论文标题：Body size in early life and risk of breast cancer

期刊：Breast Cancer Research

作者：Md. Shajedur Rahman Shawon, Mikael Eriksson & Jingmei Li

发表时间：2017/07/21

DOI：10.1186/s13058-017-0875-9

微信链接：https://mp.weixin.qq.com/s/d4Dwplv3-z5nA4iIpu6TPg

早期体型与成年乳腺癌（BC）的风险成负相关，但这种关联是否因肿瘤特征而异目前还尚不清楚。Breast Cancer Research 发表的一项研究试图了解两者之间的关系。

乳腺癌不仅是一种疾病，而且是由不同肿瘤亚型造成的混合病症。相关荟萃分析已经确定，成年体重对乳腺癌的影响取决于雌激素和孕激素受体（ER/PR）的状态（例如，ER+/PR+肿瘤的风险会比较大）。然而，对于早期体型在ER肿瘤亚型中的作用，目前研究尚未达成一致。此外，很少有研究涉及其他肿瘤特征，例如肿瘤大小和/或淋巴结转移。

在发表在Breast Cancer Research 的一项研究中，研究人员进行了两个基于瑞典乳腺癌人群的独立研究，目的是通过更年期状态和肿瘤特征来阐明早期体型与成年乳腺癌风险之间的关系。

在对两项基于瑞典人口研究的汇总分析中，研究人员研究了早期体型与BC风险之间的关系。这两项研究包括了6731例浸润性BC病例和28705例同年龄的健康对照。他们使用验证过的九级象形图（分为偏瘦、适中和偏胖三类），记录了被试7岁和18岁时的体重。在这个病例-对照分析中，该研究考虑到了所属研究、诊断时年龄、初潮年龄、孩子数目、是否有过激素替代疗法和BC家族史等因素，利用多变量逻辑回归模型估算了优势比（OR）和相应的95％置信区间（CI），并研究了7至18岁之间的体重变化与BC风险的关系。另外，研究人员通过个案分析了这种关联性是否因肿瘤特征而异。

九级象形图：用于评估被试7岁和18岁时体型

与7岁和18岁时的偏瘦体型相比，7岁和18岁时的中等体型或偏胖体型被试患BC的风险显著降低：偏胖体型与偏瘦体型相比分别为，0.78（0.70-0.86），Ptrend <0.001，以及0.72（0.64–0.80），Ptrend <0.001。大多数女性在7至18岁之间没有发生体型的改变。与7至18岁之间体型一直偏瘦的女性相比，在7至18岁之间体型都保持中等或偏胖的女性患BC的风险显著降低。研究还发现7至18岁之间体型减小与BC风险呈反比关系。7岁时的体型与肿瘤特征之间没有显著关联。18岁时的体型与肿瘤大小成反比（Ptrend = 0.006），但与雌激素受体的状态和淋巴结受累没有关联。对于所有分析，在进一步根据人体重指数进行调整后，总体的结论没有明显变化。

总之，该研究数据为早期体型与成年乳腺癌之间的负相关关系提供了进一步的支持。研究人员还发现18岁时的体型与肿瘤大小显著相关，这可能是由乳腺X线密度介导的。讨论本研究对公共健康的启示时应保持谨慎，并且应当充分考虑成年后的其他合并症。

摘要：

Background

Body size in early life is inversely associated with adult breast cancer (BC) risk, but it is unclear whether the associations differ by tumor characteristics.

Methods

In a pooled analysis of two Swedish population-based studies consisting of 6731 invasive BC cases and 28,705 age-matched cancer-free controls, we examined the associations between body size in early life and BC risk. Self-reported body sizes at ages 7 and 18 years were collected by a validated nine-level pictogram (aggregated into three categories: small, medium and large). Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated from multivariable logistic regression models in case-control analyses, adjusting for study, age at diagnosis, age at menarche, number of children, hormone replacement therapy, and family history of BC. Body size change between ages 7 and 18 were also examined in relation to BC risk. Case-only analyses were performed to test whether the associations differed by tumor characteristics.

Results

Medium or large body size at age 7 and 18 was associated with a statistically significant decreased BC risk compared to small body size (pooled OR (95% CI): comparing large to small, 0.78 (0.70–0.86), Ptrend <0.001 and 0.72 (0.64–0.80), Ptrend<0.001, respectively). The majority of the women (~85%) did not change body size categories between age 7 and 18 . Women who remained medium or large between ages 7 and 18 had significantly decreased BC risk compared to those who remained small. A reduction in body size between ages 7 and 18 was also found to be inversely associated with BC risk (0.90 (0.81–1.00)). No significant association was found between body size at age 7 and tumor characteristics. Body size at age 18 was found to be inversely associated with tumor size (Ptrend = 0.006), but not estrogen receptor status and lymph node involvement. For all analyses, the overall inferences did not change appreciably after further adjustment for adult body mass index.

Conclusions

Our data provide further support for a strong and independent inverse relationship between early life body size and BC risk. The association between body size at age 18 and tumor size could be mediated by mammographic density.

（来源：科学网）