Chavez-MacGregor Mariana, van Gils Carla H, van der Schouw Yvonne T, Monninkhof Evelyn, van Noord Paulus A H, Peeters Petra H M
Julius Center for Health Sciences and Primary care, University Medical Center, Utrecht, The Netherlands.
Breast Cancer Res Treat. 2008 Mar;108(1):101-12. doi: 10.1007/s10549-007-9574-z. Epub 2007 May 22.
Lifetime cumulative number of menstrual cycles is related to breast cancer risk. The aim of this study is to investigate the relation between this index and serum sex hormone levels in postmenopausal women.
Cross-sectional study including 860 naturally postmenopausal Dutch participants of the European Prospective Investigation into Cancer and Nutrition. Lifetime cumulative number of menstrual cycles was computed using questionnaire data on ages at menarche and menopause, number of pregnancies, breastfeeding, oral contraceptive use (OC) and regularity pattern. Measurements of hormones included estrone (E1), estradiol (E2), andostrenedione, testosterone, sex-hormone binding globulin (SHBG) and dehydroepiandrostenedione sulfate (DHEAS). The relation between the lifetime cumulative number of menstrual cycles and hormone levels was assessed using analysis of covariance. Relations between reproductive characteristics and hormone levels were also studied. Adjustments for characteristics at blood collection included age, years since menopause, BMI, hormone replacement therapy use, OC use, smoking habits, alcohol intake and physical activity were done.
Lifetime cumulative number of cycles was related with SHBG; participants in the lowest category had higher SHBG levels. For the separate characteristics, DHEAS and androstenedione increased significantly with increasing age at menarche, while androstenedione and testosterone decreased with increasing age at menopause. For the parity characteristics, SHBG levels increased according to the number of live births.
Lifetime cumulative number menstrual cycles was related only to SHBG. Therefore, free levels of estrogens or androgens may be related to this number of menstrual cycles estimate, reflecting lifetime exposure to ovarian hormones.
月经周期的终生累积数与乳腺癌风险相关。本研究旨在调查该指标与绝经后女性血清性激素水平之间的关系。
横断面研究纳入了欧洲癌症与营养前瞻性调查中860名自然绝经的荷兰参与者。使用关于初潮年龄、绝经年龄、怀孕次数、母乳喂养、口服避孕药使用情况（OC）和月经规律模式的问卷数据计算月经周期的终生累积数。激素测量包括雌酮（E1）、雌二醇（E2）、雄烯二酮、睾酮、性激素结合球蛋白（SHBG）和硫酸脱氢表雄酮（DHEAS）。使用协方差分析评估月经周期的终生累积数与激素水平之间的关系。还研究了生殖特征与激素水平之间的关系。对采血时的特征进行了调整，包括年龄、绝经年限、体重指数、激素替代疗法使用情况、OC使用情况、吸烟习惯、酒精摄入量和体育活动。
月经周期的终生累积数与SHBG相关；最低类别参与者的SHBG水平较高。对于各个特征，DHEAS和雄烯二酮随着初潮年龄的增加而显著增加，而雄烯二酮和睾酮随着绝经年龄的增加而降低。对于生育特征，SHBG水平根据活产次数增加。
月经周期的终生累积数仅与SHBG相关。因此，雌激素或雄激素的游离水平可能与这个月经周期数估计值相关，反映终生暴露于卵巢激素的情况。
