A study published in the Journals of Gerontology: Medical Sciences suggests that prostate enlargement, also referred to as benign prostatic hyperplasia (BPH), is associated with and increased risk of diabetes and higher levels of testosterone. According to Medical Xpress, prostate enlargement is one of the most prevalent diseases affecting older men in the United States. Roughly 90 percent of men in the US have prostate enlargement by the time they reach the age of 80 or higher. In 40 percent of these men, medical treatment is needed.
The factors contributing to an enlarged prostate are uncertain. The new study, however, suggests that abnormally high levels of testosterone play a role. Researchers Benjamin Trumble and Michael Gurven looked at the rate of BPH among 350 adults Tsimane males. The Tsimane are an indigenous people located in central Bolivia; the study builds on past research looking at this population.
The study found that the group of Tsimane men has practically non-existent rates of advances prostate enlargement. This is correlated with the low levels of testosterone among these individuals, which stay constant throughout their lives. “Abdominal ultrasounds show they have significantly smaller prostates—an age-adjusted 62 percent smaller prostate size—as compared to men n the U.S.,” Trumble said, according to Medical Xpress. “BPH is not inevitable for Tsimane men.”
According to the authors, the study’s findings have important implications for men who take testosterone supplements. Using testosterone therapy to counteract so-called “Low-T” may increase the risk of developing an enlarged prostate. “Basically, these guys taking testosterone replacement therapies are entering themselves into an uncontrolled experiment,” Trumble said. “And this happened to women with estrogen replacement therapy from the 1980s to the early 2000s. And then the Women’s Health Initiative study came out and showed that all these women were putting themselves at risk for breast and other cancers.”
“We also know testosterone and androgens are involved because of studies showing that eunuchs and people who don’t have testes have very low rates of BPH,” said Trumble, lead author and a postdoctoral scholar at UCSB. “Some of the best pharmacological BPH and prostate cancer treatments involve reducing androgen levels. We also know from our own previous research that Tsimane have relatively low levels of testosterone—about 30 percent lower than age-matched U.S. males—and they have very low rates of obesity and hypertension and heart disease and all the other diseases of acculturation, including metabolic disease.”
The link between prostate cancer and higher levels of testosterone among different populations has been documented in previous studies, although that relationship was not analyzed here. “Populations with higher testosterone exposure appear to have higher rates of prostate cancer,” said Trumble. “And similar to those for BPH, many of the pharmacological treatments for prostate cancer block androgens.”
The study also found that among Tsimane men, large prostates were associated with highers levels of glycated hemoglobin (HbA1c), an indicator of diabetes risk. “Despite having subclinical levels of HbA1c, men with higher HbA1c had larger prostates,” Trumble said. “Not one of the men in this study had HbA1c indicative of diabetes. These were all men with relatively low glucose levels. Among men with low testosterone and low diabetes risk, those with relatively higher testosterone or HbA1c were at higher risk of prostate enlargement,” he said.