The lifestyle factors of physical activity, sedentary behaviour, and diet are increasingly being studied for their associations with cancer. Physical activity is inversely associated with and sedentary behaviour is positively (and independently) associated with an increased risk of more than ten types of cancer, including colorectal cancer (and advanced adenomas), endometrial cancers, and breast cancer. The most consistent dietary risk factor for premalignant and invasive breast cancer is alcohol, whether consumed during early or late adult life, even at low levels. Epidemiological studies show that the inclusion of wholegrain, fibre, fruits, and vegetables within diets are associated with reduced cancer risk, with diet during early life (age <8 years) having the strongest apparent association with cancer incidence. However, randomised controlled trials of diet-related factors have not yet shown any conclusive associations between diet and cancer incidence. Obesity is a key contributory factor associated with cancer risk and mortality, including in dose-response associations in endometrial and post-menopausal breast cancer, and in degree and duration of fatty liver disease-related hepatocellular carcinoma. Obesity produces an inflammatory state, characterised by macrophages clustered around enlarged hypertrophied, dead, and dying adipocytes, forming crown-like structures. Increased concentrations of aromatase and interleukin 6 in inflamed breast tissue and an increased number of macrophages, compared with healthy tissue, are also observed in women with normal body mass index, suggesting a metabolic obesity state. Emerging randomised controlled trials of physical activity and dietary factors and mechanistic studies of immunity, inflammation, extracellular matrix mechanics, epigenetic or transcriptional regulation, protein translation, circadian disruption, and interactions of the multibiome with lifestyle factors will be crucial to advance this field.

中文翻译：

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体力活动、久坐行为、饮食和癌症：更新和不断出现的新证据。

人们越来越多地研究身体活动、久坐行为和饮食等生活方式因素与癌症的关系。体力活动与十多种癌症的风险增加呈负相关，久坐行为与十多种癌症的风险增加呈正相关（且独立），包括结直肠癌（和晚期腺瘤）、子宫内膜癌和乳腺癌。癌前和浸润性乳腺癌最一致的饮食风险因素是酒精，无论是在成年早期还是晚期饮酒，即使是低水平的饮酒。流行病学研究表明，饮食中包含全麦、纤维、水果和蔬菜可降低癌症风险，其中生命早期（<8 岁）的饮食与癌症发病率的关联最为明显。然而，饮食相关因素的随机对照试验尚未显示饮食与癌症发病率之间有任何决定性的关联。肥胖是与癌症风险和死亡率相关的关键因素，包括子宫内膜癌和绝经后乳腺癌的剂量反应关联，以及脂肪肝疾病相关肝细胞癌的程度和持续时间。肥胖会产生炎症状态，其特征是巨噬细胞聚集在肥大、死亡和垂死的脂肪细胞周围，形成冠状结构。与健康组织相比，在体重指数正常的女性中也观察到发炎的乳腺组织中芳香酶和白细胞介素 6 的浓度增加以及巨噬细胞数量的增加，这表明存在代谢性肥胖状态。新兴的体力活动和饮食因素随机对照试验以及免疫、炎症、细胞外基质力学、表观遗传或转录调控、蛋白质翻译、昼夜节律破坏以及多生物组与生活方式因素相互作用的机制研究对于推动这一领域至关重要。