Analysis of records of court eunuchs in Korea suggest that castration prolongs life. Does it really, or are there other explanations?
What did the analysis find?
Documents detailing the lives of 81 eunuchs who lived in Korea between the mid-16th and mid-19th centuries showed that, on average, they lived 14 to 19 years longer than their non-castrated peers. “It provides some of the most compelling evidence yet that the male sex hormone, (T), reduces male lifespan,” says Kyung Jin Min of Inha University in Incheon, South Korea. The conclusion supports the theory that (T)-fuelled reproduction comes at a price, increasing the risk of heart disease and cancer, and reducing the strength of the immune system.
古代文献资料详细记载了生活在16－19世纪的81位韩国宫廷阉 割的太监寿命，平均比那些没有阉 割的同僚多活14－19年。韩国仁川广域市仁荷大学的Kyung Jin Min说：“如果那是真的，那么它就为男性激素（睾丸激素）影响男子寿命提供了强有力佐证。”这个结论与睾丸激素增多要付出代价的理论相符合，即睾丸激素过多可能会加大心脏疾病与癌症和免疫系统功能低下风险。
Steady on. Isn't it a bit much to claim that castration is the key to long life?
Yes. Min says that many earlier studies show that castration prolongs the life of animals, from 24 to 27 months in rats, for example. But previous studies were equivocal, showing life extension in castrated mental patients but not castrati musicians, for example.
Min 举例说，以前对动物多项研究表明，阉 割是能延长动物寿命，老鼠实验能延长24－26个月。但是，以前研究仍有不少疑点，如阉 割对精神病人有效，却对音乐家无效。
How reliable were the sources?
How reliable are any ancient documents? Min and his colleagues relied on the Yang-Se-Gye-Bo, a record of eunuchs who served in courts of the ancient Korean Chosun Dynasty. They also used genaeological records of thousands of members of three Korean family lines – the Mok, the Shin and the Seo. Min says three of the 81 eunuchs were centenarians compared with the current incidence of one per 3500 in Japan and one per 4400 in the US.
What do other experts in ageing say?
“When (T) is lacking, the demand for amino acids to support cell proliferation and muscle-building is decreased, and it's thought that the body then shifts the use of these basic building blocks towards cellular defence and stress resistance,” says Holly Brown-Borg, who studies ageing at the University of North Dakota in Grand Forks. She guesses that the eunuchs were smaller and less muscular, with lower levels of cancer and heart disease.
What would happen if I were to get castrated now?
It depends how old you are. Any increase in lifespan may only occur if men are castrated as boys. “It's possible that (T)reduction therapy extends male lifespan, but Korean eunuchs were usually castrated before adolescence, so we don't know the effects of castration on lifespan in older men,” says Min.
男子阉 割能否延长寿命取决于当时年龄，孩童时期阉 割也许有效。Min 说：“用降低睾丸激素治疗方法有可能延长男子寿命，不过韩国宫廷太监通常是在发育前阉 割的，所以无法知道阉 割对成人延长寿命是否有效。”
What other explanations could there be?
Eunuchs probably avoided life-shortening sexually transmitted infections, but there's no way of knowing. Min tried to control for the eunuchs' high social status by comparing their life expectancies with those of the kings and other males in royal households, which turned out to be just 47 and 45 respectively. He suggests looking at eunuchs in the Chinese and Ottoman empires.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2012.01.012
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