Description

A difficult issue here is that the average age at death of the control group was about 50-55. At this age, cause of death is not usually from age-related disease such as cancer, circulatory diseases, neurodegeneration and respiratory failure. It is generally from accidents/injuries, infection, or self-inflicted causes such as diabetes and alcoholic liver disease, especially in those who do not rely on manual labour for their living. It is not unreasonable to think that the matched samples used in this paper could have had quite different lifestyles and have led less sheltered and protected lives. Castrato vs non-castrato singers are probably a better comparison, and showed no difference in lifespan; non-castrato lived average 65 years and both groups lived ‘fairly cosseted’ lives.

It is always difficult to tell whether lack of testosterone might be responsible for differences in lifestyle which can and do impact on lifespan but not ageing. In addition, in this case eunuchs were raised by eunuchs over generations; lifestyle differences may have been reinforced in this way. Often when these sorts of confounders exist, it’s worth looking at the life expectancy of those who reached 60, 65 or 70 to exclude non-ageing causes of death as listed above. Examining those groups for life expectancy might give a clearer indication. In that regard, the number of centenarians among the eunuchs is suggestive of an effect.

Overall the results are persuasive but certainly not conclusive.