The Endocrine Society now believes that the decline in male testosterone levels may be the result of health and behavior more than aging.
The preliminary findings, which studied 1,300 men for five years, were released during the Society’s 94th Annual Meeting in Houston.
“Testosterone changes are largely explained by smoking behavior and changes in health status, particularly obesity and depression,” study co-author Gary Wittert, MD, reported.
The study also found lower testosterone in those who smoked, but higher levels in married men.
According to WebMD, it was previously believed that testosterone levels begin decreasing naturally, slowing at around age 40, and then progressing to even lower levels later, with between 10 to 25 percent of men over age 50 showing low testosterone levels.
Testosterone is the primary male sex hormone that accounts for the lower voice, body hair, larger muscles and libido. A decrease in testosterone in men can affect sex drive, mood and cause other health-related issues.