Herpes virus eventually impairs glucose regulation

By Sally Robertson, B.Sc.Sep 3 2012

The common herpes virus cytomegalovirus (CMV) may be a risk factor for the development of Type 2 diabetes among elderly individuals, show study findings.

In a population of individuals aged older than 85 years, those with CMV seropositivity were significantly more likely to have Type 2 diabetes, elevated levels of glycated hemoglobin (HbA1c), and a high nonfasting glucose level.

"The present study is the first to show that CMV seropositivity is positively independently associated with indicators of glucose regulation," say Andrea Maier (Leiden University Medical Center, the Netherlands) and colleagues.

Despite accumulating evidence that chronic inflammation is a risk factor for Type 2 diabetes, there is only limited knowledge about whether infection by specific pathogens contributes to inflammation and subsequent incidence of Type 2 diabetes, says the team.

Writing in Immunity and Ageing, the team reports that among 549 elderly individuals followed-up for determinants of successful ageing as part of the Leiden 85-plus Study, the majority (n=435, 79.2%) were found to be CMV-seropositive.

The frequency of diabetes among the population was 15% (n=84).

CMV is known to be a chronic stressor for the immune system as it establishes a persistent, life-long infection that can become reactivated periodically, explain Maier et al. "It is therefore considered a potential cofactor for inflammatory disease."

Compared with individuals who were not infected with CMV, those who were CMV-seropositive were significantly more likely to have Type 2 diabetes, elevated levels of HbA1c, and an increased nonfasting glucose level, at respective odds ratios of 2.42, 1.44, and 2.50, after adjustment for potential confounders.

The team suggests that CMV may be acting on the pancreas directly, by infecting and residing in pancreatic cells and eventually influencing insulin production after repeated activations.

Alternatively, CMV may exert its effects indirectly, causing systemic inflammation that interferes with the action of insulin by suppressing intracellular insulin signal transduction, write Maier et al.

Either mechanism would explain why the association between CMV seropositivity and glucose regulation emerges in the very elderly, as significant effects would take a long time to develop in both cases, they say.

"Our findings shed light on the pathogenesis of Type 2 diabetes in the very elderly,

"More research needs to be performed to determine causality in the relationship of CMV infection with Type 2 diabetes," concludes the team.

Licensed from medwireNews with permission from Springer Healthcare Ltd. ©Springer Healthcare Ltd. All rights reserved. Neither of these parties endorse or recommend any commercial products, services, or equipment.