Obesity, Hyperglycemia, and BPH

Benign prostatic hyperplasia (BPH) is the most common benign growth process in men. But the cause of this serious condition is not well understood. A recent Hopkins study sheds light on a possible link between enlarged prostate, hyperglycemia, and obesity.

The term hyperplasia refers to an overgrowth of tissue or any abnormal accumulation of cells that causes an organ or area of the body to enlarge. In benign prostatic hyperplasia (BPH), prostate cells accumulate, and the tissue overgrowth produces nodules in the transition zone of the prostate. The increase in prostate cells is due to a slowing of apoptosis (normal programmed cell death), not because of an increase in cell production.

What triggers BPH is not well understood, but aging and testosterone (the predominant male sex hormone) are believed to be the primary influences on its development. Animal studies suggest that the female sex hormone estrogen (produced in small amounts in men) may also play a role in BPH, perhaps when a man’s testosterone production declines and the balance of the two hormones is altered.

Johns Hopkins researchers recently participated with the National Institutes of Health in a study designed to examine possible associations between BPH, obesity, and diabetes. Results of the study were reported in the Journal of Clinical Endocrinology and Metabolism (Volume 91, page 2562).

The researchers used magnetic resonance imaging (MRI) to assess prostate volume in 422 men who were participating in the ongoing Baltimore Longitudinal Study of Aging. They calculated each man’s body mass index (BMI) and did blood tests designed to detect elevated fasting glucose levels, including those high enough to indicate diabetes.

Compared with normal weight men of the same age, very obese men were 3.5 times more likely to have an enlarged prostate. Elevated fasting glucose levels tripled the risk of developing enlarged prostate or BPH. Diabetes more than doubled the risk. Obesity and elevated glucose levels are components of the metabolic syndrome, which is known to promote inflammation, production of toxic particles known as free radicals, and growth factors. These influence the development of prostate cancer and might also promote benign growth of the prostate gland.