Homocysteine, vitamin B12, folic acid levels and its association with Mild Cognitive Impairment in urban and rural dwelling Indians

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AbstractBackgroundHomocysteine (Hcy) is a sulfur containing amino acid generated in the metabolism of methionine involving co‐factors such as B vitamins and folic acid. Deficiency of these co‐factors have been associated with increased Hcy levels (Hutto, 1997). Relationship between differing levels of plasma Hcy, vitamin B12, folic acid and cognitive impairment is inconclusive.MethodCross sectional analysis was done using the baseline data from two ongoing longitudinal studies such as Tata Longitudinal Study of Ageing (TLSA, N = 984) and Srinivaspura Aging, Neuro Senescence and COGnition (SANSCOG, N = 4404), an urban and rural cohorts (Sundarakumar et al, 2020) respectively. Hcy, vitamin B12, folic acid levels were compared between the subjects of both cohorts. Comparison of these levels between healthy and MCI (Mild Cognitive Impairment) subjects within and across the cohorts were done. CDR (Clinical Dementia Rating) scale was used to classify subjects having normal cognition and MCI, considering score of 0.5 as MCI. Mann‐Whitney U test was used to compare these levels between the groups.ResultHcy, vitamin B12, folic acid levels between the two cohorts showed significant difference, with higher levels of Hcy (median (IQR)) = (17.08 (11) vs 14.63 (10); p <0.001), vitamin B12 (247 (252) vs 220 (143); p <0.001) and folic acid (8.55 (9) vs 5.55(4); p <0.05) in TLSA than SANSCOG. Significant difference seen in Hcy (17.73(11) vs 14.73 (10); p <0.001), vitamin B12 (246 (249) vs 220 (136); p <0.001) and folic acid (8.42 (9) vs 5.53 (4): p <0.001) levels for healthy subjects between cohorts, higher levels were seen in TLSA subjects. Hcy (16.08 (8) vs 14.43 (12); p <0.001) vitamin B12 (305 (341) vs 216 (174); p = 0.03) and folic acid (8.52 (9) vs 5.34 (4): p <0.001) levels were significantly high in TLSA than SANSCOG for MCI subjects. However, these levels were not significantly different between healthy and MCI subjects within cohorts.ConclusionConsistently elevated levels of Hcy was observed in urban cohort. Though elevated level of Hcy was observed with normal vitamin B12 and folic acid, it was not associated with MCI.