Eunuchs in Korea hundreds of years ago lived an average of 14-19 years longer than non-castrated men, according to a study published in the journal Current Biology. This work suggests that male sex hormones may be responsible for the shorter life span of men.
Our discovery provides clues important for understanding the differences in life expectancy between men and women, comments co-author Kyung-Jin Min of Inha University in Incheon, South Korea.
In many animal species, as well as in humans, males live shorter lives than females. According to one theory trying to explain this, male reproductive performance is at the expense of longevity. This would mean that male sex hormones, mainly testosterone, may be responsible for their shorter life.
Castration, or excision of the testicles, deprives the male organism of the source of the production of these hormones and – as research shows – prolongs the life of males in many animal species. However, until now, there has not been enough good evidence to support the existence of a similar relationship in humans. Admittedly, a 1969 study showed that castrated men in psychiatric hospitals lived on average 14 years longer than patients in the same facilities with preserved testicles. However, similar observations among singers showed no difference in life expectancy.
Kyung-Jin Min, together with colleagues from two other Korean research institutions, studied in detail the genealogical book of eunuchs employed by the royal court during the reign of the Choson (also known as Joseon) dynasty in Korea in 1392-1910.
They lost their reproductive organs either in an accident (usually as a result of being bitten by a dog), or were castrated on purpose to gain access to the royal palace at a very young age. In the Middle East and Asia, eunuchs were employed to guard and minister in harems.
In Korea, they had exceptionally many privileges, for example, they held official positions and – unlike the neuters in the Chinese Empire – they could get married. Such couples could also adopt children, girls and castrated boys. Though the eunuch families were composed of biologically unrelated members, the ties between them were said to be as strong as in ordinary families.
The genealogical book of eunuchs from the Choson dynasty is the only known document of this type in the world. It includes, among others data on the dates and places of birth and death of eunuchs, the positions they occupied, the names of their wives and adopted sons. It was written in 1805 by Yoon-Muk Lee, representing the thirteenth generation of eunuchs, beginning with the lineage precursor – Deuk-Bu Yoon.
By examining these archives, the researchers calculated that the 81 eunuchs for whom accurate data were available had a median life expectancy of around 70 years. It turned out that it was 14-19 years longer than the average life (from 51 to 55 years) of non-castrated men from three different biologically related families and belonging to the same socio-economic class.
Moreover, of the 81 eunuchs, three were centenarians (100, 101, and 109). According to the researchers, this percentage was thus 130 times higher than today in Japan and the USA.
As the authors of the study emphasize, it cannot be explained only by good conditions at court. Except for a few eunuchs, most lived outside the palace and spent time in it only when performing their official duties.
Moreover, the average life of kings and male royal family members who spent their entire lives in the palace was 47 and 45 years, respectively.
According to the authors of the study, it provides evidence that male sex hormones contribute to shortening the life of men.
In trying to explain this dependence, scientists remind that testosterone weakens the activity of the immune system. Male sex hormones also increase the risk of cardiovascular disease and life-threatening cardiovascular events such as heart attacks and strokes. (PAP)
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