Cytomegalovirus (CMV) is a persistent and very common herpesvirus that is thought to be a major contributor to the age-related decline of the immune system, due to an ever increasing portion of its limited number of cells becoming specialized to CMV and thus unavailable for other duties. Various past studies have linked CMV with forms of age-related frailty, but here the researchers find an association with type 2 diabetes - which is interesting and perhaps somewhat unexpected, given that type 2 diabetes is essentially a lifestyle disease: "Cytomegalovirus (CMV) infection has been reported to contribute to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, CMV infection has not been evaluated as a possible risk factor for type 2 diabetes. Our aim was to investigate potential associations between CMV seropositivity, CMV IgG antibody level and glucose regulation in the oldest old. ... CMV seropositive subjects were more likely to have type 2 diabetes (17.2% vs 7.9%), had a higher level of HbA1c and higher non-fasting glucose in the oldest olds. These associations remained significant after adjustment for possible confounders. CMV IgG antibody level was not significantly associated with glucose regulation ... In the oldest old, CMV seropositivity is significantly associated with various indicators of glucose regulation. This finding suggests that CMV infection might be a risk factor for the development of type 2 diabetes in the elderly."

Link: http://dx.doi.org/10.1186/1742-4933-9-18