Homocysteine and cognitive performance: modification by the ApoE genotype

Area of Science:

• Neuroscience
• Genetics
• Biochemistry

Background:

• Elevated plasma homocysteine levels are linked to cognitive decline.
• The apolipoprotein E (ApoE) genotype, particularly the epsilon4 allele, is a known risk factor for cognitive impairment and Alzheimer's disease.

Purpose of the Study:

• To investigate whether the apolipoprotein E (ApoE)-epsilon4 allele influences the association between plasma homocysteine concentrations and cognitive performance.
• To determine if the magnitude of the association between homocysteine and cognition differs between ApoE-epsilon4 carriers and non-carriers.

Main Methods:

• Cross-sectional study of 911 dementia- and stroke-free adults (aged 26-98).
• Subjects stratified into ApoE-epsilon4 carriers (n=244) and non-carriers (n=667).
• Multiple regression analyses used to assess the relationship between plasma homocysteine and cognitive performance, with adjustments for various covariates.

Main Results:

• Plasma homocysteine was inversely related to cognitive performance in both ApoE cohorts.
• The magnitude of this inverse association was significantly greater in ApoE-epsilon4 carriers compared to non-carriers.
• After adjusting for cardiovascular risk factors, the stronger association in ApoE-epsilon4 carriers persisted, while the association in non-carriers became non-significant.

Conclusions:

• The apolipoprotein E (ApoE)-epsilon4 allele significantly modifies the relationship between plasma homocysteine concentrations and cognitive performance.
• ApoE-epsilon4 carriers exhibit a more pronounced cognitive deficit associated with elevated homocysteine levels.
• These findings highlight a potential gene-environment interaction influencing cognitive health.