Objectives It is not clear whether the association between younger age at menopause and increased risk of dementia is modified by type of menopause. We examined the association of age at menopause or hysterectomy with dementia risk in three groups of women: those with natural menopause, premenopausal bilateral oophorectomy (surgical menopause) or premenopausal hysterectomy (without bilateral oophorectomy). Study design Individual-level data from 233 802 women in five prospective cohort studies (from four countries) were harmonized and pooled. Cox proportional hazards models were used to assess the associations of age at natural menopause, surgical menopause or premenopausal hysterectomy, with age at dementia, death (where available) or end of follow-up, whichever came first. Results The study followed women to the median age of 72 years (quartiles 67, 76 years). The median follow-up time was 13 years, with 3262 dementia cases during this period. Compared with women with menopause at 50–52 years, women with menopause <40 years had a higher risk of dementia (adjusted hazard ratio (aHR): 1.47, 95% confidence interval (CI): 1.39, 1.56). This level of risk was comparable to that of current smoking and stroke, which are well-established risk factors for dementia. Increased risk of dementia associated with surgical menopause or premenopausal hysterectomy (compared to natural menopause) was not apparent after adjustment for age at menopause (aHR 0.99, 95% CI: 0.93, 1.04 and aHR 0.97, 95% CI: 0.95, 1.00, respectively). Conclusion Women who experience menopause before the age of 40 years have a higher risk of dementia irrespective of type of menopause.

中文翻译：

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更年期年龄和类型与痴呆风险：对 233 802 名女性的汇总分析


目的 目前尚不清楚更年期年龄较小与痴呆风险增加之间的关联是否因更年期类型而异。我们检查了三组女性绝经或子宫切除术年龄与痴呆风险的相关性： 自然绝经、绝经前双侧卵巢切除术 （手术绝经） 或绝经前子宫切除术 （无双侧卵巢切除术）。研究设计 对来自五项前瞻性队列研究（来自 4 个国家）的 233 802 名女性的个体水平数据进行了协调和合并。Cox 比例风险模型用于评估自然绝经、手术绝经或绝经前子宫切除术年龄与痴呆年龄、死亡（如果有）或随访结束（以先到者为准）的相关性。结果 该研究跟踪了中位年龄为 72 岁 （四分位数 67 、 76 岁） 的女性。中位随访时间为 13 年，在此期间有 3262 例痴呆病例。与 50-52 岁更年期女性相比，更年期 <40 岁的女性患痴呆的风险更高（调整后的风险比 （aHR）：1.47,95% 置信区间 （CI）：1.39,1.56）。这种风险水平与当前吸烟和中风的风险水平相当，这是公认的痴呆风险因素。调整绝经年龄后，与手术绝经或绝经前子宫切除术相关的痴呆风险增加（与自然绝经相比）并不明显（分别为 aHR 0.99,95% CI：0.93、1.04 和 aHR 0.97、95% CI：0.95、1.00）。结论 在 40 岁之前经历更年期的女性无论更年期类型如何，患痴呆的风险都更高。