BACKGROUND Even though in situ breast cancer (BCIS) accounts for a large proportion of the breast cancers diagnosed, few studies have investigated potential risk factors for BCIS. Their results suggest that some established risk factors for invasive breast cancer have a similar impact on BCIS risk, but large population-based studies on lifestyle factors and BCIS risk are lacking. Thus, we investigated the association between lifestyle and BCIS risk within the European Prospective Investigation into Cancer and Nutrition cohort. METHODS Lifestyle was operationalized by a score reflecting the adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations. The recommendations utilized in these analyses were the ones pertinent to healthy body weight, physical activity, consumption of plant-based foods, energy-dense foods, red and processed meat, and sugary drinks and alcohol, as well as the recommendation on breastfeeding. Cox proportional hazards regression was used to assess the association between lifestyle score and BCIS risk. The results were presented as hazard ratios (HR) and corresponding 95% confidence intervals (CI). RESULTS After an overall median follow-up time of 14.9 years, 1277 BCIS cases were diagnosed. Greater adherence to the WCRF/AICR cancer prevention recommendations was not associated with BCIS risk (HR = 0.98, 95% CI 0.93-1.03; per one unit of increase; multivariable model). An inverse association between the lifestyle score and BCIS risk was observed in study centers, where participants were recruited mainly via mammographic screening and attended additional screening throughout follow-up (HR = 0.85, 95% CI 0.73-0.99), but not in the remaining ones (HR = 0.99, 95% CI 0.94-1.05). CONCLUSIONS While we did not observe an overall association between lifestyle and BCIS risk, our results indicate that lifestyle is associated with BCIS risk among women recruited via screening programs and with regular screening participation. This suggests that a true inverse association between lifestyle habits and BCIS risk in the overall cohort may have been masked by a lack of information on screening attendance. The potential inverse association between lifestyle and BCIS risk in our analyses is consistent with the inverse associations between lifestyle scores and breast cancer risk reported from previous studies.

中文翻译：

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遵守世界癌症研究基金会/美国癌症研究所的癌症预防建议以及欧洲癌症与营养前瞻性调查 (EPIC) 队列中原位乳腺癌的风险。


背景尽管原位乳腺癌（BCIS）占诊断乳腺癌的很大一部分，但很少有研究调查BCIS的潜在危险因素。他们的结果表明，一些已确定的浸润性乳腺癌风险因素对 BCIS 风险具有类似的影响，但缺乏针对生活方式因素和 BCIS 风险的大规模人群研究。因此，我们在欧洲癌症和营养前瞻性调查队列中调查了生活方式与 BCIS 风险之间的关联。方法 生活方式的评分反映了对世界癌症研究基金会/美国癌症研究所 (WCRF/AICR) 癌症预防建议的遵守情况。这些分析中使用的建议涉及健康体重、体力活动、植物性食品、高能量食品、红肉和加工肉类、含糖饮料和酒精的消费，以及母乳喂养的建议。 Cox 比例风险回归用于评估生活方式评分与 BCIS 风险之间的关联。结果以风险比 (HR) 和相应的 95% 置信区间 (CI) 表示。结果 经过 14.9 年的总体中位随访时间，诊断出 1277 例 BCIS 病例。更严格地遵守 WCRF/AICR 癌症预防建议与 BCIS 风险无关（HR = 0.98，95% CI 0.93-1.03；每增加一个单位；多变量模型）。在研究中心观察到生活方式评分与 BCIS 风险之间呈负相关，其中参与者主要通过乳房 X 线摄影筛查招募，并在整个随访过程中参加额外筛查（HR = 0.85，95% CI 0.73-0.99），但在其余研究中则不然。 （HR = 0.99，95% CI 0.94-1.05）。 结论 虽然我们没有观察到生活方式与 BCIS 风险之间的总体关联，但我们的结果表明，在通过筛查计划招募并定期参与筛查的女性中，生活方式与 BCIS 风险相关。这表明，整个队列中生活方式习惯与 BCIS 风险之间真正的负相关可能因缺乏筛查出勤信息而被掩盖。我们的分析中生活方式与 BCIS 风险之间潜在的负相关与之前研究报告的生活方式评分与乳腺癌风险之间的负相关一致。