运动与肿瘤风险

Physical activity and cancer risk

运动与恶性肿瘤风险之间的联系是否存在可见的剂量反应关系,是否能阐明其生物学机制。将近五年的有关职业劳动和/或休闲体育活动对各种恶性肿瘤风险作用的观察性研究进行回顾,包括队列研究和病例对照研究。在回顾运动与恶性肿瘤风险联系的研究结果时,包括饮食、体重在内的各种混杂因素被标化,在此基础上发现运动对于乳腺癌、结肠癌、子宫内膜癌和肺癌等具有保护作用。在12项报道运动对乳腺癌具有保护作用的研究中有6项研究结果提示运动与乳腺癌之间呈负相关。这种联系可能依赖于患者的暴露年龄、诊断年龄、绝经状况和其他因素如体重指数等。负相关的剂量反应关系也出现在大部分的关于结肠癌的研究结果中。对于前列腺癌和睾丸肿瘤的研究没有提示运动对其具有保护作用。运动与其他肿瘤的联系尚需更多的研究资料。运动对乳腺癌和结肠癌具有保护作用,并呈负相关,这种联系的生物学机制也被发现。但运动的复杂多样性以及相关生物学机制的认识匮乏,决定了需要更多的临床随机对照的试验性研究。

The association between physical activity and site specific cancer risk is elaborated in relation to whether any dose response association between physical activity and cancer is observed and whether any possible mechanisms can be interpreted in the association. Observational studies in latter five years were reviewed that have examined the independent effect of the volume of occupational physical activity (OPA) and/or leisure time physical activity(LPA)on site specific cancer risk.The evidence of cohort and case control studies were reviewed with the confounding effects such as diet, body weight, and parity included as a covariate in the analyses.A protective effect of physical activity was observed in the majority of site specific cancer such as breast cancer, endometrial cancer, colon cancer and lung cancer. A crude graded inverse dose response effect of physical activity on breast cancer was suggested in 6 studies of 12 studies with a positive protective effect conclusion.This association between physical activity and breast cancer risk is possibly dependent on age at exposure, age at diagnosis, menopausal status and other effect modifiers, e.g., body mass index. An observed inverse association with a dose response relationship between physical activity and colon cancer was identified in the majority of the studies. No significant evidence of a protective effect between physical activity and prostate and testicular cancer was suggested in latter studies. Data concerning carcinoma of other cancers are required.A protective effect of physical activity on site specific cancer risk with a dose response association between physical activity and colon and pre and postmenopausal breast cancer supported by identified biological mechanisms has been observed. The complicated nature of the physical activity variable, combined with lack of knowledge regarding possible biological mechanisms operating between physical activity and cancer, warrants further studies including controlled clinical randomized trials.