As we get older, our body compositions start to change, including decreased muscle mass and increased abdominal fat. A new study published in the journal Nature suggests that low testosterone might play a role. Korean researchers obtained data from over 1,600 participants between 22 and 84 years old. Each one had their testosterone level measured and underwent an abdominopelvic CT scan. The researchers found that low testosterone was highly correlated with the prevalence of metabolic syndrome. Men with decreased testosterone were closely related to increased insulin resistance and the prevalence of type 2 diabetes. But even when adjusting for metabolic syndrome, low testosterone was specifically linked to subcutaneous abdominal fat. On the other hand, higher testosterone levels were correlated to increased abdominal muscle mass. The results suggest that older adults struggling with their muscle and fat composition might talk to their doctors about testosterone and have their levels checked.