Marine n-3 fatty acids and cognitive change among older adults in the VITAL randomized trial

Apolipoprotein E and Its Association With Cognitive Change and Modification of Treatment Effects of Vitamin D3 and Omega-3s on Cognitive Change: Results From the In-Clinic Subset of a Randomized Clinical Trial

BACKGROUND

Apolipoprotein E (APOE)-ε4 allele is associated with cognitive decline; however, its potential to modify effects of vitamin D3 and omega-3s supplementation on later-life cognition is unclear. Our objectives were to estimate among the in-clinic subset of a randomized trial: (1) associations between APOE-ε4 and global and domain-specific cognitive change, with exploration of potential sex and race differences; and (2) modification by APOE-ε4 of effects of vitamin D3 and omega-3s supplementation on cognitive change.

METHODS

From an ancillary study of depression prevention within a completed 2 × 2 factorial trial testing vitamin D3 (2 000 IU per day), omega-3s (1 g per day), and/or placebos, we included 743 older adults with baseline in-person neuropsychiatric assessments and APOE genotyping data. The primary outcome was change in global cognition (averaging z-scores of 9 tests) over 2 years. Secondarily, episodic memory and executive function/attention z-scores were examined. General linear models of response profiles with multiplicative interaction terms were constructed; stratified results were reported.

RESULTS

Mean age (standard deviation) was 67.1 (5.3) years; 50.6% were females; 24.9% were APOE-ε4 carriers. Compared to noncarriers, APOE-ε4 carriers had worse 2-year change in global cognition and episodic memory; differences were more apparent among females than males. There was no variation by race in APOE-ε4 associations with cognition. APOE-ε4 did not significantly modify effects of vitamin D3 or omega-3s, compared to placebo, on change in global cognition, episodic memory, or executive function/attention.

CONCLUSIONS

APOE-ε4 was associated with worse cognition but did not modify overall effects of vitamin D3 or omega-3 supplementation on cognition over 2 years.

Fish and Omega-3 Fatty Acids: Sex and Racial Differences in Cardiovascular Outcomes and Cognitive Function

Both cardiovascular disease (CVD) and cognitive decline are common features of aging. One in 5 deaths is cardiac for both men and women in the United States, and an estimated 50 million are currently living with dementia worldwide. In this review, we summarize sex and racial differences in the role of fish and its very long chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in preventing CVD events and cognitive decline. In prospective studies, women with higher nonfried and fatty fish intake and women and Black individuals with higher plasma levels of EPA and DHA had a lower risk of CVD. In randomized controlled trials of EPA and DHA supplementation in primary CVD prevention, Black subjects benefited in a secondary outcome. In secondary CVD prevention, both men and women benefited, and Asians benefited as a prespecified subgroup. Fish and omega-3 polyunsaturated fatty acids are associated with prevention of cognitive decline in prospective studies. In randomized controlled trials of EPA and DHA supplementation, women have cognitive benefit. DHA seems more beneficial than EPA, and supplementation is more beneficial when started before cognitive decline. Although studies in women and racial groups are limited, life-long intake of nonfried and fatty fish lowers the risk of CVD and cognitive decline, and randomized controlled trials also show the benefit of EPA and DHA supplementation. These findings should be factored into recommendations for future research and clinical recommendations as dietary modalities could be cost-effective for disease prevention.

Marine omega-3 fatty acid supplementation and prevention of cardiovascular disease: update on the randomized trial evidence

To date, the VITamin D and OmegA-3 TriaL (VITAL) is the only large-scale randomized trial of marine omega-3 fatty acid (n-3 FA) supplementation for cardiovascular disease (CVD) prevention in a general population unselected for elevated cardiovascular risk. We review the findings of VITAL, as well as results from recent secondary prevention trials and updated meta-analyses of n-3 FA trials in the primary and secondary prevention of CVD. In VITAL, a nationwide sample of 25 871 US adults aged 50 and older, including 5106 African Americans, were randomized in a 2 × 2 factorial design to n-3 FAs (1 g/day; 1.2:1 ratio of eicosapentaenoic to docosahexaenoic acid) and vitamin D3 (2000 IU/day) for a median of 5.3 years. Compared with an olive oil placebo, the n-3 FA intervention did not significantly reduce the primary endpoint of major CVD events [composite of myocardial infarction (MI), stroke, and CVD mortality; hazard ratio (HR) = 0.92 (95% confidence interval 0.80-1.06)] but did significantly reduce total MI [HR = 0.72 (0.59-0.90)], percutaneous coronary intervention [HR = 0.78 (0.63-0.95)], fatal MI [HR = 0.50 (0.26-0.97)], and recurrent (but not first) hospitalization for heart failure [HR = 0.86 (0.74-0.998)]. The intervention neither decreased nor increased risk of atrial fibrillation. African Americans derived the greatest treatment benefit for MI and for recurrent hospitalization for heart failure (P interaction < 0.05 for both outcomes). Meta-analyses that include VITAL and high-risk or secondary prevention n-3 FA trials show coronary, but generally not stroke, risk reduction. More research is needed to determine which individuals may be most likely to derive net benefit. (VITAL clinicaltrials.gov identifier: NCT01169259).

Red Blood Cell DHA Is Inversely Associated with Risk of Incident Alzheimer's Disease and All-Cause Dementia: Framingham Offspring Study

Docosahexaenoic acid (DHA) might help prevent Alzheimer's disease (AD). Red blood cell (RBC) status of DHA is an objective measure of long-term dietary DHA intake. In this prospective observational study conducted within the Framingham Offspring Cohort (1490 dementia-free participants aged ≥65 years old), we examined the association of RBC DHA with incident AD, testing for an interaction with APOE-ε4 carriership. During the follow-up (median, 7.2 years), 131 cases of AD were documented. In fully adjusted models, risk for incident AD in the highest RBC DHA quintile (Q5) was 49% lower compared with the lowest quintile (Q1) (Hazard ratio [HR]: 0.51, 95% confidence interval [CI]: 0.27, 0.96). An increase in RBC DHA from Q1 to Q5 was predicted to provide an estimated 4.7 additional years of life free of AD. We observed an interaction DHA × APOE-ε4 carriership for AD. Borderline statistical significance for a lower risk of AD was observed per standard deviation increase in RBC DHA (HR: 0.71, 95% CI: 0.51, 1.00, p = 0.053) in APOE-ε4 carriers, but not in non-carriers (HR: 0.85, 95% CI: 0.65, 1.11, p = 0.240). These findings add to the increasing body of literature suggesting a robust association worth exploring dietary DHA as one strategy to prevent or delay AD.