Men’s testosterone levels largely determined by childhood environment

Men's testosterone levels are largely determined by their environment during childhood, according to new research. The Durham University-led study suggests that men who grow up in more challenging conditions where there are lots of infectious diseases, for example, are likely to have lower testosterone levels in later life than those who spend their childhood in healthier environments. Prostate cancer risk The study, published in Nature Ecology and Evolution , challenges the theory that testosterone levels are controlled by genetics or race. As high testosterone levels potentially lead to an increased risk of prostate enlargement and cancer, the researchers suggest that any screening for risk profiles may need to take a man's childhood environment into account. The study found that Bangladeshi men who grew up and lived as adults in the UK had significantly higher levels of testosterone compared to relatively well-off men who grew up and lived in Bangladesh as adults. Bangladeshis in Britain also reached puberty at a younger age and were taller than men who lived in Bangladesh throughout their childhood. Disease exposure The researchers say the differences are linked to energy investment as it may only be possible to have high testosterone levels if there are not many other demands placed on the body such as fighting off infections. In environments where people are more exposed to disease or poor nutrition, developing males direct energy towards survival at the cost of testosterone.