Characteristics of persons with marked hypocholesterolemia. A population-based study

Relation of Hypocholesterolemia With Diabetes Mellitus in Patients With Coronary Artery Disease

The association between hypocholesterolemia and diabetes mellitus (DM) in patients with coronary artery disease (CAD) remains poorly investigated. We undertook this study to investigate whether there is an association between hypocholesterolemia and odds of DM in these patients. This observational study included 14,952 patients with CAD: 8,592 without statins (statin-naive group) and 6,360 with statins on admission (statin-treated group). Hypocholesterolemia was defined as a total cholesterol within the first quintile of the total cholesterol concentration (total cholesterol <157 mg/dl). The primary outcome measure of this study was presence of DM. Hypocholesterolemia was present in 2,926 patients (20%; 1,102 statin-naive patients and 1,824 statin-treated patients). DM was present in 1,029 patients with hypocholesterolemia and 2,793 patients without hypocholesterolemia (35% vs 23%; odds ratio [OR] 1.79, 95% confidence interval [CI] 1.64 to 1.96; p <0.001). After adjustment, hypocholesterolemia was independently associated with the odds of DM in all patients (adjusted OR 1.55 [1.38 to 1.74]; p <0.001), statin-naive patients (adjusted OR 1.51 [1.25 to 1.82]; p <0.001) and statin-treated patients (adjusted OR 1.64 [1.41 to 1.91]; p <0.001). For every 20 mg/dl lower total cholesterol, the odds of being with DM increased by 14% (adjusted OR 1.14 [1.11 to 1.16]; p <0.001) with no cholesterol-by-statin interaction (P_int = 0.803). The association between hypocholesterolemia and odds of DM was entirely driven by low-density lipoprotein-cholesterol. For every 20 mg/dl lower low-density lipoprotein-cholesterol, the odds of DM increased by 14 % (adjusted OR 1.14 [1.11 to 1.16]; p <0.001). In conclusion, in patients with CAD, hypocholesterolemia was independently associated with the odds of DM with a dose-response relation and no cholesterol-by-statin interaction.

Metabonomics analysis of plasma reveals the lactate to cholesterol ratio as an independent prognostic factor of short-term mortality in acute heart failure

Objective

Mortality in heart failure (AHF) remains high, especially during the first days of hospitalization. New prognostic biomarkers may help to optimize treatment. The aim of the study was to determine metabolites that have a high prognostic value.

Methods

We conducted a prospective study on a training cohort of AHF patients (n = 126) admitted in the cardiac intensive care unit and assessed survival at 30 days. Venous plasmas collected at admission were used for ¹H NMR–based metabonomics analysis. Differences between plasma metabolite profiles allow determination of discriminating metabolites. A cohort of AHF patients was subsequently constituted (n = 74) to validate the findings.

Results

Lactate and cholesterol were the major discriminating metabolites predicting 30-day mortality. Mortality was increased in patients with high lactate and low total cholesterol concentrations at admission. Accuracies of lactate, cholesterol concentration and lactate to cholesterol (Lact/Chol) ratio to predict 30-day mortality were evaluated using ROC analysis. The Lact/Chol ratio provided the best accuracy with an AUC of 0.82 (P < 0.0001). The acute physiology and chronic health evaluation (APACHE) II scoring system provided an AUC of 0.76 for predicting 30-day mortality. APACHE II score, Cardiogenic shock (CS) state and Lact/Chol ratio ≥ 0.4 (cutoff value with 82% sensitivity and 64% specificity) were significant independent predictors of 30-day mortality with hazard ratios (HR) of 1.11, 4.77 and 3.59, respectively. In CS patients, the HR of 30-day mortality risk for plasma Lact/Chol ratio ≥ 0.4 was 3.26 compared to a Lact/Chol ratio of < 0.4 (P  =  0.018). The predictive power of the Lact/Chol ratio for 30-day mortality outcome was confirmed with the independent validation cohort.

Conclusion

This study identifies the plasma Lact/Chol ratio as a useful objective and simple parameter to evaluate short term prognostic and could be integrated into quantitative guidance for decision making in heart failure care.

PCSK9-deficient mice exhibit impaired glucose tolerance and pancreatic islet abnormalities

Proprotein convertase subtilisin/kexin type 9 (PCSK9), a liver-secreted plasma enzyme, restricts hepatic uptake of low-density lipoprotein (LDL) cholesterol by promoting the degradation of LDL receptors (LDLR). PCSK9 and LDLR are also expressed in insulin-producing pancreatic islet beta cells, possibly affecting the function of these cells. Here we show that, compared to control mice, PCSK9-null male mice over 4 months of age carried more LDLR and less insulin in their pancreas; they were hypoinsulinemic, hyperglycemic and glucose-intolerant; their islets exhibited signs of malformation, apoptosis and inflammation. Collectively, these observations suggest that PCSK9 may be necessary for the normal function of pancreatic islets.

Potential Confounding by Intermediate Phenotypes in Studies of the Genetics of Ischaemic Stroke

BACKGROUND

Family history (FHx) of stroke is perceived to be an important risk factor for ischaemic stroke. However, there are several intermediate phenotypes that are often involved in the aetiology of ischaemic stroke and that have a substantial genetic component themselves. We studied FHx of ischaemic heart disease (IHD), hypertension (HTN) and diabetes mellitus (DM) as risk factors for ischaemic stroke.

METHODS

We performed a systematic review of case-control and cohort studies reporting on FHx(IHD), FHx(HTN) or FHx(DM) as risk factors for stroke using bibliographic databases, and by hand searching reference lists and journals. Odds ratios of FHx as a risk factor for stroke were calculated within individual studies. We included unpublished data from two Oxfordshire population-based studies to assess effects on subtypes of ischaemic stroke.

RESULTS

We identified 54 studies that investigated the odds of stroke conferred by a positive FHx, 24 of which reported data on FHx of one or more intermediate phenotypes in addition to FHx of stroke. Most studies reported an increased frequency of FHx(IHD) and FHx(HTN) in stroke patients versus controls. The association was significant in 6 out of 14 studies for FHx(IHD) and 4 out of 11 studies for FHx(HTN). In contrast, FHx(DM) was not associated with stroke. FHx(IHD) was particularly associated with large vessel strokes (OR 1.72, CI 1.3-2.2, p = 0.00004).

CONCLUSIONS

FHx(IHD) and FHx(HTN) are both risk factors for stroke. It is likely that the apparent heritability of stroke is partly accounted for by heritability of HTN and large vessel atherosclerosis. Analyses of heritability of stroke and candidate gene studies should be adjusted accordingly.

[Hypocholesterolemia in hospitalized elderly: relations with inflammatory and nutritional status]

PURPOSE

Hypocholesterolemia is a common finding in hospitalized elderly people and is associated with increased mortality. Changes in plasma lipid levels are well known in the acute phase response. It has also been suggested that malnutrition is a cause of hypocholesterolemia. However, malnutrition is the reflect of general condition, and the respective roles of malnutrition and inflammation have not yet been clearly established. This research project was undertaken to examine the impact of nutritional and inflammatory status on the hypocholesterolemia.

METHODS

In a prospective study, 597 elderly patients (83 +/- 7 years) consecutively admitted in a geriatric acute care unit were included. Clinical and anthropometric data: Body Mass Index (BMI), Tricipital Skinfold Thickness (TSF), Sub-Scapular Skinfold Thickness (SSF), Mid Arm Circumference (MAC) have been collected. The blood samples were obtained within the 72 hours following the admission. Nutritional proteins (albumin, prealbumin, transferrin, retinol binding protein); inflammatory proteins (CRP, alpha-1 acid glycoprotein), and blood lipids (cholesterol, LDL, HDL cholesterol, triglycerides, apoproteins A1 and B) were dosed.

RESULTS

The anthropometric and biologic parameters have been compared on the two sexes, significant differences were observed only for blood lipids. The analyses are thus realized and presented by sex separately. Four groups of patients are generated according to the quartile of total cholesterol. Means and standard deviation for all factors are calculated within each group. Both, the trend of means and analyses of correlation show associations with cholesterol in the two sexes. The analysis of variance showed that the cholesterolemia is associated with 1/ decrease in the values of the anthropometrics, and nutritional proteins and 2/ upward trends of the inflammatory parameters. Significant correlations were observed for all transport proteins and CRP with total cholesterol in men and women. The multiple linear regression of the total cholesterol retained albumin, APO A1, APO B and RBP as predictor factors of cholesterolemia for women and APO A1, APO B and tryglicerid for men. When patients with infectious diseases were compared to the others, significant differences have been observed for total cholesterol and all blood lipids, as well as for nutritional and inflammatory proteins.

CONCLUSION

The results confirm an association between nutritional status and hypocholesterolemia, and suggest also the responsability of inflammation as a cause of hypocholesterolemia.

Epidemiology of low total plasma cholesterol concentration among young adults: the CARDIA study. Coronary Artery Risk Development in Young Adults

BACKGROUND

Data on stability of plasma total cholesterol levels and its determinants among young adults are lacking. Knowledge of factors associated with low levels of plasma total cholesterol during young adulthood may help clarify the nature of associations between hypocholesterolemia and health or illness.

METHODS

Tracking of plasma total cholesterol was investigated using data from the baseline (1985-1986), Year 5 (1990-1991), and Year 7 (1992-1993) examinations of the Coronary Artery Risk Development in Young Adults Study. Lifestyle (including dietary), physiological, medical, and psychological correlates of plasma total cholesterol were examined cross-sectionally at baseline using ANCOVA and multivariate logistic regression. The attributes of participants with persistently low plasma total cholesterol level after 7 years (i.e., remaining below the 10th percentile of sex- and race-specific distributions) were also examined.

RESULTS

The cohort in this analysis comprised 720 black men, 922 white men, 899 black women, and 944 white women who were between the ages of 18 and 30 years at baseline. Between 44 and 52% of those with plasma total cholesterol levels below the 10th percentile remained below the same percentile 7 years later. Among black men, a difference of 1 SD in age [3.7 years; odds ratio (OR) = 0.69; 95% CI = 0.52-0.91] and a difference of 1 SD in systolic blood pressure (10.5 mm Hg; OR = 0.73; 95% CI = 0.54-0.97) were independently associated with lower odds, respectively, of being in the lowest 10th percentile of the plasma total cholesterol distribution. Also among black men, current smoking and more calories from carbohydrates were associated with nonsignificantly higher odds of low total cholesterol level. Among white men, a 1 SD older age (3.4 years; OR = 0.78; 95% CI = 0.61-1.00) and a 1 SD higher physical fitness (118 sec; OR = 1.41; 95% CI = 1.09-1.82) predicted lower and higher odds, respectively, of low plasma total cholesterol. Among black women, a 1 SD difference in albumin (0.3 g/dL; OR = 0.80; 95% CI = 0.63-1.03) was related to lower odds of low plasma total cholesterol. Among white women, the factors independently associated with low plasma total cholesterol were body mass index (OR for a difference in 4.0 kg/m2 = 0.73; 95% CI = 0.54-1.00) and gamma-glutamyl transferase (OR for an increase in 9.6 IU/L = 0.41; 95% CI = 0.18-0.93). The independent predictive factors of stably low total cholesterol levels were age and uric acid among black men (both inversely related) and age, Framingham Type A Behavior (inversely), and calories from carbohydrates (positively related) among white men.

CONCLUSION

Young adults with low plasma total cholesterol level have characteristics generally associated with good cardiovascular health. However, adverse attributes such as current cigarette smoking (notably among black men) may confound future associations between low total cholesterol and disease.

Low density lipoprotein catabolism is enhanced by the cleaved form of alpha-1-antitrypsin

The frequent occurrence of hypocholesterolaemia following inflammatory processes is well known but unexplained. Elevated plasma levels of serine proteinase inhibitors (serpins) and their complexes with target enzymes have been demonstrated in inflammatory, malignant and infectious diseases which are also often accompanied by low plasma cholesterol levels. Under inflammatory conditions, uncomplexed, but cleaved inactive serpins arising from slow deacylation of the serpin-proteinase complex may be present in the circulation. To determine the influence of native and cleaved forms of serpins, such as alpha-1-antitrypsin (AAT), on lipoprotein metabolism, we investigated the effect of these forms on low density lipoprotein (LDL) catabolism in human HepG2 cell line. We have found that the cleaved form of AAT in concentrations from 125 to 2000 nmol l-1 stimulates LDL binding to the HepG2 cells, by up to 49% with a subsequent increase in LDL uptake and degradation of up to 79 and 65% respectively. Native AAT was also found to increase LDL binding and internalization by 20-25%, independently of the amount of AAT added, an effect most probably due to the cleaved form of AAT produced by local proteolysis of native AAT incubated in the cell culture. Moreover we have shown that the cleaved form of AAT interacts with LDL in vitro, and that such an interaction abolishes AAT ability to stimulate LDL binding and internalization. This study for the first time describes the ability of the cleaved form of AAT to stimulate LDL binding and internalization in HepG2 cell culture, and provides evidence that hypocholesterolaemia occurring during inflammatory processes may be mediated by cleaved forms of serpins.

High plasma insulin is associated with lower LDL cholesterol in elderly individuals

To investigate possible relationships between plasma low density lipoprotein (LDL) cholesterol and fasting plasma insulin in the elderly, cross-sectional random samples of age cohorts (65, 75, 80 and 85 years, n = 1188, M/F 38/62 percent) were studied in the neighbouring cities of Helsinki and Vantaa, Finland. Plasma total and high density lipoprotein (HDL) cholesterol, plasma triglycerides, blood glucose and plasma insulin were measured after an overnight fast. LDL cholesterol was calculated using the Friedewald equation. Statistical analyses were performed separately in subjects with non-insulin-dependent diabetes mellitus (NIDDM, n = 219) and non-diabetic subjects (n = 969). Comparison of lipid levels by insulin quartile (I < 7.4 IU/1, II 7.4-10.0, III 10.1-15.0, IV > 15.0) showed that total and LDL cholesterol decreased in the highest insulin quartile (P = 0.003). This trend prevailed after adjustments for age, gender, body mass index, blood glucose and serum triglycerides, and it was significant also in normotriglyceridemic (serum triglycerides <2.3 mmol/l) subjects. Furthermore, the association between high insulin and lower cholesterol was seen in normoglycemic (fasting blood glucose <6.7 mmol/l) and diabetic subjects. Lower LDL cholesterol in elderly subjects with higher fasting insulin may reflect poor health or a 'harvesting' effect, but the results may also be due to effects of insulin on LDL catabolism and/or cholesterol absorption.

Epidemiology of low cholesterol levels in older adults. The Cardiovascular Health Study

BACKGROUND

Low cholesterol levels have been associated with increased mortality from stroke, cancer, and other noncardiovascular diseases, but the reasons for this association remain unclear. One explanation is that persons with low cholesterol levels have early or occult disease that eventually leads to their deaths.

METHODS AND RESULTS

This possibility was explored in 2,091 men and 2,714 women 65-100 years old in the Cardiovascular Health Study, a multicenter observational study of risk factors for heart disease and stroke in older adults. Cholesterol levels < or = 160 mg/dL were present in 11.6% of men and 3.7% of women and increased in prevalence with age. After adjustment for age, total cholesterol levels in this range were associated with a twofold increased prevalence of treated diabetes in men and women and with a twofold increased prevalence of cancer diagnosed in the preceding 5 years in women only. Low cholesterol was also associated with lower levels of hemoglobin, albumin, and factor VII, suggesting a link with hepatic synthetic function. On multivariate analysis, factors most strongly associated with low cholesterol levels in men and women were decreased factor VII levels, decreased albumin, and diabetes.

CONCLUSIONS

Cross-sectional associations with low cholesterol levels differ by sex and suggest poorer health by some measures. The observed relations with treated diabetes and impaired hepatic synthetic function should be examined for risk of mortality in longitudinal data from this and other observational studies.