WASHINGTON\u2014Scientists said Monday they have new evidence about why women live longer than men, from a study of historical data showing castrated Koreans far outlived their non-eunuch contemporaries.
\nThe study, published in the scientific journal \u201cCurrent Biology,\u201d used detailed genealogical records of the Imperial nobility during Korea\u2019s Joseon dynasty, which spanned more than 500 years from the late 1300s to the early 1900s.
\nAccording to the data, most men, including kings and royal family members, died in their late-40s or early-50s.
\nBut noble-class eunuchs \u2014 men who were castrated either by accident or because of social benefits \u2014 lived, on average, to the ripe, old age of 70.
\nStudy author Kyung-Jin Min of South Korea\u2019s Inha University, told AFP the reason is probably that manly hormone, testosterone:
\n\u201cTestosterone is known to increase the incidence of coronary heart disease and reduce immune function in males,\u201d he said.
\nCastration \u201cremoves the source of male sex hormones,\u201d the study notes, adding the practice has already been proven to help many male animals live longer.
\nCastration also cuts off the possibility of reproduction, which Kyung-Jin noted could also be a factor.
\nAccording to \u201cone of the leading theories of aging, aging occurs at the expense of reproduction,\u201d he said, because the body has limited energy that can be used either to keep up reproductive function, or else to keep up everything else.
\nBut although the eunuchs could not father children biologically, they married, adopted and raised children, and generally lived lives very similar to their non-castrated peers.
\n\u201cIn order to eliminate socioeconomic factors that could have affected lifespan, the lifespan of the eunuchs was compared to the lifespan of men from other Yan-ban (noble class) families with a similar socioeconomic status,\u201d Kyung-Jin said.
\nAnd \u201cto exclude genetic factors that could have affected the lifespan, we compared the lifespan of eunuchs with multiple Yan-ban families.\u201d
\nModern men looking to extend their lifespan could consider \u201ctestosterone reduction therapy,\u201d but Kyung-Jin said it\u2019s probably premature.
\nFor one thing, it is not clear if it would have an effect if the therapy were started at an older age \u2014 the eunuchs were all castrated as children.
\nAnd for another, the therapy could have side effects that some men may feel make that longer life less worth living.
\n\u201cWe may need to consider the side effects of it,\u201d Kyung-Jin said, \u201cmainly, reduction of sex drive in males.\u201d<\/p>\n