The boy's childhood environment could establish his testosterone levels for the rest of his life

Testosterone: It is the key hormone involved in muscle mass, male fertility and the onset of male puberty. And a new paper now suggests that your testosterone levels are not determined by factors such as genetics or race, as popular wisdom says, but rather by where you lived as a child.

In the study, researchers from the University of Durham, England, compared different groups of men according to where they spent their childhood – in Bangladesh or London – and s & # 39; They had Bangladeshi or European ancestors. Their findings, published in the journal Nature Ecology & Evolution yesterday (June 25), showed that the environment of childhood was the most important factor for determining the level of testosterone, the size, the amount of testosterone, the size of the testosterone. age reached by men at puberty. .

The researchers compared five groups of men for the study: Bangladeshi-born, wealthy men still living there, Bangladeshi-born men who moved to London, Bangladeshi-born men who moved to London in adulthood, men born in the United States. Kingdom whose parents immigrated from Bangladesh and men born in the UK and of European descent. [25 Scientific Tips For Raising Happy and Healthy Kids]

While research has implications for men with very high or very low testosterone levels – both of which can cause health problems – all men in this study had testosterone levels that were within a normal and healthy range .

However, the study revealed significant differences between populations. Men born in the UK or Bangladesh, but who were raised in the UK, appeared, on average, to share testosterone, size and age similarities when they entered puberty , regardless of their ancestry. Men born and raised in Bangladesh – including those who moved to the United States as adults – found on average to have entered puberty later, were shorter and had lower testosterone levels . (Because these results are based on averages, they do not tell you anything significant about a given man's high testosterone levels in the UK or Bangladesh.)

Dr. Landon Trost, an endocrinologist at the Mayo Clinic who did not participate in the study, said the findings suggest that something is happening in childhood – something related to the environment – which can have long-term effects on testosterone production.

This is what doctors already know about how childhood illnesses can affect testosterone production, Trost said.

"We see examples in infertility, where the timing of some infections – mumps, for example – will have a long-term impact [sperm production]"Said Trost Live Science.

An infection of childhood, doctors know, can have permanent effects on testosterone levels.

Trost however warned that if the study seems to definitively show that the environment is a much more important factor than genetics in testosterone production, it is not definitive to show that these environmental factors are the most important ones in childhood.

"It is also likely that children who migrate at a younger age are more likely to adopt the lifestyle of their new home," he said, "compared to those who emigrate later – and who can to hang on to diets, traditions and customs.this consideration may explain the results noted with the study. "

In other words, it is possible that Bangladeshi men who move to the UK as adults lead quite a different adult life from that of Bangladeshi men raised in the United Kingdom. These differences explain the different levels of testosterone in both groups – as opposed to their childhood environment.

Of course, it is also important to recognize that all the differences reported in this study are based on broad averages: Any man born and raised in Bangladesh could easily have higher testosterone levels than any other male born in the country. UK. In this study. It is only in relatively large samples, such as the 359 men tested for this study, that significant differences appear.

Originally posted on Live Science.