A study led by Durham University, UK, suggests that testosterone levels are heavily influenced by a man’s childhood environment – men who grow up in more challenging conditions are likely to have lower testosterone levels in later life than those who spend their childhood in healthier environments.The study found that Bangladeshi men who grew up and lived as adults in the UK had significantly higher levels of testosterone compared to counterparts who grew up and lived in Bangladesh.

The university researchers studied saliva samples and relevant data on height, weight, age of puberty and other health informationfrom about 360 men. They then compared the following groups: men who were born and reside in Bangladesh; Bangladeshi men who moved to the UK (London) as children; Bangladeshi men who moved to the UK as adults; UK-born men whose parents were Bangladeshi migrants; and UK-born ethnic Europeans.

A stark distinction presented in Bangladeshi men who grew up and lived as adults in the UK – they had significantly higher levels of testosterone. Bangladeshis in the UK also reached puberty at a younger age and were taller than men who lived in Bangladesh throughout their childhood. This is probably due to differences in energy investment, as it may only be possible to have high testosterone levels if there are not many other demands placed on the body, including exposure to disease or poor nutrition.

While aspects of male reproductive function remain changeable up to the age of 19 and are more flexible in early childhood, the study suggests that, in adulthood, men’s testosterone levels are no longer heavily influenced by their surroundings.

Dr. Kesson Magid from Durham University’s Department of Anthropologyhighlighted that a man’s absolute levels of testosterone “are unlikely to relate to their ethnicity or living environment as adults but instead reflect their surroundings when they were children.”

On the other hand, Professor Gillian Bentley, also from Durham University, commented, “Very high and very low testosterone levels can have implications for men’s health.”

Similar to how the environment in which girls grow up in can affect their hormone levels, fertility and risk levels for reproductive cancers as adults, men with higher levels of testosterone are unfortunately at great risk of potentially adverse effects on health and ageing. Very high testosterone levels have been linked to increased risk of prostate diseases and higher aggression. Meanwhile, very low testosterone levels in men can include lack of energy, loss of libido and erectile dysfunction.

“It could be important to know more about men’s childhood circumstances to build a fuller picture of their risk factors for certain conditions or diseases,” Professor Bentley concluded.