From the article:
Results of a study published online ahead of print in the journal Diabetes Care, conducted by University at Buffalo endocrinologists, showed that 40 percent of obese participants involved in the Hypogonadism in Males (HIM) study had lower-than-normal testosterone readings.
The percentage rose to 50 percent among obese men with diabetes. Results also revealed that as body mass index (BMI) – a relationship of weight-to-height – increased, testosterone levels fell.
“The effect of diabetes on lowering testosterone levels was similar to that of a weight gain of approximately 20 pounds,” says Sandeep Dhindsa, MD, an endocrinology specialist in the UB Department of Medicine and first author on the study.
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This is the largest analysis of the association between obesity and low testosterone, and the first to compare prevalence of low testosterone with obesity and diabetes separately and together. The study shows that obesity and diabetes may exert independent influences on testosterone concentrations.
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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.