Anne Langsted

Fasting and Nonfasting Lipid Levels Influence of Normal Food Intake on Lipids, Lipoproteins, Apolipoproteins, and Cardiovascular Risk Prediction

Background— Lipid profiles are usually measured after fasting. We tested the hypotheses that these levels change only minimally in response to normal food intake and that nonfasting levels predict cardiovascular events. Methods and Results— We cross-sectionally studied 33 391 individuals 20 to 95 years of age from the Copenhagen General Population Study. We also studied 9319 individuals 20 to 93 years of age from the Copenhagen City Heart Study, 1166 of whom developed cardiovascular events during 14 years of follow-up. Compared with fasting levels, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, and albumin levels were reduced up to 3 to 5 hours after the last meal; triglycerides levels were increased up to 6 hours after the last meal; and non-HDL cholesterol level, apolipoprotein A1 level, apolipoprotein B level, ratio of total cholesterol to HDL cholesterol, and ratio of apolipoprotein B to apolipoprotein A1 did not change in response to normal food intake. The maximum changes after normal food and fluid intake from fasting levels were −0.2 mmol/L for total cholesterol, −0.2 mmol/L for low-density lipoprotein cholesterol, −0.1 mmol/L for HDL cholesterol, and 0.3 mmol/L for triglycerides. Highest versus lowest tertile of nonfasting total cholesterol, non-HDL cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, triglycerides, ratio of total cholesterol to HDL cholesterol, and ratio of apolipoprotein B/apolipoprotein A1 and lowest versus highest tertile of nonfasting HDL cholesterol and apolipoprotein A1 predicted 1.7- to 2.4-fold increased risk of cardiovascular events. Conclusions— Lipid profiles at most change minimally in response to normal food intake in individuals in the general population. Furthermore, nonfasting lipid profiles predicted increased risk of cardiovascular events.

Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cut-points—a joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine

Abstract Aims To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. Methods and results Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1–6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; −0.2 mmol/L (8 mg/dL) for total cholesterol; −0.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; −0.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/non-fasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, while fasting sampling may be considered when non-fasting triglycerides >5 mmol/L (440 mg/dL). For non-fasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral when triglycerides >10 mmol/L (880 mg/dL) for the risk of pancreatitis, LDL cholesterol >13 mmol/L (500 mg/dL) for homozygous familial hypercholesterolaemia, LDL cholesterol >5 mmol/L (190 mg/dL) for heterozygous familial hypercholesterolaemia, and lipoprotein(a) >150 mg/dL (99th percentile) for very high cardiovascular risk. Conclusion We recommend that non-fasting blood samples be routinely used for the assessment of plasma lipid profiles. Laboratory reports should flag abnormal values on the basis of desirable concentration cut-points. Non-fasting and fasting measurements should be complementary but not mutually exclusive.

Nonfasting Lipids, Lipoproteins, and Apolipoproteins in Individuals with and without Diabetes: 58 434 Individuals from the Copenhagen General Population Study

BACKGROUND Whether lipid profiles should be collected from fasting or nonfasting individuals is controversial, particularly in the diabetic population. We examined the influence of normal food intake on lipid profiles in diabetic and nondiabetic individuals. METHODS We assessed plasma concentrations of lipids, lipoproteins, apolipoproteins, and albumin as a function of time since the last meal in 58 434 individuals (participation rate 45%) from the general population, 2270 of whom had diabetes mellitus. RESULTS Similar patterns in the measured constituents were observed in the diabetic and nondiabetic populations. Triglycerides remained increased for 6-7 h in both populations after the last meal, whereas LDL cholesterol and albumin but not apolipoprotein B were reduced in both populations up to 5 h after normal food intake; after adjustment for hemodilution on the basis of albumin concentrations, the LDL cholesterol reductions were no longer present. Maximum observed mean differences from fasting concentrations in diabetic patients were -0.6 mmol/L, 0 mmol/L, 0.2 mmol/L, and 0.08 g/L (8 mg/dL) for LDL cholesterol, HDL cholesterol, triglycerides, and apolipoprotein B, respectively, and, correspondingly, -0.3 mmol/L, 0 mmol/L, 0.2 mmol/L, and 0.03 g/L (3 mg/dL) in individuals without diabetes. CONCLUSIONS Triglycerides increased up to 0.2 mmol/L after normal food intake in individuals with and without diabetes, whereas the postprandial reductions in LDL cholesterol observed in both populations likely were caused by hemodilution due to fluid intake. No statistically significant differences in postprandial apolipoprotein B concentrations were found. These data may be useful for discussion during revisions of guidelines for lipid measurements in individuals with or without diabetes.

Lipoprotein(a) as a cause of cardiovascular disease: Insights from epidemiology, genetics, and biology

Human epidemiologic and genetic evidence using the Mendelian randomization approach in large-scale studies now strongly supports that elevated lipoprotein (a) [Lp(a)] is a causal risk factor for cardiovascular disease, that is, for myocardial infarction, atherosclerotic stenosis, and aortic valve stenosis. The Mendelian randomization approach used to infer causality is generally not affected by confounding and reverse causation, the major problems of observational epidemiology. This approach is particularly valuable to study causality of Lp(a), as single genetic variants exist that explain 27–28% of all variation in plasma Lp(a). The most important genetic variant likely is the kringle IV type 2 (KIV-2) copy number variant, as the apo(a) product of this variant influences fibrinolysis and thereby thrombosis, as opposed to the Lp(a) particle per se. We speculate that the physiological role of KIV-2 in Lp(a) could be through wound healing during childbirth, infections, and injury, a role that, in addition, could lead to more blood clots promoting stenosis of arteries and the aortic valve, and myocardial infarction. Randomized placebo-controlled trials of Lp(a) reduction in individuals with very high concentrations to reduce cardiovascular disease are awaited. Recent genetic evidence documents elevated Lp(a) as a cause of myocardial infarction, atherosclerotic stenosis, and aortic valve stenosis.

Fasting is not routinely required for determination of a lipid profile: Clinical and Laboratory implications including flagging at desirable concentration cutpoints-A joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine

AIMS To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. METHODS AND RESULTS Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1-6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; -0.2 mmol/L (8 mg/dL) for total cholesterol; -0.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; -0.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/non-fasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, whereas fasting sampling may be considered when non-fasting triglycerides are >5 mmol/L (440 mg/dL). For non-fasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral for the risk of pancreatitis when triglycerides are >10 mmol/L (880 mg/dL), for homozygous familial hypercholesterolemia when LDL cholesterol is >13 mmol/L (500 mg/dL), for heterozygous familial hypercholesterolemia when LDL cholesterol is >5 mmol/L (190 mg/dL), and for very high cardiovascular risk when lipoprotein(a) >150 mg/dL (99th percentile). CONCLUSIONS We recommend that non-fasting blood samples be routinely used for the assessment of plasma lipid profiles. Laboratory reports should flag abnormal values on the basis of desirable concentration cutpoints. Non-fasting and fasting measurements should be complementary but not mutually exclusive.

Nonfasting Mild-to-Moderate Hypertriglyceridemia and Risk of Acute Pancreatitis

Importance Severe hypertriglyceridemia is associated with increased risk of acute pancreatitis. However, the threshold above which triglycerides are associated with acute pancreatitis is unclear. Objective To test the hypothesis that nonfasting mild-to-moderate hypertriglyceridemia (177-885 mg/dL; 2-10 mmol/L) is also associated with acute pancreatitis. Design, Setting, and Participants This prospective cohort study examines individuals from the Copenhagen General Population Study in 2003 to 2015 and the Copenhagen City Heart Study initiated in 1976 to 1978 with follow-up examinations in 1981 to1983, 1991 to 1994, and in 2001 to 2003. Median follow-up was 6.7 years (interquartile range, 4.0-9.4 years); and includes 116 550 individuals with a triglyceride measurement from the Copenhagen General Population Study (n = 98 649) and the Copenhagen City Heart Study (n = 17 901). All individuals were followed until the occurrence of an event, death, emigration, or end of follow-up (November 2014), whichever came first. Exposures Plasma levels of nonfasting triglycerides. Main Outcomes and Measures Hazard ratios (HRs) for acute pancreatitis (n = 434) and myocardial infarction (n = 3942). Results Overall, 116 550 individuals were included in this study (median [interquartile range] age, 57 [47-66] years). Compared with individuals with plasma triglyceride levels less than 89 mg/dL (<1 mmol/L), the multivariable adjusted HRs for acute pancreatitis were 1.6 (95% CI, 1.0-2.6; 4.3 events/10 000 person-years) for individuals with triglyceride levels of 89 mg/dL to 176 mg/dL (1.00 mmol/L-1.99 mmol/L), 2.3 (95% CI, 1.3-4.0; 5.5 events/10 000 person-years) for 177 mg/dL to 265 mg/dL (2.00 mmol/L-2.99 mmol/L), 2.9 (95% CI, 1.4-5.9; 6.3 events/10 000 person-years) for 366 mg/dL to 353 mg/dL (3.00 mmol/L-3.99 mmol/L), 3.9 (95% CI, 1.5-10.0; 7.5 events/10 000 person-years) for 354 mg/dL-442 mg/dL (4.00 mmol/L-4.99 mmol/L), and 8.7 (95% CI, 3.7-20.0; 12 events/10 000 person-years) for individuals with triglyceride levels greater than or equal to 443 mg/dL (≥5.00 mmol/L) (trend, P = 6 × 10-8). Corresponding HRs for myocardial infarction were 1.6 (95% CI, 1.4-1.9; 41 events/10 000 person-years), 2.2 (95% CI, 1.9-2.7; 57 events/10 000 person-years), 3.2 (95% CI, 2.6-4.1; 72 events/10 000 person-years), 2.8 (95% CI, 2.0-3.9; 68 events/10 000 person-years), and 3.4 (95% CI, 2.4-4.7; 78 events/10 000 person-years) (trend, P = 6 × 10-31), respectively. The multivariable adjusted HR for acute pancreatitis was 1.17 (95% CI, 1.10-1.24) per 89 mg/dL (1 mmol/L) higher triglycerides. When stratified by sex, age, education, smoking, hypertension, statin use, study cohort, diabetes, body mass index (calculated as weight in kilograms divided by height in meters squared), alcohol intake, and gallstone disease, these results were similar with no statistical evidence of interaction. Conclusions and Relevance Nonfasting mild-to-moderate hypertriglyceridemia from 177 mg/dL (2 mmol/L) and above is associated with high risk of acute pancreatitis, with HR estimates higher than for myocardial infarction.

Increased Remnant Cholesterol Explains Part of Residual Risk of All-Cause Mortality in 5414 Patients with Ischemic Heart Disease

BACKGROUND Increased concentrations of remnant cholesterol are causally associated with increased risk of ischemic heart disease. We tested the hypothesis that increased remnant cholesterol is a risk factor for all-cause mortality in patients with ischemic heart disease. METHODS We included 5414 Danish patients diagnosed with ischemic heart disease. Patients on statins were not excluded. Calculated remnant cholesterol was nonfasting total cholesterol minus LDL and HDL cholesterol. During 35836 person-years of follow-up, 1319 patients died. RESULTS We examined both calculated and directly measured remnant cholesterol; importantly, however, measured remnant cholesterol made up only 9% of calculated remnant cholesterol at nonfasting triglyceride concentrations <1 mmol/L (89 mg/dL) and only 43% at triglycerides >5 mmol/L (443 mg/dL). Multivariable-adjusted hazard ratios for all-cause mortality compared with patients with calculated remnant cholesterol concentrations in the 0 to 60th percentiles were 1.2 (95% CI, 1.1-1.4) for patients in the 61st to 80th percentiles, 1.3 (1.1-1.5) for the 81st to 90th percentiles, 1.5 (1.1-1.8) for the 91st to 95th percentiles, and 1.6 (1.2-2.0) for patients in the 96th to 100th percentiles (trend, P < 0.001). Corresponding values for measured remnant cholesterol were 1.0 (0.8-1.1), 1.2 (1.0-1.4), 1.1 (0.9-1.5), and 1.3 (1.1-1.7) (trend, P = 0.006), and for measured LDL cholesterol 1.0 (0.9-1.1), 1.0 (0.8-1.2), 1.0 (0.8-1.3), and 1.1 (0.8-1.4) (trend, P = 0.88). Cumulative survival was reduced in patients with calculated remnant cholesterol ≥1 mmol/L (39 mg/dL) vs <1 mmol/L [log-rank, P = 9 × 10(-6); hazard ratio 1.3 (1.2-1.5)], but not in patients with measured LDL cholesterol ≥3 mmol/L (116 mg/dL) vs <3 mmol/L [P = 0.76; hazard ratio 1.0 (0.9-1.1)]. CONCLUSIONS Increased concentrations of both calculated and measured remnant cholesterol were associated with increased all-cause mortality in patients with ischemic heart disease, which was not the case for increased concentrations of measured LDL cholesterol. This suggests that increased concentrations of remnant cholesterol explain part of the residual risk of all-cause mortality in patients with ischemic heart disease.

Lipoprotein(a): Fasting and nonfasting levels, inflammation, and cardiovascular risk

OBJECTIVE There are no recommendations in guidelines on measuring lipoprotein(a) in the fasting or nonfasting state, or on the influence of inflammation. We tested the hypotheses that lipoprotein(a) levels change only minimally in response to normal food intake, and to inflammation. Also, we tested whether normal food intake or inflammation influenced lipoprotein(a)s ability to predict ischemic heart disease. METHODS We studied 34 829 individuals from the Danish general population using the Copenhagen General Population Study and the Copenhagen City Heart Study. RESULTS Lipoprotein(a) levels did not change in response to normal food intake: median fasting levels were 17.3 mg/dL, while median levels at 3-4 h since last meal were 19.4 mg/dL(p = 0.38). Lipoprotein(a) levels increased minimally with increasing levels of C-reactive protein(CRP): median lipoprotein(a) levels at CRP <1 mg/L were 18.0 mg/dL, while median levels at CRP >10 mg/L were 21.1 mg/dL(p < 0.001). Furthermore, highest versus lowest tertile of lipoprotein(a) at <3 h and ≥3 h since last meal was associated with a 1.4(95%CI:1.2-1.6) and 1.4(1.2-1.6) fold increased risk of ischemic heart disease(p = 0.82), and a 1.8(1.5-2.2) and 1.4(1.1-1.7) fold increased risk of myocardial infarction(p = 0.05). The corresponding odds ratios at CRP levels of <2 mg/L and ≥2 mg/L were 1.3(1.2-1.5) and 1.4(1.2-1.6)(p = 0.80) for ischemic heart disease, and 1.5(1.2-1.8) and 1.7(1.4-2.0)(p = 0.38) for myocardial infarction. CONCLUSIONS Lipoprotein(a) levels did not change in response to normal food intake, but were minimally increased at increased levels of CRP. The ability of elevated lipoprotein(a) levels to predict ischemic heart disease and myocardial infarction in the general population was not affected by normal food intake or inflammation.

Elevated Lipoprotein(a) Does Not Cause Low-Grade Inflammation Despite Causal Association With Aortic Valve Stenosis and Myocardial Infarction: A Study of 100 578 Individuals from the General Population

CONTEXT It is unknown whether elevated lipoprotein(a) is causally associated with low-grade inflammation. OBJECTIVE We tested the hypothesis that elevated lipoprotein(a) is observationally and causally associated with low-grade inflammation together with aortic valve stenosis and myocardial infarction. DESIGN AND SETTING Using a multidirectional Mendelian randomization approach, we studied 100,578 individuals from the Danish general population with plasma levels of and/or genotypes known to affect levels of lipoprotein(a) and C-reactive protein (CRP), and using information regarding diagnosis of aortic valve stenosis and of myocardial infarction (MI) from registries. RESULTS Observationally, CRP increased by 29% (95% confidence interval [CI], 23-34) per 50-mg/dL increase in lipoprotein(a). However, two LPA single nucleotide polymorphisms (SNPs) and the kringle IV type 2 (KIV-2) genotype that were associated with 98, 95, and 68 mg/dL higher lipoprotein(a) levels were not causally associated with increased CRP levels. For aortic valve stenosis, a 1-SD increase in lipoprotein(a) levels was associated observationally with a multifactorially adjusted hazard ratio of 1.23 (95% CI, 1.06-1.41), with corresponding causal risk ratios of 1.38 (1.23-1.55) based on LPA SNPs and of 1.21 (1.06-1.40) based on LPA KIV-2 genotype. For myocardial infarction, corresponding values were 1.20 (1.10;1.31) observationally, and 1.18 (1.11;1.26) and 1.31 (1.22;1.42) causally, respectively. Observational hazard ratios for aortic valve stenosis and MI were similar after further adjustment for CRP levels. CONCLUSIONS Elevated levels of lipoprotein(a) were not causally associated with increased low-grade inflammation as measured through CRP despite a causal association with increased risk of aortic valve stenosis and MI.

PCSK9 R46L Loss-of-Function Mutation Reduces Lipoprotein(a), LDL Cholesterol, and Risk of Aortic Valve Stenosis

CONTEXT Novel, low-density lipoprotein (LDL) cholesterol-lowering proprotein convertase subtilisin/kexin type-9 (PCSK9) inhibitors also lower lipoprotein(a) levels, but the effect on aortic valve stenosis and myocardial infarction is unknown. OBJECTIVE We tested the hypothesis that the PCSK9 R46L loss-of-function mutation is associated with lower levels of lipoprotein(a) and with reduced risk of aortic valve stenosis and myocardial infarction. DESIGN We used two prospective cohort studies of the general population and one patient-based cohort. SETTING Cohort studies selected at random individuals of Danish descent. PARTICIPANTS We studied 103 083 individuals from the Copenhagen General Population Study, the Copenhagen City Heart Study, and the Copenhagen Ischemic Heart Disease Study. MAIN OUTCOME MEASURES Lipoprotein(a), LDL cholesterol, and PCSK9 R46L genotype and diagnoses of aortic valve stenosis and myocardial infarction from national registries; lipoprotein(a) was measured from 49,617 individuals. RESULTS Median (interquartile range) lipoprotein(a) levels were 10 (5-30) mg/dl for PCSK9 R46L noncarriers, 9 (4-32) mg/dl for heterozygotes, and 8 (4-42) mg/dl for homozygotes (trend P = .02). The corresponding values for LDL cholesterol levels were 124 (101-147) mg/dl, 104 (85-132) mg/dl, and 97 (85-128) mg/dl, respectively (trend P = 2 × 10(-52)). PCSK9 R46L carriers vs noncarriers had an age- and sex-adjusted odds ratio of 0.64 (95% confidence interval, 0.44-0.95) for aortic valve stenosis, 0.77 (0.65-0.92) for myocardial infarction, and 0.76 (0.64-0.89) for aortic valve stenosis or myocardial infarction. CONCLUSIONS PCSK9 R46L carriers have lower levels of lipoprotein(a) and LDL cholesterol as well as reduced risk of aortic valve stenosis and myocardial infarction. This indirectly suggests that PCSK9 inhibitors may have a role in patients with aortic valve stenosis.