Attention has recently increased for the negative health outcomes associated with inflammation. A recent study looked at the impact of inflammation on the brain, and what role genetic and non-genetic factors may play in this process.
Researchers were able to measure CRD, a marker for inflammation, at the start of the study and again five and nine years later. At each of these time points, participants were also given brain scans, a physical exam, and asked about their physical activity. They were also given a genetic test for genes associated with greater risk of Alzheimer’s. This permitted the researchers to look at the role that genetics, physical activity, and metabolic factors (a combination of body mass index, glucose levels, and insulin resistance) might play in the impact of inflammation.
When the researchers examined areas of the cerebral cortex associated with inflammation, they found a significant association of inflammation with a thinner cortex in four of the nine areas they examined, with the greatest change in the posterior cingulate, an area associated with attention and cognitive arousal. Of the three additional factors examined, only metabolic factors showed a significant relationship with CRD that led to this cortical thinning. The analysis showed that higher metabolic risk was associated with higher levels of inflammation and that the role of these metabolic factors on cortex thinning was via the inflammation they can produce. While genetic risk factors played a role in cortical thinning, this occurred independent of the role of inflammation. Physical activity did not show any relationship to this inflammation or the thinning of the cortex, although, as in other studies, greater physical activity was associated with a larger hippocampus, suggesting its impact on the brain may be limited to particular regions.
Perhaps most encouraging in this research is that the metabolic factors associated with inflammation and subsequent brain changes are modifiable via lifestyle change such as weight loss and a healthy diet.
Corlier F, Hafzalla G, Faskowitz J, et al. Systemic inflammation as a predictor of brain aging: Contributions of physical activity, metabolic risk, and genetic risk. NeuroImage (2018); 172: 118–129.