From the Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.
Menopause. 2022 Oct 1;29(10):1161-1167. doi: 10.1097/GME.0000000000002046. Epub 2022 Sep 6.
The aim of this study was to examine the association between duration of lifetime lactation and age at natural menopause.
In this prospective cohort study, we analyzed parous premenopausal women in the multiethnic Study of Women's Health Across the Nation who were followed approximately annually for 10 years (1995-2008). Lifetime lactation was defined as the duration of breastfeeding across all births in months. Age at natural menopause was defined as age in years after 12 consecutive months of amenorrhea after the final menstrual period for no other reported cause. We used Cox proportional hazard models to analyze time to natural menopause with age as the underlying time scale. Multivariable models controlled for education, race/ethnicity, parity, smoking, body mass index, and oral contraceptive use.
Among 2,377 women, 52.6% experienced natural menopause during follow-up and reported a valid final menstrual period date. The small, crude association between lifetime lactation up to 24 months and later age at natural menopause attenuated to nonsignificance in adjusted models (6 months: adjusted hazard ratio [AHR], 0.96; 95% confidence interval (CI), 0.87-1.06; 12 months: AHR, 0.95; 95% CI, 0.82-1.11; 18 months: AHR, 0.96; 95% CI, 0.82-1.13; 24 months: AHR, 0.99; 95% CI, 0.84-1.16).
Duration of lifetime lactation was not associated with age at natural menopause after controlling for sociodemographic characteristics.
本研究旨在探讨终生哺乳时间与自然绝经年龄之间的关系。
本前瞻性队列研究分析了多民族妇女健康研究中具有生育能力的绝经前妇女，这些妇女在大约 10 年内（1995-2008 年）每年接受一次随访。终生哺乳时间定义为所有分娩时母乳喂养的月数。自然绝经年龄定义为末次月经后 12 个月连续闭经后，因其他原因未报告的年龄。我们使用 Cox 比例风险模型分析了自然绝经时间与年龄之间的关系，年龄是基本的时间尺度。多变量模型控制了教育程度、种族/民族、产次、吸烟、体重指数和口服避孕药使用情况。
在 2377 名妇女中，52.6%在随访期间经历了自然绝经，并报告了有效的末次月经日期。终生哺乳时间在 24 个月以内与自然绝经年龄较大之间的小、粗略关联在调整模型中减弱至无统计学意义（6 个月：调整后的危险比[AHR]，0.96；95%置信区间[CI]，0.87-1.06；12 个月：AHR，0.95；95%CI，0.82-1.11；18 个月：AHR，0.96；95%CI，0.82-1.13；24 个月：AHR，0.99；95%CI，0.84-1.16）。
在控制社会人口特征后，终生哺乳时间与自然绝经年龄无关。
