Association of Serum Homocysteine and Vitamin B12 with Different Grades of Cognitive Impairment in Alzheimer's Disease Patients.

Background

Studies have shown a relation between Vitamin B12 (B12) and cognitive impairment in Alzheimer's disease (AD). However, B12 levels do not indicate the severity of the disease. High homocysteine-induced neuroinflammation has been related to the pathogenesis of AD.

Aim

This study aimed to determine the correlation of Vitamin B12 and serum homocysteine with the cognitive status of AD patients.

Materials And Methods

AD patients (n = 25) and healthy controls (n = 25) were recruited for this study. The revised criteria for diagnosis and staging of AD were used for the diagnosis of AD. Clinical history, laboratory investigations (B12, homocysteine, lipid profile, C-reactive protein, and serum creatinine), and Mini-Mental Status Examination (MMSE) were done. Based on MMSE score, AD patients were subdivided into four groups. All statistical analyses were done on IBM SPSSv26.

Results

In AD patients, B12 was lower (221.3 ± 54.5 vs. 396.6 ± 88.4 pg/ml, P = 0.00), serum homocysteine was higher (15.2 ± 4.6 vs. 11.7 ± 2.3 µmol/L, P = 0.00), and C-reactive protein was higher (0.95 ± ± 0.39 vs. 0.69 ± 0.12 mg/dl, P = 0.00). Among the four AD groups, we observed a gradual increase in the serum homocysteine levels with a decline in the cognitive status (lower MMSE score) (F = 13.32, P = 0.00). MMSE score had a statistically significant correlation with homocysteine (ρ = -0.85, P = 0.00), unlike B12 (ρ =0.33, P = 0.11).

Conclusion

Serum homocysteine is a better diagnostic indicator of cognitive impairment than B12. In resource-limited settings, screening with the Mini-Cog test and timely supplementation with B complex vitamins (B6, B12, and folic acid) can slow the progress of dementia in AD patients.