NEW YORK (Reuters Health) - Type 2 diabetes is associated with low serum levels of free testosterone in men, according to a new report. "The relationship between testosterone and insulin or glucose control was stressed in our study, suggesting that diabetics should have testosterone levels measured more frequently," Dr. Ernani L. Rhoden told Reuters Health.

Dr. Rhoden, from the Federal Foundation of Medical Sciences of Porto Alegre, Brazil, and colleagues evaluated the relationship between diabetes and serum testosterone levels in 746 men, including 116 men with type 2 diabetes, who attended their urological center in Brazil.

Free testosterone levels were low in 46% of diabetics and 24% of nondiabetics, the investigators report in the October issue of BJU International, and total testosterone levels were low in 34% of diabetics and 23% of nondiabetics.

After adjusting for waist-hip ratios, diabetic men were 3 times as likely as nondiabetic men to have low free testosterone levels and twice as likely to have low total testosterone levels, the researchers note.

When analyzed separately, low free testosterone levels, low total testosterone levels, body-mass index above 25, and increased waist-hip ratios were independently associated with diabetes, the results indicate.

"This study suggests that subnormal free testosterone levels and diabetes are directly associated," the investigators write, "whereas total testosterone levels appear to be more strongly related to obesity and central adiposity than to diabetes."

Whether correcting testosterone levels in diabetic men "will improve diabetic control needs to be evaluated in well designed prospective studies, but clinicians should be aware of this possibility in their clinical practice," Dr. Rhoden said. "Finally, it is important to mention that if testosterone replacement therapy is considered, a careful evaluation of the patient must be done before starting testosterone administration."

BJU International 2005;98:867-870

Copyright © 2005 Reuters Limited. All rights reserved. Republication or redistribution of Reuters Limited content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters Limited. Reuters Limited shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon.