Circulating prekallikrein levels are correlated with lipid levels in the chinese population: a cross-sectional study.

BACKGROUND: Recent evidence has revealed that circulating coagulation factor prekallikrein (PK), an important part of the kallikrein-kinin system, regulates cholesterol metabolism, but the association between serum PK and lipid levels is unclear. METHODS: This cross-sectional study included 256 subjects (aged from 1 month to 90 years) who underwent physical examinations at the First People's Hospital of Huaihua, China. After overnight fasting, serum was collected for PK and lipid testing. Spearman correlation analysis and multivariable logistic regression analysis were used to analyze the association of PK level with lipid levels and the likelihood risk of hyperlipidemia. The possible threshold value of PK was calculated according to the receiver operating characteristic (ROC) curve. RESULTS: The median serum PK level was 280.9 µg/mL (IQR 168.0, 377.0), and this level changed with age but not sex. The serum PK level was positively correlated with the serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels. A nonlinear relationship was observed between serum PK and high-density lipoprotein cholesterol (HDL-C) levels. The serum PK level was positively correlated with HDL-C when its level was lower than 240 µg/mL and negatively correlated with HDL-C when its level was higher than 240 µg/mL. The regression analysis demonstrated that an elevated serum PK level was significantly associated with the likelihood risk of hypercholesterolemia and hypertriglyceridemia. The ROC curve showed that the possible threshold values of serum PK for hypercholesterolemia and hypertriglyceridemia occurrences were 344.9 µg/mL and 305.7 µg/mL, respectively. CONCLUSIONS: Elevated serum PK levels were significantly associated with the likelihood of hypercholesterolemia and hypertriglyceridemia, and the possible threshold values of PK levels were 344.9 µg/mL and 305.70 µg/mL, respectively, suggesting that higher PK levels may be a risk factor for cardiovascular diseases.

Utilization of Small Dense Low-Density Lipoprotein Cholesterol Testing in Korean Patients Visiting Local Clinics and Hospitals.

Small dense low-density cholesterol (sdLDL) has been the focus of studies due to its potential as an independent risk factor for atherosclerotic cardiovascular diseases. We aimed to investigate the utilization of sdLDL testing by LDL particle size analysis and the prevalence of an sdLDL predominant phenotype in Korean adult patients by visiting local clinics and hospitals. Among 9222 Korean adults (4577 men and 4645 women) with a median age of 62.8 years (interquartile range, IQR 54.5 to 71.8 years) undergoing lipid profile testing using LDL particle size analysis, the prevalence of hypercholesterolemia (total cholesterol ≥ 240 mg/dL), hypo HDL cholesterolemia (<40 mg/dL), and hyper LDL cholesterolemia (≥160 mg/dL) was 7.8%, 12.9%, and 0.5%, respectively. The overall prevalence of the sdLDL predominant non-A phenotype of LDL was 46.8% of study subjects. Approximately 32.8% of the study subjects possessed lipid test results that did not exhibit increased risk except for sdLDL (only the sdLDL predominant non-A phenotype as a risk factor). In Korea, sdLDL testing was utilized in patients whose LDL cholesterol level was not increased. Future studies to clarify the clinical significance of this test in the Korean population are needed.

Serum MIG6 concentration is increased by cholesterol-lowering treatment in patients with type 2 diabetes mellitus and hypercholesterolemia.

OBJECTIVE: The protein encoded by mitogen-inducible gene 6 (MIG6) plays an essential role in the regulation of cholesterol homeostasis and bile acid synthesis in mice. However, the physiological functions of MIG6 remain poorly understood in humans. Therefore, we aimed to evaluate the relationship between the serum MIG6 concentration and low-density lipoprotein (LDL)-cholesterol in patients undergoing cholesterol-lowering treatment. METHODS: We performed a non-randomized, prospective controlled trial. In total, 63 patients with type 2 diabetes and hypercholesterolemia were treated using either rosuvastatin monotherapy or rosuvastatin/ezetimibe combination therapy for 12 weeks. We then compared their serum lipid and MIG6 concentrations before and after treatment. RESULTS: The serum LDL-cholesterol concentration of the participants significantly decreased and the concentration of MIG6 significantly increased during treatment. In addition, higher pre-treatment serum concentrations of MIG6 were associated with larger reductions in LDL-cholesterol, regardless of the therapeutic agent used. CONCLUSIONS: Serum MIG6 concentration significantly increases alongside the reduction in LDL-cholesterol achieved using cholesterol-lowering therapies in patients with diabetes and hypercholesterolemia. This is the first study to provide evidence that MIG6 may be involved in human cholesterol metabolism.CRIS registration number: KCT0003477. https://cris.nih.go.kr.

Universal Lipid Screening Among 9- to 11-Year-Old Children: Screening Results and Physician Management.

Universal lipid screening (ULS) is recommended for all 9- to 11-year-old children. We investigated ULS outcomes and long-term pediatrician management of children with dyslipidemia using a retrospective chart review of well-child visits between 2014 and 2016. Descriptive statistics summarized demographics, ULS results, and follow-up visits/testing. Pearson χ2 test examined differences between those with and without an abnormal screen. A total of 1039 children aged 9 to 11 years were seen for a well-child visit; only 33.3% (343/1039) completed screening. Of children screened, 18.1% (62/343) had abnormal screen results and were more likely to have an elevated body mass index (P < .001), though 30.1% (19/62) had no risk factors. A total of 10.2% (35/343) had dyslipidemia. A total of 77.1% of children with dyslipidemia received nutrition/exercise counseling and 57.1% received dietitian referrals; only 68.6% had a follow-up visit and 31.4% had repeat lipid testing. Pediatricians would benefit from more practical strategies for universal testing such as point-of-care testing and long-term management to ensure ULS is an effective screening tool.

High remnant cholesterol level is relevant to diabetic retinopathy in type 2 diabetes mellitus.

BACKGROUND: Diabetic retinopathy (DR) is the primary oculopathy causing blindness in diabetic patients. Currently, there is increasing interest in the role of lipids in the development of diabetic retinopathy, but it remains controversial. Remnant cholesterol (RC) is an inexpensive and easily measurable lipid parameter; however, the relationship between RC and DR in type 2 diabetes mellitus (T2DM) has not been elucidated. This research investigates the relevance between RC levels and DR severity while building a risk prediction model about DR. METHODS: In this single-centre retrospective cross-sectional study. Each hospitalised T2DM patient had no oral lipid-lowering drugs in the past three months, and coronary angiography showed epicardial coronary artery stenosis of less than 50% and completed seven-field stereo photographs, fluorescein fundus angiography, and optical coherence tomography detection. The RC value is calculated according to the internationally recognised formula. Binary logistic regression was used to correct confounding factors, and the receiver operating characteristic (ROC) analysis was used to identify risk factors and assess the nomogram's diagnostic efficiency. RESULTS: A total of 456 T2DM patients were included in the study. The RC levels in the DR team was higher [0.74 (0.60-1.12) mmo/l vs 0.54 (0.31-0.83) mmol/l P < 0.001] in the non-DR team. After adjusting for confounding elements, RC levels are still associated with DR risk (OR = 5.623 95%CI: 2.996-10.556 P < 0.001). The ratio of DR in every stage (except mild non-proliferative diabetic retinopathy) and DME in the high RC level team were further increased compared to the low-level team (all P < 0.001). After ROC analysis, the overall risk of DR was predicted by a nomogram constructed for RC, diabetes duration, and the neutrophil-lymphocyte ratio as 0.758 (95%CI 0.714-0.802 P < 0.001). CONCLUSIONS: High RC levels may be a potential risk factor for diabetic retinopathy, and the nomogram does better predict DR. Despite these essential findings, the limitation of this study is that it is single-centred and small sample size analysis.

Association of Maternal Thyroid Function with Gestational Hypercholanemia.

Background: High bile acid concentration is associated with adverse perinatal outcomes (i.e., stillbirth and preterm birth) and experimental studies indicate that thyroid hormone regulates bile acid metabolism, but this has not yet been translated to clinical data in pregnant women. We aim to explore the association of thyroid function with bile acid concentrations and the risk of gestational hypercholanemia. Methods: This study comprised 68,016 singleton pregnancies without known thyroid or hepatobiliary diseases before pregnancy and thyroid medication based on a prospective cohort. Thyroid function and serum total bile acid (TBA) were routinely screened in both early (9-13 weeks) and late pregnancy (32-36 weeks). Hypercholanemia was defined as serum TBA concentration ≥10 µmol/L. Multiple linear regression models and multiple logistic regression models were performed. Results: A higher free thyroxine (fT4) during both early or late pregnancy was associated with a higher TBA concentration and a higher risk of hypercholanemia (all p < 0.01). A higher thyrotropin (TSH) in early pregnancy was associated with a higher TBA concentration in early pregnancy (p = 0.0155), but with a lower TBA concentration during later pregnancy (p < 0.0001), and there was no association of TSH with hypercholanemia. Overt hyperthyroidism in late pregnancy was associated with a 2.12-fold higher risk of hypercholanemia ([confidence interval; CI 1.12-4.03], p = 0.021) and subclinical hyperthyroidism during later pregnancy was associated with a 1.5-fold higher risk of hypercholanemia ([CI 1.14-1.97], p = 0.0034). Sensitivity analyses indicated that a high fT4 throughout pregnancy was associated with a higher risk of hypercholanemia rather than only in early or late pregnancy. Conclusions: A higher fT4 concentration during either early or late pregnancy, but not the TSH concentration, is associated with higher TBA and a higher risk of gestational hypercholanemia. Furthermore, hyperthyroidism during pregnancy could be a novel risk factor for hypercholanemia.

Differential Effects of DPP-4 Inhibitors, Anagliptin and Sitagliptin, on PCSK9 Levels in Patients with Type 2 Diabetes Mellitus who are Receiving Statin Therapy.

AIM: Proprotein convertase subtilisin/kexin type 9 (PCSK9) degrades the low-density lipoprotein (LDL) receptor, leading to hypercholesterolemia and cardiovascular risk. Treatment with a statin leads to a compensatory increase in circulating PCSK9 level. Anagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, was shown to decrease LDL cholesterol (LDL-C) levels to a greater extent than that by sitagliptin, another DPP-4 inhibitor, in the Randomized Evaluation of Anagliptin versus Sitagliptin On low-density lipoproteiN cholesterol in diabetes (REASON) trial. We investigated PCSK9 concentration in type 2 diabetes mellitus (T2DM) and the impact of treatment with anagliptin or sitagliptin on PCSK9 level as a sub-analysis of the REASON trial. METHODS: PCSK9 concentration was measured at baseline and after 52 weeks of treatment with anagliptin (n=122) or sitagliptin (n=128) in patients with T2DM who were receiving statin therapy. All of the included patients had been treated with a DPP-4 inhibitor prior to randomization. RESULTS: Baseline PCSK9 level was positively, but not significantly, correlated with LDL-C and was independently associated with platelet count and level of triglycerides. Concomitant with reduction of LDL-C, but not hemoglobin A1c (HbA1c), by anagliptin, PCSK9 level was significantly increased by treatment with sitagliptin (218±98 vs. 242±115 ng/mL, P=0.01), but not anagliptin (233±97 vs. 250±106 ng/mL, P=0.07). CONCLUSIONS: PCSK9 level is independently associated with platelet count and level of triglycerides, but not LDL-C, in patients with T2DM. Anagliptin reduces LDL-C level independent of HbA1c control in patients with T2DM who are on statin therapy possibly by suppressing excess statin-mediated PCSK9 induction and subsequent degradation of the LDL receptor.

Pharmacological treatment with FGF21 strongly improves plasma cholesterol metabolism to reduce atherosclerosis.

AIMS: Fibroblast growth factor (FGF) 21, a key regulator of energy metabolism, is currently evaluated in humans for treatment of type 2 diabetes and non-alcoholic steatohepatitis. However, the effects of FGF21 on cardiovascular benefit, particularly on lipoprotein metabolism in relation to atherogenesis, remain elusive. METHODS AND RESULTS: Here, the role of FGF21 in lipoprotein metabolism in relation to atherosclerosis development was investigated by pharmacological administration of a half-life extended recombinant FGF21 protein to hypercholesterolaemic APOE*3-Leiden.CETP mice, a well-established model mimicking atherosclerosis initiation and development in humans. FGF21 reduced plasma total cholesterol, explained by a reduction in non-HDL-cholesterol. Mechanistically, FGF21 promoted brown adipose tissue (BAT) activation and white adipose tissue (WAT) browning, thereby enhancing the selective uptake of fatty acids from triglyceride-rich lipoproteins into BAT and into browned WAT, consequently accelerating the clearance of the cholesterol-enriched remnants by the liver. In addition, FGF21 reduced body fat, ameliorated glucose tolerance and markedly reduced hepatic steatosis, related to up-regulated hepatic expression of genes involved in fatty acid oxidation and increased hepatic VLDL-triglyceride secretion. Ultimately, FGF21 largely decreased atherosclerotic lesion area, which was mainly explained by the reduction in non-HDL-cholesterol as shown by linear regression analysis, decreased lesion severity, and increased atherosclerotic plaque stability index. CONCLUSION: FGF21 improves hypercholesterolaemia by accelerating triglyceride-rich lipoprotein turnover as a result of activating BAT and browning of WAT, thereby reducing atherosclerotic lesion severity and increasing atherosclerotic lesion stability index. We have thus provided additional support for the clinical use of FGF21 in the treatment of atherosclerotic cardiovascular disease.

DNA Methylation Profile of the SREBF2 Gene in Human Fetal Aortas.

Increasing evidence suggests that maternal cholesterol represents an important risk factor for atherosclerotic disease in offspring already during pregnancy, although the underlying mechanisms have not yet been elucidated. Eighteen human fetal aorta samples were collected from the spontaneously aborted fetuses of normal cholesterolemic and hypercholesterolemic mothers. Maternal total cholesterol levels were assessed during hospitalization. DNA methylation profiling of the whole SREBF2 gene CpG island was performed (p value <0.05). The Mann-Whitney U test was used for comparison between the 2 groups. For the first time, our study revealed that in fetal aortas obtained from hypercholesterolemic mothers, the SREBF2 gene shows 4 significant differentially hypermethylated sites in the 5'UTR-CpG island. This finding indicates that more effective long-term primary cardiovascular prevention programs need to be designed for the offspring of mothers with hypercholesterolemia. Further studies should be conducted to clarify the epigenetic mechanisms underlying the association between early atherogenesis and maternal hypercholesterolemia during pregnancy.

The Prebiotic Effects of Oats on Blood Lipids, Gut Microbiota, and Short-Chain Fatty Acids in Mildly Hypercholesterolemic Subjects Compared With Rice: A Randomized, Controlled Trial.

Phytochemicals derived from oats are reported to possess a beneficial effect on modulating dyslipidemia, specifically on lowering total and LDL cholesterol. However, deeper insights into its mechanism remain unclear. In this randomized controlled study, we assigned 210 mildly hypercholesterolemic subjects from three study centers across China (Beijing, Nanjing, and Shanghai) to consume 80 g of oats or rice daily for 45 days. Plasma lipid profiles, short chain fatty acids (SCFAs), and fecal microbiota were measured. The results showed that total cholesterol (TC) and non-high-density lipoprotein cholesterol (non-HDL-C) decreased significantly with both oats and rice intake after 30 and 45 days. The reduction in TC and non-HDL-C was greater in the participants consuming oats compared with rice at day 45 (p = 0.011 and 0.049, respectively). Oat consumption significantly increased the abundance of Akkermansia muciniphila and Roseburia, and the relative abundance of Dialister, Butyrivibrio, and Paraprevotella, and decreased unclassified f-Sutterellaceae. In the oat group, Bifidobacterium abundance was negatively correlated with LDL-C (p = 0.01, r = -0.31) and, TC and LDL-C were negatively correlated to Faecalibacterium prausnitzii (p = 0.02, r = -0.29; p = 0.03, r = -0.27, respectively). Enterobacteriaceae, Roseburia, and Faecalibacterium prausnitzii were positively correlated with plasma butyric acid and valeric acid concentrations and negatively correlated to isobutyric acid. HDL-C was negatively correlated with valeric acid (p = 0.02, r = -0.25) and total triglyceride (TG) was positively correlated to isovaleric acid (p = 0.03, r = 0.23). Taken together, oats consumption significantly reduced TC and LDL-C, and also mediated a prebiotic effect on gut microbiome. Akkermansia muciniphila, Roseburia, Bifidobacterium, and Faecalibacterium prausnitzii, and plasma SCFA correlated with oat-induced changes in plasma lipids, suggesting prebiotic activity of oats to modulate gut microbiome could contribute towards its cholesterol-lowering effect.

Baseline Insulin Resistance Is a Determinant of the Small, Dense Low-Density Lipoprotein Response to Diets Differing in Saturated Fat, Protein, and Carbohydrate Contents.

Individual responses to diet vary but causes other than genetics are poorly understood. This study sought to determine whether baseline values of homeostasis model assessment (HOMA-IR) was related to changes in small, dense low-density lipoprotein (sdLDL, i.e., LDL4, d = 1.044-1.063 g/mL) amounts quantified by isopycnic density profiling, in mildly hypercholesterolemic subjects (n = 27) consuming one of three low saturated fatty acid (SFA) diets: Dietary Approaches to Stop Hypertension (DASH), Beef in an Optimal Lean Diet (BOLD) and BOLD plus extra protein (BOLD+) when compared to a higher-SFA healthy American diet (HAD). The diets were consumed in random order for 5 wk, with 1 wk between diets. BOLD+ reduced fractional abundance (%) LDL4 (p < 0.05) relative to HAD, DASH and BOLD, and reductions in % LDL4 correlated with reductions in triglycerides (p = 0.044), total cholesterol (p = 0.014), LDL cholesterol (p = 0.004) and apolipoprotein B (p < 0.001). Responses to the four diets were similar (~12% decrease in % LDL4, p = 0.890) in the lower (<2.73 median) HOMA-IR subgroup but differed across diet conditions in the higher HOMA-IR subgroup (p = 0.013), in which % LDL4 was reduced with BOLD+ (-11%), was unchanged in BOLD and increased with the HAD (8%) and DASH (6%) diets (p < 0.05 for BOLD+ vs. HAD). Individual responses to diet interventions are influenced by presence and degree of insulin resistance as measured by HOMA-IR.

Low LXA4, RvD1 and RvE1 levels may be an indicator of the development of hypertension.

Vascular structure and integrity are at the forefront of blood pressure regulation. However, there are many factors that affect the responses of the vessels. One of these is the inflammatory processes associated with high cholesterol and its modification. 15-lipoxygenase (15-LOX) is the critical enzyme in cholesterol oxidation, but this enzyme is also responsible for the synthesis of specialized proresoving lipid mediators (SPMs) called Lipoxin (Lxs) and Resolvin (Rvs). In this study, we determined serum LXA4, RvD1 and RvE1 levels in newly diagnosed hypertension (HT) and normotension (NT) cases. We evaluated how the presence of hypercholesterolemia (HC) in the follow-up changes the levels of these SPMs. We found that the three SPMs we measured decreased significantly in the presence of HC. In addition, we found a negative and significant correlation with systolic blood pressure and total cholesterol levels for the three SPMs. In conclusion, HT and HC are independent risk factors for cardiovascular death. However, the presence of HC may be an important factor for the development of HT. Increasing cholesterol levels may cause 15-LOX to shift towards LDL oxidation, thus leading to inflammation. This situation may negatively affect the vascular functions in the regulation of blood pressure. Serum LXA4, RvD1 and RvE1 measurements may provide clues that represent a shift of 15-LOX enzyme activity towards cholesterol.

SUR1-E1506K mutation impairs glucose tolerance and promotes vulnerable atherosclerotic plaque phenotype in hypercholesterolemic mice.

BACKGROUND AND AIMS: Diabetes is a major risk factor of atherosclerosis and its complications. The loss-of-function mutation E1506K in the sulfonylurea receptor 1 (SUR1-E1506K) induces hyperinsulinemia in infancy, leading to impaired glucose tolerance and increased risk of type 2 diabetes. In this study, we investigate the effect of SUR1-E1506K mutation on atherogenesis in hypercholesterolemic LDLR-/- mice. METHODS: SUR1-E1506K mutated mice were cross-bred with LDLR-/- mice (SUR1Δ/LDLR-/-), 6 months old mice were fed a western-diet (WD) for 6 months to induce advanced atherosclerotic plaques. At the age of 12 months, atherosclerosis and plaque morphology were analyzed and mRNA gene expression were measured from aortic sections and macrophages. Glucose metabolism was characterized before and after WD. Results were compared to age-matched LDLR-/- mice. RESULTS: Advanced atherosclerotic plaques did not differ in size between the two strains. However, in SUR1Δ/LDLR-/- mice, plaque necrotic area was increased and smooth muscle cell number was reduced, resulting in higher plaque vulnerability index in SUR1Δ/LDLR-/- mice compared to LDLR-/- mice. SUR1Δ/LDLR-/- mice exhibited impaired glucose tolerance and elevated fasting glucose after WD. The positive staining area of IL-1ß and NLRP3 inflammasome were increased in aortic sections in SUR1Δ/LDLR-/- mice compared to LDLR-/- mice, and IL-18 plasma level was elevated in SUR1Δ/LDLR-/- mice. Finally, the mRNA expression of IL-1ß and IL-18 were increased in SUR1Δ/LDLR-/- bone marrow derived macrophages in comparison to LDLR-/- macrophages in response to LPS. CONCLUSIONS: SUR1-E1506K mutation impairs glucose tolerance and increases arterial inflammation, which promotes a vulnerable atherosclerotic plaque phenotype in LDLR-/- mice.

Effects of a Calorie-Restricted Mediterranean-Style Diet on Plasma Lipids in Hypercholesterolemic South Korean Patients.

The objective of this randomized cross-over trial was to evaluate the short term effects of a calorie-restricted Korean style Mediterranean diet (KMD) versus a calorie-restricted conventional diet on lipid profile and other metabolic parameters in hypercholesterolemic patients. Ninety-two patients with hypercholesterolemia were randomly assigned to two groups and switched to the other group following a 4-week intervention after a 2-week washout period. While participants during KMD intervention period received home delivery of two meals daily except for weekends, those during the control group were advised to consume a conventional diet. Total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) significantly decreased in KMD group even after adjusting for age, sex, total energy intake changes, alcohol consumption, smoking status, and physical activity changes (all p < 0.05). Anthropometric parameters, white blood cell (WBC), fasting glucose, fasting insulin, HOMA-IR, and fatty liver index (FLI) also significantly decreased after KMD intervention (all p < 0.05). In addition, WBC, fasting glucose, total cholesterol, LDL-C and FLI were significantly decreased even after adjusting for weight reduction changes. Calorie-restricted KMD not only helps to treat dyslipidemia by improving the lipid parameters but also has beneficial effects on reducing cardiovascular risk by improving chronic inflammation, insulin resistance, and fatty liver.

Clinical characteristics of cardiovascular patients with extremely low levels of high-density lipoprotein cholesterol.

BACKGROUND: Extremely low levels of high-density lipoprotein cholesterol (HDL-C) are related to high cardiovascular mortality. The underlying mechanism is not well known. This research aims to study the clinical characteristics of cardiovascular patients with extremely low levels of HDL-C. METHODS: All cardiovascular patients in a single Chinese cardiology center that were admitted from January to December 2019 were reviewed. The clinical characteristics of those with HDL-C<20 mg/dL were investigated. RESULTS: A total of 20,655 individuals were enrolled. Of these, 52.17 % were males, and the average age was 58.20 ± 12.98 years old. The prevalence of HDL-C<20 mg/dL was 0.47 % for all patients (N=98) and 1.05 % for inpatients. Of those with HDL-C<20 mg/dL, 88.8 % were inpatients, and 77.6 % were males. Their average age was 60.7 ± 15.1 years. Compared with matched patients with normal HDL-C, systemic inflammation (OR= 5.556, 95% CI 2.798-11.030), hypoalbuminemia (OR=5.714, 95% CI 2.702-12.085), hyperuricemia (OR=5.156, 95% CI 2.560-10.386), low T3 syndrome (OR=4.278, 95% CI 1.627-11.245), anemia (OR=3.577, 95% CI 1.680-7.617), diabetes (OR=3.534, 95% CI 1.693-7.376) and hypertriglyceridemia (OR=2.493, 95% CI 1.264-4.918) were identified as adverse concomitant factors of extremely low HDL-C. HDL-C levels were inversely correlated with the total risk scores in patients with HDL-C<20 mg/dL (r=-0.381, P<0.001) and more significantly correlated in patients with HDL-C<15 mg/dL (r=-0.511, P=0.004). CONCLUSIONS: Extremely low levels of HDL-C tend to occur more frequently in males, older individuals and inpatients. For cardiovascular patients, extremely low levels of HDL-C are usually due to the presence of multiple adverse factors with relatively severe conditions. This could explain the high cardiovascular mortality of individuals with extremely low levels of HDL-C.