Association of Hippocampus volume with normal serum Natrium levels and predictive analyses of cognitive adversities in non-demented middle-aged and older adults

IntroductionSerum Natrium abnormalities are largely observed in older adults and are associated with higher risks. Less is known about the association between serum Natrium variations and medial temporal brain structures, mainly involved in cognition and memory. The studys objective was to explore the association between serum Natrium and Hippocampus volume and to assess associated cognitive risks. MethodsNon-demented ADNI3 participants (healthy controls (HC) and with mild cognitive impairment (MCI)) with complete serum Natrium, ADAS13 score, and Hippocampus volume at baseline were included. Linear and non-linear associations were evaluated. To assess the odds of MCI, logistic regression adjusted was performed. Holm method was used to adjust for Family-wise error rate in the main analysis and reported as a q-value. ResultsA total of 469 cases with a median age of 70 years (IQR: 66, 76) were included. The median serum Natrium level was 141 (IQR: 139, 142). Serum Natrium levels showed a significant association with Hippocampus volume in the total study population and MCI subgroup (Adj.{beta}MCI=-95 (-162, -28), p=0.006, q=0.036). Serum Natrium levels did not show a significant association neither with the ADAS13 total score (Adj.{beta}Total=-0.04(-0.28, 0.21), p=0.8) nor with the odds of being diagnosed with MCI at baseline (ORMCI= 1.00(0.88, 1.13), p= 0.935). ConclusionsNormal Serum Natrium variations were significantly associated with Hippocampus volumes depending on the underlying neurodegenerative pathology, thus, without predicting clinically relevant cognitive adversity. Further studies are needed to better understand the mechanisms and assess protective factors. Key findingsO_LISerum Natrium levels within normal ranges were significantly associated with Hippocampus volume. C_LIO_LIThe association between Serum Natrium levels and Hippocampus volume was particularly significant in participants with mild cognitive impairment. C_LIO_LIThere was no significant association between serum Natrium and ADAS13 total score. C_LIO_LISerum Natrium levels within normal ranges did not predict concomitant risk of mild cognitive impairment. C_LI