In this study, we aimed to provide novel evidence on the impact of changing lifestyle habits on cancer risk. In the EPIC cohort, 295,865 middle-aged participants returned a lifestyle questionnaire at baseline and during follow-up. At both timepoints, we calculated a healthy lifestyle index (HLI) score based on cigarette smoking, alcohol consumption, body mass index and physical activity. HLI ranged from 0 (most unfavourable) to 16 (most favourable). We estimated the association between HLI change and risk of lifestyle-related cancers—including cancer of the breast, lung, colorectum, stomach, liver, cervix, oesophagus, bladder, and others—using Cox regression models. We reported hazard ratios (HR) with 95% confidence intervals (CI). Median time between the two questionnaires was 5.7 years, median age at follow-up questionnaire was 59 years. After the follow-up questionnaire, we observed 14,933 lifestyle-related cancers over a median follow-up of 7.8 years. Each unit increase in the HLI score was associated with 4% lower risk of lifestyle-related cancers (HR 0.96; 95%CI 0.95–0.97). Among participants in the top HLI third at baseline (HLI > 11), those in the bottom third at follow-up (HLI ≤ 9) had 21% higher risk of lifestyle-related cancers (HR 1.21; 95%CI 1.07–1.37) than those remaining in the top third. Among participants in the bottom HLI third at baseline, those in the top third at follow-up had 25% lower risk of lifestyle-related cancers (HR 0.75; 95%CI 0.65–0.86) than those remaining in the bottom third. These results indicate that lifestyle changes in middle age may have a significant impact on cancer risk.

在这项研究中，我们旨在提供新的证据来证明改变生活习惯对癌症风险的影响。在 EPIC 队列中，295,865 名中年参与者在基线和随访期间返回了生活方式调查问卷。在这两个时间点，我们根据吸烟、饮酒、体重指数和体力活动计算了健康生活方式指数 (HLI) 评分。HLI 范围从 0（最不利）到 16（最有利）。我们使用 Cox 回归模型估计了 HLI 变化与生活方式相关癌症（包括乳腺癌、肺癌、结直肠癌、胃癌、肝癌、子宫颈癌、食道癌、膀胱癌等）风险之间的关联。我们报告了具有 95% 置信区间 (CI) 的风险比 (HR)。两次问卷调查之间的中位时间为 5.7 年，随访问卷时的中位年龄为 59 岁。完成随访问卷后，我们在中位随访时间 7.8 年中观察到了 14,933 例与生活方式相关的癌症。HLI 评分每增加一个单位，生活方式相关癌症的风险就会降低 4%（HR 0.96；95%CI 0.95–0.97）。在基线时 HLI 排名前三分之一 (HLI > 11) 的参与者中，随访时排名后三分之一 (HLI ≤ 9) 的参与者患生活方式相关癌症的风险高出 21%（HR 1.21；95%CI 1.07–1.37）比那些留在前三分之一的人。在基线时 HLI 排名倒数第三的参与者中，随访时排名前三分之一的参与者患生活方式相关癌症的风险比排名倒数三分之一的参与者低 25%（HR 0.75；95%CI 0.65–0.86）。这些结果表明，中年生活方式的改变可能对癌症风险产生重大影响。