Baseline inflammatory markers predict 10-year cognitive decline in type 2 diabetes
Click Here to Manage Email Alerts
At 10 years, higher baseline levels of systemic inflammatory markers, including plasma interleukin-6 and fibrinogen, were associated with greater cognitive decline for adults with type 2 diabetes, according to data.
“At least some of this association appeared to be specific to certain cognitive domains and to be independent of vascular and diabetes-related risk factors,” Anniek J. Sluiman, PhD, senior population health researcher at the University of Edinburgh, U.K., and colleagues wrote in Diabetologia.
For the prospective Edinburgh Type 2 Diabetes Study, Sluiman and colleagues sought to assess the longitudinal association of circulating markers of systemic inflammation with subsequent long-term cognitive change in older people with type 2 diabetes.
The study included 1,066 adults aged 60 to 75 years with type 2 diabetes. At baseline, the researchers measured C-reactive protein, IL-6, tumor necrosis factor-alpha and fibrinogen, and performed neuropsychological testing on major cognitive domains. They repeated cognitive testing at 10 years for 581 participants and determined a general cognitive ability score via the battery of seven individual cognitive tests using principal component analysis.
After adjusting for age, sex and baseline general cognitive ability, researchers observed an association between higher baseline levels of fibrinogen (P = .032) and IL-6 (P = .018) and a greater decline in general cognitive ability. However, these associations no longer proved statistically significant after adjustment for baseline vascular and diabetes-related covariables.
In addition, data indicated that higher IL-6 was associated with a greater decline in tests of executive function (P = .006) and abstract reasoning (P = .001), whereas raised levels of fibrinogen (P = .001) and C-reactive protein (P = .001) were associated with a greater decline in processing speed. The statistical significance remained after adjustment for diabetes- and vascular-related risk factors, according to the researchers.
“Our results go some way to addressing the previous paucity of evidence of a prospective association between markers of systemic inflammation and cognitive decline in people with type 2 diabetes,” researchers wrote. “As this is primarily an exploratory observational study, clinical implications are limited and indirect.”
If future investigation proves the pathophysiological association causal, they wrote: “The possibility arises that efforts taken to reduce overall systemic inflammation may be beneficial in preventing the onset and severity of cognitive decline in people with type 2 diabetes. In addition, even if the findings do not translate into direct impact on therapeutic pathways, they could potentially help identify higher-risk groups within the diabetes population and so impact on clinical guidelines and decision-making.”
Perspective
Back to Top
Inflammatory factors have been shown to be associated with incident diabetes and with several complications of diabetes, for example, neuropathy and nephropathy. It is therefore not surprising that inflammatory factors have also been reported to be associated with cognitive changes, most recently in the study by Sluiman and colleagues. Whether these findings are causally related is difficult to establish since cognitive decline is also associated with many other clinical and subclinical comorbidities that accompany older age. Some of these factors were measured and accounted for in this study (eg, elevated blood pressure); other factors were not measured (eg, albuminuria, advanced glycation end products). Serum factors found in the peripheral circulation may not necessarily reflect changes in the central nervous system, which is sequestered by the blood-brain barrier. Nonetheless, this study does support the concept that the diabetic inflammatory state may, in some way, be related to cognitive change over time.
Collapse
Read more about
Click Here to Manage Email Alerts