开展，旨在评估低剂量阿司匹林和维生素 E 用于预防癌症和 CVD 的效果。参与者为年龄在 62 岁及以上、无 CVD 和癌症、完成年度问卷调查且同意在 2011-2015 年的辅助研究中使用加速度计测量 PA 的人群。参与者的随访截止到 2022 年 12 月 31 日。
MVPA 时间和步数，使用加速度计连续 7 天测量。
MVPA 时间和步数与全因死亡率和 CVD（心肌梗死、中风和 CVD 死亡率的复合结局）的相关性，调整混杂因素后进行评估。使用 Cox 比例风险回归模型、限制性平均生存时间差异和接受者操作特征曲线下面积（AUC）评估相关性。
共纳入 14399 名女性（平均[标准差]年龄，71.8[5.6]岁）。每周 MVPA 时间和步数的中位数（IQR）分别为 62（20-149）分钟和 5183（3691-7001）步/天。在中位数（IQR）为 9.0（8.0-9.9）年的随访期间，全因死亡率的 HR 每 SD 分别为 MVPA 时间的 0.82（95%CI，0.75-0.90）和步数的 0.74（95%CI，0.69-0.80）。MVPA 时间和步数较高（最高 3 个四分位距与最低四分位距相比）与死亡风险降低相关：分别在 9 年随访时，死亡无事件期延长 2.22（95%CI，1.58-2.85）个月和 2.36（95%CI，1.73-2.99）个月。MVPA 时间和步数的全因死亡率 AUC 相似：两者均为 0.55（95%CI，0.52-0.57）。这两个指标与 CVD 的相关性也相似。
本研究结果表明，在 62 岁及以上的女性中，MVPA 时间和步数与全因死亡率和 CVD 的相关性具有相似的定性特征。未来的指南应考虑基于步数的目标，同时考虑基于时间的目标，以适应个人偏好。
