Assessment of the effects of glutamic acid decarboxylase antibodies and trace elements on cognitive performance in older adults

Background: Homeostatic imbalance of trace elements such as iron (Fe), copper (Cu), and zinc (Zn) demonstrated adverse effects on brain function among older adults. Objective: The present study aimed to investigate the effects of trace elements and the presence of anti-glutamic acid decarboxylase antibodies (GADAs) in human cognitive abilities among healthy older adults. Methods: A total of 100 healthy subjects (65 males, 35 females; age range; 64-96 years) were recruited for this study. Based on Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) score, the participants were classified according to cognitive performance into normal (n = 45), moderate (n = 30), and severe (n = 25). Cognitive functioning, leisure-time physical activity (LTPA), serum trace elements - Fe, Cu, Zn, Zn/Cu, and GADAs were assessed using LOTCA battery, pre-validated physical activity (PA) questionnaire, atomic absorption, and immunoassay techniques, respectively. Results: Approximately 45% of the study population (n = 45) had normal distribution of cognitive function and 55% of the study population (n = 55) had abnormal cognitive function; they were classified into moderate (score 62-92) and severe (score 31-62). There was a significant reduction in the level of Zn and Zn/Cu ratio along with an increase in the level of Fe, Cu, and anti-GADAs in subjects of severe (P = 0.01) and moderate (P = 0.01) cognitive performance. LOTCA-cognitive scores correlated positively with sex, HbA1c, Fe, Cu, Zn, and Zn/Cu ratio, and negatively with age, PA, body mass index, and anti-GADAs. Significant inter-correlation was reported between serum trace element concentrations and anti-GADAs which suggest producing a cognitive decline via oxidative and neural damage mechanism. Conclusion: This study found significant associations among trace elements, anti-GADAs, and cognitive function in older adults. The homeostatic balance of trace elements should be recommended among older adults for better cognitive performance.