Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou, China.
Obes Rev. 2018 Feb;19(2):254-268. doi: 10.1111/obr.12627. Epub 2017 Nov 12.
Higher body fatness in adulthood has been consistently associated with an increased risk of postmenopausal breast cancer, as well as a tendency towards a lower risk of premenopausal breast cancer. However, the association between body fatness at a young age (≤30 years), body fatness gain and the risk of breast cancer is less defined. PubMed and Web of Science databases were searched to identify relevant publications. Risk estimates with 95% confidence intervals from each study were transformed into a continuous variable for each 5 kg m increase in body mass index (BMI) and were pooled under a random-effects model. Each 5 kg m increase in BMI was significantly associated with a 14%, 12% and 17% lower risk of breast cancer later in life among all women, premenopausal women and postmenopausal women, respectively. Significant heterogeneity and publication bias were observed. The results remained unchanged after the trim and fill method was applied to correct the bias. Each 5 kg m increase in BMI from a young age until cohort entry was significantly associated with a 13% and 14% higher risk of breast cancer in all women and postmenopausal women, respectively. In summary, higher body fatness at a young age may have a protective role in the later development of breast cancer in both premenopausal and postmenopausal women. However, this potential benefit should not be overemphasized, as our findings suggest that increased body fatness gain from a young age is positively associated with postmenopausal breast cancer risk. These findings further justify the need to maintain a steady weight throughout life.
成年期体脂含量较高与绝经后乳腺癌风险增加以及绝经前乳腺癌风险降低的趋势有关。然而，年轻时（≤30 岁）的体脂含量、体脂增加与乳腺癌风险之间的关系尚不明确。我们在 PubMed 和 Web of Science 数据库中检索了相关文献。对每一项研究的风险估计值及其 95%置信区间，以每增加 5kg/m 的 BMI 为一个连续变量进行转化，并采用随机效应模型进行汇总。结果显示，BMI 每增加 5kg/m，所有女性、绝经前女性和绝经后女性的乳腺癌发病风险分别降低 14%、12%和 17%。观察到存在显著的异质性和发表偏倚。应用修剪和填充方法纠正偏倚后，结果仍然不变。在所有女性和绝经后女性中，从年轻时到队列入组时 BMI 每增加 5kg/m，乳腺癌发病风险分别增加 13%和 14%。总之，年轻时体脂含量较高可能对绝经前和绝经后女性乳腺癌的后期发生具有保护作用。然而，不应过分强调这种潜在的益处，因为我们的研究结果表明，年轻时体脂增加与绝经后乳腺癌风险呈正相关。这些发现进一步证明了在整个生命周期中保持稳定体重的必要性。
