Obesity Linked to Low Testosterone in Men

Men who are tipping the scales might want to get their testosterone levels checked, according to a new study showing obese mean are more likely than others to have low levels of this sex hormone.

Forty percent of obese participants in the study had lower-than-normal testosterone readings. And for those obese men who also had diabetes that percent rose to 50 percent.

A separate study last year found that obese men who lost significant weight reported better sexual function. 

While past studies have shown a link between diabetes and low testosterone, the new one is the largest analysis to look at the association between obesity and low testosterone. In fact, the Endocrine Society now recommends that all men with type 2 diabetes have their testosterone levels measured. Now, it seems, obese men, even younger men, should also get screened for low testosterone, the researchers say.

"The effect of diabetes on lowering testosterone levels was similar to that of a weight gain of approximately 20 pounds," said lead author Dr. Sandeep Dhindsa, an endocrinology specialist at the University of Buffalo, Department of Medicine, and lead author of the study published online ahead of print in the journal Diabetes Care.

With our waistlines expanding, the results could speak to many American men. "In view of the fact that almost one-third of the U.S. is obese, these observations have profound pathophysiological, clinical, epidemiological and public health implications," Dhindsa said.

The study involved 2,165 men, 45 years or older, who provided blood samples for analysis of testosterone concentrations and who were taking part in the Hypogonadism in Males (HIM) study funded by Solvay Pharmaceuticals Inc. The study was conducted from November 2003 to February 2004 in 95 primary care practices throughout the United States. (This was an unfunded analysis of HIM data.)

Body mass index (BMI), which is a measure of height and weight that estimates body fat, was used to indicate obesity.

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.

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.

"In view of the high rates of subnormal testosterone in patients with obesity or diabetes, testosterone concentrations should be measured regularly in these populations, especially when these conditions occur together," said study researcher Dr. Paresh Dandona, head of the Division of Endocrinology, Diabetes and Metabolism at UB.

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