Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston, Massachusetts.
Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
JAMA Oncol. 2016 Sep 1;2(9):1146-53. doi: 10.1001/jamaoncol.2016.0740.
Accumulating evidence indicates that common carcinogenic pathways may underlie digestive system cancers. Physical activity may influence these pathways. Yet, to our knowledge, no previous study has evaluated the role of physical activity in overall digestive system cancer risk.
To examine the association between physical activity and digestive system cancer risk, accounting for amount, type (aerobic vs resistance), and intensity of physical activity.
DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study followed 43 479 men from the Health Professionals Follow-up Study from 1986 to 2012. At enrollment, the eligible participants were 40 years or older, were free of cancer, and reported physical activity. Follow-up rates exceeded 90% in each 2-year cycle.
The amount of total physical activity expressed in metabolic equivalent of task (MET)-hours/week.
Incident cancer of the digestive system encompassing the digestive tract (mouth, throat, esophagus, stomach, small intestine, and colorectum) and digestive accessory organs (pancreas, gallbladder, and liver).
Over 686 924 person-years, we documented 1370 incident digestive system cancers. Higher levels of physical activity were associated with lower digestive system cancer risk (hazard ratio [HR], 0.74 for ≥63.0 vs ≤8.9 MET-hours/week; 95% CI, 0.59-0.93; P value for trend = .003). The inverse association was more evident with digestive tract cancers (HR, 0.66 for ≥63.0 vs ≤8.9 MET-hours/week; 95% CI, 0.51-0.87) than with digestive accessary organ cancers. Aerobic exercise was particularly beneficial against digestive system cancers, with the optimal benefit observed at approximately 30 MET-hours/week (HR, 0.68; 95% CI, 0.56-0.83; P value for nonlinearity = .02). Moreover, as long as the same level of MET-hour score was achieved from aerobic exercise, the magnitude of risk reduction was similar regardless of intensity of aerobic exercise.
Physical activity, as indicated by MET-hours/week, was inversely associated with the risk of digestive system cancers, particularly digestive tract cancers, in men. The optimal benefit was observed through aerobic exercise of any intensity at the equivalent of energy expenditure of approximately 10 hours/week of walking at average pace. Future studies are warranted to confirm our findings and to translate them into clinical and public health recommendation.
越来越多的证据表明，常见的致癌途径可能是消化系统癌症的基础。身体活动可能会影响这些途径。然而，据我们所知，以前没有研究评估身体活动与整体消化系统癌症风险之间的关系。
检查身体活动与消化系统癌症风险之间的关联，同时考虑身体活动的量、类型（有氧运动与抗阻运动）和强度。
设计、设置和参与者：一项前瞻性队列研究跟踪了来自卫生专业人员随访研究的 43479 名男性，研究时间从 1986 年到 2012 年。在入组时，合格的参与者年龄在 40 岁或以上，没有癌症，并报告了身体活动。在每个 2 年周期中，随访率均超过 90%。
用代谢当量小时/周（MET-hours/week）表示的总身体活动量。
消化系统癌症的发病情况，包括消化道（口腔、喉咙、食管、胃、小肠和结直肠）和消化附属器官（胰腺、胆囊和肝脏）。
在超过 686924 人年的随访中，我们记录了 1370 例消化系统癌症。较高水平的身体活动与较低的消化系统癌症风险相关（风险比 [HR]，≥63.0 与 ≤8.9 MET-hours/week 相比为 0.74；95%置信区间，0.59-0.93；趋势检验 P 值 = .003）。这种反比关系在消化道癌症中更为明显（HR，≥63.0 与 ≤8.9 MET-hours/week 相比为 0.66；95%置信区间，0.51-0.87），而与消化附属器官癌症相比则不明显。有氧运动对消化系统癌症特别有益，在大约 30 MET-hours/week 时观察到最佳益处（HR，0.68；95%置信区间，0.56-0.83；非线性检验 P 值 = .02）。此外，只要通过有氧运动达到相同的 MET 小时评分，无论有氧运动的强度如何，风险降低的幅度都是相似的。
以 MET-hours/week 表示的身体活动与男性消化系统癌症风险呈负相关，特别是消化道癌症。通过任何强度的有氧运动都可以获得最佳益处，相当于每周步行 10 小时左右、以平均速度行走所消耗的能量。需要进一步的研究来证实我们的发现，并将其转化为临床和公共卫生建议。
