Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease: A Novel Analysis of the VITAL Trial Using Win Ratio and Hierarchical Composite Outcomes.

This study aimed to investigate whether n-3 fatty acid supplementation reduced cardiovascular disease (CVD) events in a novel analysis using hierarchical composite CVD outcomes based on win ratio in the VITamin D and OmegA-3 TriaL (VITAL). This was a secondary analysis of our VITAL randomized trial, which assessed the effects of marine n-3 fatty acids (1 g/day) and vitamin D3 on incident CVD and cancer among healthy older adults (n = 25,871). The primary analysis estimated win ratios of a composite of major CVD outcomes prioritized as fatal coronary heart disease, other fatal CVD including stroke, non-fatal myocardial infarction (MI), and non-fatal stroke, comparing n-3 fatty acids to placebo. The primary result was a nonsignificant benefit of this supplementation for the prioritized primary CVD outcome (reciprocal win ratio [95% confidence interval]: 0.90 [0.78-1.04]), similar to the 0.92 (0.80-1.06) hazard ratio in our original time-to-first event analysis without outcome prioritization. Its benefits came from reducing MI (0.71 [0.57-0.88]) but not stroke (1.01 [0.80 to 1.28]) components. For the primary CVD outcome, participants with low fish consumption at baseline benefited (0.79 [0.65-0.96]) more than those with high consumption (1.05 [0.85-1.30]). These results are consistent with, but slightly stronger than, those without outcome prioritization.

Genetic determinants of C-reactive protein.

C-reactive protein (CRP) levels are a complex phenotype with both genetic and environmental determinants. Recent work has highlighted the impact of genetic variants within the CRP gene as well as other candidate genes, often chosen for their role in the inflammatory pathway, on CRP levels. Emerging work shows the association of such genetic variants in CRP not only to CRP levels, but also to variation of CRP levels in the acute phase response. Work on the relation of genetic variants within CRP to cardiovascular disease has had varied results. Whole-genome association studies to investigate the genetic determinants of CRP levels in an unbiased manner are ongoing.

Lack of association between genetic variation in 9 innate immunity genes and baseline CRP levels.

It is well-known that baseline levels of C-reactive protein (CRP) are an independent cardiovascular risk factor. We hypothesized that genetic variation with significant influence on CRP levels might be found in genes of the innate immunity system. We performed a candidate gene association study examining common single nucleotide polymorphisms in 9 innate immunity genes (CARD15, IRAK1, IRAK4, LBP, LY86, MEFV, TLR2, TLR4 and NFKB1) in relation to CRP levels. Seven hundred and seventeen subjects from the Women's Health Study population were studied: 359 and 358 samples with extremely low (<0.2 mg/liter) and high (>5 mg/liter) CRP levels, respectively. SNPs were identified from publicly available resequencing data, using a minor allele frequency threshold of >5% and a linkage disequilibrium (LD)-based strategy (r(2) > 0.8) to select 63 LD-independent markers. One non-synonymous SNP in TLR4 and two non-synonymous SNPs in CARD15, previously associated with atherosclerosis and Crohn's disease, respectively, were also studied. Univariate, haplotype and gene-gene interaction analyses all indicated no significant association with CRP levels. Although this work excludes a significant association of common SNPs in these nine genes with CRP levels, it is possible that rarer alleles in these genes, or variation in other innate immunity genes, could be associated with variation in CRP.

Lack of Association Between Genetic Variation in 9 Innate Immunity Genes and Baseline CRP Levels.

It is well-known that baseline levels of C-reactive protein (CRP) are an independent cardiovascular risk factor. We hypothesized that genetic variation with significant influence on CRP levels might be found in genes of the innate immunity system. We performed a candidate gene association study examining common single nucleotide polymorphisms in 9 innate immunity genes (CARD15, IRAK1, IRAK4, LBP, LY86, MEFV, TLR2, TLR4 and NFKB1) in relation to CRP levels. Seven hundred and seventeen subjects from the Women's Health Study population were studied: 359 and 358 samples with extremely low (<0.2 mg/liter) and high (>5 mg/liter) CRP levels, respectively. SNPs were identified from publicly available resequencing data, using a minor allele frequency threshold of >5% and a linkage disequilibrium (LD)-based strategy (r2 > 0.8) to select 63 LD-independent markers. One non-synonymous SNP in TLR4 and two non-synonymous SNPs in CARD15, previously associated with atherosclerosis and Crohn's disease, respectively, were also studied. Univariate, haplotype and gene-gene interaction analyses all indicated no significant association with CRP levels. Although this work excludes a significant association of common SNPs in these nine genes with CRP levels, it is possible that rarer alleles in these genes, or variation in other innate immunity genes, could be associated with variation in CRP.