Testosterone may cut short lives of men, study of Korean eunuchs finds
Male sex hormone may be reason women die later, study of data on Korean eunuchs finds
A study of historical data showing Korean eunuchs far outlived their non-castrated contemporaries provides new evidence about why women generally live longer than men, scientists said.
The study, published on Monday in the scientific journal , used detailed genealogical records of the imperial nobility during Korea's Joseon dynasty, from the late 1300s to the early 1900s.
According to the data, most men, including kings and royal family members, died in their late 40s or early 50s. But noble-class men who were castrated lived, on average, to the age of 70.
Study author Dr Min Kyung-jin of South Korea's Inha University said the reason is probably the male hormone testosterone.
"Testosterone is known to increase the incidence of coronary heart disease and reduce immune function in males," he said.
Castration "removes the source of male sex hormones", the study notes, adding the practice has already been proven to help male animals live longer.
Castration also cuts off the possibility of reproduction, which Min noted could also be a factor. According to "one of the leading theories … ageing occurs at the expense of reproduction", he said, because the body has limited energy that can be used either to keep up reproductive function or everything else.
However, although the eunuchs could not father children biologically, they married, adopted and raised children, and generally had very similar lives to their non-castrated peers.
Modern men looking to extend their lifespan could consider "testosterone reduction therapy", but Min said it is not clear if it would have an effect if the therapy were started at an older age - the eunuchs were all castrated as children.
