Glycated hemoglobin levels and geriatric depression impact cognitive status in an Indian urban elderly community

This study explored the cognitive status of community-dwelling Indian older adults. Our objective was to observe the association of age-related cognitive change with other physiological health parameters like, glycated hemoglobin (HbA1c), and vitamin B12 in older adults in India. Urban community dwelling, consenting older adults (55-85years, n = 123), with no clinical history of cognitive or neurological problems participated in the study. The participants underwent a detailed demographic documentation and cognitive assessment comprising of tests from different cognitive domains and blood-based assessment of glycated hemoglobin (HbA1c) and vitamin B12. As expected, performance in all cognitive domains declined with increasing age. HbA1c levels correlated inversely with processing speed and executive function. Vitamin B12 levels did not correlate with performance on any cognitive test. Interestingly, geriatric depression correlated inversely with visuospatial abilities. A stepwise multiple regression revealed that HbA1c and geriatric depression contributed to 28 % variance on Montreal Cognitive Assessment while age did not qualify as a significant contributor. Using Petersen's criteria, Mild Cognitive Impairment (MCI) was observed in 17 % of participants. Participants classified as MCI had higher levels of HbA1c and geriatric depression, and lower performance in all cognitive domains compared to non-MCI participants. In conclusion, although cognitive performance declined with age, HbA1c and geriatric depression had a greater role in cognitive decline than age. With a high incidence of diabetes in India, this study highlights the prevalence of metabolism-linked changes in cognition, which are often ignored in community dwelling older adults in India.