Farland Leslie V, Eliassen A Heather, Tamimi Rulla M, Spiegelman Donna, Michels Karin B, Missmer Stacey A
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
Center for Infertility and Reproductive Surgery, Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
BMJ. 2017 Aug 29;358:j3778. doi: 10.1136/bmj.j3778.
To investigate the association between lifetime breast feeding, exclusive breast feeding, postpartum amenorrhea, and incidence of endometriosis among parous women. Prospective cohort study. Nurses' Health Study II, 1989-2011. 72 394women who reported having one or more pregnancies that lasted at least six months, 3296 of whom had laparoscopically confirmed endometriosis. For each pregnancy, women reported duration of total breast feeding, exclusive breast feeding, and postpartum amenorrhea. Incident self reported laparoscopically confirmed endometriosis (96% concordance with medical record) in parous women. Multivariable Cox proportional hazard models were used to calculate hazard ratios and 95% confidence intervals for diagnosis of endometriosis. Duration of total and exclusive breast feeding was significantly associated with decreased risk of endometriosis. Among women who reported a lifetime total length of breast feeding of less than one month, there were 453 endometriosis cases/100 000 person years compared with 184 cases/100 000 person years in women who reported a lifetime total of ≥36 months of breast feeding. For every additional three months of total breast feeding per pregnancy, women experienced an 8% lower risk of endometriosis (hazard ratio 0.92, 95% confidence interval 0.90 to 0.94; P<0.001 for trend) and a 14% lower risk for every additional three months of exclusive breast feeding per pregnancy (0.86, 0.81 to 0.90; P<0.001 for trend). Women who breastfed for ≥36 months in total across their reproductive lifetime had a 40% reduced risk of endometriosis compared with women who never breast fed (0.60, 0.50 to 0.72). The protective association with breast feeding was strongest among women who gave birth within the past five years (P=0.04 for interaction). The association with total breast feeding and exclusive breast feeding on endometriosis was partially influenced by postpartum amenorrhea (% mediated was 34% (95% confidence interval 15% to 59%) for total breast feeding and 57% (27% to 82%) for exclusive breast feeding). Among women who experienced at least one pregnancy that lasted at least six months, breast feeding was inversely associated with risk of incident endometriosis. This association was partially, but not fully, influenced by postpartum amenorrhea, suggesting that breast feeding could influence the risk of endometriosis both through amenorrhea and other mechanisms. Given the chronic and incurable nature of endometriosis, breast feeding should be further investigated as an important modifiable behavior to mitigate risk for pregnant women.
探讨经产妇终生母乳喂养、纯母乳喂养、产后闭经与子宫内膜异位症发病率之间的关联。前瞻性队列研究。护士健康研究II，1989 - 2011年。72394名报告有一次或多次持续至少6个月妊娠的女性，其中3296名经腹腔镜检查确诊为子宫内膜异位症。对于每次妊娠，女性报告了总母乳喂养时长、纯母乳喂养时长和产后闭经时长。经产妇自我报告经腹腔镜检查确诊的子宫内膜异位症（与病历的一致性为96%）。采用多变量Cox比例风险模型计算子宫内膜异位症诊断的风险比和95%置信区间。总母乳喂养时长和纯母乳喂养时长与子宫内膜异位症风险降低显著相关。在报告终生总母乳喂养时长少于1个月的女性中，子宫内膜异位症发病率为453例/100000人年，而报告终生总母乳喂养时长≥36个月的女性中，发病率为184例/100000人年。每次妊娠总母乳喂养每增加3个月，女性患子宫内膜异位症的风险降低8%（风险比0.92，95%置信区间0.90至0.94；趋势P<0.001），每次妊娠纯母乳喂养每增加3个月，风险降低14%（0.86，0.81至0.90；趋势P<0.001）。在整个生育期总母乳喂养时长≥36个月的女性与从未母乳喂养的女性相比，患子宫内膜异位症的风险降低40%（0.60，0.50至0.72）。母乳喂养与子宫内膜异位症的保护关联在过去5年内分娩的女性中最强（交互作用P = 0.04）。总母乳喂养和纯母乳喂养与子宫内膜异位症的关联部分受产后闭经影响（总母乳喂养的中介百分比为34%（95%置信区间15%至59%），纯母乳喂养为57%（27%至82%））。在经历至少一次持续至少6个月妊娠的女性中，母乳喂养与子宫内膜异位症发病风险呈负相关。这种关联部分但并非完全受产后闭经影响，表明母乳喂养可能通过闭经和其他机制影响子宫内膜异位症风险。鉴于子宫内膜异位症的慢性和不可治愈性，母乳喂养作为一种可改变的重要行为以降低孕妇风险应进一步研究。
