The role of dietary and blood inflammation on the relation of diabetes and cognition in Chinese elderly people

Diabetes and dementia are becoming the major problems in elderly people. This study evaluated the relationships of dietary inflammatory index (DII), systemic immune inflammation index (SII) and system inflammation response index (SIRI) with diabetes as well as MCI, and explored the different synergistic effects of DII, SII and SIRI on blood glucose and cognition based on diabetes status. 1050 eligible participants from Beijing were included. Cognitive function was evaluated by neuropsychological tests. Food frequency questionnaire was used to calculate energy-adjusted DII scores. Blood samples were applied to obtain fasting plasma glucose (FPG) and calculate SII, SIRI. The dietary intake between different diabetes status had no differences, while the consumption of Mg, niacin and thiamin were significantly lower in diabetes patients with MCI than others. Lower levels of DII, SIRI and SII might increase the risk of diabetes, MCI and co-morbidity of diabetes with MCI. Higher FPG enhanced the synergistic effects of DII and SII on MCI, as well as DII and SIRI. The lower levels of DII, SIRI and SII were significantly correlated with higher MoCA scores and lower FPG in diabetes patients. The relationships between inflammatory and cognition or FPG were significantly diminished or even disappeared in non-diabetes population. In conclusion, lower levels of DII, SIRI and SII might play protective roles in reducing the risks of diabetes and/or MCI. The synergistic effects of low dietary and blood inflammation on cognitive protection and FPG control were more sensitive in elderly people with diabetes.