MUNICH, Germany — Genital herpes already leaves carriers with lifelong health concerns, but a new study may cause even more trouble for these individuals. Researchers in Germany have found a link between herpes simplex viruses 2 (HSV2) and a greater risk of developing type 2 diabetes.
Study authors note that HSV2 is one of two herpesviruses that may increase a person’s chances of developing diabetes. The other is cytomegalovirus (CMV), a common virus which infects people of all ages. Unlike HSV2, a sexually transmitted disease, CMV infects nearly one in three U.S. children by the age of five.
In the new study, researchers looked at the impact having one of the eight known herpesviruses has on diabetes risk. The other strains include herpes simplex viruses 1 (HSV1), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and human herpesviruses (HHV) 6, 7, and 8.
Results show that carrying HSV2 or CMV displayed a connection to higher incidence rates of prediabetes among people with normal glucose tolerance at the start of the study. Individuals with HSV2 were 59 percent more likely to develop prediabetes than those without the STD. Meanwhile, people with CMV were 33 percent more likely to become prediabetic.
“Our study suggested that while (pre)diabetes incidence was primarily explained by age, BMI, cholesterol and fasting glucose, both HSV2 and CMV added additional complementary risk information, despite high viral prevalence and co-occurrence,” the study authors say in a media release.
Researchers discovered that both HSV2 and CMV cause chronic infections which may alter the immune system by stimulating or suppressing its ability to function. This can lead to changes in the endocrine (hormonal) system, raising the risk of diabetes onset.
Cases of diabetes are rising
Type 2 diabetes is one of the most widespread metabolic diseases in the world. Nearly one in 10 people had it as of 2019. Although behavioral, environmental, and genetic factors are the leading causes for diabetes onset, scientists have started looking at the role viruses play as well. However, previous studies have only looked at viruses as being a cause in the development of type 1 diabetes, a condition which sees the pancreas being unable to produce enough insulin.
Researchers note that having prediabetes greatly increases the risk of developing type 2 diabetes. Studies estimate that half of the U.S. population are prediabetic by the time they reach middle age.
The team studied the health of 1,967 people from KORA (Cooperative Health Research in the Augsburg Region) over several years. Each person underwent a detailed health screening between 2006 and 2008 before researchers followed up with them between 2013 and 2014. The screening included a test for human herpesviruses, oral glucose tolerance tests, and a measurement of glycated hemoglobin (HbA1c) — which reveals a person’s blood sugar control.
Cases of prediabetes increased from 27.5 percent at baseline to 36.2 percent during the follow-up period. Meanwhile, cases of type 2 diabetes rose from 8.5 percent to 14.6 percent.
How common is it to have herpes?
While study authors found that only 11 percent of the population carry HSV2, nearly half carry CMV (46%). The other herpesviruses which did not show a link to increased diabetes risk are much more prevalent throughout society. In fact, the study finds 98 percent of participants had Epstein-Barr virus, 88 percent had HSV1, 85 percent had HHV7, and 79 percent had varicella-zoster virus, according to blood samples.
While these other herpesviruses usually stay dormant and remain harmless, they generally stay in a person’s body for life.
“These results highlight the link between viruses and (pre)diabetes, and the need for more research evaluating public health viral prevention strategies, possibly including the development of effective vaccines against herpesviruses,” the study authors conclude.
The study is published in the journal Diabetologia.