Two common herpesviruses have been associated with the onset of prediabetes in a new study led by researchers in Germany. The findings build on a growing body of evidence connecting viral infections to the development of chronic disease.
Over recent years scientists have found a number of compelling associations between diseases such as cancer, multiple sclerosis or Alzheimer’s and infectious pathogens. In some cases these relationships are explicitly causal. For example, we know infections with human papilloma virus (HPV) directly cause 90 percent of cervical cancers, and new HPV vaccines are hoped to nearly eliminate this form of cancer in the near future.
Other relationships can be more of one factor amongst many in the constellation of elements that contribute to disease. One of the most groundbreaking scientific findings so far in 2022 was a major study that affirmed the link between Epstein-Barr virus infections and multiple sclerosis (MS).
This landmark study suggested EBV infections were not the singular cause of MS, after all, the virus is incredibly prevalent and not everyone infected ends up developing neurodegenerative disease. Instead, the research confirmed that although not all EBV infections will lead to MS, all MS cases are likely preceded by an EBV infection. This means it is possible a vaccine against this virus could prevent most cases of MS from developing.
The Epstein-Barr virus is one member of the larger herpesvirus family. There are eight types of herpesvirus known to cause disease in humans, including the varicella zoster virus (aka HHV-3, causing chicken pox and shingles). All of these herpesviruses are known to cause latent infections, meaning once you are infected the virus can remain in your body relatively dormant for your entire life.
This new research set out to investigate whether there were any associations between latent herpesvirus infections and the development of prediabetes, a metabolic state that often precedes the appearance of type 2 diabetes. To do this the researchers analyzed data from a long-term health study tracking several thousand people for around seven years.
The presence of seven herpesviruses was tracked at baseline, and then diabetes biomarkers were measured at follow-up several years later. Around 360 subjects were found to develop markers of prediabetes over the nearly seven-year follow-up. Of those that developed prediabetes, infection with two herpesviruses were frequently detected: herpes simplex virus 2 (HSV-2) and cytomegalovirus (CMV).
“Multivariate analyses suggested that these two viruses consistently and complementarily contributed to (pre)diabetes incidence independently of sex, age, BMI, education, smoking, physical activity, parental diabetes, hypertension, lipid levels, insulin resistance and fasting glucose,” the researchers explained in the new study. “Our variable selection approach 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.”
HSV-2 was the strongest association, with those infected being 59 percent more likely to develop prediabetes. While those with CMV were 33 percent more likely to develop prediabetes.
The researchers are clear in stating their current finding is just a preliminary observational association. Several other known diabetes risk factors, such as cholesterol and obesity, clearly play a greater role than herpesvirus in determining the likelihood of a person developing the metabolic disease. However, these new findings do offer signals that some types of herpesvirus may play a contributing role.
How exactly could these viruses influence the development of diabetes? That is unclear, and at this point the researchers can only hypothesize potential mechanisms, such as the herpesvirus modulating an immune response in a way that affects the body’s endocrine system.
Lots more work will be needed to unpack this potential link between herpesvirus and diabetes but the researchers do stress the findings call for more public health work to prevent people being infected in the first place. And, the development of herpesvirus vaccines could plausibly be used as a preventative tool to reduce rates of diabetes in the future.
The new study was published in the journal Diabetologia.
Source: Springer Nature