A new study conducted by UC Santa Barbara anthropologists suggests that testosterone-specifically, an unnatural overabundance-may be a prime culprit in benign prostatic hyperplasia (BPH), or prostate enlargement.
BPH is one of the most common diseases of older men in the United States. By the time they are 80, upwards of 90 percent of men in the U.S. experience some degree of prostate enlargement, Medical Xpress reports, and about 40 percent require medical treatment.
The factors that contribute to BPH have yet to be positively identified, Medical Xpress reports. To explore the factors, researchers Benjamin Trumble and Michael Gurven examined the prevalence of BPH among a group of approximately 350 adult males of the Tsimane, an isolated indigenous population in central Bolivia. Within that group, advanced cases of prostate enlargement were virtually nonexistent. The Tsimane also have relatively low levels of testosterone that remain constant over their lives. “[T]hey have significantly smaller prostates-an age-adjusted 62 percent smaller prostate size-as compared to men in the U.S.,” according to Trumble, a postdoctoral scholar and the paper’s lead author. BPH is not inevitable for Tsimane men, he says. The paper appears in the Journals of Gerontology: Medical Sciences.
Trumble said we “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.” Previous research shows Tsimane have relatively low levels of testosterone and they also have very low rates of obesity and hypertension and heart disease and all the other diseases of acculturation, including metabolic disease, according to Medical Xpress. Tsimane men with higher testosterone levels have larger prostates. The researchers say this finding has important implications for the millions of men who use testosterone supplements to counteract low testosterone. They may be putting themselves at risk for prostate enlargement.
Trumble says men who take testosterone replacement drugs are “entering themselves into an uncontrolled experiment.” Although this particular study did not test for prostate cancer, other studies have shown that population differences in testosterone impact prostate cancer risk as well, according to Trumble. “Populations with higher testosterone exposure appear to have higher rates of prostate cancer.” The findings raise questions about the health benefits and risks that come from attempts to stave off the natural process of aging. Gurven, a professor of anthropology and co-director of the Tsimane Health and Life History Project, says many men think that if they want to reverse the aging process, they only need to return to the high levels of testosterone youth. But Gurven said this comes at a cost and more long-term studies of testosterone replacement therapy are necessary to ensure its safety and efficacy, according to Medical Xpress.
What does the health of the Tsimane, a population of hunters and forager-farmers, tell us about a society like the U.S.? The types of chronic diseases that afflict many in the U.S. today may manifest because of the relatively rapid changes in such factors as diet, physical activity, natural fertility, infectious exposure and kin-based social networks. “Type 2 (adult onset) diabetes is one of these illnesses that under more traditional conditions wouldn’t be as prevalent as it is today in high-income countries, or becoming increasingly prevalent in urban areas of low-income countries,” Gurven said. Ultimately, the researchers argue, prostate enlargement is not necessarily an inevitable part of male aging, but a disease that our low-pathogen, resource-abundant sedentary lifestyle is creating for us.