Researchers have shown that testosterone replacement therapy reduces the complications associated with type 2 diabetes mellitus in androgen-deficient, overweight men.
Researchers have shown that testosterone replacement therapy reduces the complications of type 2 diabetes in androgen-deficient, overweight men.
The paper, which appears in the European Journal of Medical Research, may help settle an ongoing controversy about how testosterone supplementation affects diabetic men, a controversy created by apparent contradictions in past studies.
The new study’s authors randomized 85 diabetic men whose body mass indexes (BMI) ranged from 27.0 kg/m2 to 48.0 kg/m2 between a program of diet, exercise and testosterone and a program of diet, exercise and placebo.
After 6 months of treatment, the lipid profile of the testosterone group improved significantly while the lipid profile of the placebo group did not. HbA1c levels decreased significantly for both groups, but the testosterone group, again, fared better than the control group.
The testosterone group also managed slightly greater improvements in BMI, blood pressure, cholesterol and leptin. Testosterone levels themselves actually increased in both groups, but levels for the testosterone group increased significantly more.
“We have shown that testosterone replacement therapy improves insulin resistance and glycemic control in hypogonadal men with diabetes,” wrote the study authors, who all work at the National Institute of Endocrinology in Tbilisi, Georgia.
“Re-instituting physiological levels of testosterone in hypoandrogenic men, as our small study has shown, has an important role in reducing the prevalence of diabetic complications.”
Among men in the testosterone group, median BMI dropped from 35.65 to 29.68 after 6 months of treatment, while median HbA1c levels fell from 8.26 to 7.46, median leptin levels fell from 21.71 to 11.64, triglycerides fell from 185.6 to 178.31, HDL rose from 55.5 to 71.11 and LDL fell from 102.95 to 95.62.
Among men in the placebo group, median BMI dropped from 36.60 to 31.88 after 6 months of treatment while median HbA1c fell from 8.43 to 7.93, leptin fell from 23.19 to 13.93, triglycerides fell from 182.21 to 180.23, HDL rose from 54 to 68.44 and LDL fell from 99.58 to 96.3.
The paper notes that many prior studies have consistently found 3 things: that diabetic men have unusually low concentrations of serum testosterone, that low concentrations of serum testosterone are associated with increased risk of cardiovascular disease and that diabetes is associated with increased risk of cardiovascular disease.
It then asserts that the results of this study suggest that “the increased risk for cardiovascular disease in diabetic men could be partially mediated through low concentrations of testosterone.”
The study authors also conclude that their results indicate that many diabetic men suffer from a “vicious circle,” one in which health problems suppress testosterone production, which, in turn, worsens the underlying health problems — and so on.
However, they concede, the relatively small size and short duration of their study prevents it from proving anything for sure. “Our study demonstrated that it is possible to break the metabolic vicious circle,” they write, “but large-scale randomized placebo-controlled trials are needed to fully evaluate this.”
The study from Georgia supports the conclusions of another recent trial, a trial conducted in upstate New York that found a 30% increase in glucose infusion rates, along with several other significant improvements, among diabetic men who received testosterone.
But at least one other recent study, this one from Australia, found that testosterone replacement therapy for diabetic men did not improve any metric that researchers measured. A recent FDA review of all research on the topic, moreover, did not find compelling evidence that testosterone replacement provides significant benefits to diabetic men.