As males age they experience a natural and gradual decline in testosterone, and research has established a relationship between low levels of the hormone and increased incidence of type 2 diabetes. In what is described as the largest study of testosterone treatment ever carried out, scientists have found regular injections of the hormone appeared to lower the risk of developing type 2 diabetes.
Low testosterone levels in men, known as male hypogonadism or testosterone deficiency syndrome, can lead to a range of negative health outcomes, such as decreased sexual function, depression and decreases in muscle and bone mass. Research has also uncovered associations between low testosterone levels and obesity in men, and found that higher testosterone levels can reduced the risk of diabetes in men.
In fact, around a third of men with type 2 diabetes have hypogonadism, so scientists have begun to explore how testosterone therapy could reduce the risk, with some promising results. A new study led by Australia's University of Adelaide is claimed to be the largest ever carried out on the subject, enlisting more than 1,000 men between the age of 50 and 74 who were either overweight or obese.
These subjects were divided into two groups, with one receiving injections of testosterone every three months and the other receiving a placebo. In addition, all were given access to a WW (formerly Weight Watchers) lifestyle program, with 30 percent of men across both groups attending the meetings and 70 percent achieving the recommended amount of exercise.
Over the two-year study, both groups lost an average of around 4 kg (8.8 lb), while the most common adverse side effect of the testosterone therapy was an increase in red blood cells, which heightens the potential for clotting and "sludgy blood." This was seen in 22 percent of the men undergoing the testosterone treatment.
After two years, 21 percent of men in the placebo group had type 2 diabetes, while only 12 percent of men in the group receiving testosterone injections had developed the disease. This group also exhibited a greater decrease in fasting blood sugar levels, small improvements in sexual function and an increase in muscle mass.
“The proportion of men with diabetes at two years in the testosterone treatment group was significantly lower than in the placebo group,” says Professor Gary Wittert, who led the study. “Importantly, the men who were most engaged in the WW healthy lifestyle program lost the most body weight.”
The findings of the study are important when it comes to understanding the role testosterone may play in one's risk of developing type 2 diabetes, but are far from what might constitute a silver bullet for the disease. Wittert emphasizes "that this is not a signal to rush for the script pad," and that the disease is best tackled or prevented entirely by a healthy lifestyle.
“We do not know either the durability of effect or long-term safety of testosterone for preventing type 2 diabetes," he says. "Treatment with testosterone might be an option for some men, but all men need a thorough physical and mental health assessment, and support to adopt and maintain a healthy lifestyle."
The research was published in the journal The Lancet Diabetes & Endocrinology.
Source: University of Adelaide