Person:

Rimm, Eric

Background: High-density lipoproteins (HDL) are structurally and metabolically heterogeneous and subclasses with differential effects on coronary heart disease (CHD) might exist. Apolipoprotein (apo) C-III, a small proinflammatory protein that resides on the surface of lipoproteins, enhances the atherogenicity of VLDL and LDL particles, but little is known about the role apoC-III on HDL. We investigated whether the presence or absence of apoC-III differentiates HDL into subtypes with nonprotective or protective associations with risk of future CHD. Methods and Results: High-density lipoprotein cholesterol (HDL-C) levels were measured in plasma separated according to apoC-III (by immunoaffinity chromatography) in two prospective case-control studies nested within the Nurses’ Health and the Health Professionals Follow-Up Studies. Baseline was in 1990 and 1994, and 634 incident CHD cases were documented through 10 to 14 years of follow-up. The relative risk of CHD per each standard deviation of total HDL-C was 0.78 (95% confidence intervals, 0.63–0.96). The HDL-C subtypes were differentially associated with risk of CHD, HDL-C without apoC-III inversely and HDL-C with apoC-III directly (P=0.02 for a difference between the HDL types). The relative risk per standard deviation of HDL-C without apoC-III was 0.66 (0.53 to 0.93) and 1.18 (1.03 to 1.34) for HDL-C with apoC-III. HDL-C with apoC-III comprised ∼13% of the total HDL-C. Adjustment for triglycerides and apoB attenuated the risks; however, the two HDL-C subgroups remained differentially associated with risk of CHD (P=0.05). Conclusion: Separating HDL-C according to apoC-III identified two types of HDL with opposing associations with risk of CHD. The proatherogenic effects of apoC-III, as a component of VLDL and LDL, may extend to HDL. (J Am Heart Assoc. 2012;1:jah3-e000232 doi: 10.1161/JAHA.111.000232.)

Background: Few studies have examined the relationship of α‐linolenic acid (ALA 18:3n‐3), an intermediate‐chain essential n‐3 polyunsaturated fatty acid derived from plants and vegetable oils, with incident atrial fibrillation (AF). Methods and Results: The study population included participants from the Cardiovascular Health Study, a community‐based longitudinal cohort of adults aged 65 or older, free of prevalent coronary heart disease and atrial fibrillation. We assessed the associations of plasma phospholipid and dietary ALA with incident AF using Cox regression. The biomarker analysis comprised a total of 2899 participants, and the dietary analysis comprised 4337 participants. We found no association of plasma phospholipid ALA and incident AF. Comparing each of the second, third, and fourth quartiles to the lowest quartile, the hazard ratios for AF were 1.11 (95% CI, 0.90 to 1.37), 1.09 (95% CI, 0.88 to 1.35), and 0.92 (95% CI, 0.74 to 1.15), after adjustment for age, sex, race, clinic, education, smoking, alcohol, body mass index, waist circumference, diabetes, heart failure, stroke, treated hypertension, and physical activity (P trend=0.48). When dietary ALA was considered the exposure of interest, results were similar. Conclusions: Results from this prospective cohort study of older adults indicate no association of plasma phospholipid or dietary ALA and incident AF.

Background: Low‐density lipoprotein (LDL) with apolipoprotein C‐III (apoC‐III) is the lipoprotein species that most strongly predicts initial and recurring coronary heart disease (CHD) events in several cohorts. Thus, a large portion of the CHD risk conferred by LDL may be attributable to LDL that contains apoC‐III. Very‐low‐density lipoprotein (VLDL) and LDL with apoC‐III have varying amounts of apoE. We hypothesized that a high content of apoE lessens the adverse influence of apoC‐III on the risk of CHD because it promotes the clearance of VLDL and LDL from plasma. Methods and Results: We studied 2 independent cohorts, the Nurses' Health Study, composed of women, and the Health Professionals Follow‐up Study, composed of men. These cohorts contributed to this study 322 women and 418 men initially free of CVD who developed a fatal or nonfatal myocardial infarction during 10 to 14 years of follow‐up and matched controls who remained free of CHD. The apoE content of LDL with apoC‐III was inversely associated with CHD after multivariable adjustment (relative risk for top versus bottom quintile 0.53, 95% CI 0.35 to 0.80). The apoE content of VLDL with apoC‐III had a similar inverse association with CHD. The highest risks were associated with a high apoB concentration and a low apoE content of LDL with apoC‐III or of VLDL+LDL with apoC‐III. The observed associations were in both male and female cohorts and independent of traditional CHD risk factors and of C‐reactive protein. Conclusions: An increased apoE content in VLDL and LDL with apoC‐III was associated with a lower risk of CHD. Strategies to enrich VLDL and LDL in apoE are worth exploring for the prevention of CHD.

Background: Not much is known about the relations of circulating saturated fatty acids (SFAs), which are influenced by both metabolic and dietary determinants, with total and cause-specific mortality. Objective: We examined the associations of plasma phospholipid SFAs with total and cause-specific mortality among 3941 older adults from the Cardiovascular Health Study, a population-based prospective study of adults aged ≥65 y who were followed from 1992 through 2011. Methods: The relations of total and cause-specific mortality with plasma phospholipid palmitic acid (16:0), stearic acid (18:0), arachidic acid (20:0), behenic acid (22:0), and lignoceric acid (24:0) were assessed using Cox proportional hazards models. Results: During 45,450 person-years of follow-up, 3134 deaths occurred. Higher concentrations of the plasma phospholipid SFAs 18:0, 22:0, and 24:0 were associated with a lower risk of total mortality [multivariable-adjusted HRs (95% CIs)] for the top compared with the bottom quintile: 0.85 (0.75, 0.95) for 18:0; 0.85 (0.75, 0.95) for 22:0; and 0.80 (0.71, 0.90) for 24:0. In contrast, plasma 16:0 concentrations in the highest quintile were associated with a higher risk of total mortality compared with concentrations in the lowest quintile [1.25 (1.11, 1.41)]. We also found no association of plasma phospholipid 20:0 with total mortality. Conclusions: These findings suggest that the associations of plasma phospholipid SFAs with the risk of death differ according to SFA chain length and support future studies to better characterize the determinants of circulating SFAs and to explore the mechanisms underlying these relations.

BACKGROUND: Low-density lipoprotein (LDL) that contains apolipoprotein (apo) C-III makes up only 10% to 20% of plasma LDL but has a markedly altered metabolism and proatherogenic effects on vascular cells. METHODS AND RESULTS: We examined the association between plasma LDL with apoC-III and coronary heart disease in 320 women and 419 men initially free of cardiovascular disease who developed a fatal or nonfatal myocardial infarction during 10 to 14 years of follow-up and matched controls who remained free of coronary heart disease. Concentrations of LDL with apoC-III (measured as apoB in this fraction) were associated with risk of coronary heart disease in multivariable analysis that included the ratio of total cholesterol to high-density lipoprotein cholesterol, LDL cholesterol, apoB, triglycerides, or high-density lipoprotein cholesterol and other risk factors. In all models, the relative risks for the top versus bottom quintile of LDL with apoC-III were greater than those for LDL without apoC-III. When included in the same multivariable-adjusted model, the risk associated with LDL with apoC-III (relative risk for top versus bottom quintile, 2.38; 95% confidence interval, 1.54-3.68; P for trend <0.001) was significantly greater than that associated with LDL without apoC-III (relative risk for top versus bottom quintile, 1.25; 95% confidence interval, 0.76-2.05; P for trend=0.97; P for interaction <0.001). This divergence in association with coronary heart disease persisted even after adjustment for plasma triglycerides. CONCLUSIONS: The risk of coronary heart disease contributed by LDL appeared to result to a large extent from LDL that contains apoC-III.

BACKGROUND: Experimental studies suggest that long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs) may reduce the risk of atrial fibrillation (AF). Prior studies evaluating fish or n-3 PUFA consumption from dietary questionnaires and incident AF have been conflicting. Circulating levels of n-3 PUFAs provide an objective measurement of exposure. METHODS AND RESULTS: Among 3326 US men and women ≥65 years of age and free of AF or heart failure at baseline, plasma phospholipid levels of eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid were measured at baseline by use of standardized methods. Incident AF (789 cases) was identified prospectively from hospital discharge records and study visit ECGs during 31 169 person-years of follow-up (1992-2006). In multivariable Cox models adjusted for other risk factors, the relative risk in the top versus lowest quartile of total n-3 PUFAs (eicosapentaenoic acid+docosapentaenoic acid+docosahexaenoic acid) levels was 0.71 (95% confidence interval, 0.57-0.89; P for trend=0.004) and of DHA levels was 0.77 (95% confidence interval, 0.62-0.96; P for trend=0.01). Eicosapentaenoic acid and docosapentaenoic acid levels were not significantly associated with incident AF. Evaluated nonparametrically, both total n-3 PUFAs and docosahexaenoic acid showed graded and linear inverse associations with incidence of AF. Adjustment for intervening events such as heart failure or myocardial infarction during follow-up did not appreciably alter results. CONCLUSIONS: In older adults, higher circulating total long-chain n-3 PUFA and docosahexaenoic acid levels were associated with lower risk of incident AF. These results highlight the need to evaluate whether increased dietary intake of these fatty acids could be effective for the primary prevention of AF.

BACKGROUND: Long-chain ω-3 polyunsaturated fatty acids (ω3-PUFAs), including eicosapentaenoic acid (EPA) (20:5ω-3), docosapentaenoic acid (DPA) (22:5ω-3), and docosahexaenoic acid (DHA) (22:6ω-3), have been shown to reduce cardiovascular risk, but effects on cause-specific and total mortality and potential dose-responses remain controversial. Most observational studies have assessed self-reported dietary intake and most randomized trials have tested effects of adding supplements to dietary intake and evaluated secondary prevention, thus limiting inference for dietary ω3-PUFAs or primary prevention. OBJECTIVE: To investigate associations of plasma phospholipid EPA, DPA, DHA, and total ω3-PUFA levels with total and cause-specific mortality among healthy older adults not receiving supplements. DESIGN: Prospective cohort study. SETTING: 4 U.S. communities. PARTICIPANTS: 2692 U.S. adults aged 74 years (±5 years) without prevalent coronary heart disease (CHD), stroke, or heart failure at baseline. MEASUREMENTS: Phospholipid fatty acid levels and cardiovascular risk factors were measured in 1992. Relationships with total and cause-specific mortality and incident fatal or nonfatal CHD and stroke through 2008 were assessed. RESULTS: During 30 829 person-years, 1625 deaths (including 570 cardiovascular deaths), 359 fatal and 371 nonfatal CHD events, and 130 fatal and 276 nonfatal strokes occurred. After adjustment, higher plasma levels of ω3-PUFA biomarkers were associated with lower total mortality, with extreme-quintile hazard ratios of 0.83 for EPA (95% CI, 0.71 to 0.98; P for trend = 0.005), 0.77 for DPA (CI, 0.66 to 0.90; P for trend = 0.008), 0.80 for DHA (CI, 0.67 to 0.94; P for trend = 0.006), and 0.73 for total ω3-PUFAs (CI, 0.61 to 0.86; P for trend < 0.001). Lower risk was largely attributable to fewer cardiovascular than noncardiovascular deaths. Individuals in the highest quintile of phospholipid ω3-PUFA level lived an average of 2.22 more years (CI, 0.75 to 3.13 years) after age 65 years than did those in the lowest quintile. LIMITATION: Temporal changes in fatty acid levels and misclassification of causes of death may have resulted in underestimated associations, and unmeasured or imperfectly measured covariates may have caused residual confounding. CONCLUSION: Higher circulating individual and total ω3-PUFA levels are associated with lower total mortality, especially CHD death, in older adults. PRIMARY FUNDING SOURCE: National Institutes of Health.

BACKGROUND: Few previous studies have evaluated associations between long-chain ω-3 fatty acids and incidence of congestive heart failure (CHF), and those that have are typically based on diet questionnaires and yield conflicting results. Circulating fatty acid concentrations provide objective biomarkers of exposure. OBJECTIVE: To determine whether plasma phospholipid concentrations of long-chain ω-3 fatty acids, including eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), were associated with incident CHF. DESIGN: Prospective cohort study. SETTING: 4 U.S. communities. PATIENTS: 2735 U.S. adults without prevalent heart disease who were enrolled in the Cardiovascular Health Study from 1992 to 2006. MEASUREMENTS: Plasma phospholipid fatty acid concentrations and other cardiovascular risk factors were measured in 1992 by using standardized methods. Relationships with incident CHF (555 cases during 26 490 person-years, adjudicated by using medical records) were assessed by using Cox proportional hazards models. RESULTS: After multivariate adjustment, plasma phospholipid EPA concentration was inversely associated with incident CHF; risk was approximately 50% lower in the highest versus the lowest quartile (hazard ratio [HR], 0.52 [95% CI, 0.38 to 0.72]; P for trend = 0.001). In similar analyses, trends toward lower risk were seen for DPA (HR, 0.76 [CI, 0.56 to 1.04]; P for trend = 0.057) and total long-chain ω-3 fatty acids (HR, 0.70 [CI, 0.49 to 0.99]; P for trend = 0.062) but not for DHA (HR, 0.84 [CI, 0.58 to 1.21]; P for trend = 0.38). In analyses censored to the middle of follow-up (7 years) to minimize exposure misclassification over time, multivariate-adjusted HRs were 0.48 for EPA (CI, 0.32 to 0.71; P for trend = 0.005), 0.61 for DPA (CI, 0.39 to 0.95; P for trend = 0.033), 0.64 for DHA (CI, 0.40 to 1.04; P for trend = 0.057), and 0.51 for total ω-3 fatty acids (CI, 0.32 to 0.80; P for trend = 0.003). LIMITATIONS: Temporal changes in fatty acid concentrations over time may have caused underestimation of associations. Unmeasured or imperfectly measured covariates may have caused residual confounding. CONCLUSION: Circulating individual and total ω-3 fatty acid concentrations are associated with lower incidence of CHF in older adults. PRIMARY FUNDING SOURCE: National Institutes of Health.