Increased iron and oxidative stress are separately related to cognitive decline in elderly

Abstract

The aim of this study is to examine the relation between body iron, oxidative stress and cognitive function in elderly. Eighty-seven elderly residents from nursing homes were the subjects of our study. Cognitive status was screened by the Mini-Mental State Examination (MMSE). Of the 87 eligible subjects, 46 patients who obtained 24 or fewer points on the MMSE scale were considered as subjects with cognitive dysfunction. The control group consisted of 41 subjects who obtained more than 24 points on the MMSE. Routine biochemical analyses, parameters of iron metabolism, malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were determined in all subjects. There were statistically significant increases in serum iron, transferrin saturation, ferritin and MDA levels; whereas there was a statistically significant decrease in serum GSH-Px enzyme activity and serum sodium levels in subjects with cognitive dysfunction. A significant negative correlation was found between serum iron, transferrin saturation, ferritin and MMSE score. There was a negative correlation between MMSE score and serum MDA; however, a positive significant correlation was found between MMSE score and both GSH-Px enzyme activity and serum sodium. Our study provides evidence of increased markers of iron deposition and oxidative stress in patients with cognitive dysfunction. It seems likely that these markers negatively affect the MMSE score. Interestingly, we did not find any correlation between the markers of iron deposition and oxidative stress. Future studies will be required to demonstrate whether diminishing iron and oxidative stress will enhance MMSE score and thereby ameliorate cognitive impairment.