The HIM study was funded by Solvay Pharmaceuticals Inc., and was conducted from November 2003 to February 2004 in 95 primary care practices throughout the U.S. The study involved 2,165 men 45 years or older who provided blood samples for analysis of testosterone concentrations.
UB researchers excluded participants from the full study who had no BMI data or were on certain drugs that can affect testosterone levels, providing a study population of 1,849 men -- 398 with diabetes and 1,451 non-diabetics.
"With the rising prevalence of obesity in the U.S. and the rest of the world," says Paresh Dandona, MD, head of the Division of Endocrinology, Diabetes and Metabolism at UB and Kaleida Health, and senior author of the study, "it is imperative that the prevalence of low testosterone levels in obese men be defined. In addition, the magnitude of the contribution of obesity to subnormal testosterone needs to be quantified.
"We hypothesized that obese men are more likely to have low testosterone than non-obese men, and that we would find more low testosterone levels in men with diabetes than in men without diabetes, both obese and non-obese."
Results confirmed these hypotheses, showing a 40 percent higher prevalence of low testosterone in obese men compared to the non-obese participants. Men with diabetes, whether obese or not, showed lower levels of testosterone than non-diabetic men across all weight categories. Testosterone levels decreased significantly in both diabetic and non-diabetic men as BMI increased.
"In view of the increasing prevalence of obesity, even in younger populations, it would be important to conduct a similar study in the men at the prime of their reproductive years," he says.
UB endocrinologists published a study in Diabetes Care in 2008 showing that more than 50 percent of men between 18 and 35 years old with type 2 diabetes had lower than normal testosterone levels.
|Contact: Lois Baker|
University at Buffalo