Insulin sensitivity after a reduced-fat diet and a monoene-enriched diet in subjects with elevated serum cholesterol and triglyceride concentrations.

BACKGROUND AND AIMS: To investigate the effect of a reduced-fat diet and a monoene-enriched diet (MUFA diet) on serum lipids, glucose and insulin metabolism in subjects with elevated cholesterol and triglyceride concentrations. METHODS AND RESULTS: Eighteen subjects with elevated serum cholesterol and triglyceride concentrations consumed the MUFA diet (39% of energy (E%) as fat and 21 E% monoenes) and the reduced-fat diet (34 E% fat, 16 E% monoenes) for 4 weeks according to a randomized cross-over design. Both periods were preceded by consumption of a standardized baseline diet for 2 weeks. Serum lipid and lipoprotein concentrations were determined at the beginning and end of each diet period. A frequently sampled intravenous glucose tolerance test was performed after the MUFA diet and the reduced-fat diet. Insulin sensitivity index (SI) was 40% higher after the reduced-fat diet than after the MUFA diet (2.42 +/- 0.42 vs 1.73 +/- 0.24 10(-4) min-1 U-1 ml-1, p = 0.018). This change in insulin sensitivity was seen in 13 subjects and was most evident in those who began with the MUFA diet. Compared to the baseline diet (high in saturated fat), both experimental diets lowered serum total and LDL cholesterol concentrations (6.6-6.9%, p < 0.05 and 7.4-8.0%, p < 0.05 respectively). CONCLUSIONS: Both diets were equally effective in lowering serum lipid concentrations, but the reduced-fat diet resulted in better insulin sensitivity.

Measuring social class differences in cancer patient survival: is it necessary to control for social class differences in general population mortality? A Finnish population-based study.

STUDY OBJECTIVES: Estimation of cancer patient survival by social class has been performed using observed, corrected (cause specific), and relative (with expected survival based on the national population) survival rates. Each of these measures are potentially biased and the optimal method is to calculate relative survival rates using social class specific death rates to estimate expected survival. This study determined the degree to which the choice of survival measure affects the estimation of social class differences in cancer patient survival. SETTING AND PARTICIPANTS: All Finnish residents diagnosed with at least one of 10 common malignant neoplasms during the period 1977-1985 were identified from the Finnish Cancer Registry and followed up for deaths to the end of 1992. DESIGN: Survival rates were calculated by site, sex, and age at 5, 10, and 15 years subsequent to diagnosis for each of three measures of survival; relative survival, corrected (cause specific) survival, and relative survival adjusted for social class differences in general mortality. Regression models were fitted to each set of rates for the first five years of follow up. MAIN RESULTS: The degree of variation in relative survival resulting from social class decreased, although did not disappear, after controlling for social class differences in general mortality. The results obtained using corrected survival were close to those obtained using relative survival with a social class correction. The differences between the three measures were largest when the proportion of deaths from other causes was large, for example, in cancers with high survival, among older patients, and for longer follow up times. CONCLUSIONS: Although each of the three measures gave comparable results, it is recommended that relative survival rates are used with expected survival adjusted for social class when studying social class variation in cancer patient survival. If this is not an available option, it is recommended that corrected survival rates are used. Relative survival rates without the social class correction overestimate social class differences and should be used with caution.

Ten-year cardiovascular mortality in relation to risk factors and abnormalities in lipoprotein composition in type 2 (non-insulin-dependent) diabetic and non-diabetic subjects.

The purpose of the present study was to examine 10-year cardiovascular morbidity and mortality in patients with newly-diagnosed Type 2 (non-insulin-dependent) diabetes mellitus and non-diabetic control subjects and to evaluate the effects of general risk factors, plasma insulin, urinary albumin excretion, lipoprotein abnormalities characteristic of Type 2 diabetes and the degree of hyperglycaemia in diabetic patients on cardiovascular mortality. Furthermore, the extent to which the above-mentioned factors could contribute to the excessive cardiovascular mortality observed in diabetic patients was examined. In the years 1979-1981, altogether 133 (70 men, 63 women) newly-diagnosed patients with Type 2 diabetes and 144 (62 men, 82 women) non-diabetic control subjects aged 45-64 years were studied. Both groups were re-examined in the years 1985-1986 and 1991-1992. The impact of different factors on cardiovascular mortality was examined by univariate analyses after adjustment for age and sex and by multiple logistic regression analyses. The age-standardized total and cardiovascular mortality rates were substantially higher in diabetic men (17.8 and 15.0%, total and cardiovascular mortality, respectively p = 0.06 and NS) and women (18.5 and 16.6%, p < 0.01 for both) than in non-diabetic control men (5.2% both total and cardiovascular mortality) and women (4.2 and 2.2%). Cardiovascular mortality was not related to the treatment modality (diet, oral drugs, insulin) at 5 years from diagnosis. Use of diuretics, beta-blocking agents or their combination at baseline did not make a significant contribution to cardiovascular mortality either. In multiple logistic regression analysis on diabetic patients, age, LDL triglycerides, smoking, blood glucose and ischaemic ECG at baseline had independent associations with cardiovascular mortality. Interestingly, urinary albumin excretion rate measured at 5-year examination also predicted 10-year cardiovascular mortality after adjustment for the effects of major risk factors including lipoprotein abnormalities, but its predictive power reduced to a nonsignificant level when the effect of plasma glucose was taken into account. The relative risk of cardiovascular mortality associated with diabetes was 8.2 after allowing for age alone, but it declined to 3.7 when all contributing factors from the baseline examination (except blood glucose) were taken into account. In conclusion, the present results indicate that LDL triglycerides and/or other changes in lipoprotein composition characteristic of Type 2 diabetes and manifesting as elevated serum triglycerides are atherogenic and they strongly predict increased cardiovascular mortality.(ABSTRACT TRUNCATED AT 400 WORDS)

Obese men with type IIB hyperlipidemia are insulin resistant.

By using the euglycemic clamp technique and indirect calorimetry, we determined the degree of insulin resistance in 12 obese (body mass index > 27.0 kg/m2), normotensive patients with type IIB hyperlipidemia (HLIIB) (total cholesterol > or = 6.5 mmol/L and total triglycerides > or = 2.0 mmol/L) and 17 control subjects (total cholesterol < or = 6.1 mmol/L and total triglycerides < 1.8 mmol/L) who were carefully matched for sex, age, and obesity. Fasting plasma insulin was higher in HLIIB patients than in control subjects (18.4 +/- 4.6 versus 8.9 +/- 1.2 mU/L, respectively; P = .010). The rates of whole-body glucose uptake were significantly lower in HLIIB patients than in control subjects during the last hour of the clamp (42.2 +/- 3.9 versus 54.6 +/- 2.8 mumol/kg per minute, respectively; P = .013). Glucose oxidation during the last 30 minutes of the euglycemic clamp was lower in HLIIB patients than in control subjects (14.6 +/- 0.9 versus 19.0 +/- 1.3 mumol/kg per minute, respectively; P = .017). Nonoxidative glucose disposal during the last 30 minutes of the euglycemic clamp was also lower in HLIIB patients than in control subjects, but the difference was not statistically significant (27.6 +/- 3.3 versus 35.8 +/- 2.8 mumol/kg per minute, respectively; P = .069). Lipid oxidation during the clamp was completely suppressed in control subjects (-0.24 +/- 0.44 mumol/kg per minute) but was significantly less suppressed in the HLIIB patients (0.94 +/- 0.29 mumol/kg per minute, P = .024).(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between the ratio of serum low-density lipoprotein cholesterol and high-density lipoprotein cholesterol with that of serum apolipoproteins B and A-I.

Phosphowolframate/magnesium chloride, a commonly used precipitation method for the determination of high-density lipoprotein cholesterol in human serum, yields a supernatant containing almost all of the lipoproteins apo A-I and apo A-II but no lipoprotein apo B. The correlation between high-density lipoprotein cholesterol and apo A-I was very high (r = 0.94), as well as that between the precipitation method and ultracentrifugal analysis (r > 0.95, P < 0.001). In contrast, detergent precipitation (for the determination of low-density lipoprotein cholesterol in human serum) produced sediments which contained the major proportion of apo B and only minor amounts of apo A-I and apo A-II. The precipitation method for low-density lipoprotein cholesterol showed very good agreement with ultracentrifugal analysis (r = 0.99). Yields of 80.2% were obtained for apo B with both methods. Results obtained using the precipitation methods showed excellent agreement with those obtained using the Friedewald formula (r > 0.99). Results were also very similar when hypertriglyceridemic serum samples were briefly centrifuged before analysis of cholesterol, high-density lipoprotein cholesterol and triglyceride values. The present study shows highly significant correlations between cholesterol/high-density lipoprotein cholesterol or low-density lipoprotein cholesterol/high-density lipoprotein cholesterol and apo B/apo A-I ratios (P < 0.001). Apo B and apo A-I levels could be used in addition to low- and high-density lipoprotein cholesterol values when assessing the risk of cardiovascular disease, if the methods for determining serum apolipoproteins have been properly standardized.

Insulin resistance in familial and nonfamilial hypercholesterolemia.

High levels of very low density lipoprotein triglycerides and low levels of high density lipoprotein cholesterol have been found to be associated with insulin resistance measured by the euglycemic clamp technique. In contrast, the association of isolated hypercholesterolemia with insulin resistance has not been systematically studied. Therefore, we performed two separate studies designed to investigate the degree of insulin resistance in familial hypercholesterolemia (FH) (study 1) and nonfamilial hypercholesterolemia (non-FH) (study 2). Study 1 included eight young adults with FH and 13 corresponding control subjects. Fasting blood glucose, insulin, and C-peptide levels were similar in FH patients and control subjects during an oral glucose tolerance test. During the euglycemic hyperinsulinemic (1,200-1,300 pmol/l) clamp studies, FH patients and control subjects had similar rates of whole-body glucose uptake (73 +/- 6 versus 70 +/- 3 mumol/kg per minute, respectively; p = NS). Glucose oxidation, glucose nonoxidation, lipid oxidation, suppression of free fatty acid levels, and potassium disposal were similar in both groups. Study 2 included 25 middle-aged non-FH patients and 18 corresponding control subjects. Glucose, insulin, and C-peptide responses in an oral glucose tolerance test were similar in both groups. During the euglycemic hyperglycemic clamp studies, non-FH patients and control subjects had similar rates of whole-body glucose uptake (61 +/- 3 versus 58 +/- 3 mumol/kg per minute, p = NS). In addition, glucose oxidation, glucose nonoxidation, lipid oxidation, and suppression of free fatty acid levels as well as potassium disposal were similar in non-FH patients and control subjects. We conclude that FH and non-FH are not insulin-resistant states.

Effects of bezafibrate on insulin sensitivity and glucose tolerance in subjects with combined hyperlipidemia.

To investigate whether the lowering of triglyceride levels has beneficial effects on glucose metabolism, we studied 13 nondiabetic men with combined hyperlipidemia (phenotype IIB) before and after 2 months of treatment with a slow-release formulation of bezafibrate (400 mg daily). The rates of whole body glucose disposal were quantitated by the euglycemic hyperinsulinemic clamp technique (insulin infusion rate of 80 mU/m2/min). In an oral glucose tolerance test, fasting glucose level decreased slightly (5.0 +/- 0.2 versus 4.8 +/- 0.2 mmol/L; p < 0.05) during bezafibrate treatment. Glucose and insulin levels after an oral glucose load remained unchanged. Rates of whole body glucose disposal did not change during bezafibrate treatment (39.5 +/- 3.3 mumol/kg/min before treatment versus 40.6 +/- 2.7 mumol/kg/min after treatment; difference not significant). Basal hepatic glucose output also remained unchanged (8.2 +/- 0.2 mumol/kg/min before treatment versus 8.3 +/- 0.2 mumol/kg/min after treatment; difference not significant). Our findings show that bezafibrate has a triglyceride-lowering effect without any significant influence on insulin sensitivity.

Contents of apolipoprotein A-I, A-II and B of the human serum fractions for high-density and low-density lipoproteins prepared by common precipitation methods.

Two common precipitation methods for the determination of HDL-cholesterol in human serum were used, dextran sulphate/MgCl2 and phosphowolframate/MgCl2. They yield supernatants which contained almost all of the apoA-I and apoA-II lipoproteins but no lipoprotein apoB. The correlations between chol-HDL and apoA-I were about the same with these methods (r = 0.79 and 0.80). The correlation between the precipitation methods and ultracentrifugal analysis for chol-HDL was highly significant (r = > 0.95). Correspondingly, two common precipitation methods for the determination of LDL-cholesterol in human serum, buffered heparin, and polyvinyl sulphate procedures, produced sediments, which contained the major proportion of the apoB and only small amounts of apoA-I and apoA-II. However, yields of only 69.0-80.2% were obtained for apoB from the sediments and of 85.8-89.4% from supernatants calculated as the difference from chylomicron free serum. This difference might be due to alterations of the molecular structure of apoB by the precipitation reagents. Comparison of the results with the precipitation methods to those using the Friedewald formula showed excellent agreements (r = > 0.91). Very comparable results were also obtained in the case of marked hypertriglyceridaemia provided that the serum samples were briefly centrifuged before analysis of chol, chol-HDL, and triglyceride values for the formula of chol-LDL. The precipitation methods for chol-LDL showed very good agreement with the values obtained by ultracentrifugal analysis (r = > 0.93). There were no remarkable differences in the correlation of apoB and chol-LDL values measured by different methods (r = 0.85). According to the present results it was found that highly significant correlations existed between chol/chol-HDL or chol-LDL/chol-HDL and apoB/apoA-I ratios (p < 0.001). It is quite evident that apoB and apoA-I values could be used to replace chol-LDL and chol-HDL values when the risk for the cardiovascular diseases is to be assessed.

Lathosterol and other noncholesterol sterols during treatment of hypercholesterolemia with lovastatin alone and with cholestyramine or guar gum.

Sixty-two patients aged 19-64 years with primary hypercholesterolemia (mean level of total cholesterol, 10.8 mmol/l) were treated with 80 mg/day lovastatin (L) alone for 18 weeks and, after randomization to either L + 20 g/day guar gum (L + GG) or L + 16 g/day cholestyramine (L + C) treatments, for an additional 18 weeks. The total cholesterol level declined from baseline by 34% during L and by 44% and 48% during L + GG and L + C, respectively. In terms of micromoles per millimole of cholesterol, serum levels of the cholesterol synthesis precursors cholestenol, desmosterol, and lathosterol were decreased and those of the plant sterols campesterol and sitosterol were increased by treatment with L. The serum contents of cholesterol precursors were increased markedly after the combination of either GG or C with L, but the increase was greater after the addition of C (e.g., the lathosterol to cholesterol ratio was 51% versus 212% for L + GG and L + C, respectively; p less than 0.001). Thus, a higher rate of removal of bile acids by C than by GG reduced more effectively the low density lipoprotein cholesterol level but simultaneously stimulated cholesterol synthesis compensatorily to a higher level even under concurrent treatment with L. The serum sitosterol to cholesterol ratio declined by 13% during L + GG but increased by 49% during L + C compared with the value under L alone, suggesting different effects of GG and C on the metabolism of plant sterols.

Comparison between lovastatin and cholestyramine in the treatment of moderate to severe primary hypercholesterolaemia.

120 patients (64 men, 56 women) aged 19-66 years with primary hypercholesterolaemia (mean serum total cholesterol 10.1 mmol/l, range 6.5-16.3 mmol/l) with normal or moderately raised concentrations of serum triglycerides were randomised after four weeks' diet and four weeks' diet+placebo phase either to cholestyramine (40 patients) or lovastatin (80 patients) treatments for the succeeding 12 weeks. The maximal daily doses were 24 g of cholestyramine and 80 mg of lovastatin. The baseline data of the treatment groups were comparable with the exception of HDL-cholesterol concentrations, which were lower in the lovastatin group. The mean reductions in total serum cholesterol concentrations were 24.3% for cholestyramine (P less than or equal to 0.01) and 33.4% for lovastatin (P less than or equal to 0.01) (P less than or equal to 0.01 between the treatment groups), in LDL-cholesterol 32.1% (P less than or equal to 0.01) and 40.7% (P less than or equal to 0.01) (P less than or equal to 0.05 between the treatment groups) and in apolipoprotein B 23.3% (P less than or equal to 0.01) and 33.3% (P less than or equal to 0.01) (P less than or equal to 0.01 between the treatment groups), respectively. Lovastatin was the only drug to reduce serum triglyceride concentrations, it did so by 26.0%. HDL-cholesterol increased by 7.7% (P = NS) when cholestyramine was taken and by 13.5% (P less than or equal to 0.05) with lovastatin (P = NS between the treatment groups). Apolipoprotein A1 remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Combination therapy with lovastatin and guar gum versus lovastatin and cholestyramine in treatment of hypercholesterolemia.

Sixty-two patients (34 men and 28 women) aged 19-64 years, half of whom had familial hypercholesterolemia, treated initially for 18 weeks with lovastatin alone were randomly allocated either to lovastatin (L) and cholestyramine (16 g/day) or lovastatin and guar gum (L + GG 20 g/day) treatment for 18 additional weeks to compare the hypocholesterolemic effects of these two combination therapies. The patients were selected for this study from a larger study of patients (n = 120) with severe hypercholesterolemia [serum total cholesterol (serum Chol) 6.5-16.3 mM before treatment], and only those patients in whom serum Chol after lovastatin alone (dose 80 mg/day) remained greater than or equal to 5.2 mM were eligible for evaluation of combination therapies. Serum Chol decreased from 10.6 +/- 1.6 to 5.9 +/- 1.3 mM (mean +/- SD) (p less than 0.001) and low-density lipoprotein cholesterol (LDL Chol) from 8.5 +/- 1.8 to 4.1 +/- 1 mM (p less than 0.001) in patients treated with L + GG (values before the beginning of lovastatin and at the end of the combination therapy). The respective changes were from 10.9 +/- 2.2 to 5.5 +/- 1.2 mM (p less than 0.001) and from 8.7 +/- 2.3 to 3.5 +/- 1.2 mM (p less than 0.001) in patients treated with lovastatin and cholestyramine (L + C). At the end of the study, both serum Chol (p less than 0.005) and LDL Chol (p less than 0.01) were significantly lower with L + C than with L + GG.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial aggregation of non-insulin dependent diabetes and coronary heart disease are accompanied by different effects on serum lipids, lipoproteins and apolipoproteins.

This study was designed to investigate whether the presence of non-insulin-dependent diabetes mellitus (NIDDM) or coronary heart disease (CHD) in probands have different effects on serum lipid, lipoprotein and apolipoprotein concentrations in the first-degree relatives. Altogether 161 probands (114 men, 47 women) and 788 first-degree relatives of these probands (174 brothers, 246 sisters, 180 sons, 188 daughters) were included in the analyses. The presence of NIDDM in the proband was associated with lowered total, LDL and HDL cholesterol and apolipoprotein A1 and elevated total triglyceride levels in the brothers (P less than 0.05) and elevated total and LDL cholesterol levels in the sisters (P less than 0.05). Total LDL and VLDL cholesterol and apolipoprotein B were higher (P less than 0.05) and HDL/total cholesterol ratio and apolipoprotein A1/B ratio lower (P less than 0.05) in the daughters of the nondiabetic and diabetic probands were pooled, CHD in the proband was associated particularly with low apolipoprotein A1/B ratio. In conclusion, (1) the presence of NIDDM in the proband appears to be associated in siblings with more profound lipid and lipoprotein changes (especially low HDL cholesterol and high total triglycerides) than a history of CHD in the proband, (2) a history of CHD in the proband is associated in children with apolipoprotein changes favouring atherosclerosis (low apolipoprotein A1, high apolipoprotein B, low apolipoprotein A1/B ratio). Different effects of a history of NIDDM and CHD in the proband on lipid, lipoprotein and apolipoprotein levels in the first-degree relatives warrants more population-based studies.

5-year incidence of atherosclerotic vascular disease in relation to general risk factors, insulin level, and abnormalities in lipoprotein composition in non-insulin-dependent diabetic and nondiabetic subjects.

The 5-year incidence of myocardial infarction and claudication was examined in a group of middle-aged patients (n = 133, 70 men and 63 women) with newly diagnosed non-insulin-dependent diabetes and nondiabetic control subjects (n = 144, 62 men and 82 women). The effects of general risk factors, plasma insulin level, and lipoprotein abnormalities on the incidence of myocardial infarction and claudication were also evaluated by univariate analyses in both diabetic patients and nondiabetic subjects and by multivariate analyses combining both groups. The age-adjusted incidence of myocardial infarction was higher both in diabetic men (19.4%) and diabetic women (11.0%) than in nondiabetic men (3.2%, p = 0.009) and nondiabetic women (3.0%, p = 0.047). Similarly, the age-adjusted incidence of claudication was higher among the diabetic patients (20.3% vs. 8.0% for men, p = 0.06; 21.8% vs. 4.2% for women, p = 0.003). None of the general risk factors (i.e., low density lipoprotein [LDL] cholesterol, blood pressure, smoking, and high density lipoprotein [HDL] cholesterol) showed an association with the risk of myocardial infarction either in the diabetic or nondiabetic groups of subjects, but an ischemic electrocardiographic abnormality at the baseline examination predicted myocardial infarction in diabetic men. In univariate analyses in diabetic subjects, high serum total cholesterol, low HDL cholesterol, high very low density lipoprotein (VLDL) cholesterol, and high total, LDL and VLDL triglycerides, and in nondiabetic subjects, high VLDL cholesterol and LDL triglycerides were associated with the appearance of claudication. In multivariate analyses including both diabetic and control subjects, only diabetes had an independent association with myocardial infarction, whereas smoking, high LDL triglycerides or VLDL cholesterol, and high fasting plasma insulin showed independent relations to claudication. The present results indicate that changes in lipoprotein composition characteristic of non-insulin-dependent diabetes are atherogenic and increase the risk of atherosclerotic vascular disease. Furthermore, high plasma insulin might also be involved in atherogenesis, independent of lipoprotein abnormalities.

Microalbuminuria predicts the development of serum lipoprotein abnormalities favouring atherogenesis in newly diagnosed type 2 (non-insulin-dependent) diabetic patients.

We studied the relationship of slight albuminuria (microalbuminuria) to serum lipid and lipoproteins in a representative group of middle-aged Type 2 (non-insulin-dependent) diabetic patients. A random sample of non-diabetic control subjects was also examined. Diabetic patients had both at diagnosis and after five years higher total, LDL- and VLDL-triglyceride levels and higher VLDL-cholesterol, but lower HDL-cholesterol levels than non-diabetic subjects. No consistent difference was found in LDL-cholesterol levels between diabetic and non-diabetic subjects. The prevalence of microalbuminuria (greater than 35 mg/24h) remained about the same in diabetic patients at both examinations (19-20%). The diabetic patients with persistent microalbuminuria were slightly hyperglycaemic and they tended to have lower creatinine clearance at the 5-year examination than those without persistent microalbuminuria. There were no differences in the blood pressure levels or the occurrence of hypertension between the diabetic groups with and without microalbuminuria. At the baseline examination, no differences were seen in serum lipids and lipoproteins between diabetic patients with and without microalbuminuria. In patients with persistent microalbuminuria, a statistically significant increase in VLDL-cholesterol (p less than 0.05) and VLDL- and LDL-triglyceride levels (p less than 0.05) and a decrease in HDL-cholesterol level (p less than 0.05) was seen at the 5-year follow-up. These changes could not be explained by age, sex, body mass index or HbA1. In conclusion, persistent microalbuminuria predicts and aggravates abnormalities in lipoprotein composition and a decrease in HDL-cholesterol in patients with Type 2 diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol lowering effect of metformin in combined hyperlipidemia: placebo controlled double blind trial.

Metformin, an antidiabetic biguanide derivative, prevents experimental atherosclerosis and induces structural changes in lipoproteins in experimental animals. In the present study we investigated the effect of metformin on serum lipoproteins and platelet function in 24 non-diabetic patients with type II B hyperlipidemia. The patients were randomly given metformin in two dosage levels (1.0 g/day and 2.0 g/day) and placebo for periods of nine weeks in a crossover trial. Metformin caused a dose dependent fall in the concentrations of total serum cholesterol and of LDL-cholesterol. The average concentration of total cholesterol was 8.54 +/- 0.22 (SE) mmol/l, 8.12 +/- 0.19 mmol/l and 7.79 +/- 0.15 mmol/l during placebo, metformin 1.0 g/day and 2.0 g/day treatments, respectively. Both metformin values differed significantly (P less than 0.05) from the placebo value. Thus there was an average fall of 8.1% in total cholesterol after the higher metformin dose. LDL-cholesterol was 5.25 +/- 0.23 mmol/l after placebo, falling by 3.1% and 9.6% after metformin doses of 1.0 g/day and 2.0 g/day, respectively. The concentrations of HDL-cholesterol and total serum triglycerides showed no significant changes. Body weight, blood glucose, plasma insulin, blood lactate, platelet function and urinary excretion of prostanoids remained unchanged during the study. The reduction of total- and LDL-cholesterol levels may be a welcome additional consequence of metformin during treatment of diabetic patients with hypercholesterolemia.

Stopping insulin treatment in middle-aged diabetic patients with high postglucagon plasma C-peptide. Effect on glycaemic control, serum lipids and lipoproteins.

We studied the successfulness of stopping insulin treatment in middle-aged diabetic patients aged 45-64 with a high postglucagon C-peptide level and the effects of this change on glycaemic control, serum lipids and lipoproteins. Insulin treatment was successfully stopped in 15 of our 22 patients who satisfied the inclusion criteria for the study and were selected on the basis of a computer file including practically all diabetic patients treated with insulin in the Kuopio University Central Hospital region (population base 250,000 inhabitants). Insulin therapy was restarted in seven patients during the first 3 months after discharge. During the following 9 months insulin therapy was restarted in another three patients so that after a 1-year follow-up period half of the diabetic patients whose insulin therapy was stopped had been switched back to insulin. Insulin therapy was seldom successfully stopped if the postglucagon C-peptide value was under the limit of 1.0 nmol/l. Glycaemic control did not change during the follow-up, although there was a significant weight loss in diabetic patients. No changes were observed in serum lipids or lipoproteins with the exception of LDL cholesterol, which showed a significant reduction during the 3-month follow-up. In conclusion, insulin therapy can often be successfully stopped in patients with postglucagon C-peptide over the limit of 1.0 nmol/l without worsening of glycaemic control and without unfavourable changes in serum lipid and lipoprotein levels.

Relationship of branched-chain alpha-keto-acids and lipids in sera of hypertriglyceridemic subjects.

According to the present study, in hyperlipidemias where triglyceride values in serum are raised, the triglyceride values are associated with increased amounts of branched-chain alpha-keto-acids (BCKA) in the serum. In particular, the concentration of alpha-ketoisocaproic acid (KICA), which in the control sera was 34.4 mumol/l, was in type IIB hyperlipidemia 40.4% and in type IV 49.4% higher than in controls with normal serum lipid values. In type IV hyperlipidemia, values for alpha-ketoisovaleric acid (KIVA) and alpha-keto-beta-methyl-n-valeric acid (KMVA) were also high when compared to the corresponding mean values of the controls, 7.1 and 18.8 mumol/l. The respective differences were 57.7 and 44.1 per cent. In type IIB hyperlipidemia, KIVA was significantly and KMVA insignificantly increased compared to the control group. In type IIA hyperlipidemia with normal triglyceride values, none of the three BCKA differed significantly from the controls. These results also indicate that the increased amounts of individual BCKA somehow depend on the concentration of triglycerides in serum, while no relationship was found between BCKA values and cholesterol concentration.

Relationship between postheparin plasma lipases and high-density lipoprotein cholesterol in different types of diabetes.

We measured serum lipids, lipoproteins and post-heparin plasma lipases, lipoprotein lipase and hepatic lipase, in 12 female patients with Type 1 (insulin-dependent) diabetes (postglucagon C-peptide undetectable), in 11 female insulin-treated patients with Type 2 (non-insulin-dependent) diabetes (postglucagon C-peptide greater than 0.60 nmol/l) and in 16 non-diabetic female control subjects. These three groups of subjects were similar with respect to age and obesity. Insulin dose was similar in patients with Type 1 and with Type 2 diabetes. HDL and HDL2 cholesterol were lower in patients with Type 2 diabetes than in non-diabetic control subjects (p less than 0.05) but did not differ between patients with Type 1 diabetes and non-diabetic control subjects. No difference in lipoprotein lipase activity was seen between the groups. The highest levels of lipoprotein lipase and hepatic lipase activities were observed in patients with Type 2 diabetes. Lipoprotein lipase activity correlated significantly with HDL cholesterol in patients with Type 1 diabetes (p less than 0.01) and in patients with Type 2 diabetes (p less than 0.001) but not in control subjects. Hepatic lipase activity did not correlate significantly with HDL cholesterol in any of the groups. In conclusion, postheparin plasma lipoprotein lipase and hepatic lipase activities do not seem to explain the difference in HDL cholesterol concentration between patients with Type 1 and Type 2 diabetes.

Lack of effect of hepatic enzyme induction on metabolic control in patients with type 2 (non-insulin-dependent) diabetes.

A placebo-controlled, double-blind crossover study was carried out in 11 non-insulin-dependent (type 2) diabetic patients to find out the effects of a hepatic enzyme inducer (phenobarbital, 100 mg/day for 2 months) on the metabolic control, plasma C-peptide, insulin, serum, and lipoprotein lipid levels. Phenobarbital induced a significant increase in hepatic antipyrine metabolizing activity, but no significant changes were found in fasting or postload blood glucose, plasma C-peptide, or insulin levels during the study. There was a significant increase in serum total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, as well as in serum total and very low-density lipoprotein triglycerides, during phenobarbital treatment as compared with placebo.

Plasma insulin and serum lipids and lipoproteins in middle-aged non-insulin-dependent diabetic and non-diabetic subjects.

The relationship between fasting plasma insulin and serum lipid and lipoprotein levels was studied in 1982-1983 in Kuopio, East Finland in 225 patients with non-insulin-dependent diabetes mellitus (119 men and 106 women) and 124 non-diabetic controls (65 men and 59 women). Compared to the non-diabetic controls, diabetic subjects showed significantly lower levels of high density lipoprotein (HDL) cholesterol and high density lipoprotein2 (HDL2) cholesterol and higher levels of total triglycerides and very low density lipoprotein (VLDL) triglycerides. Fasting plasma insulin correlated significantly with total triglycerides and VLDL triglycerides and negatively with HDL cholesterol and HDL2 cholesterol in both male and female diabetic subjects and non-diabetic control subjects. The correlation between fasting plasma insulin and HDL cholesterol remained statistically significant in non-insulin-dependent diabetic subjects and in female non-diabetic control subjects after adjustment for body mass index, alcohol intake, physical activity, smoking, and fasting plasma glucose. The correlation between fasting plasma insulin and total triglycerides remained significant after adjustment for these variables only in females. By multiple stepwise linear regression analysis, fasting plasma insulin had an independent association with HDL cholesterol in female non-diabetic control subjects and in male diabetic subjects and with triglycerides in female non-diabetic control subjects and in female diabetic subjects. The results show that hyperinsulinemia is related to low HDL cholesterol and HDL2 cholesterol and high total triglycerides and VLDL triglycerides in both non-insulin-dependent diabetic subjects and non-diabetic control subjects. This effect of hyperinsulinemia on lipid and lipoprotein patterns may be one explanation why high plasma insulin can promote accelerated atherosclerosis, particularly in patients with non-insulin-dependent diabetes mellitus.