荷尔蒙是男女大脑健康差异的关键

自“比基尼医学”时代以来，医学已经取得了长足的进步," when the only time doctors managed a woman's health differently than a man's was when treating the parts of her body found under a bikini.

在过去的几十年中, researchers have uncovered countless ways in which women's and men's bodies react differently to the same diseases. And just as it's now widely recognized women experience heart disease differently than men, scientists are beginning to understand why the sexes experience illness differently in another vital organ – the brain.

这并不是说男性和女性的大脑构造不同, 丽莎·莫斯科尼说, director of the Women's Brain Initiative at Weill Cornell Medicine in New York. 而是他们变老的方式不同.

Women bear the brunt of Alzheimer's disease, the most common form of dementia, accounting for 每3个人中就有2个人(链接在新窗口中打开) 诊断. 女性患重度抑郁症的可能性是男性的两倍. 他们是 三倍的可能性(链接在新窗口中打开) to be 诊断 with autoimmune disorders that attack the brain, such as multiple sclerosis. 他们是 四倍的可能性(链接在新窗口中打开) 也有偏头痛 更有可能(链接在新窗口中打开) 死于中风.

是什么导致了这些差异? 虽然有多种因素在起作用, Mosconi说, it's hormones – testosterone in men and estrogen in women – that are the orchestral conductors of the brain. 他们要对系统是否运行良好负责.

"We are used to thinking of sex hormones as important for fertility and reproduction," Mosconi说. “但荷尔蒙在大脑健康中也起着至关重要的作用."

雌二醇, the type of estrogen produced by the ovaries during a woman's reproductive years, 大脑健康最重要的驱动因素是什么, 博士说. Kejal Kantarci, director of the Women's Health Research Center and a radiology professor at Mayo Clinic in Rochester, 明尼苏达州. 她的 research suggests longer exposure to estradiol may offer some protection to the brain.

在一项2020年发表于 大脑通信(链接在新窗口中打开), she showed women with longer reproductive periods – measured from the time they start menstruation to the time they enter menopause – were better protected against progressive forms of multiple sclerosis. 研究还表明，女性怀孕的次数越多, 她的病情进展越慢, 这表明怀孕期间大量的雌激素增加了保护作用.

另一方面，失去雌二醇会损害大脑. The end of a woman's reproductive years and the accompanying drop in estradiol triggers numerous brain changes, 其中一些, 研究人员正在学习, 可能要到几十年后才会变得明显.

例如, 研究表明阿尔茨海默病, 通常在女性70多岁时被诊断出来, 很可能在她50多岁时就开始发育了. Mosconi的研究 发现了证据(链接在新窗口中打开) 淀粉样斑块, 这些蛋白质与阿尔茨海默病的发展有关, were already accumulating in the brains of women as they transitioned to menopause, 尽管这些女性在那个年龄没有表现出认知能力下降的迹象. 她还发现女性大脑的记忆中心萎缩.

"We never talk about Alzheimer's disease as something that happens in midlife," Mosconi说. “但对于女性来说，这是我们需要考虑的沙巴足球体育平台线."

还有其他迹象表明，人到中年，大脑正在发生变化, 当雌二醇的流失使女性更容易患病, Mosconi说. 研究表明焦虑会增加, 抑郁症, 绝经期多发性硬化症和其他免疫紊乱. “对于那些易患这些疾病的女性来说, 这似乎是病症被激活的时候."

Mosconi已经 利用成像技术跟踪(链接在新窗口中打开) brain energy levels, showing that, on average, it "declines by 20% or more during menopause.同一年龄段的男性则没有变化, 她说, which could be because they don't typically experience a hormone decline as rapidly or as early as women do.

但是更多的雌激素并不总是更好，kantarctic说. “你不能说雌激素对你有好处. 事情没那么简单."

A growing body of research suggests that it's not just about how much estrogen a woman's brain gets exposed to – but when.

例如，2005年的一篇评论 发表在《沙巴足球体育平台》上(链接在新窗口中打开) about clinical trials in postmenopausal women 65 or older showed women who received hormone therapy, 包括雌激素, 患痴呆症和其他类型认知能力下降的风险增加了吗. 但是一个 最近的研究(链接在新窗口中打开) in 2019 in the journal Menopause found taking estrogen therapy earlier – within the first five years of menopause – might protect against cognitive decline. It also showed women exposed longer to natural estrogen because of more reproductive years had better cognitive function later in life.

Kantarci's work supports the idea that the transition to menopause offers a critical window for intervention. 她的 研究发现(链接在新窗口中打开) women given estradiol in a patch during their 50s showed less brain shrinkage in later years. “大脑的前部, 哪一个用于决策和注意力, 保存得相对较好,她说. “它没有像安慰剂组那样下降得那么多."

在一个正在进行的研究中, she and her team will continue to explore whether hormone therapy given during the transition to menopause is associated with any long-term cognitive impacts.

但Kantarci警告说，不要把所有的责任都归咎于激素.

“女性也是痴呆症患者的看护人, and they are at higher risk for mental health issues that may also increase their risk of cognitive impairment,她说. “他们活得更久，而且他们是照顾者. 因为他们是护理人员，所以他们的风险更高. 这是一个循环问题."

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