Center for Clinical Research and Prevention, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.
Section of Environmental Health, Department of Public Health, University of Copenhagen, Denmark.
Cancer Epidemiol. 2023 Dec;87:102479. doi: 10.1016/j.canep.2023.102479. Epub 2023 Oct 26.
Associations between a high body mass index (BMI) at single timepoints during child- and adulthood and risks of post-menopausal breast cancer are well-established, but associations with BMI across the lifecourse remains largely unknown. Therefore, we examined whether lifecourse BMI trajectories were associated with risks of post-menopausal breast cancer overall and by estrogen receptor (ER) status.
We included 6698 Danish women born 1930-1946. Information on BMI at ages 6-15 years came from the Copenhagen School Health Records Register, and information on BMI at ages 20, 30, 40, 50 and/or 50-64 years came from the Diet, Cancer and Health cohort. Breast cancer cases (n = 577) were identified in the Danish Breast Cancer Cooperative Group database. Six BMI trajectories were identified using latent class trajectory modelling. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression models.
Compared to women with a trajectory characterized by an average BMI gain across life, women with the two trajectories with steep increases in BMI during childhood and adolescence that thereafter largely stabilized, had lower risks of post-menopausal breast cancer and ER-positive tumors. The adjusted HRs for ER-positive tumors were 0.67 (95% CI: 0.47-0.95) and 0.68 (95% CI: 0.46-1.01), respectively. In contrast, women with a trajectory with a low gain in BMI during childhood and adolescence followed by a subsequent steep increase during adulthood, had higher risks of post-menopausal breast cancer and ER-positive tumors when compared to women with an average BMI gain. The adjusted HR for ER-positive tumors was 1.28 (95% CI: 0.98-1.67).
Our findings suggest that the timing of excess gain in BMI across the lifecourse impacts subsequent post-menopausal breast cancer risks. Thus, the BMI development across life is likely useful in the identification of women at increased risks of post-menopausal breast cancer.
在儿童期和成年期的单一时间点，较高的体重指数（BMI）与绝经后乳腺癌的风险之间存在关联已得到充分证实，但与整个生命过程中的 BMI 之间的关联在很大程度上仍不清楚。因此，我们研究了一生中 BMI 轨迹是否与绝经后乳腺癌的总体风险以及雌激素受体（ER）状态有关。
我们纳入了 6698 名丹麦女性，她们出生于 1930-1946 年。6-15 岁时的 BMI 信息来自哥本哈根学校健康记录登记处，20、30、40、50 岁及/或 50-64 岁时的 BMI 信息来自饮食、癌症与健康队列。丹麦乳腺癌合作组数据库中确定了 577 例乳腺癌病例。使用潜在类别轨迹建模确定了 6 种 BMI 轨迹。使用 Cox 回归模型估计风险比（HR）和 95%置信区间（CI）。
与一生中 BMI 平均增长的轨迹相比，儿童期和青春期 BMI 急剧增加但此后基本稳定的两种轨迹的女性，绝经后乳腺癌和 ER 阳性肿瘤的风险较低。ER 阳性肿瘤的调整 HR 分别为 0.67（95%CI：0.47-0.95）和 0.68（95%CI：0.46-1.01）。相比之下，与一生中 BMI 平均增长的女性相比，儿童期和青春期 BMI 增长缓慢，成年后 BMI 急剧增加的女性，绝经后乳腺癌和 ER 阳性肿瘤的风险更高。ER 阳性肿瘤的调整 HR 为 1.28（95%CI：0.98-1.67）。
我们的研究结果表明，一生中 BMI 过度增长的时间会影响随后的绝经后乳腺癌风险。因此，一生中 BMI 的发展可能有助于识别绝经后乳腺癌风险增加的女性。
