Insulin and 2-hour glucose levels are inversely related to Lp(a) concentrations controlled for LPA genotype

Lipoprotein(a) as a cardiovascular risk factor among patients with and without diabetes Mellitus: the Mass General Brigham Lp(a) Registry

BACKGROUND

Diabetes mellitus (DM) and Lp(a) are well-established predictors of coronary artery disease (CAD) outcomes. However, their combined association remains poorly understood.

OBJECTIVE

To investigate the relationship between elevated Lp(a) and DM with CAD outcomes.

METHODS

Retrospective analysis of the MGB Lp(a) Registry involving patients ≥ 18 years who underwent Lp(a) measurements between 2000 and 2019. Exclusion criteria were severe kidney dysfunction, malignant neoplasms, and prior atherosclerotic cardiovascular disease (ASCVD). The primary outcome was a combination of cardiovascular death or myocardial infarction (MI). Elevated Lp(a) was defined as > 90th percentile (≥ 216 nmol/L).

RESULTS

Among 6,238 patients who met the eligibility criteria, the median age was 54, 45% were women, and 12% had DM. Patients with DM were older, more frequently male, and had a higher prevalence of additional cardiovascular risk factors. Over a median follow-up of 12.9 years, patients with either DM or elevated Lp(a) experienced higher rates of the primary outcome. Notably, those with elevated Lp(a) had a higher incidence of the primary outcome regardless of their DM status. The annual event rates were as follows: No-DM and Lp(a) < 90th% - 0.6%; No-DM and Lp(a) > 90th% - 1.3%; DM and Lp(a) < 90th% - 1.9%; DM and Lp(a) > 90th% - 4.7% (p < 0.001). After adjusting for confounders, elevated Lp(a) remained independently associated with the primary outcome among both patients with DM (HR = 2.66 [95%CI: 1.55-4.58], p < 0.001) and those without DM (HR = 2.01 [95%CI: 1.48-2.74], p < 0.001).

CONCLUSIONS

Elevated Lp(a) constitutes an independent and incremental risk factor for CAD outcomes in patients with and without DM.

Is inverse association between lipoprotein(a) and diabetes mellitus another paradox in cardiometabolic medicine?

INTRODUCTION

The impact of Type II Diabetes mellitus (T2DM) on cardiovascular disease (CVD) is well-established, while lipoprotein(a) [Lp(a)] has recently emerged as a recognized CVD risk factor. The rising prevalence of T2DM resulting from modern lifestyles and the development of specific Lp(a)-lowering agents brought the association between T2DM and Lp(a) in the forefront.

AREAS COVERED

Despite advancements in T2DM treatment, diabetic patients remain at very-high risk of CVD. Lp(a) may, to some extent, contribute to the persistent CVD risk seen in diabetic patients, and the coexistence of T2DM and elevated Lp(a) levels appears to synergistically amplify overall CVD risk. The relationship between T2DM and Lp(a) is paradoxical. On one hand, high Lp(a) plasma concentrations elevate the risk of diabetic microvascular and macrovascular complications. On the other hand, low Lp(a) plasma concentrations have been linked to an increased risk of developing T2DM.

EXPERT OPINION

Comprehending the association between T2DM and Lp(a) is critical due to the pivotal roles both entities play in overall CVD risk, as well as the unique aspects of their relationship. The mechanisms underlying the inverse association between T2DM and Lp(a) remain incompletely understood, necessitating further meticulous research.

Association between lipoprotein(a) and insulin resistance in Chinese adults: results from the China health and nutrition survey

Background

Lipoprotein(a) [Lp(a)] is a well-established risk factor for cardiovascular diseases. However, the relationship between Lp(a) and insulin resistance (IR) remains controversial. The aim of the current study was to investigate the association between Lp(a) concentrations and IR in Chinese adults.

Methods

Cross-sectional study of 1908 cases and 5725 controls was performed for identifying the association of Lp(a) with IR. IR was assessed using the triglyceride glucose (TyG) index, and patients with a TyG index greater than the third quartile were defined as having IR.

Results

The distribution of Lp(a) in Chinese adults was skewed, with a median of 7.90mg/dL. Lp(a) concentrations were significantly and progressively lower with increasing TyG index values in Chinese adult males, but not in females. Multiple regression analysis adjusted for a wide range of risk factors showed that Lp(a) concentrations were inversely and independently associated with IR in Chinese adult males, but not in females. The suggested Lp (a) cutoff for discriminating IR from non-IR was 4.7 mg/dL in Chinese adult males. Lp(a) interacts with gender in IR on both additive and multiplicative scale in Chinese adults.

Conclusion

Lp(a) concentrations inversely associated with IR in Chinses adult males, but the association in women needs further study. In Chinese adults, Lp(a) interacts with gender in IR.

Consensus document on Lipoprotein(a) from the Italian Society for the Study of Atherosclerosis (SISA)

AIMS

In view of the consolidating evidence on the causal role of Lp(a) in cardiovascular disease, the Italian Society for the Study of Atherosclerosis (SISA) has assembled a consensus on Lp(a) genetics and epidemiology, together with recommendations for its measurement and current and emerging therapeutic approaches to reduce its plasma levels. Data on the Italian population are also provided.

DATA SYNTHESIS

Lp(a) is constituted by one apo(a) molecule and a lipoprotein closely resembling to a low-density lipoprotein (LDL). Its similarity with an LDL, together with its ability to carry oxidized phospholipids are considered the two main features making Lp(a) harmful for cardiovascular health. Plasma Lp(a) concentrations vary over about 1000 folds in humans and are genetically determined, thus they are quite stable in any individual. Mendelian Randomization studies have suggested a causal role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis and observational studies indicate a linear direct correlation between cardiovascular disease and Lp(a) plasma levels. Lp(a) measurement is strongly recommended once in a patient's lifetime, particularly in FH subjects, but also as part of the initial lipid screening to assess cardiovascular risk. The apo(a) size polymorphism represents a challenge for Lp(a) measurement in plasma, but new strategies are overcoming these difficulties. A reduction of Lp(a) levels can be currently attained only by plasma apheresis and, moderately, with PCSK9 inhibitor treatment.

CONCLUSIONS

Awaiting the approval of selective Lp(a)-lowering drugs, an intensive management of the other risk factors for individuals with elevated Lp(a) levels is strongly recommended.

Lipoprotein(a) as a Higher Residual Risk for Coronary Artery Disease in Patients with Type 2 Diabetes Mellitus than without

Purpose

Lipoprotein(a) (Lp[a]) is well-known as a residual risk factor for coronary artery disease (CAD). However, the different adverse effects of Lp(a) about CAD in patients with or without type 2 diabetes mellitus (T2DM) are unclear. This study aimed to investigate the Lp(a) thresholds for CAD diagnosis in T2DM and non-T2DM patients, and further compare the Lp(a) alarm values along with optimal low-density lipoprotein cholesterol (LDL-C) level.

Methods

This retrospective study consecutively enrolled patients with suspected CAD who underwent coronary angiography in Guangdong Provincial People's Hospital between September 2014 and July 2015. A logistic regression model was established to explore the association of Lp(a) and CAD in patients. Restricted cubic splines were used to compare the threshold values of Lp(a) for CAD in patients with and without T2DM, and further in optimal LDL-C level situation.

Results

There were 1522 patients enrolled finally. After multivariable adjustment, Lp(a) was an independent risk factor for CAD in patients with T2DM (odds ratio [OR]: 1.98, 95% CI]: 1.12-3.49, p = 0.019) and without T2DM (OR: 3.42, 95% CI: 2.36-4.95, p < 0.001). In the whole population, the Lp(a) threshold of CAD was 155, while 145 mg/L for T2DM and 162 mg/L for non-T2DM ones, respectively. In patients with LDL-C<1.8 mmol/l, the alarm value of Lp(a) was even lower in T2DM than non-T2DM patients (155 vs 174 mg/L).

Conclusion

Lp(a) was a significant residual risk for CAD in patients whether with T2DM or not. And Lp(a) had a lower alarm value in T2DM patients, especially in optimal LDL-C level.

Prognostic impacts of diabetes status and lipoprotein(a) levels in patients with ST-segment elevation myocardial infarction: a prospective cohort study

OBJECTS

This study aimed to investigate the impact of lipoprotein(a) [Lp(a)] levels on the prognosis of Chinese patients with ST-segment elevation myocardial infarction (STEMI), and to explore if the impact may differ in the diabetes mellitus (DM) and nonDM groups.

METHODS

Between March 2017 and January 2020, 1543 patients with STEMI who underwent emergency percutaneous coronary intervention (PCI) were prospectively recruited. The primary outcome was a composite of all-cause death, MI recurrence (reMI), and stroke, known as major adverse cardiovascular events (MACE). Analyses involving the Kaplan-Meier curve, Cox regression, and restricted cubic spline (RCS) were conducted.

RESULTS

During the 1446-day follow-up period, 275 patients (17.8%) experienced MACEs, including 141 with DM (20.8%) and 134 (15.5%) without DM. As for the DM group, patients with Lp(a) ≥ 50 mg/dL showed an apparently higher MACE risk compared to those with Lp(a) < 10 mg/dL (adjusted hazard ratio [HR]: 1.85, 95% confidence interval [CI]:1.10-3.11, P = 0.021). The RCS curve indicates that the HR for MACE appeared to increase linearly with Lp(a) levels exceeding 16.9 mg/dL. However, no similar associations were obtained in the nonDM group, with an adjusted HR value of 0.57 (Lp(a) ≥ 50 mg/dL vs. < 10 mg/dL: 95% CI 0.32-1.05, P = 0.071). Besides, compared to patients without DM and Lp(a) ≥ 30 mg/dL, the MACE risk of patients in the other three groups (nonDM with Lp(a) < 30 mg/dL, DM with Lp(a) < 30 mg/dL, and DM with Lp(a) ≥ 30 mg/dL) increased to 1.67-fold (95% CI 1.11-2.50, P = 0.013), 1.53-fold (95% CI 1.02-2.31, P = 0.041), and 2.08-fold (95% CI 1.33-3.26, P = 0.001), respectively.

CONCLUSIONS

In this contemporary STEMI population, high Lp(a) levels were linked to an increased MACE risk, and very high Lp(a) levels (≥ 50 mg/dL) significantly indicated poor outcomes in patients with DM, while not for those without DM.

TRIAL REGISTRATION

clinicaltrials.gov NCT: 03593928.

Low Lipoprotein(a) Levels Predict Hepatic Fibrosis in Patients With Nonalcoholic Fatty Liver Disease

Dyslipidemia and cardiovascular complications are comorbidities of nonalcoholic fatty liver disease (NAFLD), which ranges from simple steatosis to nonalcoholic steatohepatitis, fibrosis, and cirrhosis up to hepatocellular carcinoma. Lipoprotein(a) (Lp(a)) has been associated with cardiovascular risk and metabolic abnormalities, but its impact on the severity of liver damage in patients with NAFLD remains to be clarified. Circulating Lp(a) levels were assessed in 600 patients with biopsy-proven NAFLD. The association of Lp(a) with liver damage was explored by categorizing serum Lp(a) into quartiles. The receiver operating characteristic curve was used to analyze the accuracy of serum Lp(a) in hepatic fibrosis prediction. Hepatic expression of lipoprotein A (LPA) and of genes involved in lipid metabolism and fibrogenic processes were evaluated by RNA sequencing in a subset of patients with NAFLD for whom Lp(a) dosage was available (n = 183). In patients with NAFLD, elevated Lp(a) levels were modestly associated with circulating lipids, carotid plaques, and hypertension (P < 0.05). Conversely, patients with low serum Lp(a) displayed insulin resistance (P < 0.05), transaminase elevation (P < 0.05), and increased risk of developing severe fibrosis (P = 0.007) and cirrhosis (P = 0.002). In addition, the diagnostic accuracy of Lp(a) in predicting fibrosis increased by combining it with transaminases (area under the curve fibrosis stage 4, 0.87; P < 0.0001). Hepatic LPA expression reflected serum Lp(a) levels (P = 0.018), and both were reduced with the progression of NAFLD (P < 0.05). Hepatic LPA messenger RNA levels correlated with those of genes involved in lipoprotein release, lipid synthesis, and fibrogenesis (P < 0.05). Finally, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, apolipoprotein E (ApoE) rs445925, and proprotein convertase subtilisin/kexin type 9 (PCSK9) rs7552841, known variants that modulate circulating lipids, may influence serum Lp(a) levels (P < 0.05). Conclusion: Circulating Lp(a) combined with transaminases may represent a novel noninvasive biomarker to predict advanced fibrosis in patients with NAFLD.

Association between new markers of cardiovascular risk and hepatic insulin resistance in those at high risk of developing type 2 diabetes

AIM/HYPOTHESIS

Hepatic insulin resistance (HIR) is considered to be an independent predictor of metabolic disorders and plays an important role in systemic inflammation, which contributes to abnormalities in cardiovascular disease (CVD) risk factors. The aim of this study was to investigate the relationship between HIR and new markers of cardiovascular risks, including leptin/adiponectin ratio (L/A), lipoprotein(a) [Lp(a)], and tumor necrosis factor alpha (TNF-α), at comparable whole body insulin sensitivity in non-diabetic individuals with or without CVD and at high risk of developing type 2 diabetes.

METHODS

The HIR index, L/A, Lp(a), and TNF-α were measured in 50 participants with CVD and in 200 without CVD (1:4 ratio). These were also matched for the homeostatic model assessment for insulin resistance (HOMA-IR) and Matsuda-insulin sensitivity index (ISI) in an observational study design.

RESULTS

The HIR index (1.52 ± 0.14 vs. 1.45 ± 0.17, p < 0.02), L/A (3.22 ± 3.10 vs. 2.09 ± 2.27, p < 0.004), and levels of Lp(a) (66.6 ± 49.5 vs. 37.9 ± 3 6.8 mg/dL, p < 0.0001) and TNF-α (18.9 ± 21.8 vs. 5.4 ± 7.1 pg/mL, p < 0.0001) were higher in those with CVD than those without CVD. HOMA-IR and ISI were not significantly different (p = 0.88 and p = 0.35, respectively). The HIR index was directly correlated with L/A (r = 0.41, p < 0.0001), Lp(a) (r = 0.20, p < 0.002), TNF- α (r = 0.14, p < 0.03), and diastolic blood pressure (DBP) (r = 0.13, p < 0.03). The stepwise model analysis showed that L/A, Lp(a), and TNF-α explained about 20% of the variation in the HIR indices of all the participants (p < 0.02).

CONCLUSIONS/INTERPRETATIONS

Our results suggest a positive association between HIR and new markers of cardiovascular risk [L/A, Lp(a), and TNF- α] at comparable whole body insulin sensitivity in those with or without CVD and at high risk of developing type 2 diabetes.

Lipoprotein(a) Concentrations Correlate With LDL-C in Children With Type 1 and 2 Diabetes

Context

Elevated levels of lipoprotein(a) (Lp[a]) is an independent risk factor for atherosclerotic cardiovascular disease especially in patients with diabetes. Adult levels of Lp(a) are thought to be is expressed by the second year of life.

Objective

We hypothesized that Lp(a) would be influenced by low density lipoprotein cholesterol (LDL-C), race, and HbA1C.

Methods

Retrospective electronic medical record review of children and adolescents with type 1 diabetes (T1D) (n = 607) and type 2 diabetes (T2D) (n = 93).

Results

Total of 700 subjects, ages 12-19 years with T1D (n = 607) and T2D (n = 93), 49% were male, mean age was 13.2 ± 3.08 years, and the median Lp(a) was 8.00 mg/dL, IQR 5.00-12.00. The Black subjects had an increased relative risk (RR) of higher Lp(a) compared with White subjects (RR 1.25, P < .0001). Among patients with T1D, Black people had an increased relative risk of higher Lp(a) than White people (RR 1.23, P = .0002). In T2D, Black subjects have 43% higher risk of having elevated Lp(a) than White subjects (RR 1.43, P = .268). In T1D, a 5 mg/dL increase in LDL-C results in 2% increase in Lp(a) (P < .0001). In T2D, a 5 mg/dL increase of LDL-C results in an increase of Lp(a) by 3%. LDL-C and BMI are independently associated with Lp(a) (RR = 1.02, P < .001; RR = 0.98, P < .001).

Conclusion

Our data suggest that Lp(a) is associated with LDL-C in children with diabetes. Lp(a) is differentially increased at higher concentrations of LDL-C. Black children with diabetes have a significant burden of Lp(a) concentrations compared with White children.

Lipoprotein(a): Knowns, unknowns and uncertainties

Over the last 10 years, there have been advances on several aspects of lipoprotein(a) which are reviewed in the present article. Since the standard immunoassays for measuring lipoprotein(a) are not fully apo(a) isoform-insensitive, the application of an LC-MS/MS method for assaying molar concentrations of lipoprotein(a) has been advocated. Genome wide association, epidemiological, and clinical studies have established high lipoprotein(a) as a causal risk factor for atherosclerotic cardiovascular diseases (ASCVD). However, the relative importance of molar concentration, apo(a) isoform size or variants within the LPA gene is still controversial. Lipoprotein(a)-raising single nucleotide polymorphisms has not been shown to add on value in predicting ASCVD beyond lipoprotein(a) concentrations. Although hyperlipoproteinemia(a) represents an important confounder in the diagnosis of familial hypercholesterolemia (FH), it enhances the risk of ASCVD in these patients. Thus, identification of new cases of hyperlipoproteinemia(a) during cascade testing can increase the identification of high-risk individuals. However, it remains unclear whether FH itself increases lipoprotein(a). The ASCVD risk associated with lipoprotein(a) seems to follow a linear gradient across the distribution, regardless of racial subgroups and other risk factors. The inverse association with the risk of developing type 2 diabetes needs consideration as effective lipoprotein(a) lowering therapies are progressing towards the market. Considering that Mendelian randomization analyses have identified the degree of lipoprotein(a)-lowering that is required to achieve ASCVD benefit, the findings of the ongoing outcome trial with pelacarsen will clarify whether dramatically lowering lipoprotein(a) levels can reduce the risk of ASCVD.

Association of sex-specific differences in lipoprotein(a) concentrations with cardiovascular mortality in individuals with type 2 diabetes mellitus

Background

Compared to individuals without type 2 diabetes mellitus, the relative increase in cardiovascular mortality is much higher in women than in men in individuals with type 2 diabetes mellitus.

Methods

We evaluated data from 7443 individuals (3792 women, 50.9%), aged 20 to 81 years, from two independent population-based investigations, SHIP-0 and MONICA/KORA S3. We analyzed the longitudinal sex-specific associations of lipoprotein(a) with cardiovascular mortality in individuals with and without type 2 diabetes mellitus using Cox regression.

Results

During a median follow-up of 20.5 years (136,802 person-years), 657 participants (404 men and 253 women) died of cardiovascular causes. Among individuals without type 2 diabetes mellitus, men had a significantly higher risk for cardiovascular mortality compared to women in unadjusted model and after adjustment. On the other hand, in participants with type 2 diabetes mellitus, the risk for cardiovascular mortality was not different between men and women in the unadjusted model and after adjustment for age, body mass index, low-density lipoprotein-cholesterol, fasting status and study sample (SHIP-0, MONICA/KORA S3). Further adjustment for lipoprotein(a) concentrations had no impact on the hazard ratio (HR) for cardiovascular mortality comparing men versus women in individuals without type 2 diabetes mellitus [HR: 1.94; 95% confidence interval (CI) 1.63 to 2.32; p < 0.001]. In individuals with type 2 diabetes mellitus, however, further adjustment for lipoprotein(a) led to an increased risk for cardiovascular mortality in men and a decreased risk in women resulting in a statistically significant difference between men and women (HR: 1.53; 95% CI 1.04 to 2.24; p = 0.029).

Conclusions

Women are described to have a stronger relative increase in cardiovascular mortality than men when comparing individuals with and without type 2 diabetes mellitus. Higher lipoprotein(a) concentrations in women with type 2 diabetes mellitus than in men with type 2 diabetes mellitus might partially explain this finding.

High lipoprotein(a) concentrations are associated with lower type 2 diabetes risk in the Chinese Han population: a large retrospective cohort study

Background

Lipoprotein (a) [Lp(a)] is a proven independent risk factor for coronary heart disease. It is also associated with type 2 diabetes mellitus (T2DM). However, the correlation between Lp(a) and T2DM has not been clearly elucidated.

Methods

This was a retrospective cohort study involving 9248 T2DM patients and 18,496 control individuals (1:2 matched). Patients were randomly selected from among inpatients in the Second Affiliated Hospital of Nanchang University between 2006 and 2017. Clinical characteristics were compared between the two groups. Spearman rank-order correlation coefficients were used to evaluate the strength and direction of monotonic associations of serum Lp(a) with other metabolic risk factors. Binary logistic regression analysis was used to establish the correlation between Lp(a) levels and T2DM risk.

Results

The median Lp(a) concentration was lower in T2DM patients than in controls (16.42 vs. 16.88 mg/dL). Based on four quartiles of Lp(a) levels, there was a decrease in T2DM risk from 33.7% (Q1) to 31.96% (Q4) (P for trend < 0.0001). Then, Lp(a) levels > 28.72 mg/dL (Q4) were associated with a significantly lower T2DM risk in the unadjusted model [0.924 (0.861, 0.992), P = 0.030]. Similar results were obtained in adjusted models 1 [Q4, 0.925 (0.862, 0.993), P = 0.031] and 2 [Q4, 0.919 (0.854, 0.990), P = 0.026]. Furthermore, in the stratified analysis, Q4 of Lp(a) was associated with a significantly lower T2DM risk among men [0.813 (0.734, 0.900), P < 0.001] and those age > 60 years [0.819 (0.737, 0.910), P < 0.001]. In contrast, the low-density lipoprotein cholesterol (LDL-C) levels and coronary heart disease (CHD) did not impact these correlations between Lp(a) and diabetes.

Conclusions

There is an inverse association between Lp(a) levels and T2DM risk in the Chinese population. Male patients, especially those aged more than 60 years with Lp(a) > 28.72 mg/dL, are low-risk T2DM individuals, regardless of LDL-C levels and CHD status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01504-x.

Lipoprotein (a) and diabetes mellitus: causes and consequences

PURPOSE OF REVIEW

This review provides an update on the role of lipoprotein (a) [Lp(a)] in diabetes, including its impact as a risk factor as well as its contribution to the development of cardiovascular disease.

RECENT FINDINGS

Although a specific role for Lp(a) has not yet been conclusively established, it appears to have an inverse association with risk of diabetes. Several population-based studies have demonstrated associations between low levels of Lp(a) and increased risk of type 2 diabetes, but Mendelian randomization studies do not consistently support causality. Conversely, in patients with type 2 diabetes, elevated Lp(a) levels are associated with an increased risk of cardiovascular events.

SUMMARY

Although Lp(a) contributes to the development of cardiovascular disease in patients with diabetes, few trials have investigated the benefits of reducing Lp(a) within this patient population. Furthermore, guidelines do not specifically address the risk associated with elevated Lp(a) levels. Despite this, Lp(a) should be measured in patients with diabetes and considered when evaluating their overall risk burden.

Effect of bariatric surgery on plasma levels of oxidised phospholipids, biomarkers of oxidised LDL and lipoprotein(a)

BACKGROUND

Obesity is associated with adverse cardiovascular outcomes and this is improved following bariatric surgery. Oxidised phospholipids (OxPL) are thought to reflect the pro-inflammatory effects of lipoprotein(a) [Lp(a)], and both are independent predictors of cardiovascular disease.

OBJECTIVE

Our study sought to determine the impact of bariatric surgery on OxPL, biomarkers of oxidised LDL (OxLDL) and Lp(a).

METHODS

This is a prospective, observational study of 59 patients with severe obesity undergoing bariatric surgery. Blood samples were obtained prior to surgery and at 6 and 12 months after. Sixteen patients attending the tertiary medical weight management clinic at the same centre were also recruited for comparison. Lipid and metabolic blood parameters, OxLDL, OxPL on apolipoprotein B-100 (OxPL-apoB), IgG and IgM autoantibodies to MDA-LDL, IgG and IgM apoB-immune complexes and Lp(a) were measured.

RESULTS

Reduction in body mass index (BMI) was significant following bariatric surgery, from median 48 kg/m2 at baseline to 37 kg/m2 at 6 months and 33 kg/m2 at 12 months. OxPL-apoB levels decreased significantly at 12 months following surgery [5.0 (3.2-7.4) to 3.8 (3.0-5.5) nM, p = 0.001], while contrastingly, Lp(a) increased significantly [10.2 (3.8-31.9) to 16.9 (4.9-38.6) mg/dl, p = 0.002]. There were significant post-surgical decreases in IgG and IgM biomarkers, particularly at 12 months, while OxLDL remained unchanged.

CONCLUSIONS

Bariatric surgery results in a significant increase in Lp(a) but reductions in OxPL-apoB and other biomarkers of oxidised lipoproteins, suggesting increased synthetic capacity and reduced oxidative stress. These biomarkers might be clinically useful to monitor physiological effects of weight loss interventions.

The Association of Lipoprotein(a) Plasma Levels With Prevalence of Cardiovascular Disease and Metabolic Control Status in Patients With Type 1 Diabetes

OBJECTIVE

To investigate the association of the cardiovascular risk factor lipoprotein (Lp)(a) and vascular complications in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Patients with type 1 diabetes receiving regular care were recruited in this observational cross-sectional study and divided into four groups according to their Lp(a) levels in nmol/L (very low <10, low 10-30, intermediate 30-120, high >120). Prevalence of vascular complications was compared between the groups. In addition, the association between metabolic control, measured as HbA_1c, and Lp(a) was studied.

RESULTS

The patients (n = 1,860) had a median age of 48 years, diabetes duration of 25 years, and HbA_1c of 7.8% (61 mmol/mol). The median Lp(a) was 19 (interquartile range 10-71) nmol/L. No significant differences between men and women were observed, but Lp(a) levels increased with increasing age. Patients in the high Lp(a) group had higher prevalence of complications than patients in the very low Lp(a) group. The age- and smoking-status-adjusted relative risk ratio of having any macrovascular disease was 1.51 (95% CI 1.01-2.28, P = 0.048); coronary heart disease, 1.70 (95% CI 0.97-3.00, P = 0.063); albuminuria, 1.68 (95% CI 1.12-2.50, P = 0.01); and calcified aortic valve disease, 2.03 (95% CI 1.03-4.03; P = 0.042). Patients with good metabolic control, HbA_1c <6.9% (<52 mmol/mol), had significantly lower Lp(a) levels than patients with poorer metabolic control, HbA_1c >6.9% (>52 mmol/mol).

CONCLUSIONS

Lp(a) is a significant risk factor for macrovascular disease, albuminuria, and calcified aortic valve disease in patients with type 1 diabetes. Poor metabolic control in patients with type 1 diabetes is associated with increased Lp(a) levels.

Lipoprotein(a) concentration is associated with risk of type 2 diabetes and cardiovascular events in a Chinese population with very high cardiovascular risk

PURPOSE

Evidences have shown that elevated lipoprotein(a) [Lp(a)] levels were associated with a lower risk of type 2 diabetes, but a higher risk of cardiovascular events in general populations. We aim to demonstrate the effect of Lp(a) concentrations on type 2 diabetes and cardiovascular events in a Chinese population with very high cardiovascular risk.

METHODS

Seven hundred ninety-eight participants who underwent coronary angiography between March and November 2013 with normal glucose metabolism were followed up from July to December 2018.

RESULTS

Five hundred thirty-five participants completed follow-up, and 395 of them had blood glucose data. Among 395 participants with blood glucose data, a total of 28 incident type 2 diabetes were identified during a median follow-up period of 4.42 years. Compared with the patients in the lowest tertile of Lp(a), the multifactorial adjusted HR for type 2 diabetes was 0.29 in the highest tertile (95% confidence intervals (CI) 0.10-0.89; P for trend = 0.03). Among 535 patients who completed follow-up, a total of 80 cases of major adverse cardiovascular events (MACE) were identified during a median follow-up period of 5.08 years. Compared with the patients in the lowest tertile of Lp(a), the multifactorial adjusted HR for MACE was 1.95 in the highest tertile (95% CI 1.05-3.65; P for trend = 0.03).

CONCLUSIONS

Elevated Lp(a) levels were associated with a lower risk of type 2 diabetes, but a higher risk of cardiovascular events in a Chinese population with very high cardiovascular risk.

Lipoprotein(a) plasma levels are not associated with incident microvascular complications in type 2 diabetes mellitus

AIMS/HYPOTHESIS

Microvascular disease in type 2 diabetes is a significant cause of end-stage renal disease, blindness and peripheral neuropathy. The strict control of known risk factors, e.g. lifestyle, hyperglycaemia, hypertension and dyslipidaemia, reduces the incidence of microvascular complications, but a residual risk remains. Lipoprotein (a) [Lp(a)] is a strong risk factor for macrovascular disease in the general population. We hypothesised that plasma Lp(a) levels and the LPA gene SNPs rs10455872 and rs3798220 are associated with the incident development of microvascular complications in type 2 diabetes.

METHODS

Analyses were performed of data from the DiaGene study, a prospective study for complications of type 2 diabetes, collected in the city of Eindhoven, the Netherlands (n = 1886 individuals with type 2 diabetes, mean follow-up time = 6.97 years). To assess the relationship between plasma Lp(a) levels and the LPA SNPs with each newly developed microvascular complication (retinopathy n = 223, nephropathy n = 246, neuropathy n = 236), Cox proportional hazards models were applied and adjusted for risk factors for microvascular complications (age, sex, mean arterial pressure, non-HDL-cholesterol, HDL-cholesterol, BMI, duration of type 2 diabetes, HbA_1c and smoking).

RESULTS

No significant associations of Lp(a) plasma levels and the LPA SNPs rs10455872 and rs3798220 with prevalent or incident microvascular complications in type 2 diabetes were found. In line with previous observations the LPA SNPs rs10455872 and rs3798220 did influence the plasma Lp(a) levels.

CONCLUSIONS/INTERPRETATION

Our data show no association between Lp(a) plasma levels and the LPA SNPs with known effect on Lp(a) plasma levels with the development of microvascular complications in type 2 diabetes. This indicates that Lp(a) does not play a major role in the development of microvascular complications. However, larger studies are needed to exclude minimal effects of Lp(a) on the development of microvascular complications.

Serum Spexin is Correlated with Lipoprotein(a) and Androgens in Female Adolescents

The Spexin gene is considered the most dysregulated in obese human fat. Limited data suggest that the novel peptide spexin may potentially impact food intake, weight regulation and body adiposity. The aim of this case-control study was to compare fasting serum spexin concentrations between normal weight (NW) and overweight/obese (OB/OW) adolescent females and explore the relationship between circulating spexin and anthropometric, bone and fat mass, metabolic and hormonal parameters. Eighty post-menarcheal females (mean age ± SD 16.23 ± 2.26 years); 55 NW (mean BMI ± SD 19.72 ± 2.52 kg/m²) and 25 OB/OW (mean BMI ± SD 29.35 ± 3.89 kg/m²) participated in the study. Circulating spexin levels did not differ significantly (p = 0.378) between NW (median (interquartile range), 0.26 (0.17) ng/mL) and OB/OW (median (interquartile range), 0.28 (0.06) ng/mL) adolescents and did not correlate with BMI (r_s = −0.090, p = 0.438), % body fat (r_s = −0.173, p = 0.409), glucose or insulin resistance indices derived from fasting and oral glucose tolerance states. In the total study sample, spexin concentrations correlated positively with lipoprotein(a) (r_s = 0.402, p = 0.046). In the OB/OW adolescents spexin levels correlated positively with testosterone (r_s = 0.727, p = 0.011) and free androgen index (r_s = 0.755, p = 0.007). In the NW adolescents, spexin concentrations correlated negatively with dehydroepiandrosterone sulphate (r_s = −0.445, p = 0.038). Results may suggest potential involvement of spexin in the regulation of lipoprotein(a) and of the reproductive/adrenal axis in post-menarcheal adolescent females.

Effect of the Interaction between Obstructive Sleep Apnea and Lipoprotein(a) on Insulin Resistance: A Large-Scale Cross-Sectional Study

Both obstructive sleep apnea (OSA) and decreased serum lipoprotein(a) (Lp(a)) concentrations are associated with insulin resistance. However, their interaction effect on insulin resistance has never been investigated. Therefore, we performed a cross-sectional study on OSA-suspected Chinese Han participants. Laboratory-based polysomnographic variables, biochemical indicators, anthropometric measurements, and medical history were collected. Linear regression and binary logistic regression analyses with interaction terms were used to investigate the potential effects of the interaction between the severity of OSA (assessed by the apnea-hypopnea index (AHI)) and Lp(a) concentrations on insulin resistance (assessed by the homeostasis model assessment of insulin resistance (HOMA-IR)), after adjusting for potential confounders including age, gender, body mass index, waist-to-hip circumference ratio, mean arterial pressure, smoking status, drinking status, and lipid profiles. A total of 4,152 participants were enrolled. In the OSA-suspected population, AHI positively correlated with insulin resistance and serum Lp(a) concentrations independently and inversely correlated with insulin resistance. In addition, the interaction analysis showed that the linear association between lgAHI and lgHOMA-IR was much steeper and more significant in subjects with relatively low Lp(a) concentrations, suggesting a significant positive interaction between lgLp(a) and lgAHI on lgHOMA-IR (P = 0.013). Furthermore, the interaction on a multiplicative scale also demonstrated a significant positive interaction (P = 0.044). A stronger association between AHI quartiles and the presence of insulin resistance (defined as HOMA-IR > 3) could be observed for participants within lower Lp(a) quartiles. In conclusion, a significant positive interaction was observed between OSA and decreased Lp(a) with respect to insulin resistance. This association might be relevant to the assessment of metabolic or cardiovascular disease risk in OSA patients.

Baseline and on-statin treatment lipoprotein(a) levels for prediction of cardiovascular events: individual patient-data meta-analysis of statin outcome trials

BACKGROUND

Elevated lipoprotein(a) is a genetic risk factor for cardiovascular disease in general population studies. However, its contribution to risk for cardiovascular events in patients with established cardiovascular disease or on statin therapy is uncertain.

METHODS

Patient-level data from seven randomised, placebo-controlled, statin outcomes trials were collated and harmonised to calculate hazard ratios (HRs) for cardiovascular events, defined as fatal or non-fatal coronary heart disease, stroke, or revascularisation procedures. HRs for cardiovascular events were estimated within each trial across predefined lipoprotein(a) groups (15 to <30 mg/dL, 30 to <50 mg/dL, and ≥50 mg/dL, vs <15 mg/dL), before pooling estimates using multivariate random-effects meta-analysis.

FINDINGS

Analyses included data for 29 069 patients with repeat lipoprotein(a) measurements (mean age 62 years [SD 8]; 8064 [28%] women; 5751 events during 95 576 person-years at risk). Initiation of statin therapy reduced LDL cholesterol (mean change -39% [95% CI -43 to -35]) without a significant change in lipoprotein(a). Associations of baseline and on-statin treatment lipoprotein(a) with cardiovascular disease risk were approximately linear, with increased risk at lipoprotein(a) values of 30 mg/dL or greater for baseline lipoprotein(a) and 50 mg/dL or greater for on-statin lipoprotein(a). For baseline lipoprotein(a), HRs adjusted for age and sex (vs <15 mg/dL) were 1·04 (95% CI 0·91-1·18) for 15 mg/dL to less than 30 mg/dL, 1·11 (1·00-1·22) for 30 mg/dL to less than 50 mg/dL, and 1·31 (1·08-1·58) for 50 mg/dL or higher; respective HRs for on-statin lipoprotein(a) were 0·94 (0·81-1·10), 1·06 (0·94-1·21), and 1·43 (1·15-1·76). HRs were almost identical after further adjustment for previous cardiovascular disease, diabetes, smoking, systolic blood pressure, LDL cholesterol, and HDL cholesterol. The association of on-statin lipoprotein(a) with cardiovascular disease risk was stronger than for on-placebo lipoprotein(a) (interaction p=0·010) and was more pronounced at younger ages (interaction p=0·008) without effect-modification by any other patient-level or study-level characteristics.

INTERPRETATION

In this individual-patient data meta-analysis of statin-treated patients, elevated baseline and on-statin lipoprotein(a) showed an independent approximately linear relation with cardiovascular disease risk. This study provides a rationale for testing the lipoprotein(a) lowering hypothesis in cardiovascular disease outcomes trials.

FUNDING

Novartis Pharma AG.

Lipoprotein(a) and apolipoprotein(a) isoform size: Associations with angiographic extent and severity of coronary artery disease, and carotid artery plaque

BACKGROUND AND AIMS

Lipoprotein(a) [Lp(a)] is an emerging genetic risk factor for cardiovascular disease (CVD). We examined whether plasma Lp(a) concentration and apolipoprotein(a) [apo(a)] isoform size are associated with extent and severity of coronary artery disease (CAD), and the presence of carotid artery plaque.

METHODS

We included in our study male participants (n = 263) from a cohort with angiographically defined premature CAD (Carotid Ultrasound in Patients with Ischemic Heart Disease). The angiographic extent and severity of CAD were determined by the modified Gensini and Coronary Artery Stenosis≥20% (CAGE) scores. Carotid artery plaque was assessed by bilateral carotid B-mode ultrasound. Apo(a) isoform size was determined by LPA Kringle IV-2 copy number (KIV-2 CN).

RESULTS

Lp(a) concentration, but not KIV-2 CN, was positively associated with the Gensini score. The association remained significant following adjustment for conventional CVD risk factors (all p < 0.05). Lp(a) concentration and elevated Lp(a) [≥50 mg/dL] were positively associated with the CAGE≥20 score, independent of conventional CVD risk factors. KIV-2 C N Q1 (lowest KIV-2 CN quartile) was associated with CAGE≥20 score and KIV-2 CN, with the CAGE≥20 score in those without diabetes. In multivariate models that included phenotypic familial hypercholesterolemia or low-density lipoprotein cholesterol, Lp(a) concentration, but not KIV-2 CN, was independently associated with the Gensini and CAGE≥20 scores. No significant associations between Lp(a) concentration and KIV-2 CN with carotid artery plaque were observed.

CONCLUSIONS

Lp(a) concentration, but not apo(a) isoform size, is independently associated with angiographic extent and severity of CAD. Neither Lp(a) nor apo(a) isoform size is associated with carotid artery plaque.

Inverse association of lipoprotein (a) with markers of insulin resistance in dyslipidemic subjects

Lipoprotein (a) [Lp(a)] is an LDL-like particle that contains an apolipoprotein B100 molecule covalently bound to a plasminogen-like glycoprotein, apolipoprotein (a) [apo(a)]. Epidemiological evidence supports a direct and causal association between Lp(a) levels and coronary risk. On the contrary, a few prospective findings demonstrate inverse association of Lp(a) levels with risk of type 2 diabetes (T2DM). The aim of our study was to evaluate the association of Lp(a) with indicators of insulin resistance (IR) and metabolic syndrome (MS), which precede development of T2DM. We enrolled 607 asymptomatic dyslipidemic subjects (295 men and 312 women, mean age 45.6+/-14.0 years) into our cross-sectional study. Lp(a) concentrations correlated inversely with TG, AIP, insulin, HOMA, C-peptide, BMI, waist circumference, and number of MS components (p<0.01 for all). Subjects with MS had significantly lower Lp(a) concentrations in comparison with those without the presence of this phenotype (p<0.0001). Serum concentrations of Lp(a) in the lower (1(th)-3(rd)) quartiles of insulin and HOMA were significantly higher than in the 4(th) quartile of these insulin resistance markers (p<0.001). Odds ratios of having increased markers of IR (TG, HOMA) and MS in top quartile of Lp(a) also indicate inverse association of Lp(a) with IR. The results of our study support an inverse association of Lp(a) levels with IR and MS that precedes overt T2DM diagnosis.

Lipoprotein(a)-activated immunity, insulin resistance and new-onset diabetes

OBJECTIVES

Some evidence suggests that serum lipoprotein[Lp](a) may be inversely linked to type-2 diabetes. We aimed to determine in nondiabetic people the relationship of serum [Lp](a) with insulin resistance and new-onset diabetes (NOD).

MATERIALS AND METHODS

Population-based middle-aged adults (n = 1685) were categorized by fasting glucose and stratified to gender, having excluded prevalent diabetic subjects. NOD (n = 90) occurred over a median 5 years' follow-up.

RESULTS

Subjects that subsequently developed NOD, derived both from the normoglycemia and impaired fasting glucose (IFG) groups,were distinguished, among others, primarily by significantly elevated serum gamma glutamyltransferase, reduced Lp(a) (by 31%) and, compared to IFG, by low total cholesterol levels. Partial correlation of Lp(a) with homeostatic model assessment (HOMA) was inverse in normoglycemic men; such correlation, neutral in normoglycemic women, proved inverse in IFG (r = -0.17). Circulating Lp(a) in individuals with paired measures increased significantly (1.55-fold) in the period from baseline up to NOD. Multivariable-adjusted logistic regression analysis for NOD in combined sexes indicated independent and additive prediction by serum Lp(a), albeit inverse in direction (RR 0.84, [95%CI 0.72; 0.97]).

CONCLUSION

Lp(a) is significantly reduced in the period preceding NOD and is inversely associated with HOMA index, observations consistent with underlying autoimmune activation.

Insulin resistance contributes more to the increased risk for diabetes development in subjects with low lipoprotein(a) level than insulin secretion

Background

Recent studies suggest an association between Lipoprotein(a) [Lp(a)] and the development of diabetes mellitus. We analyzed the association between baseline Lp(a) levels and diabetes development after 4 years of follow-up, in a population of apparently healthy Korean subjects.

Methods

A total of 2,536 non-diabetic participants (mean age: 41 years, men: 92%) of a health checkup program were included in the study. Diabetes development was defined by fasting blood glucose ≥126 mg/dL, HbA1c ≥6.5%, and self-reported treatment of diabetes. Homeostasis model assessment (HOMA) indices were used to assess insulin resistance (IR) and insulin secretion (IS). Presence of IR and impaired IS was defined by being in the highest quartile of HOMA-IR and in the lowest quartile HOMA-IS.

Results

After four years, 3.4% of the participants developed diabetes. The odds ratio (OR) of developing diabetes was lowest in the 4^th quartile group of baseline Lp(a) (0.323 [95% CI 0.153–0.685])with the 1^st quartile group as the reference. The subjects with both IR & impaired IS plus baseline Lp(a)<50 mg/dL showed the higher OR for diabetes development compared with those without IR and normal IS as the reference (67.277 [20.218–223.871], and those with IR plus Lp(a)<50 mg/dL showed higher OR for diabetes than in those with impaired IS and Lp(a)<50 mg/dL (3.811 [1.938–7.495] vs. 3.452 [1.620–7.353]).

Conclusions

The subjects with low baseline Lp(a) level showed higher risk for development of diabetes compared with high baseline Lp(a) level, and this was prominent in those with IR than in those with impaired IS.

Long-term statin therapy could be efficacious in reducing the lipoprotein (a) levels in patients with coronary artery disease modified by some traditional risk factors

BACKGROUND

Lipoprotein (a) [Lp (a)] is a well-established risk factor for coronary artery disease (CAD). However, up till now, treatment of patients with higher Lp (a) levels is challenging. This current study aimed to investigate the therapeutic effects of short-, medium and long-term statin use on the Lp (a) reduction and its modifying factors.

METHODS

The therapeutic duration was categorized into short-term (median, 39 days), medium term (median, 219 days) and long-term (median, 677 days). The lipid profiles before therapy served as baselines. Patients at short-, medium or long-term exactly matched with those at baseline. Every patient's lipid profiles during the follow-ups were compared to his own ones at baselines.

RESULTS

The current study demonstrated that long-term statin therapy significantly decreased the Lp (a) levels in CAD patients while short-term or medium term statin therapy didn't. When grouped by statin use, only long-term simvastatin use significantly decreased the Lp (a) levels while long-term atorvastatin use insignificantly decreased the Lp (a) levels. Primary hypertension (PH), DM, low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) could modify the therapeutic effects of statin use on the Lp (a) levels in CAD patients.

CONCLUSIONS

The long-term statin therapy could be efficacious in reducing the Lp (a) levels in CAD patients, which has been modified by some traditional risk factors. In the era of commercial unavailability of more reliable Lp (a) lowering drugs, our findings will bolster confidence in fighting higher Lp (a) abnormalities both for patients and for doctors.

Lipoprotein(a) and incident type-2 diabetes: results from the prospective Bruneck study and a meta-analysis of published literature

Aims

We aimed to (1) assess the association between lipoprotein(a) [Lp(a)] concentration and incident type-2 diabetes in the Bruneck study, a prospective population-based study, and (2) combine findings with evidence from published studies in a literature-based meta-analysis.

Methods

We used Cox proportional hazards models to calculate hazard ratios (HR) for incident type-2 diabetes over 20 years of follow-up in 815 participants of the Bruneck study according to their long-term average Lp(a) concentration. For the meta-analysis, we searched Medline, Embase and Web of Science for relevant prospective cohort studies published up to October 2016.

Results

In the Bruneck study, there was a 12% higher risk of type-2 diabetes for a one standard deviation lower concentration of log Lp(a) (HR = 1.12 [95% CI 0.95–1.32]; P = 0.171), after adjustment for age, sex, alcohol consumption, body mass index, smoking status, socioeconomic status, physical activity, systolic blood pressure, HDL cholesterol, log high-sensitivity C-reactive protein and waist–hip ratio. In a meta-analysis involving four prospective cohorts with a total of 74,575 participants and 4514 incident events, the risk of type-2 diabetes was higher in the lowest two quintiles of Lp(a) concentrations (weighted mean Lp(a) = 3.3 and 7.0 mg/dL, respectively) compared to the highest quintile (62.9 mg/dL), with the highest risk of type-2 diabetes seen in quintile 1 (HR = 1.28 [1.14–1.43]; P < 0.001).

Conclusions

The current available evidence from prospective studies suggests that there is an inverse association between Lp(a) concentration and risk of type-2 diabetes, with a higher risk of type-2 diabetes at low Lp(a) concentrations (approximately <7 mg/dL).

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0520-z) contains supplementary material, which is available to authorized users.

Fasting glycemia and glycated hemoglobin categories: Relationship to serum lipoprotein(a) level and disparity in 2 geographic regional groups of Turkey

OBJECTIVE

The goal of the present study was to determine covariates of serum lipoprotein (Lp) (a) within fasting glucose and glycated hemoglobin (HbA1c) categories, and to detect features that were different among covariates based on residence in Marmara and Central Anatolia (Marm-CA) regions or remaining 5 geographic regions of Turkey.

METHODS

Data of randomly-selected group of 1167 men and women (mean age 61 years) who participated in biennial surveys of 2013 and 2015 were cross-sectionally analyzed in 6 categories.

RESULTS

In multiple linear regression analysis of nondiabetic women, homeostatic model assessment (HOMA) index score was inversely associated with Lp(a) (ß coefficient 0.49; p=0.001); this was not true for men. In the whole sample, Lp(a) was significantly positively associated with female sex and with serum creatinine, and inversely in each sex with HOMA index (ß coefficient 0.63; p<0.001). Linear models within separate categories showed significant associations of Lp(a) only in individuals with no evidence of diabetes other than HbA1c >6.5%: in women, positive association with total cholesterol and inverse relationship with creatinine were found, and in men, positive association with apolipoprotein (apo) B was determined. Similar age, diastolic blood pressure, fasting glucose, triglyceride, uric acid, and C-reactive protein values were obtained from participants of 2 regional groups. Residents of the Marm-CA region who were nondiabetic exhibited significantly (by 23%) lower serum Lp(a) among individuals with HbA1c ≥5.7%, significantly higher HOMA index score, concentrations of apoB, and low-density lipoprotein cholesterol.

CONCLUSION

Hallmark of prediabetic and diabetic glycemia/HbA1c categories seems to be an independent inverse association between Lp(a) protein (yet not of apoB) and HOMA score, this being primarily so in residents of Marm-CA region.

Association between lipoprotein(a) and nonalcoholic fatty liver disease among Korean adults

BACKGROUND

Lipoprotein(a) [Lp(a)] and nonalcoholic fatty liver disease (NAFLD) are risk factors for cardiovascular diseases. We investigated the relationship between Lp(a) concentrations and NAFLD among Korean adults.

METHODS

A total of 2242 nondiabetic subjects undergoing routine health screening examination were enrolled. Anthropometric and biochemical parameters, including Lp(a) were measured. NAFLD were assessed by ultrasonography. Adjusted Odds ratios for the presence of NAFLD according to Lp(a) tertiles were estimated using logistic regression.

RESULTS

Subjects were grouped according to the severity of NAFLD and Lp(a) concentrations. Lp(a) concentrations were decreased across the severity of NAFLD and the prevalence of NAFLD decreased with the Lp(a) tertiles. Compared with subjects in the lowest tertile of Lp(a), those in the highest tertile had higher total cholesterol and LDL-C concentrations and lower body mass index, blood pressure, fasting glucose, triglyceride, ALT, and HOMA-IR concentrations. In the logistic regression analysis after adjusting for multiple risk factors, the relationship between Lp(a) concentrations and the presence of NAFLD remained significant. However, this association was attenuated after adjusting for insulin resistance.

CONCLUSIONS

Lp(a) was inversely associated with the presence of NAFLD, but it was not an independent risk factor for NAFLD among Korean adults.

Lipoprotein(a): novel target and emergence of novel therapies to lower cardiovascular disease risk

PURPOSE OF REVIEW

This article summarizes recent observations on the role of lipoprotein(a) [Lp(a)] as a risk factor mediating cardiovascular disease.

RECENT FINDINGS

Lp(a) is a highly prevalent cardiovascular risk factor, with levels above 30 mg/dl affecting 20-30% of the global population. Up until now, no specific therapies have been developed to lower Lp(a) levels. Three major levels of evidence support the notion that elevated Lp(a) levels are a causal, independent, genetic risk factor for cardiovascular disease: epidemiologic studies and meta-analyses, genome-wide association studies and Mendelian randomization studies. Recent studies also have noted that individuals with low levels of Lp(a) are associated with a higher risk of incident type 2 diabetes mellitus, and conversely individuals with high levels have a lower risk, but this association does not appear to be causal. Novel therapies to lower Lp(a) include PCSK9 inhibitors and antisense oligonucleotides directly preventing translation of apolipoprotein(a) mRNA.

SUMMARY

With this robust and expanding clinical database, a reawakening of interest in Lp(a) as clinical risk factor is taking place. Trials are underway with novel drugs that substantially lower Lp(a) and may reduce its contribution to cardiovascular disease.

Fatty liver disease: Disparate predictive ability for cardiometabolic risk and all-cause mortality

AIM: To assess the association of a surrogate of fatty liver disease (FLD) with incident type-2 diabetes, coronary heart disease, and all-cause mortality.

METHODS: In a prospective population-based study on 1822 middle-aged adults, stratified to gender, we used an algorithm of fatty liver index (FLI) to identify associations with outcomes. An index ≥ 60 indicated the presence of FLD. In Cox regression models, adjusted for age, smoking status, high-density lipoprotein cholesterol, and systolic blood pressure, we assessed the predictive value of FLI for incident diabetes, coronary heart disease (CHD), and all-cause mortality.

RESULTS: At a mean 8 year follow-up, 218 and 285 incident cases of diabetes and CHD, respectively, and 193 deaths were recorded. FLD was significantly associated in each gender with blood pressure, total cholesterol, apolipoprotein B, uric acid, and C-reactive protein; weakly with fasting glucose; and inversely with high-density lipoprotein-cholesterol and sex hormone-binding globulin. In adjusted Cox models, FLD was (with a 5-fold HR) the major determinant of diabetes development. Analyses further disclosed significant independent prediction of CHD by FLD in combined gender [hazard ratio (HR) = 1.72, 95% confidence interval (CI): 1.17-2.53] and men (HR = 2.35, 95%CI: 1.25-4.43). Similarly-adjusted models for all-cause mortality proved, however, not to confer risk, except for a tendency in prediabetics and diabetic women.

CONCLUSION: A surrogate of FLD conferred significant high risk of diabetes and coronary heart disease, independent of some metabolic syndrome traits. All-cause mortality was not associated with FLD, except likely in the prediabetic state. Such a FLI may reliably be used in epidemiologic studies.

Lipoprotein (a): impact by ethnicity and environmental and medical conditions

Levels of lipoprotein (a) [Lp(a)], a complex between an LDL-like lipid moiety containing one copy of apoB, and apo(a), a plasminogen-derived carbohydrate-rich hydrophilic protein, are primarily genetically regulated. Although stable intra-individually, Lp(a) levels have a skewed distribution inter-individually and are strongly impacted by a size polymorphism of the LPA gene, resulting in a variable number of kringle IV (KIV) units, a key motif of apo(a). The variation in KIV units is a strong predictor of plasma Lp(a) levels resulting in stable plasma levels across the lifespan. Studies have demonstrated pronounced differences across ethnicities with regard to Lp(a) levels and some of this difference, but not all of it, can be explained by genetic variations across ethnic groups. Increasing evidence suggests that age, sex, and hormonal impact may have a modest modulatory influence on Lp(a) levels. Among clinical conditions, Lp(a) levels are reported to be affected by kidney and liver diseases.

Relationship of the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio to the remainder of the lipid profile: The Very Large Database of Lipids-4 (VLDL-4) study

BACKGROUND

High levels of the triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio are associated with obesity, metabolic syndrome, and insulin resistance.

OBJECTIVES

We evaluated variability in the remaining lipid profile, especially remnant lipoprotein particle cholesterol (RLP-C) and its components (very low-density lipoprotein cholesterol subfraction 3 and intermediate-density lipoprotein cholesterol), with variability in the TG/HDL-C ratio in a very large study cohort representative of the general U.S.

METHODS

We examined data from 1,350,908 US individuals who were clinically referred for lipoprotein cholesterol ultracentrifugation (Atherotech, Birmingham, AL) from 2009 to 2011. Demographic information other than age and sex was not available. Changes to the remaining lipid profile across percentiles of the TG/HDL-C ratio were quantified, as well as by three TG/HDL-C cut-off points previously proposed in the literature: 2.5 (male) and 2 (female), 3.75 (male) and 3 (female), and 3.5 (male and female).

RESULTS

The mean age of our study population was 58.7 years, and 48% were men. The median TG/HDL-C ratio was 2.2. Across increasing TG/HDL-C ratios, we found steadily increasing levels of RLP-C, non-HDL-C and LDL density. Among the lipid parameters studied, RLP-C and LDL density had the highest relative increase when comparing individuals with elevated TG/HDL-C levels to those with lower TG/HDL-C levels using established cut-off points. Approximately 47% of TG/HDL-C ratio variance was attributable to RLP-C.

CONCLUSIONS

In the present analysis, a higher TG/HDL-C ratio was associated with an increasingly atherogenic lipid phenotype, characterized by higher RLP-C along with higher non-HDL-C and LDL density.

Type-2 diabetes and coronary heart disease: common physiopathology, viewed from autoimmunity

Two highly prevalent diseases, Type-2 diabetes mellitus and coronary heart disease (CHD), share risk factors. Excess levels of LDL-cholesterol have been overemphasized to uniformly encompass the development of CHD, and the origin of insulin resistance underlying Type-2 diabetes has not been fully elucidated. Autoimmune response has been recognized to be responsible only of a small minority of diabetes. The increasing trend in the worldwide prevalence of diabetes and the risk factors for both diseases are reviewed, the independent mediation for CHD of (central) adiposity in both diseases and the 'hypertriglyceridemic waist' phenotype are outlined. Evidence is described that serum lipoprotein (Lp)(a) concentrations, not only in excess, but also in apparently 'reduced' levels, as a result of autoimmune response, underlie both disorders and are closely related to insulin resistance.

Relationships of plasma lipoprotein(a) levels with insulin resistance in hypertensive patients

BACKGROUND

Lipoprotein(a) [Lp(a)] is an emergent cardiovascular risk factor that is related to the presence and severity of cardiovascular damage in hypertensive patients. In these patients, insulin resistance is frequently detected but its relationship with plasma Lp(a) is not clear. The aim of this study was to examine the relationships between Lp(a) and variables of glucose metabolism in hypertension.

METHODS

In 527 consecutive, non-diabetic, middle-aged hypertensive patients we measured anthropometric indexes, 24-hour creatinine clearance, lipid profile including Lp(a) levels, fasting glucose, insulin and C-peptide, and calculated the Homeostatic Model Assessment (HOMA) index.

RESULTS

Lp(a) levels were significantly and progressively lower with increasing HOMA-index values. Lp(a) was inversely related to fasting glucose, insulin, and C-peptide, HOMA-index, and creatinine clearance and directly related to LDL-cholesterol. Multiple regression analysis adjusted for age, sex, body mass index, blood pressure, smoking habit, alcohol intake, renal function, lipid profile, history of cardiovascular events, and drug use showed that HOMA-index and creatinine clearance were inversely and independently associated to Lp(a) levels.

CONCLUSIONS

Insulin resistance and higher fasting insulin levels are associated with lower plasma Lp(a) in hypertensive patients. This association might be relevant in the assessment of cardiovascular risk in these patients.

Lipoprotein (a): gene genie

PURPOSE OF REVIEW

Despite being both the longest known and the most prevalent genetic risk marker for atherosclerotic cardiovascular disease (CVD), little progress has been made in agreeing a role for lipoprotein (a) [Lp(a)] in clinical practice and developing therapies with specific Lp(a)-lowering activity. We review barriers to progress, and discuss areas of controversy which are important to future research.

RECENT FINDINGS

Epidemiological and genetic studies have supported a causal role for Lp(a) in accelerated atherosclerosis, independent of other risk factors. Progress continues to be made in the understanding of Lp(a) metabolism, and Lp(a) levels, rather than apolipoprotein (a) isoform size, have been shown to be more closely related to CVD risk. Selective Lp(a) apheresis has offered some evidence that Lp(a)-lowering can improve cardiovascular end-points.

SUMMARY

We have acquired a great deal of knowledge about Lp(a), but this has not yet led to reductions in CVD. This is at least partially due to disagreement over Lp(a) measurement methodologies, its physiological role and the importance of the elevations seen in renal diseases, diabetes mellitus and familial hypercholesterolaemia. Renewed focus is required to bring assays into clinical practice to accompany new classes of therapeutic agents with Lp(a)-lowering effects.

The association between circulating lipoprotein(a) and type 2 diabetes: is it causal?

Epidemiological evidence supports a direct and causal association between lipoprotein(a) [Lp(a)] levels and coronary risk, but the nature of the association between Lp(a) levels and risk of type 2 diabetes (T2D) is unclear. In this study, we assessed the association of Lp(a) levels with risk of incident T2D and tested whether Lp(a) levels are causally linked to T2D. We analyzed data on 18,490 participants from the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort that included adults aged 40-79 years at baseline 1993-1997. During an average 10 years of follow-up, 593 participants developed incident T2D. Cox regression models were used to estimate the association between Lp(a) levels and T2D. In Mendelian randomization analyses, based on EPIC-Norfolk combined with DIAbetes Genetics Replication And Meta-analysis data involving a total of 10,088 diabetes case participants and 68,346 control participants, we used a genetic variant (rs10455872) as an instrument to test whether the association between Lp(a) levels and T2D is causal. In adjusted analyses, there was an inverse association between Lp(a) levels and T2D: hazard ratio was 0.63 (95% CI 0.49-0.81; P trend = 0.003) comparing the top versus bottom quintile of Lp(a). In EPIC-Norfolk, a 1-SD increase in logLp(a) was associated with a lower risk of T2D (odds ratio [OR] 0.88 [95% CI: 0.80-0.95]). However, in Mendelian randomization analyses, a 1-SD increase in logLp(a) due to rs10455872, which explained 26.8% of the variability in Lp(a) levels, was not associated with risk of T2D (OR 1.03 [0.96-1.10]; P = 0.41). These prospective findings demonstrate a strong inverse association of Lp(a) levels with risk of T2D. However, a genetic variant that elevated Lp(a) levels was not associated with risk of T2D, suggesting that elevated Lp(a) levels are not causally associated with a lower risk of T2D.

Lipoprotein(a) concentrations, isoform size, and risk of type 2 diabetes: a Mendelian randomisation study

BACKGROUND

Low concentrations of lipoprotein(a) in plasma are associated with increased risk of type 2 diabetes, but whether this association is causal is unclear. Variations in the LPA gene affect lipoprotein(a) isoform size and concentrations in plasma. We therefore did a Mendelian randomisation study to investigate whether large isoform size, low concentrations in plasma, or both, are causally associated with type 2 diabetes.

METHODS

We assessed data for adults from the Danish general population enrolled in the Copenhagen City Heart Study and the Copenhagen General Population Study, with and without type 2 diabetes. Eligible participants had data for lipoprotein(a) concentrations in plasma, LPA kringle IV type 2 (KIV-2) sums of repeats (affecting both isoform size and plasma concentrations), and carrier status for the LPA single-nucleotide polymorphism rs10455872 (mainly affecting concentrations in plasma).

FINDINGS

77,901 individuals had lipoprotein(a) data, of whom 28,567 (36·7%) had all three measurements. Low concentrations of lipoprotein(a) in plasma were associated with risk of type 2 diabetes, with adjusted odds ratios of 1·26 (1·09-1·45), 1·17 (1·01-1·36), 1·04 (0·90-1·21), and 1·05 (95% CI 0·90-1·22), respectively, for quintiles 1-4, compared with quintile 5 concentrations. High KIV-2 sums of repeats were associated with risk of type 2 diabetes (adjusted odds ratio 1·16, 95% CI 1·05-1·28) for KIV-2 quintile 5 versus quintiles 1-4 combined. Being a carrier of rs10455872 did not affect risk of type 2 diabetes. For a halving of lipoprotein(a) concentrations, the instrumental variable estimate of the causal odds ratio for type 2 diabetes was 1·15 (95% CI 1·05-1·27) for KIV-2 sum of repeats and 0·99 (0·95-1·03) for rs10455872 genotype.

INTERPRETATION

Low lipoprotein(a) concentrations alone seem not to be causally associated with type 2 diabetes, but a causal association for large lipoprotein(a) isoform size cannot be excluded.

FUNDING

Danish Heart Foundation, Danish Council for Independent Research-Medical Sciences, IMK Almene Fund, and Johan and Lise Boserup's Fund.

Lipoprotein(a) is not related to markers of insulin resistance in pregnancy

BACKGROUND

Dyslipidemia, a major risk factor for cardiovascular disease is a common finding in patients with type 2 diabetes and among women with gestational diabetes. Elevated levels of lipoprotein(a) [Lp(a)] are linked to increased risk of cardiovascular disease. However, its relationship with insulin resistance, type 2 diabetes and gestational diabetes is controversial and unproven. Here we aimed to clarify whether Lp(a) levels are associated with insulin sensitivity in pregnancy.

METHODS

Sixty-four women with gestational diabetes and 165 with normal glucose tolerance were enrolled in the study. Fasting Lp(a) serum levels were measured in all women at 24-28 weeks of gestation.

RESULTS

In pregnancy, there was no significant difference in serum Lp(a) concentrations between the two groups. Its level did not correlate with markers of insulin resistance (HOMA-IR), insulin sensitivity (HOMA-S%), pancreatic beta-cell function (HOMA-B%) and insulin sensitivity in dynamic conditions (OGIS). In addition, fasting glucose and insulin levels and those throughout an oral glucose tolerance test were independent of Lp(a) concentrations in our study group.

CONCLUSIONS

Lp(a) levels in pregnant women do not differ with respect to the presence or absence of gestational diabetes. Although influenced by some components of the lipid profile, such as triglycerides and HDL-C, insulin resistance in pregnancy is not affected by Lp(a).

Variations of lipoprotein(a) levels in the metabolic syndrome: a report from the Maracaibo City Metabolic Syndrome Prevalence Study

BACKGROUND

Lipoprotein(a) [Lp(a)] is a known risk factor for cardiovascular disease, yet its influence on metabolic syndrome (MS) is still controversial. The purpose of this study was to assess the impact generated by this diagnosis in serum Lp(a) concentrations.

MATERIALS AND METHODS

A total of 1807 subjects of both genders (55.3% women and 44.7% men) belonging to the Maracaibo City Metabolic Syndrome Prevalence Study were evaluated. Results were expressed as Mean ± SD, determining differences through Student's t-test and One-Way ANOVA test. Multiple logistic regression models were utilized for analyzing factors associated with elevated serum Lp(a) levels and MS. Total cholesterol and LDL-C were corrected according to Lp(a)-Cholesterol when necessary.

RESULTS

No differences were found in Lp(a) values between genders; P = 0,292. The association between MS and the classification of Lp(a) was statistically significant (χ (2) = 28.33; P < 0,0001), with greater levels in subjects with this diagnosis. In the univariate analysis, subjects with each of the separate diagnostic criteria showed higher serum Lp(a) concentrations, except for hyperglycemia.

CONCLUSIONS

Lp(a) values exhibit important variations regarding MS and each of its components. Impaired fasting glucose appeared as a protecting factor against elevated Lp(a) concentrations, whereas its association with LDL-C and hs-CRP suggests a potential pro-inflammatory role.

Lipoprotein(a): resurrected by genetics

Plasma lipoprotein(a) [Lp(a)] is a quantitative genetic trait with a very broad and skewed distribution, which is largely controlled by genetic variants at the LPA locus on chromosome 6q27. Based on genetic evidence provided by studies conducted over the last two decades, Lp(a) is currently considered to be the strongest genetic risk factor for coronary heart disease (CHD). The copy number variation of kringle IV in the LPA gene has been strongly associated with both Lp(a) levels in plasma and risk of CHD, thereby fulfilling the main criterion for causality in a Mendelian randomization approach. Alleles with a low kringle IV copy number that together have a population frequency of 25-35% are associated with a doubling of the relative risk for outcomes, which is exceptional in the field of complex genetic phenotypes. The recently identified binding of oxidized phospholipids to Lp(a) is considered as one of the possible mechanisms that may explain the pathogenicity of Lp(a). Drugs that have been shown to lower Lp(a) have pleiotropic effects on other CHD risk factors, and an improvement of cardiovascular endpoints is up to now lacking. However, it has been established in a proof of principle study that lowering of very high Lp(a) by apheresis in high-risk patients with already maximally reduced low-density lipoprotein cholesterol levels can dramatically reduce major coronary events.

Lipoprotein(a) and cardiovascular disease in diabetic patients

Lipoprotein(a) (Lp[a]) is a LDL-like particle consisting of an ApoA moiety linked to one molecule of ApoB(100). Recent data from large-scale prospective studies and genetic association studies provide highly suggestive evidence for a potentially causal role of Lp(a) in affecting risk of cardiovascular disease (CVD) in general populations. Patients with Type 2 diabetes display clustered metabolic abnormalities and elevated risk of CVD. Lower plasma Lp(a) levels were observed in diabetic patients in several recent studies. Epidemiology studies of Lp(a) and CVD risk in diabetic patients generated inconsistent results. We recently found that Lp(a)-related genetic markers did not predict CVD in two diabetic cohorts. The current data suggest that Lp(a) may differentially affect cardiovascular risk in diabetic patients and in the general population. More prospective studies, Mendelian randomization analysis and functional studies are needed to clarify the causal relationship of Lp(a) and CVD in diabetic patients.

High levels of lipoprotein(a) are associated with a lower prevalence of diabetes with advancing age: results of a cross-sectional epidemiological survey in Gran Canaria, Spain

BACKGROUND

Recent data suggest that concentrations of lipoprotein(a) [Lp(a)] may be inversely associated with the risk of diabetes. This study analyzed the relationships between Lp(a) and both diabetes and insulin resistance in an adult cohort from the island of Gran Canaria, Spain.

METHODS

Lp(a), homeostasis model assessment for insulin resistance (HOMA-IR) and conventional risk factors for diabetes were assessed in a sample of 1,030 adult individuals participating in a cross-sectional population-based epidemiological survey in the city of Telde. Diabetes was defined according to the WHO 1999 criteria, or as a previous diagnosis of diabetes. To identify patients at risk for diabetes, an Lp(a) cutoff level of 46 mg/dl was selected previously using classification and regression tree analysis. A multivariate logistic regression model with L2-regularization was used to assess the independent effect of Lp(a) on diabetes and its interactions with variables traditionally linked to the disease. Additionally, to investigate the effect of Lp(a) on insulin resistance, a parametric model was developed to describe the relationship between age and HOMA-IR values in subjects with levels of Lp(a) ≤ 46 or >46 mg/dl.

RESULTS

Along with variables known to be associated with diabetes, including age, mean blood pressure, serum triglycerides, and an interaction term between age and low HDL cholesterol, the logistic model identified a significant inverse association for diabetes and the interaction term between age and Lp(a) levels >46 mg/dl. According to the proposed parametric model, HOMA-IR was significantly lower in subjects of all ages who had Lp(a) levels >46 mg/dl.

CONCLUSIONS

These results suggest that the age-related increase in the probability of having diabetes is significantly lower in subjects with Lp(a) levels >46 mg/dl. This could be explained in part by a lower insulin resistance in this subset of the population.

Lipoprotein(a) in type 2 diabetic subjects and its relationship to diabetic microvascular complications

AIM: To estimate the level of serum lipoprotein (a) [Lp (a)] in type 2 diabetes mellitus patients and to determine the relationship between Lp(a) in type 2 diabetes mellitus patients and micro-vascular complications.

METHODS: A cross sectional study was performed that enrolled 144 subjects with type 2 diabetes mellitus above the age of 25 years attending outpatient clinic of Government Medical College, Kozhikode. Lp(a) levels were measured quantitatively in venous samples using Turbidimetric Immunoassay in all subjects. Each patient was evaluated for micro vascular complications, namely diabetic retinopathy, nephropathy and neuropathy. The relationship between Lp(a) levels and the micro vascular complications was assessed by univariate analysis.

RESULTS: Mean age of cases was 53.93 ± 10.74 years with a male to female ratio of 1.3:1. Mean duration of diabetes was 9.53 ± 7.3 years. Abnormal Lp(a) levels (≥ 30 mg/dL) were observed in 38 (26.4%) diabetic subjects. Seventy-eight (54.16%) cases had diabetic nephropathy and significantly higher Lp(a) levels were found among these cases [Median 28.2 mg/dL (Interquartile range; IQR 24.4-33.5) vs 19.3 mg/dL (IQR 14.7-23.5); P < 0.05]. Retinopathy was present among 66 (45.13%) cases and peripheral neuropathy was detected among 54 (37.5%) cases. However, Lp(a) levels were not significantly different among those with or without retinopathy and neuropathy. Positive correlation was found between higher Lp(a) levels and duration of diabetes (r = 0.165, P < 0.05) but not with HbA1c values (r = – 0.083).

CONCLUSION: Abnormal Lp(a) levels were found among 26.4% of diabetic subjects. Patients with diabetic nephropathy had higher Lp(a) levels. No association was found between Lp(a) levels and diabetic retinopathy or neuropathy. Longer duration of diabetes correlated with higher Lp(a) levels.

Genetic variants, plasma lipoprotein(a) levels, and risk of cardiovascular morbidity and mortality among two prospective cohorts of type 2 diabetes

AIMS

To examine the relations between genetic loci, plasma lipoprotein(a) [Lp(a)] levels, and cardiovascular disease (CVD) risk among diabetic patients and compare with the observations in the general population.

METHODS AND RESULTS

In two prospective cohorts of patients with type 2 diabetes (n= 2308) from the Nurses' Health Study and the Health Professional Follow-Up Study, we performed (i) genome-wide association (GWA) scans for plasma Lp(a); (ii) prospective analysis of plasma Lp(a) for CVD risk and mortality; and (iii) genetic association analysis for CVD risk and mortality. Meta-analysis of the two GWA scans yielded 71 single-nucleotide polymorphisms (SNPs) on chromosome 6q associated with plasma Lp(a) levels at a genome-wide significance level (P< 5 × 10(-8)). The SNP rs10455872 in LPA was most strongly associated with Lp(a) (P= 4.60 × 10(-39)). Forward-selection analysis indicated that rs10455872 and other five SNPs in a region encompassing LPA, PLG, SLC22A3, and LPAL2 genes were independently associated with Lp(a) levels and jointly explained ∼20% of variation in diabetic patients. In prospective analysis, we did not find any significant association between plasma levels and CVD incidence; the relative risk for coronary heart disease (CHD), CVD, and CVD death was 1.05 [95% confidence interval (CI): 0.95-1.15], 1.05 (0.96-1.15), and 1.21 (0.99-1.47) per 1-SD higher log-transformed Lp(a) levels, respectively. Consistently, none of the Lp(a) SNPs were associated with CVD risk or mortality (all P> 0.09). For the best SNP rs10455872 for plasma Lp(a) levels, the OR for CHD, CVD, and CVD death was 0.94 (95% CI: 0.69-1.28), 0.97 (0.72-1.29), and 1.23 (0.79-1.92), respectively. The genetic effect on CHD risk showed a significant heterogeneity between the diabetic and the general populations (P= 0.006).

CONCLUSION

Our data indicate that the effect of Lp(a) on CVD risk among diabetic patients might be different from that in the general population. Diabetes status may attenuate the relation between Lp(a) and cardiovascular risk.

Lipoprotein(a) and risk of type 2 diabetes

BACKGROUND

Previous studies have demonstrated that cardiovascular risk is higher with increased lipoprotein(a) [Lp(a)]. Whether Lp(a) concentration is related to type 2 diabetes is unclear.

METHODS

In 26 746 healthy US women (mean age 54.6 years), we prospectively examined baseline Lp(a) concentrations and incident type 2 diabetes (n = 1670) for a follow-up period of 13 years. We confirmed our findings in 9652 Danish men and women with prevalent diabetes (n = 419). Analyses were adjusted for risk factors that included age, race, smoking, hormone use, family history, blood pressure, body mass index, hemoglobin A(1c) (Hb A(1c)), C-reactive protein, and lipids.

RESULTS

Lp(a) was inversely associated with incident diabetes, with fully adjusted hazard ratios (HRs) and 95% CIs for quintiles 2-5 vs quintile 1 of 0.87 (0.75-1.01), 0.80 (0.68-0.93), 0.88 (0.76-1.02), and 0.78 (0.67-0.91); P for trend 0.002. The association was stronger in nonfasting women, for whom respective HRs were 0.79 (0.58-1.09), 0.78 (0.57-1.08), 0.66 (0.46-0.93), and 0.56 (0.40-0.80); P for trend 0.001; P for interaction with fasting status 0.002. When we used Lp(a) > or =10 mg/L and Hb A(1c) <5% as reference values, the adjusted HRs were 1.62 (0.91-2.89) for Lp(a) <10 mg/L and Hb A(1c) <5%, 3.50 (3.06-4.01) for Lp(a) > or =10 mg/L and Hb A(1c) 5%-<6.5%, and 5.36 (4.00-7.19) for Lp(a) <10 mg/L and Hb A(1c) 5%-<6.5%. Results were similar in nonfasting Danish men and women, for whom adjusted odds ratios were 0.75 (0.55-1.03), 0.64 (0.46-0.88), 0.74 (0.54-1.01), and 0.58 (0.42-0.79) for Lp(a) quintiles 2-5 vs quintile 1; P for trend 0.002.

CONCLUSIONS

Our results indicated that Lp(a) was associated inversely with risk of type 2 diabetes independently of risk factors, in contrast to prior findings of positive associations of Lp(a) with cardiovascular risk.

Levels of sex steroid and cardiovascular disease measures in premenopausal and hormone-treated women at midlife: implications for the "timing hypothesis"

BACKGROUND

The "timing hypothesis," in addressing findings from the Women's Health Initiative trial, suggests that hormone therapy (HT) should be initiated within 6 years of the menopause transition to extend a favorable estrogenic environment after menopause.

METHODS

We compared sex steroid and cardiovascular profiles at the 5-year follow-up visit in a community-based, longitudinal study of the menopause transition (Study of Women's Health Across the Nation). Women aged 47 to 57 years were in 1 of 4 groups: premenopausal, women using conjugated equine estrogen with or without progestin, or postmenopausal (<5 years) without HT use. Cardiovascular assays included low-density lipoprotein cholesterol, oxidized low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoproteins A-I and B, F(2a)-isoprostanes, C-reactive protein, and lipoprotein (a)-1. Sex steroid assays were performed for estradiol, estrogen receptor ligand load, 2-hydroxyestrone, 16alpha-hydroxyestrone, total testosterone, and sex hormone-binding globulin.

RESULTS

Users of HT had 50% higher levels of sex hormone-binding globulin (P < .001 for both HT groups), which limits binding of sex steroids to their receptors, and higher excreted estrone metabolites (more than 60%; P < .001 for both HT groups) than premenopausal or postmenopausal women. These findings were, in turn, associated with higher levels of F(2a)-isoprostanes, an oxidative stress measure, than in premenopausal women. The HT users had a more favorable ratio of high-density to low-density lipoprotein cholesterol than did premenopausal or postmenopausal women (P < .01), but higher triglyceride levels (P < .01).

CONCLUSION

Although HT users had some more favorable lipid profiles than premenopausal and postmenopausal women, there was evidence of adverse HT effects even in women free of atherosclerosis studied within the approximate 6-year period proposed with the timing hypothesis.

Lipoprotein(a) is associated with coronary heart disease independent of metabolic syndrome

AIM

To assess (i) the association between lipoprotein(a) [Lp(a)] with the likelihood of coronary heart disease and metabolic syndrome (MS) and (ii) its covariates in Turkish adults.

METHODS

Cross-sectional evaluation of 1309 adults, who had serum Lp(a) determinations by Behring nephelometry, and followed for a mean 1.0 year. MS was defined by ATPIII criteria modified for male abdominal obesity.

RESULTS

Mean age of the sample was 56.8+/-11.3 years. After adjustment for sex, age, and smoking status, log-transformed Lp(a) levels were associated significantly with coronary heart disease likelihood in both sexes combined [odds ratio: 1.53 (95% confidence interval: 1.06; 2.20)]. This association persisted after additional adjustment for MS [odds ratio: 1.57 (95% confidence interval: 1.09; 2.26)]. The Lp(a) mid-tertile (5-17 mg/dl), accompanied by significantly lower serum triglycerides than the two remaining tertiles, was inversely associated significantly with MS in either sex; in women, this association was independent of waist circumference. In a linear regression comprising seven variables, excepting total cholesterol, only gamma-glutamyltransferase in women (P=0.002) and waist circumference (P=0.057) in men were inverse covariates of modest magnitude of Lp(a).

CONCLUSION

Coronary heart disease likelihood, significantly associated with Lp(a) concentrations, is independent of MS and insulin resistance. Suggestive evidence was provided that intermediary Lp(a) concentrations, when accompanied by the presence of MS, could accelerate progression of vascular disease, especially in women.