Shafrir Amy L, Schock Helena, Poole Elizabeth M, Terry Kathryn L, Tamimi Rulla M, Hankinson Susan E, Rosner Bernard A, Tworoger Shelley S
Division of Adolescent/Young Adult Medicine, Boston Center for Endometriosis, Boston Children's Hospital, 1 Autumn Street, 5th Floor, Boston, MA, 02115, USA.
Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
Cancer Causes Control. 2017 May;28(5):371-383. doi: 10.1007/s10552-017-0876-0. Epub 2017 Mar 13.
Oral contraceptives (OCs) have been consistently associated with a reduced ovarian cancer risk; however, most previous studies included women in older birth cohorts using high-dose OC formulations. We assessed OC use, including type and dose, and ovarian cancer risk among women born between 1947 and 1964 using more recent formulations.
We included 110,929 Nurses' Health Study II participants. Women reported duration of OC use and brands used from age 13 to baseline (1989) and every 2 years thereafter through 2009. We categorized brands by estrogen and progestin type, dose, and potency, and used Cox proportional hazards models, adjusted for age, calendar time, reproductive factors, and body mass index, to assess associations with ovarian cancer.
Over 2,178,679 person-years of follow-up, we confirmed 281 cases. At baseline, 83% of participants reported ever using OCs. Compared to never use, we observed an increased risk of ovarian cancer with ≤6 months of OC use (HR 1.82; 95% CI 1.13-2.93) but a non-significant 57% (95% CI 0.18-1.03) decreased risk with ≥15 years of OC use. The increased risk among short-term users (≤1 year) was restricted to OCs containing mestranol (HR 1.83; 95% CI 1.16-2.88) and first-generation progestin (HR 1.72; 95% CI 1.11-2.65).
The associations between OCs and ovarian cancer observed for this younger birth cohort differ substantially from the results of previous cohort studies, possibly reflecting changes in OC formulations and use patterns over time, although these results could be due to chance. Additional studies should evaluate newer OC formulations and ovarian cancer risk.
口服避孕药（OCs）一直与卵巢癌风险降低相关；然而，以往大多数研究纳入的是使用高剂量OC制剂的老年出生队列中的女性。我们评估了1947年至1964年出生的女性使用OCs的情况，包括类型和剂量，以及使用更新制剂后患卵巢癌的风险。
我们纳入了110,929名护士健康研究II的参与者。女性报告了从13岁到基线（1989年）以及此后每两年直至2009年期间使用OCs的持续时间和品牌。我们根据雌激素和孕激素的类型、剂量和效力对品牌进行分类，并使用Cox比例风险模型，对年龄、日历时间、生殖因素和体重指数进行调整，以评估与卵巢癌的关联。
在超过2,178,679人年的随访中，我们确认了281例病例。在基线时，83%的参与者报告曾使用过OCs。与从未使用相比，我们观察到使用OCs≤6个月时卵巢癌风险增加（风险比[HR] 1.82；95%置信区间[CI] 1.13 - 2.93），但使用OCs≥15年时风险降低57%（95% CI 0.18 - 1.03），差异无统计学意义。短期使用者（≤1年）中风险增加仅限于含有炔雌醇甲醚的OCs（HR 1.83；95% CI 1.16 - 2.88）和第一代孕激素（HR 1.72；95% CI 1.11 - 2.65）。
在这个较年轻的出生队列中观察到的OCs与卵巢癌之间的关联与以往队列研究的结果有很大不同，这可能反映了OC制剂和使用模式随时间的变化，尽管这些结果可能是偶然的。更多研究应评估更新的OC制剂与卵巢癌风险。
