Associations between risk of overall mortality, cause-specific mortality and level of inflammatory factors with extremely low and high high-density lipoprotein cholesterol levels among American adults

Lactate-to-albumin ratio and cholesterol levels predict neurological outcome in cardiac arrest survivors

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) increases lactate levels and reduces albumin levels on admission and tends to lead to a poor neurological prognosis. In our experience, reduced cholesterol levels predict poor neurological prognosis. However, the relationship between cholesterol levels and neurological prognosis in OHCA survivors remains unclear.

METHODS

This retrospective observational study included data from January 2015 to June 2023 on 219 OHCA survivors at our intensive care unit. Patients were categorized into two groups based on cerebral functional classification (CPC) scores: Group A (CPC score of 1 or 2), including patients with a favorable neurological outcome, and Group B (CPC scores of 3 to 5), comprising those with a poor neurological outcome. We analyzed their lactate, albumin levels, and lipid profiles measured at 6 h after resuscitation. A model to predict the neurological prognosis of admission of OHCA survivors was developed.

RESULTS

Approximately 40% of the patients had favorable neurological outcomes at the 30-day follow-up. The lactate-to-albumin ratio (LAR) was significantly lower in Group A than in Group B (3.1 vs. 5.0 mmol/dag, p < 0.001). However, the albumin, total cholesterol, and high-density lipoprotein (HDL) cholesterol levels were significantly higher in Group A than in Group B (3.6 vs. 2.9 g/dL, 166.1 vs. 131.4 mg/dL, and 38.8 vs. 29.7 mg/dL, respectively, p < 0.001). Favorable neurological outcome was indicated at the following thresholds: LAR < 3.7 mmol/dag, albumin level > 3.1 g/dL, total cholesterol level > 146.4 mg/dL, and HDL-cholesterol level > 31.9 mg/dL. These findings underscore the high sensitivity and negative predictive value of the biomarkers. Furthermore, the area under the curve values for LAR, albumin, total cholesterol, and HDL-cholesterol levels were 0.70, 0.75, 0.71, and 0.71, respectively. The corresponding odds ratios were 3.37, 7.08, 3.67, and 3.94, respectively.

CONCLUSIONS

The LAR, albumin, total cholesterol, and HDL-cholesterol levels measured on admission may predict neurological prognosis in OHCA survivors. Thus, routine practice should include the measurement of these biomarkers at 6 h after resuscitation, especially in patients with a lactate level of > 5 mmol/L.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02633358.

Association of total and free testosterone with cardiovascular disease in a nationally representative sample of white, black, and Mexican American men

Associations of total testosterone (T) and calculated free T with cardiovascular disease (CVD) remain poorly understood. Particularly how these associations vary according to race and ethnicity in a nationally representative sample of men. Data included 7058 men (≥20 years) from NHANES. CVD was defined as any reported diagnosis of heart failure (HF), coronary artery disease (CAD), myocardial infarction (MI), and stroke. Total T (ng/mL) was obtained among males who participated in the morning examination. Weighted multivariable-adjusted logistic regression models were conducted. We found associations of low T (OR = 1.57, 95% CI = 1.17-2.11), low calculated free T (OR = 1.53, 95% CI = 1.10-2.17), total T (Q1 vs Q5), and calculated free T (Q1 vs Q5) with CVD after adjusting for estradiol and SHBG. In disease specific analysis, low T increased prevalence of MI (OR = 1.72, 95% CI = 1.08-2.75) and HF (OR = 1.74, 95% CI = 1.08-2.82), but a continuous increment of total T reduced the prevalence of CAD. Similar inverse associations were identified among White and Mexican Americans, but not Blacks (OR = 0.93, 95% CI = 0.49-1.76). Low levels of T and calculated free T were associated with an increased prevalence of overall CVD and among White and Mexican Americans. Associations remained in the same direction with specific CVD outcomes in the overall population.

Higher high-density lipoprotein cholesterol levels increased vertebral osteoporotic fracture, but reduced hip fracture in men based on the National Health Insurance Service-National Health Screening Cohort

BACKGROUND CONTEXT

Lipids are currently known to play an important role in bone metabolism.

PURPOSE

This study aimed to investigate the effect of high-density lipoprotein cholesterol (HDL-C) on osteoporotic fractures beyond its beneficial effects on the cardiovascular system.

STUDY DESIGN/SETTING

This was a retrospective, observational study that used data from the National Health Insurance Service-Health Screening cohort database.

PATIENT SAMPLE

This study included 318,237 participants who were 50 years or older and with HDL-C levels of 10 to 200 mg/dL.

OUTCOMES MEASURES

Physiologic measure-Diagnosis of osteoporotic fracture during the follow-up period.

METHODS

The study participants were categorized into four quartiles according to baseline HDL-C levels. The Cox proportional hazards model was used to assess osteoporotic fracture risk according to HDL-C levels.

RESULTS

After full adjustment and with the Q1 group as the reference group, estimates of hazard ratios (HRs; 95% confidence intervals [CIs]) for any osteoporotic fracture in men were 1.03 (0.94-1.12), 1.02 (0.93-1.11), and 1.07 (0.98-1.18) for the Q2, Q3, and Q4 groups, respectively. After classifying osteoporotic fractures according to the body location, the fully adjusted HRs for vertebral and hip fractures in the men's Q4 groups were 1.16 (1.02-1.31) and 0.74 (0.57-0.96), respectively. In women, fully adjusted HRs (95% CIs) of the female Q4 group for any osteoporotic, vertebral, and hip fractures were 1.03 (0.95-1.11), 0.96 (0.86-1.07), and 1.06 (0.80-1.41), respectively.

CONCLUSION

In this study, HDL-C levels were positively associated with vertebral fractures in both men and women but inversely related to hip fractures in men. Therefore, monitoring the lipid profiles of patients with osteoporosis may be beneficial for the prevention of osteoporotic fractures.

Rethinking HDL-C: An In-Depth Narrative Review of Its Role in Cardiovascular Health

The interplay between HDL-C and LDL levels are closely intertwined with the cardiovascular system. High-Density Lipoprotein Cholesterol (HDL-C) is a well-known biomarker traditionally being interpreted as higher the HDL-C levels, minimal the risk of adverse cardiovascular disease (CVD) outcomes. However, recent research has unveiled a more complex relationship between HDL-C levels and cardiovascular outcomes, including genetic influences and potential risks associated with extremely high HDL-C levels. Intriguingly, extremely high HDL-C levels have been linked to unexpected cardiovascular risks. Up To date research suggests that individuals with genetically linked ultra-high HDL-C levels may depict an increased susceptibility to CVD, challenging the conventional realm that higher HDL-C is always beneficial. The mechanisms underlying this mystery are not fully understood but may involve HDL particle functionality and composition. In a nutshell, the relationship between HDL-C levels and cardiovascular outcomes is multifactorial. While low HDL-C remains a recognized risk factor for CVD, the genetic determinants of HDL-C levels add complexity to this association. Furthermore, extremely high HDL-C levels may not exhibit the expected protective benefits and may even pose unprecedented cardiovascular risks. A comprehensive understanding of these dynamics is essential for advancing our knowledge of CVD risk assessment and developing targeted therapeutic interventions. Further studies are needed to unravel the intricacies of HDL-C's role in cardiovascular health and disease.

Association of HDL-Cholesterol, hypertension and left ventricular hypertrophy in youths with overweight or obesity

BACKGROUND AND AIM

To evaluate the relationship between HDL-Cholesterol (HDL-C), hypertension, and left ventricular hypertrophy (LVH) in a large sample of Caucasian youths with overweight/obesity (OW/OB).

METHODS AND RESULTS

A cross-sectional multicenter study was performed in 1469 youths (age 6-16 years) with OW/OB observed in the period 2016-2020. An additional independent sample of 244 youths with an echocardiographic evaluation, observed in a single center was analyzed. The sample was divided in six quantiles (Q) of HDL-C: Q1: >56, Q2: ≤56 > 51, Q3: ≤51 > 45, Q4: ≤45 > 41, Q5: ≤41 > 39, Q6: <39 mg/dL. The nadir of the relationship was identified in youths in the first quantile. Among HDL-Cholesterol quantiles the distribution of hypertension was non-linear with a percentage of 25.0%, 40.1%, 33.6%, 31.3%, 35.2% and 39.7% in the six quantiles, respectively. The percentage of LVH was 21.8%, 43.6%, 48.8%, 35.5%, 38.5% and 52.0% in the six quantiles, respectively. The highest odds [95%Cl] of hypertension were 2.05 (1.33-3.16) (P < 0.01) in Q2, 1.67 (1.10-2.55) (P < 0.05) in Q3 and 1.59 (1.05-2.41) (P < 0.05) in Q6 vs Q1. The odds of LVH were 3.86 (1.15-10.24) (P < 0.05) in Q2, 4.16 (1.58-10.91) (P < 0.05) in Q3 and 3.60 (1.44-9.02) (P < 0.05) in Q6 vs Q1, independently by centers, age, sex, prepubertal stage, and body mass index.

CONCLUSION

Contrary to the common belief, the present study shows that high levels of HDL-C may be not considered a negative predictor of hypertension and LVH, two risk factors for future CV disease.

Does Elevated High-Density Lipoprotein Cholesterol Protect Against Cardiovascular Disease?

High-density lipoprotein (HDL) contributes to reverse cholesterol transport, which is 1 of the main explanations for the described inverse association between HDL-cholesterol (HDL-C) and atherosclerotic cardiovascular disease (ASCVD) risk. However, efforts to therapeutically raise HDL-C levels with niacin, fibrates, or cholesteryl ester transfer protein inhibitors have not demonstrated a reduction in ASCVD events when compared with placebo among individuals treated with statins. Furthermore, mendelian randomization studies suggest that HDL-C is unlikely to be a direct biologic variable impacting ASCVD risk. More recently, observations from well-conducted epidemiologic studies have indicated a nonlinear U-shaped relationship between HDL-C and subclinical atherosclerosis, and that very high HDL-C (≥80 mg/dL in men, ≥100 mg/dL in women) is paradoxically associated with higher all-cause and ASCVD-related mortality. These observations suggest that HDL-C is not a universal protective factor for atherosclerosis. Thus, there are several opportunities for reframing the contribution of HDL-C to ASCVD risk and related clinical calculators. Here, we examine our growing understanding of HDL-C and its role in ASCVD risk assessment, treatment, and prevention. We discuss the biological functions of HDL-C and its normative values in relation to demographics and lifestyle markers. We then summarize original studies that observed a protective association between HDL-C and ASCVD risk and more recent evidence indicating an elevated ASCVD risk at very high HDL-C levels. Through this process, we advance the discussion regarding the future role of HDL-C in ASCVD risk assessment and identify knowledge gaps pertaining to the precise role of HDL-C in atherosclerosis and clinical ASCVD.

Association of high-density lipoprotein cholesterol with all-cause and cause-specific mortality in a Chinese population of 3.3 million adults: a prospective cohort study

Background

High-density lipoprotein cholesterol (HDL-C) has been inversely associated with cardiovascular disease (CVD) risk, but recent evidence suggests that extremely high levels of HDL-C are paradoxically related to increased CVD incidence and mortality. This study aimed to comprehensively examine the associations of HDL-C with all-cause and cause-specific mortality in a Chinese population.

Methods

The China Health Evaluation And risk Reduction through nationwide Teamwork (ChinaHEART) project included 3,397,547 participants aged 35-75 years with a median follow-up of 3.9 years. Baseline HDL-C levels were measured, and mortality data was ascertained from the National Mortality Surveillance System and Vital Registration of Chinese Center for Disease Control and Prevention.

Findings

This study found U-shaped associations of HDL-C with all-cause, cardiovascular and cancer mortality. When compared with the groups with the lowest risk, the adjusted hazard ratios (95% CIs) for HDL-C <30 mg/dL was 1.23 (1.17-1.29), 1.33 (1.23-1.45) and 1.18 (1.09-1.28) for all-cause, CVD and cancer mortality, respectively. For HDL-C >90 mg/dL, the corresponding HR (95% CIs) was 1.10 (1.05-1.15), 1.09 (1.01-1.18) and 1.11 (1.03-1.19). Similar U-shaped patterns were also found in associations of HDL-C with ischemic heart disease, ischemic stroke, and liver cancer. About 3.25% of all-cause mortality could be attributed to abnormal levels of HDL-C. The major contributor to mortality was ischemic heart disease (16.06 deaths per 100,000 persons, 95% UI: 10.30-22.67) for HDL-C <40 mg/dL and esophageal cancer (2.29 deaths per 100,000 persons, 95% UI: 0.57-4.77) for HDL-C >70 mg/dL.

Interpretation

Both low and high HDL-C were associated with increased mortality risk. We recommended 50-79 mg/dL as the optimal range of HDL-C among Chinese adults. Individuals with dyslipidemia might benefit from proper management of both low and high HDL-C.

Funding

The CAMS Innovation Fund for Medical Science (2021-1-I2M-011), the National High Level Hospital Clinical Research Funding (2022-GSP-GG-4), the Ministry of Finance of China and National Health Commission of China, and the 111 Project from the Ministry of Education of China (B16005), the Program for Guangdong Introducing Innovative and Enterpreneurial Teams (2019ZT08Y481), Sanming Project of Medicine in Shenzhen (SZSM201811096), the Young Talent Program of the Academician Fund, Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen (YS-2022-006) and Guangdong Basic and Applied Basic Research Foundation (2023A1515010076 & 2021A1515220173).

The association of lipid metabolism with bone metabolism and the role of human traits: a Mendelian randomization study

Background

The impact of lipid metabolism on bone metabolism remains controversial, and the extent to which human traits mediate the effects of lipid metabolism on bone metabolism remains unclear.

Objective

This study utilized mendelian randomization to investigate the effects of blood lipids on bone mineral density (BMD) at various skeletal sites and examined the mediating role of human traits in this process.

Methods

We leveraged genetic data from large-scale genome-wide association studies on blood lipids (n=1,320,016), forearm bone mineral density (FA-BMD) (n=10,805), lumbar spine bone mineral density (LS-BMD) (n=44,731), and femoral neck bone mineral density (FN-BMD) (n=49,988) to infer causal relationships between lipid and bone metabolism. The coefficient product method was employed to calculate the indirect effects of human traits and the proportion of mediating effects.

Results

The results showed that a 1 standard deviation(SD) increase in HDL-C, LDL-C and TC was associated with a decrease in LS-BMD of 0.039 g/cm2, 0.045 g/cm2 and 0.054 g/cm2, respectively. The proportion of mediating effects of systolic blood pressure (SBP) on HDL-C to LS-BMD was 3.17%, but suppression effects occurred in the causal relationship of LDL-C and TC to LS-BMD. Additionally, the proportion of mediating effects of hand grip strength (HGS) on the TC to LS-BMD pathway were 6.90% and 4.60% for the left and right hands, respectively.

Conclusion

In conclusion, a negative causal relationship was established between lipid metabolism and bone metabolism. Our results indicated that SBP and HGS served as mediators for the effects of lipid metabolism on bone metabolism.

High-Density Lipoprotein Cholesterol in Atherosclerotic Cardiovascular Disease Risk Assessment: Exploring and Explaining the "U"-Shaped Curve

PURPOSE OF REVIEW

Review updates for the association of HDL-cholesterol with atherosclerotic cardiovascular disease (ASCVD) and discuss the approach to incorporating HDL-cholesterol within risk assessment.

RECENT FINDINGS

There is a U-shaped relationship between HDL-cholesterol and ASCVD. Both low HDL-cholesterol (< 40 mg/dL in men, < 50 mg/dL in women) and very-high HDL-cholesterol (≥ 80 mg/dL in men) are associated with a higher risk of all-cause and ASCVD mortality, independent from traditional risk factors. There has been inconsistency for the association between very-high HDL-cholesterol and mortality outcomes in women. It is uncertain whether HDL-cholesterol is a causal ASCVD risk factor, especially due to mixed results from Mendelian randomization studies and the collinearity of HDL-cholesterol with established risk factors, lifestyle behaviors, and socioeconomic status. HDL-cholesterol is a risk factor or risk enhancer in primary prevention and high-risk condition in secondary prevention when either low (men and women) or very-high (men). The contribution of HDL-cholesterol to ASCVD risk calculators should reflect its observed U-shaped association with all-cause and ASCVD mortality.

Associations between serum total cholesterol level and bone mineral density in older adults

BACKGROUND

Osteoporosis is a major clinical problem in elderly men and women. The correlation between total cholesterol and bone mineral density remains controversial. NHANES is the cornerstone for national nutrition monitoring to inform nutrition and health policy.

METHODS

Sample sizes and the location of the study and the time when it was conducted: we obtained 4236 non-cancer elderly from NHANES (National Health and Nutrition Examination Survey) database from 1999 to 2006. Data were analyzed with the use of the statistical packages R and EmpowerStats. We analyzed the relationship between total cholesterol and lumbar bone mineral density. We performed research population description, stratified analysis, single factor analysis, multiple equation regression analysis, smooth curve fitting, and threshold effect and saturation effect analysis.

RESULTS

A significant negative association between serum cholesterol levels and bone mineral density of the lumbar spine in US non cancer affected older adults aged 60 years or older. Older adults ≥ 70 years of age had an inflection point at 280 mg / dl, and those with moderate physical activity had an inflection point at 199 mg / dl, The smooth curves they fitted were all U-shaped.

CONCLUSIONS

There is a negative association between total cholesterol and lumbar spine bone mineral density in non-cancer elderly greater than or equal to 60 years of age.

Hyperuricemia increases the risk of cardiovascular mortality associated with very high HdL-cholesterol level

BACKGROUND AND AIMS

Whether the association between very high HDL-cholesterol levels and cardiovascular mortality (CVM) is modulated by some facilitating factors is unclear. Aim of the study was to investigate whether the risk of CVM associated with very high HDL-cholesterol is increased in subjects with hyperuricemia.

METHODS AND RESULTS

Multivariable Cox analyses were made in 18,072 participants from the multicentre URRAH study stratified by sex and HDL-cholesterol category. During a median follow-up of 11.4 years there were 1307 cases of CVM. In multivariable Cox models a J-shaped association was found in the whole population, with the highest risk being present in the high HDL-cholesterol group [>80 mg/dL, adjusted hazard ratio (HR), 1.28; 95%CI, 1.02-1.61; p = 0.031)]. However, a sex-specific analysis revealed that this association was present only in women (HR, 1.34; 95%CI, 1.02-1.77; p = 0.034) but not in men. The risk of CVM related to high HDL-cholesterol was much greater in the women with high uric acid (>0.30 mmol/L, HR 1.61; 95%CI, 1.08-2.39) than in those with low uric acid (HR, 1.17; 95%CI, 0.80-1.72, p for interaction = 0.016). In women older than 70 years with hyperuricemia the risk related to high HDL-cholesterol was 1.83 (95%CI, 1.19-2.80, p < 0.005). Inclusion of BMI in the models weakened the strength of the associations.

CONCLUSION

Our data indicate that very high HDL-cholesterol levels in women are associated with CVM in a J-shaped fashion. The risk of CVM is increased by concomitant hyperuricemia suggesting that a proinflammatory/oxidative state can enhance the detrimental cardiovascular effects associated with high HDL-cholesterol.

Effects of vitamin D deficiency on blood lipids and bone metabolism: a large cross-sectional study

To investigate the relationship between serum high-density lipoprotein (HDL-C) and spinal bone mineral density (BMD) under different serum 25-hydroxyvitamin D (25 (OH) D) levels in adults over 40 years old and to explore its mechanism. We include participants over the age of 40 with data on HDL-C, 25 (OH) D, spinal BMD, and other variables in the National Health and Nutrition Examination Survey 2007-2010 in the analysis. A weighted multiple linear regression model was used to evaluate the association between serum HDL-C and spinal BMD in different gender, ages, and serum 25 (OH) D levels. A total of 3599 subjects aged ≥ 40 years old were included in this study. Univariate analysis of the complete correction model showed a negative correlation between serum HDL-C and spinal BMD. In the two subgroups of serum 25 (OH) D, we found that the higher the serum HDL-C in the female with serum 25 (OH) D < 75 nmol/L aged 40-59 years old, the lower the total spinal BMD, and a similar relationship was found in the lumbar spine. However, no similar relationship was found in all populations with serum 25 (OH) D ≥ 75 nmol/L and males with serum 25 (OH) D < 75 nmol/L. These results suggest that among Americans over the age of 40, the increase in serum HDL-C is related to decreased BMD of spine only in women aged 40-59 years with vitamin D insufficiency or deficiency.

Low testosterone and high cholesterol levels in relation to all-cause, cardiovascular disease, and cancer mortality in White, Black, and Hispanic men: NHANES 1988-2015

PURPOSE

The role of testosterone (T) deficiency (T ≤ 300 ng/dL) and hypercholesterolemia (total cholesterol ≥ 240 mg/dL) in the risk of all-cause cardiovascular diseases (CVD) and cancer mortality among a nationally representative sample of non-Hispanic White (NHW), non-Hispanic Black (NHB) and Hispanic men remains poorly understood.

METHODS

Data included a full sample (NHANES 1988-1991, 1999-2004, 2011-2014) and subset sample (excluding 2011-2012, no estradiol and SHBG levels available) of 5379 and 3740 men, respectively. Participants were aged ≥ 20 y with serum T and cholesterol data (median follow-up 7.6 years). Weighted multivariable-adjusted Cox proportional hazards models were used in this study.

RESULTS

In the overall population of full and subset samples, hypercholesterolemia was inversely associated with all-cause (HR = 0.76, 95% CI, 0.63-0.91) and cancer mortality (HR = 0.56, 95% CI, 0.34-0.90). Similar findings were observed among NHW men, but higher T levels increased the risk of CVD mortality in the subset sample (T₃ vs T_1, P_trend = 0.02). Among NHB men in the full and subset samples, T deficiency increased the risk of CVD mortality, but T₃ vs. T₁ decreased it (P_trend = 0.03), and hypercholesterolemia decreased cancer mortality. Among Hispanic men in the full and subset samples, T deficiency increased, and hypercholesterolemia decreased the risk of CVD mortality.

CONCLUSION

Hypercholesterolemia was inversely associated with cancer mortality. However, higher levels of T were positively associated with CVD mortality among NHW and were inversely associated with CVD mortality among NHB and Hispanic men. Larger prospective studies are warranted to clarify the underlying relationship between T and cholesterol with mortality among racial and ethnic groups.

The role of statins in lung cancer

Lung cancer is one of the most common causes of cancer-related mortality in the 21^st century. Statins as inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase not only reduce the cholesterol levels in the blood and decrease the risk of cardiovascular disease but may also play an important role in the prevention and treatment of lung cancer. Statins have several antitumor properties including the ability to reduce cell proliferation and angiogenesis, decrease invasion and synergistic suppression of lung cancer progression. Statins induce tumor cell apoptosis by inhibition of downstream products such as small GTP-binding proteins, Rho, Ras and Rac, which are dependent on isoprenylation. Statins reduce angiogenesis in tumors by down-regulation of pro-angiogenic factors, such as vascular endothelial growth factor. In this review, the feasibility and efficacy of statins in the prevention and treatment of lung cancer are discussed.

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.

Characterising the relationships between physiological indicators and all-cause mortality (NHANES): a population-based cohort study

BACKGROUND

Mortality risk stratification based on dichotomising a physiological indicator with a cutoff point might not adequately capture increased mortality risk and might not account for non-linear associations. We aimed to characterise the linear and non-linear relationships of 27 physiological indicators with all-cause mortality to evaluate whether the current clinical thresholds are suitable in distinguishing patients at high risk for mortality from those at low risk.

METHODS

For this observational cohort study of the US non-institutionalised population, we used data from adults (≥18 years) included in the 1999-2014 National Health and Nutrition Examination Survey (NHANES) linked with National Death Index mortality data collected from Jan 1, 1999, up until Dec 31, 2015. We used Cox proportional hazards regression models adjusted for age, sex, and race or ethnicity to assess associations of physiological indicators with all-cause mortality. We assessed non-linear associations by discretising the physiological indicator into nine quantiles (termed novemtiles) and by using a weighted sum of cubic polynomials (spline). We used ten-fold cross validation to select the most appropriate model using the concordance index, Nagelkerke R2, and Akaike Information Criterion. We identified the level of each physiological indicator that led to a 10% increase in mortality risk to define our cutoffs used to compare with the current clinical thresholds.

FINDINGS

We included 47 266 adults of 82 091 assessed for eligibility. 25 (93%) of 27 indicators showed non-linear associations with substantial increases compared with linear models in mortality risk (1·5-2·5-times increase). Height and 60 s pulse were the only physiological indicators to show linear associations. For example, participants with an estimated glomerular filtration rate (GFR) of less than 65 mL/min per 1·73 m2 or between 90-116 mL/min per 1·73 m2 are at moderate (hazard ratio 1-2) mortality risk. Those with a GFR greater than 117 mL/min per 1·73 m2 show substantial (hazard ratio ≥2) mortality risk. Both lower and higher values of cholesterol are associated with increased mortality risk. The current clinical thresholds do not align with our mortality-based cutoffs for fat deposition indices, 60 s pulse, triglycerides, cholesterol-related indicators, alkaline phosphatase, glycohaemoglobin, homoeostatic model assessment of insulin resistance, and GFR. For these indicators, the misalignment suggests the need to consider an additional bound when only one is provided.

INTERPRETATION

Most clinical indicators were shown to have non-linear associations with all-cause mortality. Furthermore, considering these non-linear associations can help derive reliable cutoffs to complement risk stratification and help inform clinical care delivery. Given the poor alignment with our proposed cutoffs, the current clinical thresholds might not adequately capture mortality risk.

High-density Lipoprotein Cholesterol Is Negatively Correlated with Bone Mineral Density and Has Potential Predictive Value for Bone Loss

Background

Many studies have shown that lipids play important roles in bone metabolism. However, the association between high-density lipoprotein cholesterol (HDL-C) and bone mineral density (BMD) is unclear. Therefore, this study aimed to investigate the linear or nonlinear relation between HDL-C levels and BMD and addressed whether the HDL-C levels had the potential values for predicting the risk of osteoporosis or osteopenia.

Methods

Two researchers independently extracted all information from the National Health and Nutrition Examination Survey (NHANES) database. Participants over 20 years of age with available HDL-C and BMD data were enrolled in the final analysis. The linear relationship between HDL-C levels and BMD was assessed using multivariate linear regression models. Moreover, the nonlinear relationship was also characterized by fitted smoothing curves and generalized additive models. In addition, the odds ratio (OR) for osteopenia and osteoporosis was evaluated with multiple logistic regression models.

Results

The weighted multivariable linear regression models demonstrated that HDL-C levels displayed an inverse association with BMD, especially among females and subjects aged 30 to 39 or 50 to 59. Moreover, the nonlinear relationship characterized by smooth curve fittings and generalized additive models suggested that (i) HDL-C levels displayed an inverted U-shaped relationship with BMD among women 30 to 39 or over 60 years of age; (ii) HDL-C levels exhibited a U-shaped association with BMD among women 20 to 29 or 50 to 59 years of age. In addition, females with high HDL levels (62-139 mg/dL) had an increased risk of osteopenia or osteoporosis.

Conclusion

This study demonstrated that HDL-C levels exhibit an inverse correlation with BMD. Especially in females, clinicians need to be alert to patients with high HDL-C levels, which may indicate an increased risk of osteoporosis or osteopenia. For these patients, close monitoring of BMD and early intervention may be necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01497-7.

HDL in Atherosclerotic Cardiovascular Disease: In Search of a Role

For a long time, high-density lipoprotein cholesterol (HDL-C) has been regarded as a cardiovascular disease (CVD) protective factor. Recently, several epidemiological studies, while confirming low plasma levels of HDL-C as an established predictive biomarker for atherosclerotic CVD, indicated that not only people at the lowest levels but also those with high HDL-C levels are at increased risk of cardiovascular (CV) mortality. This “U-shaped” association has further fueled the discussion on the pathophysiological role of HDL in CVD. In fact, genetic studies, Mendelian randomization approaches, and clinical trials have challenged the notion of HDL-C levels being causally linked to CVD protection, independent of the cholesterol content in low-density lipoproteins (LDL-C). These findings have prompted a reconsideration of the biological functions of HDL that can be summarized with the word “HDL functionality”, a term that embraces the many reported biological activities beyond the so-called reverse cholesterol transport, to explain this lack of correlation between HDL levels and CVD. All these aspects are summarized and critically discussed in this review, in an attempt to provide a background scenario for the “HDL story”, a lipoprotein still in search of a role.

A Non-Linear Association of High-Density Lipoprotein Cholesterol with All-Cause and Cause-Specific Mortality in Diabetic Patients

BACKGROUND

The association between high-density lipoprotein cholesterol (HDL-C) and the risk of death among people with diabetes remains to be verified.

METHODS

This was a nationwide, population-based cohort study in United States. A total of 6549 diabetes patients were included from the National Health and Nutrition Examination Surveys (NHANES). HDL-C concentration was divided into quintiles, and the lowest risk group (Q4: 1.32 to 1.53 mmol/L) was used as reference. Multivariate Cox proportional hazards models and restrictive cubic curves were performed to estimate hazard ratios (HRs) with 95% confidence interval (CI) for all-cause and cause-specific mortality.

RESULTS

During a median follow-up of 82.36 ± 50.11 months, 1546 (23.61%) cases of all-cause, 389 (5.94%) cardiovascular and 262 (4.00%) cancer mortality have occurred, respectively. After adjusting for potential covariates, a U-shaped association was found between HDL-C and all-cause mortality (minimum mortality risk at 1.37 mmol/L); the risk for all-cause mortality was significantly higher in the groups with HDL-C concentration <0.96 mmol/L (HR: 1.30; 95% CI: 1.09, 1.56; P=0.0046) and with HDL-C concentration ≥1.55 mmol/L (HR: 1.20; 95% CI: 1.00, 1.44; P=0.0481) than participants with HDL-C concentrations ranging from 1.32 to 1.53mmol/L. Nonlinear associations of HDL-C levels with both cardiovascular and cancer mortality were also observed.

CONCLUSION

A non-linear association was observed association of HDL-C with all-cause, cardiovascular and cancer mortality among diabetic patients.

Novel Insights From Human Studies on the Role of High-Density Lipoprotein in Mortality and Noncardiovascular Disease

The vast majority of research about HDL (high-density lipoprotein) has for decades revolved around the possible role of HDL in atherosclerosis and its therapeutic potential within cardiovascular disease prevention; however, failures with therapies aimed at increasing HDL cholesterol has left questions as to what the role and function of HDL in human health and disease is. Recent observational studies have further shown that extreme high HDL cholesterol is associated with high mortality leading to speculations that HDL could in some instances be harmful. In addition, evidence from observational, and to a lesser extent genetic studies has emerged indicating that HDL might be associated with the development of other major noncardiovascular diseases, such as infectious disease, autoimmune disease, cancer, type 2 diabetes, kidney disease, and lung disease. In this review, we discuss (1) the association between extreme high HDL cholesterol and mortality and (2) the emerging human evidence linking HDL to several major diseases outside the realm of cardiovascular disease.

U-Shaped Association of High-Density Lipoprotein Cholesterol with All-Cause and Cardiovascular Mortality in Hypertensive Population

Purpose

Whether the paradox of high-density lipoprotein cholesterol (HDL-C) and elevated mortality risk extends to hypertensive patients is unclear. We aimed to investigate the association between HDL-C and all-cause and cardiovascular disease mortality in adults with hypertension.

Methods

In the National Health and Nutrition Examination Surveys, 11,497 hypertensive participants aged ≥18years old and examined at baseline between 1999 and 2014 were followed up until December 2015. We categorized the HDL-C concentration as ≤30, 31–40, 41–50, 51–60 (reference), 61–70, >70 mg/dL and examined their associations with all-cause and cardiovascular mortality, respectively. Multivariate Cox regression was used to calculated hazard ratio (HR) and 95% confidence interval (CI) for mortality risk.

Results

During follow-up (median: 9.2 ± 3.8 years), 3012 deaths and 713 cardiovascular deaths were observed. In the restrictive cubic curves, associations of HDL-C levels and all-cause and cardiovascular mortality were detected to be U-shaped. After multivariable adjustment, HRs for all-cause mortality were for the lowest HDL-C concentration (≤30 mg/dL) 1.29 (95% CI, 1.07–1.56) and the highest (>70 mg/dL) 1.20 (1.06–1.37), comparing with the reference group. For cardiovascular mortality, HRs were 1.31 (0.83–1.48) and 1.09 (0.83–1.43), respectively. Similar results were obtained in subgroups stratified by age, gender, race, and taking lipid-lowering drugs. The lowest all-cause mortality risk was observed at HDL-C 66 mg/dL (concentration) and 51–60 mg/dL (range).

Conclusion

Both lower and higher HDL-C concentration appeared to be associated with higher mortality in hypertensive population. Further investigation is warranted to clarify the underlying mechanisms.

The U Shaped Relationship Between High-Density Lipoprotein Cholesterol and All-Cause or Cause-Specific Mortality in Adult Population

Purpose

The associations of high-density lipoprotein cholesterol (HDL-C) with mortality are still unclear. We explored the associations of HDL-C with all-cause and cause-specific mortality in an adult population.

Methods

Deaths were classified into all-cause, cardiovascular, and cancer mortality. Survival curve, multivariate Cox regression, and subgroup analyses were conducted, and hazard ratio (HR) and 95% confidence interval (CI) were performed. We fitted Cox regression models for all-cause, cardiovascular, and cancer mortality to evaluate their associations with categories of HDL-C (≤30, 31-40, 41-50, 51-60 [reference], 61-70, >70 mg/dL).

Results

A total of 42,145 (20,415 (48.44%) males, mean age 47.12±19.40 years) subjects were enrolled. At an average follow-up of 97.52±54.03 months, all-cause, cardiovascular, and cancer mortality numbers were 5,061 (12.01), 1,081 (2.56%), and 1,061 (2.52%), respectively. When compared with the reference group (HDL-C: 51-60 mg/dL), a U-shaped association was apparent for all-cause mortality, with elevated risk in participants with the lowest (≤30 mg/dL) (HR=1.33; 95% CI=1.14- 1.56) and highest (>70 mg/dL) (HR=1.14; 95% CI=1.02-1.27) HDL-C concentration. Associations for cardiovascular and cancer mortality were non-linear. An elevated risk for cancer mortality was observed in those with the highest HDL-C concentration (HR=1.06; 95% CI-0.84-1.34) compared with the reference group, although it was not statistically significant. The effect of HDL-C on mortality was adjusted by some traditional risk factors including age, gender, race, or comorbidities.

Conclusion

A U-shaped association was observed between HDL-C and all-cause mortality among an adult population.

Is HDL cholesterol protective in patients with type 2 diabetes? A retrospective population-based cohort study

BACKGROUND

The protective role of high HDL cholesterol levels against cardiovascular diseases has been recently questioned. Limited data are available on this specific topic in patients with type 2 diabetes mellitus (T2DM). We aimed to evaluate the association of HDL cholesterol concentrations with all-cause and cause-specific mortality in a historical cohort of T2DM patients with 14 years of follow-up.

METHODS

This is a retrospective population-based cohort study involving 2113 T2DM patients attending the Diabetic Clinic of Asti. Survival analyses were performed to assess hazard ratios for overall and specific-cause mortality by HDL cholesterol tertiles, using the middle HDL cholesterol tertile as a reference.

RESULTS

The mean age was 66 ± 11 years; 51.4% of patients had low HDL-cholesterol levels. After a 14-year follow-up, 973/2112 patients had died (46.1%). The HDL cholesterol tertile cut-off points were 37.5 and 47.5 mg/dL (males) and 41.5 and 52.0 mg/dL (females). No associations between lower and upper HDL cholesterol tertiles respectively and all-cause (HR = 1.12; 95% CI 0.96-1.32; HR = 1.11; 0.95-1.30), cardiovascular (HR = 0.97; 0.77-1.23; HR = 0.94; 0.75-1.18) or cancer (HR = 0.92; 0.67-1.25; HR = 0.89; 0.66-1.21) mortality were found. A significantly increased risk for infectious disease death was found both in the lower (HR = 2.62; 1.44-4.74) and the upper HDL-cholesterol tertiles (HR = 2.05; 1.09-3.85) when compared to the reference. Individuals in the upper tertile showed an increased risk for mortality due to diabetes-related causes (HR = 1.87; 1.10-3.15).

CONCLUSIONS

Our results corroborate the hypothesis that HDL cholesterol levels are nonprotective in T2DM patients. The U-shaped association between HDL-cholesterol levels and mortality associated with infectious diseases should be verified by further studies.

HDL-C is associated with mortality from all causes, cardiovascular disease and cancer in a J-shaped dose-response fashion: a pooled analysis of 37 prospective cohort studies

Objective

The association between high-density lipoprotein cholesterol (HDL-C) levels and mortality remains controversial. We aimed to investigate the potential dose–response associations between HDL-C levels and mortality from all causes, cardiovascular disease and cancer in the general population.

Methods

PubMed and Embase were searched through April 2019. Prospective cohort studies reporting risk estimates of HDL-C levels and mortality were included. Linear and non-linear dose–response analyses were conducted. A random-effects model was employed to calculate pooled hazard ratio.

Results

Thirty-seven studies, involving 3,524,505 participants and more than 612,027 deaths, were included. HDL-C level was found to be associated with mortality from all causes, cardiovascular disease and cancer in a J-shaped dose–response pattern, with the lowest risk observed at HDL-C levels of 54–58 mg/dL, 68–71 mg/dL and 64–68 mg/dL, respectively. Compared with HDL-C level of 56 mg/dL, the pooled hazard ratios for all-cause mortality were 1.03 (95% confidence interval (CI) 1.01, 1.05) and 1.10 (95% CI 1.09, 1.12) for each 10-mg/dL increase and decrease in HDL-C levels, respectively; furthermore, compared with the reference category, the pooled hazard ratios for all-cause mortality were 1.21 (95% CI 1.09, 1.36) and 1.36 (95% CI 1.21, 1.53) for the highest and the lowest categories of HDL-C levels, respectively. Similar results were obtained for cardiovascular and cancer mortality.

Conclusions

In the general population, HDL-C level is associated with mortality from all causes, cardiovascular disease and cancer in a J-shaped dose–response manner; both extremely high and low HDL-C levels are associated with an increased risk of mortality.

Apolipoprotein B/Apolipoprotein A-I Ratio Is a Better Predictor of Cancer Mortality Compared with C-Reactive Protein: Results from Two Multi-Ethnic US Populations

BACKGROUND

There is a lack of evidence regarding the link between apolipoproteins and cancer mortality. By using two nationally representative samples of US adults, we prospectively evaluated the associations between apolipoprotein B (apoB) levels and apoB/apoA-I ratio with cancer mortality. We also examined the role of C-reactive protein (CRP) in these associations.

MATERIALS AND METHODS

Adults aged ≥20 years, enrolled in the 3rd National Health and Nutrition Examination Survey (NHANES III, 1988-1994) and continuous NHANES (2005-2010), and followed up to 31 December 2011, were included in the analysis. Multiple Cox regressions were applied to evaluate the associations between the variables of interest and cancer mortality.

RESULTS

Overall, 7695 participants were included (mean age: 49.2 years; 50.4% men, median follow-up: 19.1 years). In the fully adjusted model, participants in the highest quartile (Q4) of apoB/apoA-I had a significantly greater risk for cancer mortality (hazard ratio (HR): 1.40; 95% confidence interval (CI): 1.25-1.93) compared with those in the first quartile (Q1). In the same model, a positive and significant association between apoB levels and cancer mortality was observed for individuals in Q3 (HR: 1.12; 95% CI: 1.09-1.16) and Q4 (HR: 1.17; 95% CI: 1.09-1.25) compared with those in Q1. When CRP levels were added in the analysis, the apoB/apoA-I ratio, but not apoB levels, remained significantly related to cancer mortality (Q4 = HR: 1.17; 95% CI: 1.09-1.25). In contrast, CRP levels were not able to predict cancer death after correction for apoB/apoA-I ratio.

CONCLUSIONS

In a large representative sample of the US adult population, the apoB/apoA-I ratio and apoB levels significantly predicted cancer mortality, independently of several cardiometabolic risk factors. The predictive value of apoB/apoA-I, but not apoB levels, remained significant after taking into account CRP, whereas CRP was not associated with cancer mortality after adjustment for apoB/apoA-I ratio. If further evidence supports our findings, apoA-I and apoB measurements could be considered in general healthcare policies.

Lower than average HDL cholesterol efflux capacity in Lithuanian population

Background

The aim of our study was to evaluate high-density lipoprotein cholesterol (HDL-C) efflux capacity in healthy controls and patients with severe dyslipidemia. Evaluation of HDL function may be beneficial for better understanding of cardiovascular diseases, as well as for taking actions to minimize residual cardiovascular risk.

Methods

During 2016–2017 a total of 93 participants – 48 (51.6%) women and 45 (48.4%) men – were included in this cross-sectional study. Data of 45 (48.4%) participants with severe dyslipidemia (SD) and 48 (51.6%) controls without dyslipidemia was used for statistical analysis. Total lipid panel, concentration of lipoprotein (a) and apolipoproteins were measured, data about cardiovascular risk factors were collected and detailed evaluation of HDL-C quality was performed for all patients.

Results

Increased HDL-C concentration was associated with higher ApoA1 (r = 0.866 in controls, r = 0.63 in SD group), ApoA2 (r = 0.41 in controls, r = 0.418 in SD group) and LDL-C concentrations (r = − 0.412 in SD group), lower ApoE (r = − 0.314 in SD group) and TG concentrations (r = − 0.38 in controls, r = − 0.608 in SD group), lower ApoB/ApoA1 ratio (r = − 0.567 in control group), below average HDL-C efflux capacity (r = − 0.335 in SD group), lower BMI (r = − 0.327 in controls, r = − 0.531 in SD group) and abdominal circumference (r = − 0.309 in women with SD). Below-average HDL-C efflux capacity was found in 67.7% (N = 63) of participants. It was more often found among patients with normal weight or BMI 30–31 kg/m2. HDL-C efflux capacity was inversely associated with HDL-C concentration (r = − 0.228).

Conclusion

Abnormal HDL function may be associated with residual cardiovascular risk in Lithuanian population.