Role of white matter hyperintensities, hemoglobin and vitamin B‐12 on cognitive decline: Two‐year follow‐up data from the Tata Longitudinal Study of Ageing (TLSA)

Abstract

AbstractBackgroundThe presence of white matter hyperintensities is commonly seen in elderly individuals and many studies have identified its relation to cognitive decline, however the effect size of this relationship has been seen to be relatively small. Evidence also suggests that among older individuals, low levels of hemoglobin and Vitamin B‐12 are indicators of cognitive decline. This study seeks to identify the role of white matter hyperintensities, hemoglobin and Vitamin B‐12 on cognitive change among an urban elderly population in Bangalore, India.MethodA subset of 87 individuals (49 Males and 38 Females, mean age=65.9 years) from TLSA Cohort above the age of 45 participated in the TATA longitudinal Study of Ageing, conducted in Bangalore, India. All participants underwent the Addenbrooke’s Cognitive Examination III (ACE‐III), blood investigations and Magnetic Resonance Imaging (MRI) scans as per the Alzheimer's Disease Neuroimaging Initiative (ADNI‐II) protocol at baseline. Brain images were acquired with a 3T Siemens Skyra MR Scanner. MRI scans were then visually rated on Fazeka’s scale for white matter lesions. Cognitive assessments were repeated two years later, on all participants. Change in cognition was calculated by subtracting followup scores from baseline scores. Regression analysis was conducted in order to examine the relation between White matter hyperintensities, vitamin b‐12 and hemoglobin at baseline with change in cognitive scores over time.ResultThe results indicate that Fazeka’s deep white matter scores, hemoglobin and vitamin B‐12 are significant predictors of changes in ACE‐III Memory scores at a 2 year follow up. A significant regression equation was found (F(3,38)=6.73, p<0.001), with an R2 of 0.347.ConclusionThe findings of the study suggest that an individual’s deep white matter hyperintensity, along with hemoglobin levels and Vitamin B12 at baseline are potential indicator of cognitive change during follow up. Future longitudinal studies with larger sample size are required to examine whether this model is a significant predictor of cognitive decline and dementia.