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Objectives: Elevated total plasma homocysteine is a risk factor for Alzheimer's disease (AD) and there is some evidence that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can modulate the effects of homocysteine-lowering B vitamins on AD related pathologies. Hence we investigated the relationship between total plasma homocysteine and cortical β-amyloid (Aβ) in older adults at risk of dementia. The role of erythrocyte membrane n-3 PUFAs (omega 3 index) on this relationship was also explored., Design: This is a cross-sectional study using data from the Multidomain Alzheimer Preventive Trial (MAPT); a randomised controlled trial., Setting: French community dwellers aged 70 or over reporting subjective memory complaints, but free from a diagnosis of clinical dementia., Participants: Individuals were from the MAPT trial (n = 177) with data on total plasma homocysteine at baseline and cortical Aβ load., Measurements: Cortical-to-cerebellar standard uptake value ratios were assessed using [18F] florbetapir positron emission tomography (PET). Total baseline plasma homocysteine was measured using an enzymatic cycling assay. Baseline omega 3 index was measured using gas chromatography. Cross-sectional associations were explored using adjusted multiple linear regression models., Results: We found that total baseline plasma homocysteine was not significantly associated with cortical Aβ as demonstrated using multiple linear regression models adjusted for age, sex, education, cognitive status, time interval between baseline and PET-scan, omega-3 index, MAPT group allocation and Apolipoprotein E ε4 status (B-coefficient -0.001, 95 % CI: -0.008,0.006, p = 0.838). Exploratory analysis showed that homocysteine was however significantly associated with cortical Aβ in subjects with low baseline omega-3 index (< 4.72 %) after adjustment for Apolipoprotein E ε4 status (B-coefficient 0.041, 95 % CI: 0.017,0.066, p = 0.005, n = 10), but not in subjects with a high baseline omega-3 index (B-coefficient -0.010, 95 % CI: -0.023,0.003, p = 0.132, n = 66)., Conclusions: The role of n-3 PUFAs on the relationship between homocysteine and cerebral Aβ warrants further investigation., Competing Interests: The authors declare that they have no conflict of interest.

Objectives: To elucidate the mechanism through which vitamin D is associated with decreased falls., Design: This was a convenience sample from a larger observational study examining correlations between vitamin D and 1) falls, 2) motor function, and 3) cognition (n=159)., Setting: Falls data were collected via weekly on-line surveys completed in the participants' homes. Yearly evaluations of motor and cognitive function were conducted in an out-patient setting of a large tertiary medical center., Participants: Participants from the Intelligent Systems for Assessment of Aging Changes Study (ISAAC), a community-based cohort study of independently living older adults over age 70, who had vitamin D concentration within 6 months of clinical evaluations were included in the analysis., Results: Participants mean age was 85 years and 74% were women. Fallers (n=37) had significantly lower vitamin D concentration (32.9ng/ml) compared to non-fallers (39.2ng/ml) (p<0.01). The relationship between vitamin D and falls remained significant after adjusting for age, health status (via CIRS), and supplement use (p=0.004). Vitamin D concentration were significantly associated with cognitive impairment (Clinical Dementia Rating = 0.5) (p=0.02) and MMSE (p<0.01) after adjusting for age, gender, and education. Vitamin D concentrations did not correlate with any motor measures., Conclusion: Vitamin D concentrations correlated with cognition and falls, but not with motor measures. Further research is needed to demonstrate a causal relationship between vitamin D and cognitive function and determine if cognition plays a role in falls reduction.

Objectives: Elevated total plasma homocysteine is a risk factor for Alzheimer's disease (AD) and there is some evidence that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can modulate the effects of homocysteine-lowering B vitamins on AD related pathologies. Hence we investigated the relationship between total plasma homocysteine and cortical β-amyloid (Aβ) in older adults at risk of dementia. The role of erythrocyte membrane n-3 PUFAs (omega 3 index) on this relationship was also explored. Design: This is a cross-sectional study using data from the Multidomain Alzheimer Preventive Trial (MAPT); a randomised controlled trial. Setting: French community dwellers aged 70 or over reporting subjective memory complaints, but free from a diagnosis of clinical dementia. Participants: Individuals were from the MAPT trial (n = 177) with data on total plasma homocysteine at baseline and cortical Aβ load. Measurements: Cortical-to-cerebellar standard uptake value ratios were assessed using [18F] florbetapir positron emission tomography (PET). Total baseline plasma homocysteine was measured using an enzymatic cycling assay. Baseline omega 3 index was measured using gas chromatography. Cross-sectional associations were explored using adjusted multiple linear regression models. Results: We found that total baseline plasma homocysteine was not significantly associated with cortical Aβ as demonstrated using multiple linear regression models adjusted for age, sex, education, cognitive status, time interval between baseline and PET-scan, omega-3 index, MAPT group allocation and Apolipoprotein E ε4 status (B-coefficient -0.001, 95 % CI: -0.008,0.006, p = 0.838). Exploratory analysis showed that homocysteine was however significantly associated with cortical Aβ in subjects with low baseline omega-3 index (< 4.72 %) after adjustment for Apolipoprotein E ε4 status (B-coefficient 0.041, 95 % CI: 0.017,0.066, p = 0.005, n = 10), but not in subjects with a high baseline omega-3 index (B-coefficient -0.010, 95 % CI: -0.023,0.003, p = 0.132, n = 66). Conclusions: The role of n-3 PUFAs on the relationship between homocysteine and cerebral Aβ warrants further investigation. [ABSTRACT FROM AUTHOR]