Association between stress hyperglycemia ratio and cognitive function in older patients with diabetes or prediabetes: a cross-sectional study from the NHANES

To explore the association between stress hyperglycemia ratio (SHR) levels and cognitive function in older patients with diabetes or prediabetes. Cognitive function was assessed through a composite Z-score, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) subtest, the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). SHR was calculated as the fasting blood glucose divided by the estimated average glucose from glycated hemoglobin. In subsequent analyses, SHR was divided into quartiles (quartiles 1 to 4), with the second quartile serving as the reference group. A weighted linear regression model was used to assess the association between SHR and cognitive function. After adjusting the corresponding covariates, the analysis revealed that compared to the second quartile, the first [β: -0.26; 95% confidence interval (CI): -0.39- -0.12], third (β: -0.13, 95% CI: -0.25- -0.02), and fourth (β: -0.21, 95% CI: -0.36- -0.06) quartiles were all associated with a decrease in Z-score. The first quartile was associated with a decline in AFT (β: -1.46, 95% CI: -2.57- -0.36). The first (β: -3.72, 95% CI: -6.06- -1.38) and fourth (β: -2.58, 95% CI: -4.98- -0.17) quartiles were associated with a decline in DSST. No statistically significant associations were observed between any of the quartile groups and CERAD (all p > 0.05). Both higher and lower SHR were associated with poorer overall cognitive function, with higher and lower SHR being related to worse memory dimensions, while lower SHR was associated with impaired executive function.