Serum lipoprotein(a) in patients with diabetes mellitus

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.

Association between lipoprotein(a) level and type 2 diabetes: no evidence for a causal role of lipoprotein(a) and insulin

AIMS

Inverse relationships have been described between the largely genetically determined levels of serum/plasma lipoprotein(a) [Lp(a)], type 2 diabetes (T2D) and fasting insulin. Here, we aimed to evaluate the nature of these relationships with respect to causality.

METHODS

We tested whether we could replicate the recent negative findings on causality between Lp(a) and T2D by employing the Mendelian randomization (MR) approach using cross-sectional data from three independent cohorts, Berlin Aging Study II (BASE-II; n = 2012), LIFE-Adult (n = 3281) and LIFE-Heart (n = 2816). Next, we explored another frequently discussed hypothesis in this context: Increasing insulin levels during the course of T2D disease development inhibits hepatic Lp(a) synthesis and thereby might explain the inverse Lp(a)-T2D association. We used two fasting insulin-associated variants, rs780094 and rs10195252, as instrumental variables in MR analysis of n = 4937 individuals from BASE-II and LIFE-Adult. We further investigated causality of the association between fasting insulin and Lp(a) by combined MR analysis of 12 additional SNPs in LIFE-Adult.

RESULTS

While an Lp(a)-T2D association was observed in the combined analysis (meta-effect of OR [95% CI] = 0.91 [0.87-0.96] per quintile, p = 1.3x10^-4), we found no evidence of causality in the Lp(a)-T2D association (p = 0.29, fixed effect model) when using the variant rs10455872 as the instrumental variable in the MR analyses. Likewise, no evidence of a causal effect of insulin on Lp(a) levels was found.

CONCLUSIONS

While these results await confirmation in larger cohorts, the nature of the inverse Lp(a)-T2D association remains to be elucidated.

Lipoprotein (a) is not significantly associated with type 2 diabetes mellitus: cross-sectional study of 1604 cases and 7983 controls

AIMS

Lipoprotein (a) (Lp(a)), a well-established risk factor for coronary artery diseases (CAD), would also be anticipated to be associated in a similar manner with risk of type 2 diabetes mellitus (T2DM) based on the common soil hypothesis of etiology of T2DM and CAD. Unfortunately, there remains considerable uncertainty regarding the association of Lp(a) with the risk of T2DM. We aimed to examine the association of Lp(a) with T2DM.

METHODS

Cross-sectional study of 1604 cases and 7983 controls was performed for identifying the association of Lp(a) with T2DM, its possible interactions with risk factors and threshold effects on T2DM. The association of Lp(a) with CAD was also examined and compared within the same study.

RESULTS

On a continuous scale, 10 mg/L higher Lp(a) levels were insignificantly associated with a fully adjusted OR of 1.011, 95% CI 0.961-1.063 for T2DM. On a categorical scale, the fully adjusted ORs for T2DM were 0.733 (0.526-1.022), 0.554 (0.387-0.793), 0.848 (0.612-1.176), 0.727 (0.515-1.026), 0.692 (0.488-0.981), 0.696 (0.492-0.985), 0.719 (0.509-1.016), 0.74 (0.523-1.045), 0.809 (0.571-1.146), and 0.99 (0.962-1.019) for decile 2-10 in reference to decile 1. The magnitude of association did not increase with increasing decile (P for trend test = 0.990). In contrast, higher Lp(a) levels were significantly associated with prevalent CAD on a continuous or categorical scale in a fully adjusted model. No threshold effects were observed in terms of association of Lp(a) with T2DM or with CAD in Lp(a) <50 mg/dL.

CONCLUSIONS

The current study suggested that there was a lack of association of Lp(a) levels with prevalent T2DM. In contrast, Lp(a) levels were significantly associated with CAD in a dose-responding manner. Our findings provided evidence for differential approaches to higher Lp(a) levels in patients with T2DM or with CAD.

Serum Lipoprotein (a) Levels in Black South African Type 2 Diabetes Mellitus Patients

Lipoprotein (a) (Lp(a)) which is a low-density lipoprotein-like particle containing apo(a) is considered as an emergent cardiovascular risk factor. Type 2 diabetes mellitus (T2DM) is associated with a two- to threefold increase in the risk of cardiovascular disease (CVD). The aim of this study was to investigate the levels of Lp(a) in Black South African T2DM patients and its association with other metabolic factors. 67 T2DM patients and 48 healthy control participants were recruited for the cross-sectional study. The Lp(a) level was determined by ELISA and the result was analyzed using SPSS. The Lp(a) level in diabetics was found to be significantly increased (P = 0.001) when compared to the normal healthy group. In the diabetic group, the Lp(a) levels correlated significantly with the duration of diabetes (P = 0.008) and oxidized LDL (ox-LDL) levels (P = 0.03) and decreased total antioxidant capacity (P = 0.001). The third tertile of Lp(a) was significantly correlated with increased ox-LDL, C-reactive protein, and triglycerides and decreased total antioxidant capacity.

Lipoprotein (a): structure, pathophysiology and clinical implications

The chemical structure of lipoprotein (a) is similar to that of LDL, from which it differs due to the presence of apolipoprotein (a) bound to apo B100 via one disulfide bridge. Lipoprotein (a) is synthesized in the liver and its plasma concentration, which can be determined by use of monoclonal antibody-based methods, ranges from < 1 mg to > 1,000 mg/dL. Lipoprotein (a) levels over 20-30 mg/dL are associated with a two-fold risk of developing coronary artery disease. Usually, black subjects have higher lipoprotein (a) levels that, differently from Caucasians and Orientals, are not related to coronary artery disease. However, the risk of black subjects must be considered. Sex and age have little influence on lipoprotein (a) levels. Lipoprotein (a) homology with plasminogen might lead to interference with the fibrinolytic cascade, accounting for an atherogenic mechanism of that lipoprotein. Nevertheless, direct deposition of lipoprotein (a) on arterial wall is also a possible mechanism, lipoprotein (a) being more prone to oxidation than LDL. Most prospective studies have confirmed lipoprotein (a) as a predisposing factor to atherosclerosis. Statin treatment does not lower lipoprotein (a) levels, differently from niacin and ezetimibe, which tend to reduce lipoprotein (a), although confirmation of ezetimibe effects is pending. The reduction in lipoprotein (a) concentrations has not been demonstrated to reduce the risk for coronary artery disease. Whenever higher lipoprotein (a) concentrations are found, and in the absence of more effective and well-tolerated drugs, a more strict and vigorous control of the other coronary artery disease risk factors should be sought.

Serum lipoprotein (a) concentrations are inversely associated with T2D, prediabetes, and insulin resistance in a middle-aged and elderly Chinese population

Lipoprotein (a) [Lp(a)], an LDL-like particle, has been proposed as a causal risk factor for CVD among general populations. Meanwhile, both serum Lp(a) and diabetes increase the risk of CVD. However, the relationship between serum Lp(a) and T2D is poorly characterized, especially in the Asian population. Therefore, we conducted a cross-sectional study in 10,122 participants aged 40 years or older in Jiading District, Shanghai, China. Our study found that the prevalence of T2D was decreased from 20.9% to 15.0% from the lowest quartile to the highest quartile of serum Lp(a) concentrations (P for trend <0.0001). Logistic regression analyses showed that the odds ratios and 95% confidence intervals of prevalent T2D for quartiles 2-4 versus quartile 1 were 0.86 (0.73-1.01), 0.88 (0.75-1.04), and 0.76 (0.64-0.90) (P for trend = 0.0002), after adjustment for traditional confounding factors. Moreover, the risks for prevalent prediabetes, insulin resistance, and hyperinsulinemia were also decreased from the lowest to the top quartile. This inverse association between serum Lp(a) and T2D was not appreciably changed after we adjusted hypoglycemic medications or excluded the subjects with hypoglycemic and/or lipid-lowering agents and/or a history of self-reported CVD.

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.

Lipoprotein (a), C-reactive protein and some metabolic cardiovascular risk factors in type 2 DM

BACKGROUND

Lipoprotein (a) (LP (a) is an independent cardiovascular risk factor that is not widely studied in people of sub-Saharan African origin. The aim of this report is to determine the frequency of occurrence of elevated Lp (a) and possible relationship with total cholesterol (TCHOL), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), C reactive protein (CRP) and serum uric acid (SUA).

METHODS

This is a cross sectional study carried out in 200 Nigerian patients with type 2 DM and 100 sex and age matched healthy Controls aged between 32-86 years. We determined the frequency of occurrence of elevated Lp (a) levels in the study subjects and compared clinical and biochemical variables between type 2 diabetic patients and non-diabetic patients. Clinical and biochemical parameters were also compared between subjects with type 2 DM who had elevated LP (a) and normal LP (a) levels. Long term glycaemic control using glycosylated haemoglobin was determined and compared in the study subjects. Test statistics used include chi square, correlation coefficient analysis and Student's t test.

RESULTS

The mean Lp(a) concentration differed significantly between type 2 diabetic patients and the Control subjects (18.7 (5.8) mg/dl vs 23 (6.8) mg/dl, 0.00001). Similarly, the prevalence of high LP (a) levels in type 2 DM patients was significantly higher than that of the Control subjects (12.5% vs 4%, p-0.019). The mean levels of the lipid profile parameters (TCHOL, LDL-C, TG, LDL/HDL) and CRP were significantly higher in DM patients than in the Control subjects. The mean LP (a) levels were comparable in both sexes and in DM subjects with and without hypertension. TG was the only parameter that differed significantly between subjects with elevated Lp (a) levels and those with normal Lp (a) levels. There was a significant positive correlation (r) between Lp(a) levels and TG, LDL-C. TCHOL, LDL/HDL and uric acid. No association was found between Lp(a) and clinical parameters such as age and anthropometric indices.

CONCLUSION

We have showed that Lp (a), CRP and other CVS risk factors cluster more in patients with DM than non DM patients. Serum Lp (a) levels are not associated with anthropometric and glycaemic indices.

Lipoprotein (a) in type 2 diabetes mellitus: Relation to LDL:HDL ratio and glycemic control

BACKGROUND

Increased lipoprotein (a) [Lp (a)] concentrations are predictive of coronary artery disease (CAD). Type 2 diabetes mellitus also leads to dyslipidemia, like elevated triglyceride levels and low HDL levels, which are known risk factors for CAD. This study was designed to investigate the levels of Lp (a) in type 2 diabetic patients and their association with LDL: HDL ratio and glycemic control.

MATERIALS AND METHODS

The study included 60 patients of type 2 diabetes and 50 age and sex matched controls. The Lp(a) levels in the diabetic group were compared with the control group and the relationship between the Lp(a) levels and LDL: HDL ratio was evaluated. Diabetic group was further divided into three subgroups according to levels of glycated hemoglobin. Lp(a) levels and glycated hemoglobin in controlled and uncontrolled diabetes mellitus were also compared to find out any correlation between them. Statistical analysis was done using the students 't' test and Chi square test.

RESULTS

Lp(a) levels were found to be significantly increased in the diabetic group as compared to the control group (P< 0.001). LDL: HDL ratio was also increased in the diabetic group as compared to the control group. Lp(a) levels showed no association with LDL: HDL ratio and degree of glycemic control in these patients.

CONCLUSIONS

The results of the present study suggest that Lp(a) levels are increased in type 2 diabetic patients. The elevated Lp(a) levels do not reflect the glycemic status and are also independent of increase in LDL:HDL ratio suggesting different metabolic pathways and the genetic connection for LDL and Lp(a).

Lipoprotein(a), type 2 diabetes and vascular risk in coronary patients

BACKGROUND

Lipoprotein(a) [Lp(a)] is an important cardiovascular risk factor in the general population. However, prospective data on the vascular risk conferred by Lp(a) in patients with diabetes mellitus are scarce and controversial. It is not known whether the diabetic state affects the association of Lp(a) with vascular events among coronary patients.

DESIGN

We measured Lp(a) in 587 consecutive patients undergoing coronary angiography for the evaluation of coronary artery disease. The incidence of vascular events was recorded over 4 years.

RESULTS

At baseline, Lp(a) was significantly lower in patients with type 2 diabetes (T2DM) (n = 136) than in nondiabetic individuals (11 (0.8-30) mg dL(-1) vs. 16 (0.8-51) mg dL(-1); P = 0.025). Prospectively, Lp(a) was a strong and independent predictor of vascular events in nondiabetic patients (standardized adjusted hazard ratio (HR) = 1.461 (1.121-1.904); P = 0.005), but not in patients with T2DM [HR = 0.812 (0.539-1.223); P = 0.320]. An interaction term diabetes x Lp(a) was significant (P = 0.008), indicating that Lp(a) was a significantly stronger predictor of vascular events in nondiabetic patients than in patients with T2DM.

CONCLUSIONS

Lp(a) in diabetic coronary patients is low and not associated with the incidence of vascular events. Although measurement of Lp(a) provides useful information in nondiabetic coronary patients, it is of little value in coronary patients with T2DM.

Diabetes treatments have differential effects on nontraditional cardiovascular risk factors

OBJECTIVE

The aim of this study was to determine the effect of basal insulin, alone or with a sensitizer, or a combination of oral agents on nontraditional risk factors for cardiovascular disease (CVD).

RESEARCH DESIGN AND METHODS

We randomized 57 patients with T2DM to either (1) continuous subcutaneous basal Lispro insulin at a single rate using an insulin pump (basal insulin) or (2) basal insulin and oral pioglitazone 30 mg daily (basal insulin +Pio) or (3) a sulfonylurea and metformin (SU+M). We measured glycosylated hemoglobin (HbA1c), plasma high-sensitivity C-reactive protein (hs-CRP), plasminogen activator inhibitor-1 (PAI-1), 8-epi-prostaglandin F2 alpha (PGF2alpha), serum lipoprotein (a) [Lp (a)], and lipoprotein profile at baseline and after 20 weeks of treatment.

RESULTS

HbA1c decreased by >or=2% (P<.001) and to comparable levels (P=NS) in all groups. Despite improved glycemia, hsCRP did not change in any group, whereas plasma PAI-1 fell with basal insulin +Pio (P<.02) and SU+M (P<.01). PGF2alpha declined with basal insulin (P<.02) and SU+M (P<.001). High-density lipoprotein cholesterol (HDL-C) increased only with basal insulin +Pio (18.2%, P<.05). Lp (a) increased with basal insulin therapy alone (P<.01). Data were pooled from all groups to determine the overall effect of glycemic control-there was a significant (P<.001) decline in HbA1c, PAI-1, and PGF2alpha and an increase in HDL-C (P<.001). There was no correlation between HbA1c reduction and changes in these parameters.

CONCLUSIONS

We conclude that excellent glycemic control per se does not impact nontraditional risk factors for CVD equally, but various diabetes medications have different effects on these risk factors. These findings may have implications for making appropriate therapeutic choices for patients with Type 2 diabetes, although larger studies with more appropriate treatment comparisons may be necessary.

Lipoprotein(a) in patients who have non-insulin-dependent diabetes with and without coronary artery disease

OBJECTIVE

To determine whether the level of lipoprotein(a) [Lp(a)] contributes to an increased risk of coronary artery disease (CAD) in patients with non-insulin-dependent diabetes mellitus (NIDDM).

METHODS

We prospectively evaluated established cardiovascular risk factors, metabolic control, and Lp(a) levels in 53 men with NIDDM and CAD and compared these variables in 42 male patients with NIDDM but without CAD.

RESULTS

The groups were comparable for age, diabetes control, treatment and duration of diabetes, obesity, and other cardiac risk factors. Lp(a) levels did not differ between the groups (12.2 versus 12.4 mg/dL in those with and without CAD, respectively) and were unrelated to age, duration of diabetes, diabetes control, obesity, smoking, hypertension, urinary albumin, cholesterol, triglycerides, or high-density lipoprotein cholesterol. Patients with retinopathy had a higher Lp(a) concentration than did those without retinopathy (24.9 +/- 6.0 versus 10.1 +/- 1.5 mg/dL; P = 0.01). A significant correlation existed between Lp(a) and low-density lipoprotein cholesterol concentrations (P = 0.01).

CONCLUSION

Routine measurement of Lp(a) level in patients with NIDDM does not seem warranted because no association was found between Lp(a) concentration and CAD in this study population.

Insulin sensitivity and Lp(alpha) concentrations in normoglycemic offspring of type 2 diabetic parents

Background

Offspring of at least 1 parent with type 2 diabetes are more resistant to the insulin action, exhibit higher incidence of dyslipidemia and are more prone to cardiovascular diseases. The association between Lp(α) and coronary heart disease is well established. An association between Lp(α) concentration and insulin sensitivity was examined in this study.

We investigated the serum LP(α) in 41 offspring of 41 families of type 2 diabetic subjects (group I) with normal glucose tolerance, compared to 49 offspring who their parents had no history of type 2 diabetes, matched for sex, age, BMI, WHR and blood pressure (group II). Serum Lp(α), triglycerides, insulin resistant index, HDL, LDL-cholesterol and insulin were measured.

Results

The offspring of type 2 diabetic subjects had higher fasting serum triglycerides (mean ± SD 199.3 ± 184.2 vs. 147.1 ± 67.9 ng/dl, p < 0.05) lower HDL-cholesterol (37.3 ± 9.0 vs. 44.6 ± 7.8, p < 0.001) and particularly higher Insulin resistance Index (HOMA-IR) (2.84 ± 1.39 vs. 1.67 ± 0.77, p < 0.001).

They also had higher serum LP(α) concentration (15.4 ± 6.7 vs. 8.6 ± 6.0, p < 0.001). By simple linear analysis in the offspring of type 2 diabetic parents there was no correlation of Lp(α) concentration with insulin resistance index Homa-IR (r = 0,016 p = NS).

Conclusions

We conclude that serum LP(α) is significantly increased in offspring of type 2 diabetic subjects but was not related to insulin sensitivity.

Lipoprotein(a): an emerging cardiovascular risk factor

Lipoprotein(a) is a cholesterol-enriched lipoprotein, consisting of a covalent linkage joining the unique and highly polymorphic apolipoprotein(a) to apolipoprotein B100, the main protein moiety of low-density lipoproteins. Although the concentration of lipoprotein(a) in humans is mostly genetically determined, acquired disorders might influence synthesis and catabolism of the particle. Raised concentration of lipoprotein(a) has been acknowledged as a leading inherited risk factor for both premature and advanced atherosclerosis at different vascular sites. The strong structural homologies with plasminogen and low-density lipoproteins suggest that lipoprotein(a) might represent the ideal bridge between the fields of atherosclerosis and thrombosis in the pathogenesis of vascular occlusive disorders. Unfortunately, the exact mechanisms by which lipoprotein(a) promotes, accelerates, and complicates atherosclerosis are only partially understood. In some clinical settings, such as in patients at exceptionally low risk for cardiovascular disease, the potential regenerative and antineoplastic properties of lipoprotein(a) might paradoxically counterbalance its athero-thrombogenicity, as attested by the compatibility between raised plasma lipoprotein(a) levels and longevity.

Influence of lipoprotein(a) on restenosis after femoropopliteal percutaneous transluminal angioplasty in Type 2 diabetic patients

OBJECTIVE

The influence of vascular morphology and metabolic parameters including lipoprotein(a) (Lp(a)) on restenosis after peripheral angioplasty has been compared in Type 2 diabetes (DM) vs. non-diabetic patients (ND).

RESEARCH DESIGN AND METHODS

The clinical course and risk profile of 132 (54 DM vs. 78 ND) patients with peripheral arterial occlusive disease (PAD) were observed prospectively following femoropopliteal angioplasty (PTA). Clinical examination, oscillometry, ankle brachial blood pressure index (ABI) and the toe systolic blood pressure index (TSPI) were used during follow-up. Duplex sonography and reangiography were also used to verify suspected restenosis or reocclusion.

RESULTS

At the time of intervention patients with DM had a lower median Lp(a) of 9 vs. 15 mg/dl (P < 0.01) in patients without diabetes. Recurrence within 1 year after PTA occurred in 25 diabetic (= 46%, Lp(a) 12 mg/dl) and 30 non-diabetic (= 38%, Lp(a) 48 mg/dl) patients. DM patients with 1 year's patency had a median Lp(a) of 7 vs. 11 mg/dl in non-diabetic patients (P < 0.05). However, 12 months after angioplasty Lp(a) correlated negatively with the ABI (r = -0.44, P < 0.01) in diabetic and in non-diabetic patients (r = -0.20, P < 0.05). The probability of recurrence after PTA continuously increased with higher levels of Lp(a) in each subgroup of patients.

CONCLUSIONS

Our data indicate that Lp(a) is generally lower in those with peripheral arterial occlusive disease and Type 2 diabetes than in non-diabetic individuals. The increased risk for restenosis with rising levels of Lp(a) is set at a lower Lp(a) in diabetes and may be more harmful for diabetic patients.

Relation of lipoprotein(a) as coronary risk factor to type 2 diabetes mellitus and low-density lipoprotein cholesterol in patients > or =65 years of age (The Italian Longitudinal Study on Aging)

High levels of serum lipoprotein(a) [Lp(a)] have been associated with increased risk of coronary artery disease (CAD), but this association apparently is not confirmed in elderly people. We evaluated the interactions of Lp(a) with lipid and nonlipid CAD risk factors in a sample of subjects enrolled in the prevalence survey (1992 to 1993) of the Italian Longitudinal Study on Aging (ILSA). The entire population consisted of 5,632 elderly people, aged 65 to 84 years, randomly selected in 8 Italian municipalities. The present cross-sectional study included 400 free-living elderly subjects (74 +/- 6 years) from the randomized cohort of Casamassima (Bari, Southern Italy) (n = 704). The results showed that in the elderly population, high serum Lp(a) is a CAD risk factor dependent on type 2 diabetes mellitus and elevated low-density lipoprotein (LDL) cholesterol levels. In particular, the combined effect of high Lp(a) (> or =20 mg/dl) and high LDL cholesterol (> or =3.63 mmol/L [> or =140 mg/dl]), increases coronary risk by 2.75 (95% confidence interval 7.70 to 0.99); finally, the effect of Lp(a) > or =20 mg/dl and LDL cholesterol > or =3.63 mmol/L (> or =140 mg/dl), combined with type 2 diabetes mellitus, increases risk of CAD by 6.65 (95% confidence interval 35.40 to 1.25). In the elderly, elevated Lp(a) levels appear not to be an independent predictor of CAD, but this lipoprotein is a risk factor only in subjects with type 2 diabetes mellitus and elevated LDL cholesterol.

Lipoprotein(a) in American Indians is low and not independently associated with cardiovascular disease. The Strong Heart Study

PURPOSE

To evaluate the distribution of lipoprotein(a) (Lp(a)) and assess its association to cardiovascular disease (CVD) in American Indians.

METHODS

Lp(a) was measured in 3991 American Indians (aged 45-74 years with no prior history of CVD at baseline) from 13 communities in Arizona, Oklahoma, and South/North Dakota. They were followed prospectively from 1989 to 1997 for CVD. The distribution of Lp(a) was examined by center, sex, and diabetic status. Spearman correlation coefficients and Cox regression models were used to evaluate the association of Lp(a) to CVD.

RESULTS

A total of 388 participants subsequently developed CVD. Median Lp(a) concentration in American Indians was 3.0 mg/dl. This was almost half of that in whites and one sixth in blacks from the CARDIA study measured by the same method. Nondiabetic participants had significantly higher Lp(a) levels than diabetic participants for both genders. Lp(a) levels were higher in women than in men for nondiabetic participants, but there was no gender difference for diabetic participants. Correlation analysis showed Lp(a) was significantly negatively correlated with the degree of Indian heritage, insulin, triglycerides (TG), fasting plasma glucose (FPG), and 2-hour plasma glucose (2hPG), and positively with low-density lipoproteins (LDL), apoprotein B (apoB), and fibrinogen (FIB). In Cox regression models, adjusting for other risk factors, Lp(a) was no longer a significant predictor of CVD in either diabetic or nondiabetic participants.

CONCLUSIONS

The lower concentration of Lp(a) in American Indians and the high correlation with Indian heritage confirm the concept that Lp(a) concentration is in large part genetically determined. Lp(a) concentration is not an independent predictor of CVD among American Indians; it is higher in those who develop CVD because of its positive correlation with LDL, apoB, and FIB.

Impact of glycemic control on serum lipoprotein (a) in Arab children with type 1 diabetes

BACKGROUND

Lipoprotein (a) (Lp (a)) is an independent risk factor for coronary artery disease (CAD), a major cause of death in patients with type 1 diabetes mellitus. Both type 1 diabetes and CAD represent major problems in Kuwait. Data on the effect of metabolic control on Lp (a) in diabetic children are limited and this is particularly true for Arab children. The objectives of the present study were to analyze serum Lp (a) levels in patients with type 1 diabetes compared with non-diabetic children, taking into account the effect of glycemic control.

METHODS

Circulating lipids, including Lp (a), were measured in serum samples from 60 prepubertal non-diabetic children and 58 prepubertal children with type 1 diabetes. Comparisons of Lp (a) concentrations were made between the non-diabetic and diabetic children with good to fair control (glycosylated hemoglobin (GHb) <11%) and a group of diabetic children with poor control (GHb > or = 11%).

RESULTS

The mean serum Lp (a) level in all diabetic children was 187.62+160.43 mg/L, compared with 162.88+156.06 mg/L in the control group. The group of children with poor glycemic control had higher median Lp (a) levels (147.50 mg/L) than either the group of diabetic children with good to fair control (95 mg/L; P<0.028) or the group of non-diabetic children (125 mg/L; P<0.04). Moreover, 38.3% of poorly controlled diabetic children had elevated Lp (a) levels > or = 250 mg/L, compared with 12.5% of diabetic children with good to fair control and 16.7% of non-diabetic children (P<0.025 and P<0.039, respectively). No association was found between Lp (a), diabetes duration and insulin dose.

CONCLUSIONS

In Arab children, highest Lp (a) levels are associated with poorest metabolic control. The prevalence of Lp (a) levels associated with cardiovascular risk is higher in poorly controlled diabetic children. Increased levels of Lp (a) may be another contributing factor to the high risk for CAD in diabetic patients.

Glycation amplifies lipoprotein(a)-induced alterations in the generation of fibrinolytic regulators from human vascular endothelial cells

Increased lipoprotein(a) [Lp(a)] in plasma is an independent risk factor for premature cardiovascular diseases. The levels of glycated Lp(a) are elevated in diabetic patients. The present study demonstrated that glycation enhanced Lp(a)-induced production of plasminogen activator inhibitor-1 (PAI-1), and further decreased the generation of tissue-type plasminogen activator (t-PA) from human umbilical vein endothelial cells (HUVEC) and human coronary artery EC. The levels of PAI-1 mRNA and its antigen in the media of HUVEC were significantly increased following treatments with 5 microgram/ml of glycated Lp(a) compared to equal amounts of native Lp(a). The secretion and de novo synthesis of t-PA, but not its mRNA level, in EC were reduced by glycated Lp(a) compared to native Lp(a). Treatment with aminoguanidine, an inhibitor for the formation of advanced glycation end products (AGEs), during glycation normalized the generation of PAI-1 and t-PA induced by glycated Lp(a). Butylated hydroxytoluene, a potent antioxidant, inhibited native and glycated Lp(a)-induced changes in PAI-1 and t-PA generation in EC. The results indicate that glycation amplifies Lp(a)-induced changes in the generation of PAI-1 and t-PA from venous and arterial EC. This may attenuate fibrinolytic activity in blood circulation and potentially contributes to the increased incidence of cardiovascular complications in diabetic patients with hyperlipoprotein(a). EC-mediated oxidative modification and the formation of AGEs may be implicated in glycated Lp(a)-induced alterations in the generation of fibrinolytic regulators from vascular EC.

Cardiovascular risk factors in non-insulin-dependent diabetics compared to non-diabetic controls: a population-based survey among Asians in Singapore

Cardiovascular risk factors were compared between 126 people with non-insulin-dependent diabetes mellitus (NIDDM) and 530 non-diabetics (controls), in a random sample of people (Chinese, Malays, and Asian Indians) aged 40-69 years from the general population of Singapore. Data were adjusted for age and ethnicity. For both genders, people with NIDDM had higher mean body mass indices, waist-hip ratios and abdominal diameters. They also had a higher prevalence of hypertension, higher mean levels of fasting serum triglyceride, slightly lower mean levels of serum high-density-lipoprotein cholesterol, and higher mean levels of plasma plasminogen activator inhibitor-1 and tissue plasminogen activator (antigen). These factors are components of syndrome X (metabolic syndrome) and increase the risk of atherosclerosis and thrombosis. In contrast, there were no important differences for cigarette smoking, serum total and low-density-lipoprotein cholesterol, serum apolipoproteins A1 and B, plasma factor VIIc and plasma prothrombin fragment 1 + 2. Females with NIDDM, but not males, had a higher mean serum fibrinogen level than non-diabetics, which could explain why NIDDM has a greater cardiovascular effect in females than males. Serum lipoprotein(a) concentrations were lower in people with NIDDM. Mean levels of serum ferritin, a pro-oxidant, were higher in people with NIDDM than controls, but there were no important differences for plasma vitamins A, C and E, and serum selenium, which are anti-oxidants.

Effects of physical activity and diet on lipoprotein(a)

Lipoprotein(a) [Lp(a)] represents a class of lipoproteins with some structural similarity to low density lipoprotein (LDL), but containing a unique apoprotein, apoprotein(a). First reported in 1963, Lp(a) is now considered to have an independent role in the development of atherosclerotic lesions. The level of Lp(a) in the blood is under strong genetic influence and does not appear to be alterable by lifestyle factors known to influence other lipoproteins. Regular moderate exercise has been shown to favorably alter other lipoproteins, and recent attention has focused on whether Lp(a) level can be influenced by physical activity. Current data from cross-sectional and intervention studies show little effect of moderate exercise on serum Lp(a) concentration. One possible exception may be an elevation of serum Lp(a) concentration in adult endurance and power athletes who exercise intensely on a daily basis. However, not all studies have taken into account possible racial or ethnic differences in Lp(a) concentrations and the skewed distribution observed within most populations. Standard dietary intervention such as a low fat diet recommended for weight loss and control of other blood lipids has little effect on serum Lp(a) level. At present, serum Lp(a) concentration does not appear to be significantly altered by realistic dietary changes and moderate physical activity as recommended for health. The synergistic effect on cardiovascular disease risk when both LDL-cholesterol and Lp(a) are elevated highlight the importance of attending to those risk factors that can be modified by exercise and other lifestyle changes.

Lipoprotein(a) concentration and molecular weight of apolipoprotein(a) in patients with cerebrovascular disease and diabetes mellitus

Plasma lipoprotein(a) [Lp(a)] concentrations are genetically determined, and hyper-Lp(a)-emia is an independent risk factor for atherosclerosis and thrombosis. To study the implications of Lp(a) in cerebrovascular disease (CVD) and diabetes mellitus (DM), we examined plasma Lp(a) levels and molecular weights of apolipoprotein(a) [apo(a)] in 118 patients with CVD, and 125 cases with DM. Although mean Lp(a) concentrations were higher in those cases with atherothrombotic brain infarction than in those with brain hemorrhage and lacunar infarction, the difference was not statistically significant. Lp(a) levels were significantly higher in the DM cases treated with insulin and in those treated with oral hypoglycemic agents than in those on diet therapy alone, suggesting that insulin and oral agents modulate apo(a) expression. Lp(a) concentrations correlated significantly with the low-molecular-weight isoforms of apo(a) in all CVD and DM groups.

Lack of association of lipoprotein (a) with coronary heart disease in Spaniard type 2 diabetic patients

We tried to elucidate the possible relationship between lipoprotein (a) levels and coronary heart disease by assessing the presence of lipoprotein (a) covariates in NIDDM. We selected 41 type 2 diabetic patients with coronary heart disease and 82 type 2 diabetic patients free from cardiovascular disease. They were adjusted for age, sex and duration of diabetes. Routine chemical analysis was carried out using standard procedures, HbA1c by HPLC and lipoprotein (a) and urinary albumin excretion rate by immunonephelometry. No difference has been found in lipoprotein (a) levels between both groups of patients (18 [144.25] mg/dl in cases vs. 23 [197.25] mg/dl in controls (median [range]), Mann Whitney U-test, P > 0.1). No association has been found between coronary heart disease and lipoprotein (a) levels greater than 30 mg/dl (Pearson's chi 2, P > 0.1). Significant and independent linear relationships have been found between the square root of lipoprotein (a) levels, serum creatinine and total cholesterol (multiple r2: 0.15, P < 0.001). Patients treated with insulin had greater square root of lipoprotein (a) levels, even after adjusting for serum creatinine and total cholesterol (5.87 +/- 0.35 vs. 4.76 +/- 0.36 (mean +/- S.E.), ANCOVA, P < 0.05). These data do not show an association between symptomatic coronary heart disease and lipoprotein (a) in NIDDM. Significant and independent relationships have been found between this variable and serum creatinine, total cholesterol and insulin therapy.

Lipids and lipoproteins as risk factors for coronary heart disease in non-insulin-dependent diabetes mellitus

Dyslipidaemia is frequent in non-insulin-dependent diabetes mellitus (NIDDM). Lipid and lipoprotein abnormalities include particularly elevated levels of total and very-low-density lipoprotein (VLDL) triglycerides and reduced levels of high-density lipoprotein (HDL) cholesterol. The worsening of glycaemic control further deteriorates lipid and lipoprotein abnormalities and furthermore, total and low-density lipoprotein (LDL) cholesterol levels are often elevated in poor glycaemic control. Epidemiological data show that total cholesterol is as powerful risk factor for coronary heart disease (CHD) in NIDDM patients as in nondiabetic subjects. High total triglycerides and low HDL cholesterol may be even stronger risk factors for CHD in NIDDM patients than in nondiabetic individuals, but more prospective studies are needed to substantiate this view. Compositional changes in LDL and VLDL particles may further increase the risk of CHD but epidemiological data are missing to support this notion.

Lipoprotein(a) concentrations and non-insulin-dependent diabetes mellitus: relationship to glycaemic control and diabetic complications

The aim of our study was to determine the lipoprotein(a) (Lp(a)) levels in patients with non-insulin-dependent diabetes mellitus (NIDDM) and to evaluate Lp(a) concentrations in relation to glycaemic control and diabetic complications. We evaluate in a cross-sectional study a total of 103 NIDDM patients (52 males and 51 females; mean age of 62.5 years; mean of diabetes duration: 12 years) referred to our hospital because of poor glycaemic control, and a group of 108 non-diabetic subjects (57 males and 51 females).

RESULTS

mean Lp(a) concentration did not significantly differ between NIDDM patients and non-diabetic subjects (11.1 +/- 14 vs. 16.2 +/- 14 mg/dl). The distribution of Lp(a) levels was highly skewed towards the lower levels in both groups, being over 30 mg/dl in only 6% of NIDDM patients and 12% of controls. Patients with Lp(a) levels over 10 mg/dl had lower haemoglobin Alc (HbA1c) than patients with Lp(a) levels over 10 mg/dl (8.5% vs. 10.4%; P < 0.01). Lp(a) concentration was positively correlated with body mass index (BMI) (P < 0.05) and HbA1c (P < 0.05). No association was found between Lp(a) and sex, age, other lipidic parameters, microalbuminuria, type of treatment and presence of cardiovascular disease. These findings may suggest that glycaemic control could have a modulatory role on Lp(a) concentration in NIDDM patients. In this study, diabetic complications did not seem to be associated with higher Lp(a) concentrations.

Hypercoagulability and high lipoprotein(a) levels in patients with type II diabetes mellitus

Diabetes mellitus is associated with disturbances in hemostasis that could contribute to the development of diabetic vascular disease. We investigated the changes in parameters of blood coagulation and the fibrinolytic system and in plasma levels of lipoprotein(a)(Lp(a)) in 124 patients with type II diabetes mellitus and 44 healthy control subjects matched for age and body mass index (BMI) to determine whether hemostatic disturbances may lead to increased cardiovascular mortality. Median levels of fibrinogen (P < 0.0001), thrombin-antithrombin III complex (TAT) (P < 0.005), and plasminogen activator inhibitor-1 (PAI-1) activity (P < 0.05) in plasma were significantly elevated in diabetic patients compared with controls. The median concentration of Lp(a) was significantly higher in diabetic patients than in normal controls (18.2 vs. 12.6 mg/dl. P < 0.0005). Lp(a) levels tended to be elevated in patients with a prolonged history of diabetes. There was no evidence that Lp(a) levels were affected by metabolic control or by type of treatment. Twenty-two diabetics with coronary heart disease (CHD) had significantly higher levels of fibrinogen (P < 0.05), TAT (P < 0.05), and Lp(a) (24.7 vs. 13.7 mg/dl, P < 0.01) than the 51 patients without diabetic angiopathy. Our data indicate that impaired hemostatic balance in diabetes may cause hypercoagulability and may thus contribute to the increased cardiovascular mortality in diabetes.

Lipoprotein(a) in health and disease

Lipoprotein(a) [Lp(a)] represents an LDL-like particle to which the Lp(a)-specific apolipoprotein(a) is linked via a disulfide bridge. It has gained considerable interest as a genetically determined risk factor for atherosclerotic vascular disease. Several studies have described a correlation between elevated Lp(a) plasma levels and coronary heart disease, stroke, and peripheral atherosclerosis. In healthy individuals, Lp(a) plasma concentrations are almost exclusively controlled by the apo(a) gene locus on chromosome 6q2.6-q2.7. More than 30 alleles at this highly polymorphic gene locus determine a size polymorphism of apo(a). There exists an inverse correlation between the size (molecular weight) of apo(a) isoforms and Lp(a) plasma concentrations. The standardization of Lp(a) quantification is still an unresolved task due to the large particle size of Lp(a), the presence of two different apoproteins [apoB and apo(a)], and the large size polymorphism of apo(a) and its homology with plasminogen. A working group sponsored by the IFCC is currently establishing a stable reference standard for Lp(a) as well as a reference method for quantitative analysis. Aside from genetic reasons, abnormal Lp(a) plasma concentrations are observed as secondary to various diseases. Lp(a) plasma levels are elevated over controls in patients with nephrotic syndrome and patients with end-stage renal disease. Following renal transplantation, Lp(a) concentrations decrease to values observed in controls matched for apo(a) type. Controversial data on Lp(a) in diabetes mellitus result mainly from insufficient sample sizes of numerous studies. Large studies and those including apo(a) phenotype analysis came to the conclusion that Lp(a) levels are not or only moderately elevated in insulin-dependent patients. In noninsulin-dependent diabetics, Lp(a) is not elevated. Conflicting data also exist from studies in patients with familial hypercholesterolemia. Several case-control studies reported elevated Lp(a) levels in those patients, suggesting a role of the LDL-receptor pathway for degradation of Lp(a). However, recent turnover studies rejected that concept. Moreover, family studies also revealed data arguing against an influence of the LDL receptor for Lp(a) concentrations. Several rare diseases or disorders, such as LCAT- and LPL-deficiency as well as liver diseases, are associated with low plasma levels or lack of Lp(a).

Lipoprotein(a) concentrations in non-insulin-dependent diabetes mellitus and borderline hyperglycemia: a population-based study

The objective of the study was to compare lipoprotein(a) [Lp(a)] concentrations in population-based samples of individuals with non-insulin-dependent diabetes mellitus (NIDDM), borderline hyperglycemia, and normoglycemia. From 2,740 male Italian Telephone Company employees aged 40 to 59 years participating in a health screening, we selected all those with NIDDM (n = 100) plus a random sample of 950 nondiabetic individuals. Diabetes was defined as fasting plasma glucose (FPG) of at least 140 mg/dL or current use of hypoglycemic drugs. Among nondiabetic individuals, 854 were defined as normoglycemic (FPG < 115 mg/dL) and 95 were defined as borderline hyperglycemic (115 < FPG < 140 mg/dL). Lp(a) level was measured on frozen plasma by enzyme-linked immunosorbent assay. Lp(a) concentrations were similar in people with NIDDM, borderline hyperglycemia, and normoglycemia: 11.2 +/- 14, 14.1 +/- 20, and 13.9 +/- 18 mg/dL, respectively (F = 1.03). Accordingly, the proportion of subjects with Lp(a) levels of at least 30 mg/dL was comparable in the three groups (12%, 15%, and 14%; chi 2 = 3.95, P = .41). Results were not confounded by differences in age, body mass index (BMI), waist to hip ratio, plasma lipids, alcohol consumption, physical activity, and use of drugs. Furthermore, within the diabetic group Lp(a) levels were not significantly different for those on diet only versus those on oral agents (10.8 +/- 14.1 v 11.7 +/- 14.7, P = .7) or for people with FPG of at least 180 as compared with people with FPG less than 180 mg/dL (9.9 +/- 12.8 v 11.5 +/- 14.8, P = .5).(ABSTRACT TRUNCATED AT 250 WORDS)

Levels of lipoprotein(a), apolipoprotein B, and lipoprotein cholesterol distribution in IDDM. Results from follow-up in the Diabetes Control and Complications Trial

Levels of lipoprotein(a) [Lp(a)], apolipoprotein (apo) B, and lipoprotein cholesterol distribution using density-gradient ultracentrifugation were measured as part of a cross-sectional study at the final follow-up examination (mean 6.2 years) in the Diabetes Control and Complications Trial. Compared with the subjects in the conventionally treated group (n = 680), those subjects receiving intensive diabetes therapy (n = 667) had a lower level of Lp(a) (Caucasian subjects only, median 10.7 vs 12.5 mg/dl, respectively; P = 0.03), lower apo B (mean 83 vs. 86 mg/dl, respectively; P = 0.01), and a more favorable distribution of cholesterol in the lipoprotein fractions as measured by density-gradient ultracentrifugation with less cholesterol in the very-low-density lipoprotein and the dense low-density lipoprotein fractions and greater cholesterol content of the more buoyant low-density lipoprotein. Compared with a nondiabetic Caucasian control group (n = 2,158), Lp(a) levels were not different in the intensive treatment group (median 9.6 vs. 10.7 mg/dl, respectively; NS) and higher in the conventional treatment group (9.6 vs. 12.5 mg/dl, respectively; P < 0.01). No effect of renal dysfunction as measured by increasing albuminuria or reduced creatinine clearance on Lp(a) levels could be demonstrated in the diabetic subjects. Prospective follow-up of these subjects will determine whether these favorable lipoprotein differences in the intensive treatment group persist and whether they influence the onset of atherosclerosis in insulin-dependent diabetes.

Lipoprotein (a) and vascular disease in diabetic patients

In order to assess the potential role of lipoprotein (a) as a risk factor for cardiovascular disease in diabetes mellitus, plasma concentrations were measured in a large group (n = 500) of non-insulin-dependent (NIDDM, n = 355) and insulin-dependent (IDDM, n = 145) patients. Concentrations of lipoprotein (a) were compared in diabetic patients with (n = 153) or without (347) documented vascular disease (ischaemic heart disease, peripheral vascular disease or macroangiopathy). They were significantly higher (p < 0.05) in patients with ischaemic heart disease (mean [interquartile range] 15.5 (5.0-38.0) vs 9.0 (4.5-26.0) mg/dl) or macroangiopathy (13.0 (5.0-38.0) vs 9.0 (4.0-25.0) mg/dl) compared to patients without manifestations of vascular disease. In addition, stepwise logistic regression analysis identified lipoprotein (a) levels > or = 30 mg/dl as being independently associated with the presence of cardiovascular disease. Lipoprotein (a) was an independent risk factor for ischaemic heart disease and macroangiopathy in this group of IDDM and NIDDM patients.

The role of lipoprotein(a) in the vascular complications of diabetes mellitus

Lipoprotein(a) has been identified as an independent risk factor for atherosclerotic vascular disease in non-diabetic populations. Because of its potential role in the pathogenesis of both microvascular and macrovascular complications in diabetes, there have recently been many reports on lipoprotein(a) in diabetic populations. Some studies indicate an association between elevated lipoprotein(a) and macrovascular disease in non-insulin-dependent diabetes mellitus (NIDDM), but this link has not been found with insulin-dependent diabetes mellitus (IDDM). In IDDM, elevated lipoprotein(a) has been found in groups with diabetic nephropathy and retinopathy, raising the possibility that it plays a causative role. The relationship between glycaemic control and the lipoprotein(a) level has not been fully resolved. Most studies have not found any connection in NIDDM, but some found higher lipoprotein(a) levels in hyperglycaemic IDDM patients. Potentially, lipoprotein(a) is an important factor linking the microvascular and macrovascular complications of diabetes.

Effect of insulin treatment on serum lipoprotein(a) in non-insulin-dependent diabetes

In order to evaluate whether Lp(a), a lipoprotein that is potentially thrombogenic and atherogenic, is a potential risk factor for CAD in non-insulin-dependent diabetes (NIDDM), we compared the Lp(a) and its distribution in 145 NIDDM patients with that in 94 healthy control subjects. Furthermore, we studied the effect of insulin treatment on serum Lp(a) in 108 patients with NIDDM. Male and female NIDDM patients had similar Lp(a) concentrations to healthy controls (median value 167 mg L-1, range 15-1550 mg L-1 vs. 157 mg L-1, range 15-919 mg L-1, NS and 92, range 15-1190 mg L-1 vs. 103 mg L-1, range 15-842 mg L-1, NS). Also, the cumulative distribution of Lp(a) did not differ between the NIDDM patients and healthy subjects. Insulin treatment increased Lp(a) in diabetics with a Lp(a) concentration of less than 300 mg L-1, but this effect was not related to the concomitant improvement in metabolic control (mean change (+/- SEM) of HbA1c from 9.80 +/- 0.15 to 8.00 +/- 0.12; P < 0.001). In subjects with elevated Lp(a) concentrations (> 300 mg L-1) the Lp(a) concentration was unaffected by insulin, despite a similar improvement in glycaemic control. These results suggest that insulin may modulate the concentration of Lp(a).

Are lipoprotein profile and lipoprotein (a) levels altered in men with psoriasis?

BACKGROUND

Previous studies have demonstrated that patients with psoriasis may have an increased risk of a variety of noncutaneous diseases, including arterial and venous occlusive diseases. Changes in plasma lipid and lipoprotein composition in patients with psoriasis may be the reason for the increased risk of atherosclerosis in these patients. Lipoprotein (a) (Lp(a)) is a genetically determined lipoprotein associated with an increased prevalence of atherosclerotic and thrombotic cardiovascular diseases.

OBJECTIVE

The aim of this prospective study was to determine the lipid profile and to define the significance of Lp(a) levels in men with psoriasis. The other purpose was to learn whether a correlation exists between psoriasis area and severity index score and serum Lp(a) or other lipids.

METHODS

Serum Lp(a) levels were measured with a commercially available noncompetitive enzyme-linked immunosorbent assay in 32 men with psoriasis and in 13 healthy men. Total serum cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, apolipoprotein A-I and apolipoprotein B levels, and atherosclerotic risk factors other than hyperlipidemia were determined. Secondary hyperlipidemia from various diseases and drugs was ruled out in both groups.

RESULTS

Serum Lp(a) levels were higher in men with psoriasis than in healthy male subjects, but the difference was not significant (p = 0.063). Serum fasting glucose levels were also found to be higher in the psoriasis group (p < 0.05). Higher serum Lp(a) and fasting glucose levels tended to occur in patients with extensive and severe skin involvement. No statistical differences were observed in the total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, apolipoprotein A-I, and apolipoprotein B levels between the two groups (p > 0.05).

CONCLUSION

Our results suggest that the increased Lp(a) level might be a factor involved in occlusive vascular disorders in patients with psoriasis and that patients with extensive and severe skin involvement are more predisposed to relatively high Lp(a) levels.

Association of elevated lipoprotein(a) levels and coronary heart disease in NIDDM patients. Relationship with apolipoprotein(a) phenotypes

Non-insulin-dependent diabetes mellitus (NIDDM) is a strong and independent risk factor for coronary heart disease. We assessed the potential relationship between plasma Lp(a) levels, apo(a) phenotypes and coronary heart disease in a population of NIDDM patients. Seventy-one patients with coronary heart disease, who previously have had transmural myocardial infarction, or significant stenosis on coronary angiography, or positive myocardial thallium scintigraphy, or in combination, were compared with 67 patients without coronary heart disease, who tested negatively upon either coronary angiography, myocardial thallium scintigraphy or a maximal exercise test. The prevalence of plasma Lp(a) levels elevated above the threshold for increased cardiovascular risk (> 0.30 g/l) was significantly higher (p = 0.005) in patients with coronary heart disease (33.8%) compared to the control group (13.4%). The relative risk (odds ratio) of coronary heart disease among patients with high Lp(a) concentrations was 3.1 (95% confidence interval, 1.31-7.34; p = 0.01). The overall frequency distribution of apo(a) phenotypes differed significantly between the two groups (p = 0.043). However, the frequency of apo(a) isoforms of low apparent molecular mass (< or = 700 kDa) was of borderline significance (p = 0.067) between patients with or without coronary heart disease (29.6% and 16.4%, respectively). In this Caucasian population of NIDDM patients, elevated Lp(a) levels were associated with coronary heart disease, an association which was partially accounted for by the higher frequency of apo(a) isoforms of small size. In multivariate analyses, elevated levels of Lp(a) were independently associated with coronary heart disease (odds ratio 3.48, p = 0.0233).

Lipids and Lp(a) lipoprotein levels and coronary artery disease in subjects with non-insulin-dependent diabetes mellitus

OBJECTIVE

To determine whether increased Lp(a) lipoprotein levels are associated with either non-insulin-dependent diabetes mellitus (NIDDM) or coronary artery disease (CAD) in patients with NIDDM and to examine the relationship between Lp(a) levels and glycemic control.

DESIGN

We conducted a cross-sectional study of subjects with NIDDM who were participants in the Rochester Diabetic Neuropathy Study and healthy control subjects from the population of Rochester, Minnesota.

MATERIAL AND METHODS

Lipids and Lp(a) lipoprotein levels were compared in 227 subjects with NIDDM and 163 control subjects and, among the subjects with NIDDM, in those with (N = 96) and without (N = 131) CAD. The correlation between Lp(a) levels and glycosylated hemoglobin was investigated.

RESULTS

Subjects with NIDDM had higher triglyceride and lower high-density lipoprotein cholesterol levels than did control subjects. Subjects with NIDDM and CAD had higher total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels and lower high-density lipoprotein cholesterol levels than did subjects with NIDDM without CAD. Subjects with NIDDM had significantly higher Lp(a) levels than did control subjects, but subjects with NIDDM and CAD did not have significantly higher Lp(a) levels than did those without CAD. Among subjects with NIDDM, the level of Lp(a) was not significantly correlated with glycosylated hemoglobin.

CONCLUSION

Although subjects with NIDDM have higher Lp(a) levels than do control subjects, Lp(a) does not seem to be associated with CAD in subjects with NIDDM. In this study, no association was found between Lp(a) level and glycemic control.