Metabolic Syndrome and Cognition: Follow-Up Study of Chinese Over-55-Year-Olds.

BACKGROUND/AIM: Studies of the associations of the metabolic syndrome (MetS) with cognitive function and decline are inconclusive. We investigated the associations of the MetS with cognitive functions in 823 Chinese >55-year-olds followed up over 4.5 years. METHODS: The relationships between the MetS and baseline and follow-up z-scores of cognitive domain functions were examined using mixed model analysis. RESULTS: There were specific inverse cross-sectional associations of single cardiometabolic risk factors with cognition, such as hyperglycemia with processing speed (p = 0.045). The MetS was negatively associated with 3 out of 4 cognitive domains (p = 0.018 to p = 0.003), and the count of cardiometabolic risk factors with all cognitive domains (p = 0.025 to p = 0.002). Longitudinally, dyslipidemia was associated with worse decline in memory and learning (p = 0.022). The count of cardiometabolic risk factors was associated with worse declines in cognition (p = 0.032 for global cognition). CONCLUSION: Among middle-aged and older Asians, an increased number of component cardiometabolic risk factors of the MetS was associated with a worse decline in cognitive function over time.

One-Carbon Metabolism Biomarkers and Risks of Incident Neurocognitive Disorder among Cognitively Normal Older Adults.

There is a lack of evidence supporting an association between folate and vitamin B12 exposure with cognitive outcomes. We examined serum folate and vitamin B12 and plasma homocysteine in 690 cognitively-normal adults (aged ≥ 55) from the Singapore Longitudinal Aging Study (SLAS-2) followed-up over 4.5 years on incident neurocognitive disorder (NCD): mild cognitive impairment (MCI) and dementia. At follow-up, 5.7% (39) of participants developed NCD (34 MCI and 5 dementia). Comparing with those who remained cognitively-normal, participants progressed to NCD had significantly lower mean baseline vitamin B12 (420 [SD ± 221] vs. 510 [SD ± 290] pmol/L, p = 0.026), higher homocysteine (14.6 [SD ± 4.2] vs. 12.9 [SD ± 4.3], p = 0.018) and lower one-carbon index (Z-scores: -0.444 [SD ± 0.819] vs. -0.001 [SD ± 0.990], p = 0.006). Adjusted for confounders, significant associations with incident NCD were found for lower vitamin B12 (per-SD OR = 2.10, 95%CI = 1.26-3.52), higher homocysteine (per-SD OR = 1.96, 95%CI = 1.18-3.24) and lower one-carbon index (per-SD OR = 1.67, 95%CI = 1.06-2.64). Folate was not significantly associated with progression to NCD. Notably, low B12 in the presence of high folate was significantly associated with incident NCD (adjusted OR = 3.81, 95%CI = 1.04-13.9). Low B12, high homocysteine, low B12 in the presence of high folate, and a one-carbon index of hypo-methylation were independently associated with progression to NCD among cognitively normal.