The Association Between Homocysteine and Memory in Older Adults

Plasma homocysteine and longitudinal change in cognitive function among urban adults

BACKGROUND

Cross-sectional and longitudinal studies have inconsistently linked cognitive performance and change over time to an elevated level of homocysteine (Hcy), with few conducted among urban adults.

METHODS

Longitudinal data [Visit 1 (2004-2009) and Visit 2 (2009-2013)] were analyzed from up to 1430 selected Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) participants. Baseline and follow-up blood Hcy was measured, while 11 cognitive function test scores were assessed at either of these two visits. Overall, sex- and race-stratified associations were evaluated using mixed-effects linear regression models, adjusting for key potential confounders. Interaction effects between Hcy and serum levels of folate and vitamin B-12 were also tested.

RESULTS

We found that greater LnHcyv1 was significantly associated with poorer baseline attention based on higher Loge (TRAILS A, in seconds) [β (SE): 0.101 (0.031), P = 0.001]. Heterogeneity was also found by sex and by race. Most notably, among men only, LnHcyv1 was associated with faster decline on the BVRT (# of errors), a measure of visuo-spatial memory (β (SE): 0.297(0.115), P = 0.010, reduced model); while among African American adults only, an elevated and increasing LnHcy over time was associated with faster rate of decline on Loge (TRAILS B, in seconds) [β (SE): +0.012 (0.005), p = 0.008], a measure of executive function. Interactions between Hcy, folate and vitamin B-12 blood exposures were also detected.

CONCLUSIONS

In summary, sex- and race-specific adverse association between elevated Hcy and cognitive performance over time were detected among middle-aged urban adults, in domains of attention, visuo-spatial memory and executive functioning.

Cognitive Function Trajectories and Factors among Chinese Older Adults with Subjective Memory Decline: CHARLS Longitudinal Study Results (2011-2018)

Older adults with subjective cognitive decline are at increased risk of future pathological cognitive decline and dementia. Subjective memory decline is an early sign of cognitive decline; preventing or slowing cognitive decline in at-risk populations remains an elusive issue. This study aimed to examine the cognitive trajectories and factors in older adults with subjective memory decline. Latent growth curve models (LGCMs) were fitted to examine the cognitive function trajectories and factors among 1465 older adults (aged 60+ years) with subjective memory decline. Data were obtained from four waves from the China Health and Retirement Longitudinal Study (CHARLS, 2011-2018), which is a large nationally representative sample of the Chinese population. The results showed that older adults with better initial cognition had a slower decline rate, which may be accelerated by advanced age, low-level education, a rapid decrease in instrumental activities of daily living (IADL) ability, and rapid increase in depression levels. This study was the first to examine the trajectories of cognitive function and its factors in a high-risk population with subjective memory decline. These findings may guide prevention approaches to tackle the issues of cognitive function decline and dementia.

Gender difference in association between H-type hypertension and subcortical ischemic vascular disease

Background

Subcortical ischemic vascular disease (SIVD) is a leading cause of vascular dementia. The present study tries to explore not only the gender-specific association between H-type hypertension and SIVD but also the indirect effects of H-type hypertension on cognition through the ischemic brain injury caused by SIVD.

Materials and methods

A total of 601 SIVD patients were included, comprising 322 males and 279 females. H-type hypertension was defined as hypertension accompanied with elevated serum total homocysteine (tHcy) level. The imaging manifestations of ischemic brain injury caused by SIVD were also evaluated, including white matter lesions (WML), lacunar infarction (LI) and brain atrophy (BA). Gender-specific subgroup analyses in association between H-type hypertension and SIVD were conducted, followed by a structural equation model based evaluation of the gender-specific mediating effects of SIVD on the relationship between H-type hypertension and cognition.

Results

For males, there was no noticeable difference in WML, LI and BA scores among control group, isolated hypertension group, isolated high tHcy group, and H-type hypertension group in most brain regions, but significant difference was found in all brain regions for females. Multiple regression analyses showed that H-type hypertension was significantly associated with WML, LI and BA for females, but not for males. For males, H-type hypertension mainly affected cognition through direct effect, while the H-type hypertension effect was mediated by ischemic brain injury caused by SIVD for females.

Conclusion

H-type hypertension was more closely related to SIVD for females than males, suggesting a gender-specific difference in association patterns between H-type hypertension and cognition.

Dose-response association between plasma homocysteine and white matter lesions in patients with hypertension: a case-control study

White matter lesions (WMLs) are common MRI changes that are indicative of cerebral small vessel disease (CSVD). Elevated plasma homocysteine (Hcy) levels are related to an increased risk of vascular disease. We aimed to analyze the relationship between Hcy levels and WMLs in patients with hypertension. A total of 1961 patients with WMLs and 15,463 patients without WMLs were matched at a 1:1 ratio by age and sex. Hyperhomocysteinemia (HHcy) was defined as an abnormally high level (>15 µmol/l) of Hcy in a plasma sample. In total, 1888 (WML group) and 1888 (No-WMLs group) patients were enrolled, with 51.6% of the sample being male and a mean age of 63 years. Multivariate logistic regression analysis showed a significant association between a higher level of plasma Hcy and a higher prevalence of WMLs (OR 1.03 95% CI, 1.02-1.04) when the Hcy level was used as a continuous variable. Patients with Hcy levels of 15-20 µmol/l (OR 1.54, 95% CI 1.31-1.81) and >20 µmol/l (OR 1.51, 95% CI 1.26-1.82) also had a significantly higher risk of WMLs than patients with Hcy levels <15 µmol/l. Multivariable-adjusted spline regression models showed that the risk of WMLs started to increase only in patients with Hcy levels above 13.85 µmol/l (P < 0.001). In subgroup analyses of WMLs, there was no significant interaction between the Hcy group and subgroup heterogeneity for the prevalence of WMLs (P > 0.05). Our study found a dose-response association between plasma homocysteine levels, especially a Hcy level >13.85 µmol/l, and the prevalence of WMLs, implying that lowering Hcy levels might be a target for prevention.

Intrinsic Capacity Declines with Elevated Homocysteine in Community-Dwelling Chinese Older Adults

Purpose

Intrinsic capacity (IC) reflects the overall health status of older adults and has great public health significance. But few studies described the related biomarkers for IC. The aim of this study was to investigate the association between homocysteine (Hcy) and IC in older adults.

Participants and Methods

This cross-sectional study included 1927 community-dwelling Chinese older adults aged 60–98 years from May 2020 to December 2020. Data were collected through interviews, physical examinations, and laboratory tests. IC involved five domains of cognition, locomotion, sensory, vitality, and psychology evaluated by the Mini-cog scale, 4-m walk test, self-reported visual and hearing conditions, MNA-SF scale, and GDS-4 scale, respectively. The score of each domain dichotomized as 0 (normal) and 1 (impaired) was added together to an IC total score. Low IC was defined as a score of 3–5, and high IC as 0–2. Hcy was measured by a two-reagent enzymatic assay. A restricted cubic spline regression model was used to explore the non-linear relationship between Hcy and low IC.

Results

Hcy was higher in the low IC group than in the high IC group. Restricted cubic spline analysis revealed a J-shaped nonlinear association between Hcy and low IC. The risk of IC decline was slowly decreased until 8.53 µmol/L of Hcy (OR=0.753, 95% CI=0.520–1.091, P=0.132), and increased with elevations of per 5 µmol/L Hcy afterwards (OR=1.176, 95% CI=1.059–1.327, P=0.005). Among the five domains of IC, Hcy had ORs of 1.116 (1.009–1.247) for cognition impairment, 1.167 (1.055–1.305) for vitality, and 1.160 (1.034–1.303) for psychology per 5 µmol/L increase in Hcy above the change point. Additional sensitivity analysis also demonstrated the nonlinear association between Hcy and low IC.

Conclusion

Hcy had a J-shaped association with low IC. Higher Hcy (Hcy ≥8.53µmol/L) might provide clinical implications for early identifying the risk of low IC.

Hypertension With High Homocysteine Is Associated With Default Network Gray Matter Loss

Hypertension with high homocysteine (Hcy, ≥10 μmol/L) is also known as H-type hypertension (HHT) and proposed as an independent risk factor for stroke and cognitive impairment. Although previous studies have established the relationships among hypertension, Hcy levels, and cognitive impairment, how they affect brain neuroanatomy remains unclear. Thus, we aimed to investigate whether and to what extent hypertension and high Hcy may affect gray matter volume in 52 middle-aged HHT patients and 51 demographically matched normotensive subjects. Voxel-based morphological analysis suggested that HHT patients experienced significant gray matter loss in the default network. The default network atrophy was significantly correlated with Hcy level and global cognitive function. These findings provide, to our knowledge, novel insights into how HHT affects brain gray matter morphology through blood pressure and Hcy.