Comparison of low-density lipoprotein cholesterol/high-density lipoprotein cholesterol and total cholesterol/high-density lipoprotein cholesterol for the prediction of thin-cap fibroatheroma determined by intravascular optical coherence tomography

BackgroundThe correlation among the ratios of low-density lipoprotein cholesterol/high-density lipoprotein cholesterol (LDL-C/ HDL-C), total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) and thin-cap fibroatheroma has not yet been established.MethodsIt was a single center, retrospective observational study. In total, we recruited 421 patients (82.4% men; mean age 65.73 ± 10.44 years) with one culprit vessel which determined by intravascular optical coherence tomography (OCT). The thinnest-capped fibroatheroma (TCFA) group was defined as lipid contents in > 2 quadrants, with the thinnest fibrous cap measuring less than 65 μm. Univariate and multivariate logistic regression were carried out to explore the relationship between lipoprotein ratios, TCFA and other characteristics of plaque. To compare different ratios, the area under curve (AUC) of receiver-operating characteristic (ROC) curve was assessed.ResultsOCT was performed in 421 patients (TCFA group (n = 109), non-TCFA group (n = 312)). LDL-C/HDL-C in the TCFA group was significantly higher than in the non-TCFA group (2.95 ± 1.20 vs. 2.43 ± 0.92, P < 0.05), as was TC/LDL in TCFA and non-TCFA group (4.57 ± 1.58 vs. 4.04 ± 1.13, P < 0.05). Both LDL-C/HDL-C (OR: 1.002 (1.002-1.003), P < 0.05) and TC/HDL-C (OR: 1.001 (1.001-1.004), P < 0.05) were considered independent factors for the prediction of TCFA according to the logistic regression. Based on the AUC comparison, LDL-C/ HDL-C and TC/HDL-C had no significant difference statistically (LDL-C/HDL-C AUC: 0.63; TC/HDL-C AUC: 0.61; P = 0.10) for the prediction of TCFA.ConclusionsLDL-C/HDL-C and TC/HDL-C could be the independent factors for predicting the presence of TCFA, indicating coronary plaque vulnerability in CAD patients. Moreover, TC/HDL-C also showed a comparative performance for the prediction of TCFA as LDL-C/HDL-C.     

Cigarette smoking,high-density lipoprotein cholesterol subfractions,and lecithin: cholesterol acyltransferase in young women

Much of the published data on the relationship of cigarette smoking (CS) with serum lipids and lipoproteins is based on studies of middle-aged individuals. Data on young women are scarce. This study examined the relationship of CS with high-density lipoprotein cholesterol (HDL-C) subfractions and lecithin:cholesterol acyltransferase (LCAT) activity in Japanese collegiate women. Twenty-three current smokers were individually matched for physical activity scores, age, and body mass index (BMI) with 23 nonsmokers. There were no significant differences between smokers and nonsmokers in the mean nutrient intakes. Smokers had significantly lower mean HDL-C, HDL2-C, total cholesterol, and LCAT activity than nonsmokers. In univariate analyses, BMI significantly negatively correlated with HDL-C and HDL2-C. LCAT activity significantly positively correlated with HDL3-C, LDL-C, total cholesterol (TC) and triglycerides (TG). In multiple regression analyses, the number of CS was positively related to TG. BMI was negatively related to TC. LCAT activity was positively related to LDL-C, TC, and TG. These results suggest that the known associations in older adults of CS with HDL-C subfractions and LCAT activity are already apparent in young women.     

Longitudinal and secular trends in lipoprotein cholesterol measurements in a general population sample. The Framingham Offspring Study

Two fasting lipoprotein cholesterol measurements have been made on Framingham Offspring Study participants, first in 1971-75 and again in 1979-83. Longitudinal analysis (n = 2433, age 20-49 at first exam) using multivariate regression found aging, weight gain, vasectomy, menopause, and increased smoking are associated with worsening lipoprotein profiles, while increased alcohol consumption is associated with increased high density lipoprotein cholesterol (HDL-C). Average increases in low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) in women accelerate with age; in men the increases are similar or perhaps decelerate with age. Secular trends were measured using age-adjusted mean values for individuals aged 25-54. Averages of total cholesterol, LDL-C (men only), systolic and diastolic blood pressure, body mass index, number of cigarettes per day, and alcohol consumption were lower at the second examination. Two secular trends in women indicate a possible worsening of population lipoprotein profiles: mean VLDL-C was higher and mean HDL-C lower at the second exam.     

血清胆红素和血脂的综合指数与冠心病的关系研究

目的探讨血清胆红素与血脂的综合指数与冠心病(CHD)的关系.方法将80名行冠状动脉造影术的患者分为2组:CHD组与对照组(冠状动脉正常).测定血清总胆红素水平(TBIL),总胆固醇(TC),高密度脂蛋白胆固醇(HDL-C),低密度脂蛋白胆固醇(LDL-C),计算出其综合指数:LDL-C/(HDL-C TBIL)和TC/(HDL-C TBIL),分析其与CHD之间的关系.结果CHD患者血清TBIL水平明显低于非冠心病患者(P＜0.05).CHD患者总胆固醇(TC),低密度脂蛋白胆固醇(LDL-C),LDL-C/(HDL-C TBIL)比值,TC/(HDL-C TBIL)比值水平明显高于冠状动脉正常组(P＜0.05).进行Logistic回归分析,TC,LDL-C,LDL-C/(HDL-C TBIL),TC/(HDL-C TBIL)可引入Logistic回归模型,它们为CHD的危险因素.结论CHD的发生与TBIL的降低有一定的相关性,综合考虑血脂、血清胆红素与血脂的综合指数有助于CHD的诊断.     

Low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio as a useful marker for early-stage carotid atherosclerosis

A higher ratio of low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C) is associated with a greater risk of cardiovascular events in patients with coronary heart disease. However, the role of this lipid index during early-stage atherosclerosis has not yet been established. This study investigated relationships between LDL-C/HDL-C ratio and carotid plaque score as assessed by ultrasonography in 825 subjects from the general population (527 men, 298 women; mean age, 60.5 years). To identify factors strongly associated with plaque score, stepwise multiple regression analysis was performed using various clinical variables including conventional lipid indices. In both sexes, increased LDL-C/HDL-C ratio was associated with increased plaque score (men: β = 0.132, P = .001; women: β = 0.150, P = .012). This association was maintained in men with normal LDL-C level (<140 mg/dL). The highest quartile of LDL-C/HDL-C ratio (>2.9 in men, >2.6 in women) showed significantly increased plaque score even when adjusted by factors included in the final model of stepwise analysis (P = .007 in men, P = .033 in women). No association was seen between LDL-C and plaque score in the multivariate-adjusted model. These findings indicate that increased LDL-C/HDL-C ratio may also be associated with initiation of atherosclerosis. Assessment of this lipid ratio may thus facilitate early management of atherosclerotic risks better rather than assessment of LDL-C alone.     

女性原发性高血压患者绝经前后脂蛋白(a)及血脂水平变化的研究

目的　观察女性原发性高血压患者绝经前后脂蛋白 (a) [L p(a) ]及血脂水平的变化 ,探讨其对女性冠心病发病情况可能存在的影响。方法　女性原发性高血压患者 12 1例 ,测定 L p(a)、总胆固醇 (TC)、三酰甘油 (TG)、低密度脂蛋白胆固醇 (L DL- C)和高密度脂蛋白胆固醇 (HDL- C)。对比绝经前后 L p(a)及血脂水平的变化 ,并与女性健康体检者 (对照组 )进行对比。结果　高血压组 L p(a)、TC、TG、L DL - C均显著高于对照组 ,而 HDL - C及 HDL - C/TC则明显低于对照组 ,在所有原发性高血压患者中 ,绝经后的患者 L p(a)、TC、TG、L DL - C显著高于绝经前患者 ,而 HDL - C/ TC则前者低于后者。结论　绝经后原发性高血压患者 L p(a)、TC、L DL - C均明显高于绝经前患者 ,而HDL- C/ TC则低于绝经前患者 ,提示绝经后女性原发性高血压患者 L p(a)及血脂水平增高与内源性雌激素水平下降有关 ,是绝经后冠心病发病率明显上升的重要原因。     

Risk determination of dyslipidemia in populations characterized by low levels of high-density lipoprotein cholesterol

Background

Current guidelines for managing dyslipidemia qualify patients for treatment based on low-density lipoprotein cholesterol (LDL-C) levels and other risk factors for coronary heart disease (CHD). However, when LDL-C is the sole lipid criterion for initiating therapy, patients with levels below the treatment initiation threshold who are at high risk because of low levels (<40 mg/dL) of high-density lipoprotein cholesterol (HDL-C) might not be identified. Twenty percent of male patients with CHD in the United States fall into this category. The total cholesterol/HDL-C (TC/HDL-C) ratio predicts CHD risk regardless of the absolute LDL-C and HDL-C.

Methods

We compared guidelines based on TC/HDL-C and LDL-C with those recommended by the National Cholesterol Education Program Adult Treatment Panel III (ATP III). Both sets of guidelines were applied to 9837 adults (>20 years of age) in the Turkish Heart Study, which has shown that 75% of men and 50% of women in Turkey have HDL-C <40 mg/dL.

Results

ATP III guidelines identified 14% of Turkish adults, 20 years or older, as candidates for lifestyle treatment only and an additional 18% for drug treatment. In conjunction with ATP III LDL-C thresholds, the TC/HDL-C ratio (>3.5, patients with CHD; ≥6.0, 2+ risk factors, ≥7.0, 0 to 1 risk factor) assigned lifestyle therapy alone to 18% and drug treatment to an additional 36%. Among primary prevention subjects at high risk because of age (men ≥45 years; women ≥55 years), both sets of guidelines prescribed lifestyle therapy for only 5%; however, drug treatment was recommended for an additional 13% by ATP III guidelines and an additional 18% by TC/HDL-C and LDL-C.

Conclusions

In populations at risk for CHD caused by low HDL-C, qualification of subjects for treatment based on either the TC/HDL-C ratio or LDL-C thresholds identifies more high-risk subjects for treatment than LDL-C threshold values alone, and use of the ratio, instead of risk tables, simplifies the approach for physicians.     

Lipids, lipoproteins, lifestyle, adiposity and fat-free mass during middle age: the Fels Longitudinal Study

INTRODUCTION: Although lipid profiles tend to worsen with age, it is not fully known if such age-related changes are influenced primarily by body composition and lifestyle or by other aspects of aging. OBJECTIVE: We investigated the extent to which the fat and fat-free components of body mass index (BMI) and lifestyle factors influence patterns of change in lipids independent of age. DESIGN: Serial data were analyzed using sex-specific longitudinal models. These models use serial data from individuals to assume a general pattern of change over time, while allowing baseline age and the rate of change to vary among individuals. SUBJECTS: Serial data were obtained from 940 examinations of 269 healthy white participants (126 men, 143 women), aged 40-60 years, in the Fels Longitudinal Study. MEASUREMENTS: Measurements included age, the fat (FMI) and fat-free mass (FFMI) components of BMI, high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C), triglycerides (TG), total cholesterol (TC), fasting glucose and insulin, physical activity, alcohol use and smoking, and women's menopausal status and estrogen use. RESULTS: In both sexes, increased FMI was significantly associated with increased LDL-C, TG and TC, and decreased HDL-C. Increased FFMI was significantly related to decreased HDL-C and increased TG. Independent age effects remained significant only for LDL-C and TC in men and TC in women. Increased insulin was significantly related to increased TG in women. Moderate alcohol consumption was associated with higher HDL-C in men. Physical activity lowered male LDL-C and TC levels, and increased female HDL-C levels. Menopause was associated with increases in LDL-C. Premenopausal women not using estrogen had significantly lower HDL-C, TG, and TC than postmenopausal women taking estrogen. CONCLUSIONS: (1) Age is an important independent predictor for LDL-C and TC in men, and TC in women, but it is not as influential as body composition and lifestyle on HDL-C and TG in men and women, and LDL-C in women. (2) Increasing FMI is the major contributor to elevated TC, LDL-C and TG levels, and decreased HDL-C levels in men and women. (3) FFMI significantly influences HDL and TG levels in both sexes. (4) Maintaining a lower BMI via a reduced fat component may be more beneficial in lowering CVD risks than other factors.     

Chlorpropamide lowers serum and lipoprotein cholesterol in insulin-dependent diabetes

Changes in serum lipids and lipoproteins were examined during eight weeks chlorpropamide therapy in eight C-peptide negative, insulin-dependent diabetic patients (mean age 40 years, mean onset of diabetes 20 years). Chlorpropamide was found to have a generalized cholesterol lowering effect (progressive significant fall in mean total cholesterol, LDL-C, HDL-C, and HDL3-C) with no significant change in the ratio of high-density lipoprotein to low-density lipoprotein cholesterol which was independent of insulin secretion.     

Prognostic value of lipoprotein fractions in essential hypertension

Background: To evaluate distribution and prognostic value of total cholesterol and lipoprotein fractions in essential hypertension. Methods: In a prospective cohort study, 2649 initially untreated subjects with essential hypertension (aged 51, 46.5% women) were investigated at entry and followed for a mean of 5.6 years (range: 1-16). Results: At entry, subjects with total cholesterol (TC) ≥240 mg/dl (≥6.22 mmol/l) or high-density lipoprotein (HDL) cholesterol (HDL-C) 6 were 47.7%. TC, HDL-C, LDL-C and triglycerides (TG) did not show any association with office or 24-h ambulatory blood pressure (BP). During follow-up there were 167 first cardiac events and 122 first cerebrovascular events. TC, HDL-C, LDL-C and TC/HDL-C ratio showed an association with cardiac events, but not with cerebrovascular events. TG did not show any association with cardiac or cerebrovascular events. After adjustment for age, sex, diabetes, smoking, left ventricular (LV) hypertrophy and 24-h pulse pressure, the hazard ratio for cardiac events was 1.83 (95% CI 1.23-2.71) in association with a TC ≥6.22 mmol/l, 2.23 with a HDL-C 6.0 (95% CI 2.23-6.81). When forced in the same model, HDL-C and LDL-C showed an independent association with cardiac events. Conclusions: Abnormalities of TC and lipoproteins are common in essential hypertension. HDL-C and LDL-C independently predict the risk of cardiac, but not cerebrovascular, events. Their predictive value is independent of several confounding factors including LV hypertrophy and ambulatory BP.     

Total cholesterol/HDL cholesterol ratio vs LDL cholesterol/HDL cholesterol ratio as indices of ischemic heart disease risk in men: the Quebec Cardiovascular Study.

BACKGROUND: Total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C)/HDL-C ratios are used to predict ischemic heart disease risk. There is, however, no consensus on which of these 2 indices is superior. The objective of the present study was to present evidence that the LDL-C/HDL-C ratio may underestimate ischemic heart disease risk in overweight hyperinsulinemic patients with high triglyceride (TG)-low HDL-C dyslipidemia. METHODS: A total of 2103 middle-aged men in whom measurements of the metabolic profile were performed in the fasting state were recruited from 7 suburbs of the Quebec metropolitan area. RESULTS: The relationship of LDL-C/HDL-C to TC/HDL-C ratios was examined among men in the Quebec Cardiovascular Study classified into tertiles of fasting TG levels. For any given LDL-C/HDL-C ratio, the TC/HDL-C ratio was higher among men in the top TG tertile (>168 mg/dL [>1.9 mmol/L]) than in men in the first and second TG tertiles. Adjustment of the TC/HDL-C ratio for LDL-C/HDL-C by covariance analysis generated significant differences in average TC/HDL-C ratios among TG tertiles (P<.001). Greater differences in features of the insulin resistance syndrome (insulinemia, apolipoprotein B, and LDL size) were noted across tertiles of the TC/HDL-C ratio than tertiles of the LDL-C/HDL-C ratio. CONCLUSION: Variation in the TC/HDL-C ratio may be associated with more substantial alterations in metabolic indices predictive of ischemic heart disease risk and related to the insulin resistance syndrome than variation in the LDL-C/HDL-C ratio.     

Association of the apolipoprotein B/apolipoprotein A-I ratio and low-density lipoprotein cholesterol with insulin resistance in a Chinese population with abdominal obesity

The aim of this study is to assess the relationships among the apolipoprotein B/apolipoprotein A-I ratio (apoB/apoA-I ratio), low-density lipoprotein cholesterol (LDL-C) and insulin resistance (IR) in a Chinese population with abdominal obesity. This is a population-based, cross-sectional study of 3,945 men and 2,141 women with abdominal obesity. Individuals were referred to a primary health service and recruited for analysis. IR was measured using a homeostasis model assessment of insulin resistance (HOMA2-IR) with a HOMA2 calculator. Metabolic syndrome (MetS) was diagnosed using International Diabetes Federation (IDF) criteria. Comparing the apoB/apoA-I ratio and lipid indices using the HOMA2-IR showed that the ratio, LDL-C, total cholesterol level (TC) and triglyceride level (TG) were higher; and the high-density lipoprotein cholesterol level (HDL-C) was lower in the fourth than in the first quartile in both sexes (p????0.001). After adjustment for age, HOMA2-IR was positively correlated with the apoB/apoA-I ratio, LDL-C, TC and TG; and negatively correlated with HDL-C in men (all p?<?0.0001). HOMA2-IR was also positively correlated with the apoB/apoA-I ratio, LDL-C, TC and TG; and negatively correlated with HDL-C in women (all p?<?0.01). After adjustment for age and LDL-C, HOMA2-IR was found to be correlated with the apoB/apoA-I ratio in both men and women (r?=?0.066 and 0.116, p?<?0.0001). After adjustment for age and the apoB/apoA-I ratio, HOMA2-IR was correlated with LDL-C in men and women (r?=?0.063 and 0.044, p?<?0.0001 and p?=?0.0431, respectively). Gender, age, LDL-C, BMI, HOMA2-IR and apoB/apoA-I were the covariates independently associated with presence of the MetS (Odds ratio, OR: 2.183, 1.034, 1.013, 1.157, 1.726 and 1.570, respectively; all p?<?0.05). In conclusion, the study showed that the apoB/apoA-I ratio and LDL-C were positively correlated with IR. Excluding reciprocal interactions, the apoB/apoA-I ratio and LDL-C were still significantly correlated with IR, but the apoB/apoA-I ratio showed a greater correlation with IR than LDL-C in women with abdominal obesity, compared with men with abdominal obesity. Both LDL-C and apoB/apoA-I were independent risk factors of MetS, and the apoB/apoA-I ratio was stronger in this regard than LDL-C for this obese population.     

Low-density lipoprotein cholesterol: association with mortality and hospitalization in hemodialysis patients

BACKGROUND/AIMS: Hypocholesterolemia is a common finding in hospitalized elderly people, critically ill surgical patients, septic patients and end-stage renal disease patients. The different effect of lipid subfractions on patients with end-stage renal disease has never been demonstrated. We aim to study the effect of lipid subfractions on hospitalization and mortality in maintenance hemodialysis (MHD) patients. METHODS: Lipid subfractions, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were measured in 210 patients with MHD in a single dialysis center. Patients were stratified into three groups based on the tertiles of lipid levels, and differences in patient characteristics and survival were evaluated. RESULTS: Of a total of 22 deceased patients in our MHD cohort, infection-related mortality (50%) was higher than cardiovascular-related mortality (18.2%). Significant differences (p < 0.05) in the duration and frequency of hospitalization and in mortality events were observed when patients were divided into different subgroups according to the tertiles of baseline TC and LDL-C levels. Patients with lower LDL had significantly lower levels of albumin, TC and TG. The LDL-C tertiles were similar in terms of age, hypertension, diabetes, biochemical results, hematocrit, adequacy of hemodialysis and normalized protein catabolism rate. Both TC and LDL-C predicted survival (p < 0.001), but not TG and HDL-C in the Kaplan-Meier model. The Cox proportional hazard model demonstrated that baseline serum LDL-C was the best lipid subfraction in predicting all-cause death with an adjusted hazard ratio (95% confidence interval) for each 10 mg/dl of 0.752 (0.631-0.898; p = 0.002). CONCLUSIONS: We firstly demonstrated that lipid subfractions, including TC and LDL-C, predict poor outcomes in a MHD cohort with high infection-related mortality.     

Association between the severity of obstructive sleep apnea and the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol

The positive association between the ratio of serum low-density lipoprotein cholesterol (LDL-C) to serum high-density lipoprotein cholesterol (HDL-C) and cardiovascular events has recently been receiving much attention. However, the association between the severity of obstructive sleep apnea (OSA) and this ratio has not yet been investigated. Accordingly, we sought to clarify this association and the effect of continuous positive airway pressure (CPAP) therapy on the ratio. We performed polysomnography and LDL-C/HDL-C measurements in 215 patients who were suspected of having OSA. Furthermore, LDL-C/HDL-C was again evaluated 6 months after polysomnography in 30 OSA patients for whom CPAP therapy was initiated and continued, and in 11 age- and sex-matched OSA patients for whom the therapy could not be initiated. The LDL-C/HDL-C correlated positively with apnea-hypopnea index (ρ = 0.28, P < .001) and negatively with the lowest arterial oxyhemoglobin saturation (ρ = -0.30, P < .001). Multivariate regression analysis revealed that ln apnea-hypopnea index (or ln lowest arterial oxyhemoglobin saturation) was independently associated with LDL-C/HDL-C. The LDL-C/HDL-C decreased after 6 months in the CPAP group (2.29 ± 0.67 to 2.11 ± 0.74, P = .02), whereas it did not change in the non-CPAP group (2.65 ± 0.82 to 2.62 ± 0.66, P = .81). The severity of OSA was independently associated with LDL-C/HDL-C, and LDL-C/HDL-C was significantly reduced at 6 months after CPAP therapy. These findings suggest that LDL-C/HDL-C increases in proportion to the severity of OSA, which may contribute partly to an increased risk for cardiovascular events in OSA patients.     

Sustained alterations in lipoprotein cholesterol concentrations dependent on the daily distribution of lipid intake

Since the fat content of a single meal influences chylomicron size and hence intestinal apoprotein synthesis, we determined the chronic effects of the daily distribution of fat intake on plasma concentrations of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C). Eight normal male subjects ingested 100 g of fat (a) as a bolus at the evening meal (SL) or (b) equally distributed over 4 meals (q4h) (DL). Each diet was consumed for 7 days; studies were performed 14 days apart using a crossover design and paired comparisons. Nutrient intake and body weight were held constant. At the end of the DL dietary regimen, fasting plasma concentrations of TC, LDL-C and HDL-C were significantly increased as compared to the SL phase of study (TC: 174 +/- 2.9 (mean +/- SEM) vs 161 +/- 2.7; LDL-C: 108 +/- 3.2 vs 98 +/- 3.3 and HDL-C: 53 +/- 1.1 vs 48 +/- 0.8) (P less than 0.05). The consumption of 100 g/day of fat in several small meals results in a sustained increase in LDL-C and HDL-C. This may be due to increased synthesis of lipoprotein components (e.g. apoprotein A-I) or to altered metabolism of intestinal and hepatic TG-rich lipoproteins dependent on size, number and apoprotein composition.     

Relationship between total cholesterol/high-density lipoprotein cholesterol ratio, triglyceride/high-density lipoprotein cholesterol ratio, and high-density lipoprotein subclasses

Alterations in plasma lipid levels can influence the composition, content, and distribution of plasma lipoprotein subclasses that affect atherosclerosis risk. This study evaluated the relationship between plasma total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio, triglyceride (TG)/HDL-C ratio, and HDL subclass distribution. The apolipoprotein A-I contents of plasma HDL subclasses were quantitated by 2-dimensional gel electrophoresis coupled with immunodetection in 442 Chinese subjects. The particle size of HDL shifted toward smaller size with the elevation of TC/HDL-C and TG/HDL-C ratios. The ratio of large-sized HDL(2b) to small-sized prebeta(1)-HDL (HDL(2b)/prebeta(1)-HDL) was about 4.7 in the subjects with TC/HDL-C of 3.3 or lower and TG/HDL-C of 2.5 or lower, whereas it was only approximately 1.1 in subjects with TC/HDL-C greater than 6 and TG/HDL-C greater than 5. Pearson correlation analysis revealed that the TC/HDL-C ratio was positively correlated with prebeta(1)-HDL and HDL(3a) but negatively correlated with HDL(2a) and HDL(2b), whereas the TC/HDL-C ratio was only inversely correlated with HDL(2b). The TC/HDL-C and TG/HDL-C ratios together may be a good indicator of HDL subclass distribution. When these 2 ratios increased simultaneously, the trend toward smaller HDL size was obvious, which, in turn, indicated that the maturation of HDL might be impeded and the reverse cholesterol transport might be weakened. In addition, the TG/HDL-C ratio might be a more powerful factor to influence the distribution of HDL subclasses.     

Seasonal variation of serum high density lipoprotein cholesterol levels in men

To determine if there are seasonal variations in serum high density lipoprotein cholesterol (HDL-C), the concentration of HDL-C was measured monthly for 12 consecutive months in 31 healthy men and 24 male inpatients with schizophrenia. In addition to HDL-C, total cholesterol (TC) and triglyceride (TG) concentrations in serum were assayed, and low density lipoprotein cholesterol (LDL-C) was estimated by calculation. Mean serum HDL-C levels of schizophrenic patients were significantly low compared with those of healthy controls, 35 +/- 12 and 49 +/- 11 mg/dl, respectively. The TC levels of schizophrenic patients were significantly higher in January and March as compared with August. The HDL-C levels in summer and autumn were significantly lower than those in winter and spring in both healthy men and schizophrenic patients. The concentration of LDL-C was significantly high in September and October as compared with April in healthy men. In patients with schizophrenia, LDL-C level seemed higher in January and March as compared with August.     

Subclinical hypothyroidism and lipid abnormalities in older women attending a vascular disease prevention clinic: effect of thyroid replacement therapy

The authors evaluated the frequency and type of lipid disorders associated with subclinical hypothyroidism (SH) in older women referred to their university vascular disease prevention clinic. They also assessed the results of thyroid replacement therapy. Fasting serum lipid profiles and thyroid function tests were measured in 333 apparently healthy women (mean age: 71.8 +/- 7 years). These women were divided into 3 groups: group I: 60-69 years old (n = 132); group II: 70-79 years old (n = 153); group III: 80-89 years old (n = 48). SH was defined as a serum thyrotropin concentration higher than 3.20 mlU/mL with a normal free thyroxine concentration. The prevalence of SH was 7.5%. Thyrotropin was higher than 3.20 mU/mL in 25 women; 7 (5.3%), 14 (9.2%), and 4 (8.3%) in groups I, II, and III, respectively. Low-density lipoprotein cholesterol (LDL-C) concentrations were higher in the women with SH (p = 0.037). The mean values of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), TC/HDL-C ratio, lipoprotein (a) (Lp[a]), apolipoprotein A-I (apo AI) apolipoprotein B100 (apo B) and apo B/apo A ratio were higher and triglycerides (TG) were lower, compared with those with normal levels of thyrotropin. However, none of these differences reached significance. Restoration of euthyroid status (thyroxine: 50-100 microg/day) in 17 SH women significantly improved TC (p = 0.017), LDL-C (p = 0.014), TC/HDL-C (p = 0.05), LDL-C/HDL-C (p = 0.03), apo B (p = 0.013), and Lp(a) (p = 0.0005) values. SH is relatively common in older women attending a vascular disease prevention clinic. Thyroid hormone replacement therapy significantly improved serum lipids. In particular, the reduction in LDL-C and Lp(a) concentrations may be of clinical benefit.     

新疆牧区哈萨克族与蒙古族低密度脂蛋白胆固醇水平调查与影响因素分析

目的 调查新疆牧区哈萨克族、蒙古族低密度脂蛋白胆同醇(LDL-C)水平,观察其差异,分析其影响因素.方法 采用整群随机抽样的方法选取新疆和丰县牧区年龄≥30岁的牧民632人为调查对象,其中哈萨克族325人,蒙古族307人;抽取空腹12 h静脉m 3ml,采用日立7600全自动生化分析仪测定血浆总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)的浓度,并根据公式计算出LDL-C的浓度,对资料进行汇总,并采用t检验、方差分析或协方差分析的方法观察两民族间血浆LDL-C水平的差异,并进一步采用多元逐步同归分析的统计方法研究其影响因素.结果 哈萨克族、蒙占族的LDL-C平均水平分别为(3.68±1.16)mmol/L和(3.29±1.23)mmol/L,两民族间LDL-C平均水平存在明显的差异(P<0.001);哈萨克族人群中LDL-C水平主要与平均动脉压相关,而蒙占族主要与体质指数密切相关.结论 血浆LDL-C水平受多种因素的影响,存在明显的民族差异,即便是主要劳动方式和生活习惯十分相似的民族问LDL-C水平的主要影响凶素也各不相同.     

Different clinical and coronary angiographic findings according to ratios of total cholesterol to high-density lipoprotein cholesterol during the acute phase of myocardial infarction

OBJECTIVES: Several pathological studies have shown that a higher ratio of the serum total cholesterol concentration to the high-density lipoprotein cholesterol concentration (TC/HDL-C ratio) is associated with plaque rupture in patients with acute coronary syndromes. We examined the relationship between the serum total cholesterol concentration and the TC/HDL-C ratio, and clinical and angiographic findings in patients with first acute myocardial infarction. METHODS: Two hundred eighty patients were classified into quartiles according to the TC/HDL-C ratio measured within 24 hr from symptom onset: 70 patients in the first quartile (group L: mean TC/HDL-C ratio, 3.0), 140 in the second and third quartiles (group M: mean TC/HDL-C ratio, 4.6), and 70 in the fourth quartile (group H: mean TC/HDL-C ratio, 7.5). RESULTS: There were no differences among the three groups with regard to sex, diabetes mellitus or hypertension. Patients in group L were older (66 +/- 9 vs 60 +/- 11, 56 +/- 10 years, p < 0.01) and had a higher incidence of stable angina before acute myocardial infarction (26% vs 14%, 10%, p < 0.05) than in patients groups M and H. Although coronary angiograms revealed no difference in the number of diseased vessels among the three groups, extent index indicating the proportion of each coronary segment that appears angiographically abnormal was lowest in group L (0.7 +/- 0.5), followed by group M (1.3 +/- 0.6), and high- est in group H ( 1.7 +/- 0.6, p < 0.01). The number of segments with calcification and the incidence of calcification in the culprit lesion were higher in group L than in groups M and H. CONCLUSIONS: Our findings suggest that the clinical presentations and angiographic appearances differ according to the TC/HDL-C ratio in the acute phase of acute myocardial infarction.