Blood-sugar and arterial disease

Hemoglobin A1c-Using Epidemiology to Guide Medical Practice: Kelly West Award Lecture 2020

The discovery that HbA1c was a valid and reliable measure of average glucose exposure was one of the most important advances in diabetes care. HbA1c was rapidly adopted for monitoring glucose control and is now recommended for the diagnosis of diabetes. HbA1c has several advantages over glucose. Glucose assessment requires fasting, has poor preanalytic stability, and is not standardized; concentrations are acutely altered by a number of factors; and measurement can vary depending on sample type (e.g., plasma or whole blood) and source (e.g., capillary, venous, interstitial). HbA1c does not require fasting, reflects chronic exposure to glucose over the past 2-3 months, and has low within-person variability, and assays are well standardized. One reason HbA1c is widely accepted as a prognostic and diagnostic biomarker is that epidemiologic studies have demonstrated robust links between HbA1c and complications, with stronger associations than those observed for usual measures of glucose. Clinical trials have also demonstrated that lowering HbA1c slows or prevents the development of microvascular disease. As with all laboratory tests, there are some clinical situations in which HbA1c is unreliable (e.g., certain hemoglobin variants, alterations in red blood cell turnover). Recent studies demonstrate that fructosamine and glycated albumin may be substituted as measures of hyperglycemia in these settings. Other approaches to monitoring glucose have recently been introduced, including continuous glucose monitoring, although this technology relies on interstitial glucose and epidemiologic evidence supporting its routine use has not yet been established for most clinical settings. In summary, a large body of epidemiologic evidence has convincingly established HbA1c as a cornerstone of modern diabetes care.

The Framingham Heart Study and the epidemiology of cardiovascular disease: a historical perspective

On Sept 29, 2013, the Framingham Heart Study will celebrate 65 years since the examination of the first volunteer in 1948. During this period, the study has provided substantial insight into the epidemiology and risk factors of cardiovascular disease. The origins of the study are closely linked to the cardiovascular health of President Franklin D Roosevelt and his premature death from hypertensive heart disease and stroke in 1945. In this Review we describe the events leading to the foundation of the Framingham Heart Study, and provide a brief historical overview of selected contributions from the study.

The effect of clofibrate on glucose tolerance, insulin secretion, triglycerides and fibrinogen in patients with coronary heart disease

The effects of clofibrate treatment have been monitored in a double-blind cross-over study conducted in 16 male patients with coronary heart disease. Most had latent diabetes mellitus with elevated and delayed insulin release after i.v. glucose administration. Blood glucose and insulin levels were measured during repeated i.v. glucose tolerance tests in each patient and serum triglyceride and plasma fibrinogen were estimated at intervals. Clofibrate treatment significantly lowered fasting blood glucose levels (p less than 0.01) and improved the glucose tolerance (p less than 0.01). Fasting plasma insulin levels and those at 30 min after glucose loading were reduced (p less than 0.05). Serum triglycerides (p less than 0.01) and plasma fibrinogen levels (p less than 0.05) were lowered during the treatment period. The change in k-value (glucose utilization) did not correlate to changes in triglyceride or fibrinogen. This study confirms the beneficial effect of clofibrate therapy on abnormal glucose tolerance observed by other workers. It is suggested that clofibrate acts by reducing peripheral insulin resistance.

Lipid abnormalities in the metabolic syndrome

The metabolic syndrome is the constellation of adverse metabolic and clinical effects of insulin resistance. Its high and increasing prevalence and its profound impact on the major diseases of the western world require that clinicians consider its diagnosis and management on a routine basis. Recently published guidelines on its definition now make convenient and reliable diagnosis possible. Also, there is new and better understanding of the complex dyslipidemias and other risk factors strongly associated with the metabolic syndrome, which greatly increase the risk of clinical atherosclerotic events. Comprehensive clinical evaluation of these dyslipidemias and associated atherosclerosis risk factors can lead to their aggressive treatment, customized according to the circumstances of each patient. These steps are now more feasible and more clearly desirable than ever before. Statins alone greatly reduce atherosclerosis risk, but combination lipid therapy is often required for optimal dyslipidemia management and atheroprevention.

The impact of gender and general risk factors on the occurrence of atherosclerotic vascular disease in non-insulin-dependent diabetes mellitus

While it is generally accepted that non-insulin-dependent diabetes mellitus (NIDDM) increases atherosclerotic risk, controversy remains as to whether this effect is greater for women than men (thus reducing the usual gender differential). Furthermore, it is unclear to what extent changes in general risk factors may account for this increased risk. The literature was reviewed with meta-analyses. Gender specific overall relative risks with 95% confidence intervals for coronary heart disease (CHD) mortality (ICD codes 410-414) were calculated. Similarly, overall gender specific odds ratios for prevalent myocardial infarction (MI) are presented. Data are generated from both fixed effects and random effects models. Frequency counts of studies showing specific cardiovascular disease (CVD) risk factor effects in diabetes are given as is the number of studies showing diabetes to be an independent risk factor. The overall relative risk (the ratio of men to women) for CHD mortality in diabetes was 1.46 (1.21-1.75) and 2.29 (2.05-2.55) in nondiabetes suggesting that the gender differential is reduced in diabetes. However, heterogeneity was high (P < 0.001). Exclusion of studies that were exclusively in elderly subjects eliminated heterogeneity (P > 0.05), but retained a separation of the confidence intervals. Overall odds ratios (men:women) show no suggestion of a diabetes effect on the gender difference for prevalent MI, 1.77 (diabetes) and 1.79 (no diabetes). The effects of six general CVD risk factors were unclear, although the largest study showed a clear effect of cholesterol, smoking, and blood pressure. All 10 studies in women report diabetes to be an independent risk factor as do 8 out of 12 studies in men. NIDDM reduces the gender differential in CHD mortality, but not for prevalent MI (or other end points). Although the effect of specific CVD risk factors is inconsistent across studies, this is likely to reflect limited sample size and power. The major three risk factors, cholesterol, blood pressure, and smoking, probably operate in NIDDM but do not fully explain the increased risk of CVD in NIDDM.

Misclassification of diabetic subjects may account for the increased vascular risk of impaired glucose tolerance: the Islington Diabetes Survey

We have studied the associations of macrovascular disease and hypertension with impaired glucose tolerance in a recall sample of 223 subjects selected from a population aged greater than or equal to 40 years who had been screened for diabetes using two separate glucose tolerance tests. Blood pressure was higher in subjects with diabetes, but not in those with impaired glucose tolerance, than in normals. Coronary heart disease, based on ECG criteria and history, was more frequent both in subjects with impaired glucose tolerance (odds ratio 1.94, 95% CI 1.02-3.69) and those with diabetes (odds ratio 3.88, 95% CI 1.33-11.97) than in normals, but the excess in the impaired glucose tolerance group was reduced, and was no longer significant, when adjusted for other variables (odds ratio 1.29, 95% CI 0.62-2.66). Peripheral vascular disease was more frequent in subjects with diabetes, but not in those with impaired glucose tolerance. When the subjects with impaired glucose tolerance on a single test were reclassified according to the results of a separate glucose tolerance test, the prevalence of coronary heart disease increased significantly with increasing degrees of glucose intolerance. Subjects with impaired glucose tolerance on both tests had an adjusted odds ratio of coronary heart disease of 0.90 (95% CI 0.42-1.94) compared with normal subjects. The excess of macrovascular disease in subjects with impaired glucose tolerance may result, at least in part, from the admixture of 'false negative diabetics' in that class.

Long-term follow-up of patients who underwent yttrium-90 pituitary implantation for treatment of proliferative diabetic retinopathy

Between 1960 and 1976 117 patients underwent pituitary implantation with yttrium-90 (90Y) for treatment of proliferative retinopathy at the Hammersmith Hospital, London. Mean age at operation was 35 +/- 11 years (mean +/- SD), and mean duration of diabetes 18.6 +/- 10.0 years. Mean insulin dosage prior to implant was 67.2 +/- 24 units, falling to 30.4 +/- 14.9 units post-implant. Thirty-two per cent of patients are still living, 60% are deceased and 8% are lost to follow-up. The 5-year survival rate was 82%. Of the causes of death, 21% died of infection, adrenal insufficiency or hypoglycaemia, 12% of renal failure, and 47% of myocardial or cerebral vascular disease. Ophthalmological follow-up was carried out on the 100 patients operated on between 1965 and 1976. The mean age of this group at implant was 35 +/- 10.5 years, and mean duration of diabetes 17.2 +/- 8.7 years. Visual acuity in the better eye at operation was 6/12 or better in 84% of patients, and this percentage remained similar at the time of the 5 and 10 year follow-up. Blindness (6/60 or worse) in both eyes was present in 12% of patients at the time of 5 and 10 year assessments. By 5 years new vessels on the disc had improved from a mean grading of 2.7 +/- 1.6 to 0.8 +/- 1.2 (p less than 0.001), and by 10 years there was no disc neovascularisation in any eye. There was a similar improvement in the grading of hard exudates, microaneurysms and haemorrhages, but there was an increase in fibrous retinitis proliferans.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetes and atherosclerosis: an epidemiologic view

Diabetes is associated with changes in plasma lipids and lipoproteins into atherogenic direction. In IDDM these changes are small or absent if good metabolic control can be maintained. Diabetic nephropathy is, however, associated with the appearance of dyslipoproteinemia. In NIDDM plasma total and VLDL triglyceride levels are elevated, and HDL-cholesterol level is decreased, and this pattern of dyslipoproteinemia does not always respond to improved control of hyperglycemia. Abnormalities of lipoprotein metabolism, not reflected in conventional plasma lipid and lipoprotein level measurements, and glucosylation of lipoproteins and resulting alterations in lipoprotein catabolism may be of importance in the enhanced atherogenesis in diabetes. Both IDDM and NIDDM are associated with an increased frequency of hypertension, but the underlying mechanisms appear to be different. In IDDM hypertension is usually associated with the development of diabetic nephropathy and thus with a long duration of the disease. In NIDDM hypertension is often present already at the time of diagnosis, and also in IGT, the precursor stage of NIDDM, the prevalence of hypertension is already increased. Obesity explains only in part the high prevalence of hypertension in patients with NIDDM. Diabetes is known to be associated with multiple abnormalities in hemostatic factors and, although these abnormalities may contribute importantly to the increased risk of ASVD in diabetic patients, information about their real role is scanty and conflicting. The impact of general major risk factors for ASVD, elevated plasma cholesterol, elevated blood pressure, and smoking, on the risk of ASVD appears to be similar in diabetics and nondiabetics. Only a relatively small proportion of the excessive occurrence of ASVD in diabetics can, however, be explained by the effects of diabetes on the levels of general risk factors for ASVD. This proportion mediated through the effects of diabetes on risk factors is larger in female diabetics than in male diabetics. The major proportion of the excess of ASVD in diabetics remains, however, unexplained and must be due to effects of diabetes itself through mechanisms that are incompletely understood.

Genetic and metabolic risk factors for the development of late complications in type I (insulin-dependent) diabetes

The genetic background seems to be involved in the development of type I diabetes and it might also be involved in the development of diabetic complications, but studies carried out so far have yielded conflicting results. The aim of this study was to evaluate the influence of some genetic markers and metabolic factors in the development of late diabetic complications. One hundred and twenty-seven patients (69 males, 58 females) with type I diabetes were evaluated for ABO and Rh blood groups, chlorpropamide alcohol flush (CPAF) and acetylator phenotype (AP) as well as for life-habits (smoking, alcohol use, diet and drug compliance), metabolic indexes (M-value, HbA1, cholesterol and triglyceride levels) and late complications of diabetes [coronary heart disease (CHD), arterial hypertension (AH), retinopathy and nephropathy]. Diabetic patients were more frequently fast acetylators and CPAF positive than controls and CPAF was more frequent among females than among males. None of the genetic markers used in this study appeared as a risk factor for the development of diabetic complications. At multiple logistic analysis different risk factors appeared for each microangiopathic complication. For retinopathy: female sex, duration of disease and triglyceride levels; for nephropathy: male sex, cholesterol levels and hypertension. These risk factors have already been recognized in previous studies, while the genetic markers evaluated in our study do not identify a greater or smaller risk for the development of late complications.

Microalbuminuria in elderly hyperglycaemic patients and controls

Detailed examination was performed in 1781 subjects with occult fasting hyperglycaemia (FH), 211 known diabetics (KD), and their corresponding non-diabetic controls (80 CFH, 216 CKD), all found by screening of a well-defined population aged 60-74 years. All but one FH and 90% of KD could be classified as non-insulin-dependent diabetes mellitus (NIDDM) when evaluated by a glucagon-C-peptide test. Urine excretion of albumin and beta 2-microglobulin and the creatinine clearance were examined over 1 hour in the resting state. The results show that elderly non-diabetics have a wide range of albumin excretion rates. Occult fasting hyperglycaemia is associated with increased albuminuria not detectable by conventional tests for urinary proteins in males, whereas females do not have increased microalbuminuria. Known NIDDM is associated with increased albuminuria in both sexes indicating a sex difference in the threshold for albuminuria only in subjects with occult fasting hyperglycaemia. The albumin/beta 2-microglobulin excretion ratio indicates that the higher albumin excretion rates associated with occult fasting hyperglycaemia and known NIDDM are of glomerular origin.

Prevalence of coronary heart disease, left ventricular failure and hypertension in middle-aged, newly diagnosed type 2 (non-insulin-dependent) diabetic subjects

The prevalence of coronary heart disease, left ventricular failure and hypertension was examined in a representative group of 133 newly diagnosed Type 2 (non-insulin-dependent) diabetic subjects (70 men, 63 women), aged 45 to 64 years, and in a group of 144 randomly selected non-diabetic control subjects (62 men, 82 women) of the same age group. The prevalence of previous myocardial infarction (major Q-QS abnormalities in resting ECG and/or myocardial infarction verified at hospital) was increased 1.7-fold in male (NS) and 4.4-fold in female (p = 0.007) diabetic patients compared with that found in non-diabetic subjects. Chest pain symptoms and ischaemic ECG abnormalities were about twice as common among diabetic than among non-diabetic subjects. The frequency of coronary heart disease defined by chest pain symptoms and ECG abnormalities was 3.5 times higher in male (p = 0.001) and 3.1 times higher in female (p = 0.001) diabetic patients than in the respective non-diabetic subjects. The frequency of current digitalis therapy was increased 3.3-fold in male (p = 0.006) and 3.9-fold in female (p = 0.001) diabetic patients suggesting an increased frequency of left ventricular failure among diabetic subjects. The prevalence of hypertension, based on the elevated blood pressure levels and/or current use of antihypertensive drugs, was increased 1.6-1.7-fold among the diabetic patients.

An alternative sampling approach to the study of diabetes prevalence

Sampling methods hitherto used in epidemiological surveys have generally faced two major sorts of potential bias: a latent period between listing and testing of listed individuals which can cause a misrepresentation of the population under study, compared with the population basis; population migration and death during the study period, which may result in a discrepancy between the population selected for study and the part of the population examined. A Central Population Register, found in all Scandinavian countries, permits an evaluation of the size of these problems of bias and makes it possible to use an alternative sampling method based on test samples successively drawn from the actual dynamic population. The feasibility of this new approach was tested in an epidemiological survey of diabetes mellitus among individuals in the age group 60-74 years living in a Danish municipality (Fredericia). It is concluded that this alternative dynamic method produces a more representative study population with less bias, thanks to the smaller number of deaths and migration among non-responders during the study, than do the methods previously used. Furthermore, the length of the study period, the size of the test samples, as well as the intervals between selecting samples may be adjusted to the capacity available, thus reducing the resources required. By using a correction in the computer program for selecting test sample size, the sex and age profile of the whole study population may be chosen in accordance with the incidence of the disease studied. In the Scandinavian countries a unique possibility exists to carry out prevalence studies on all kinds of diseases by the method described and evaluated here.

Type 2 (non-insulin-dependent) diabetes mellitus and coronary heart disease-chicken, egg or neither?

review of the literature yields much evidence against a correlation between duration of non-insulin-dependent diabetes mellitus (Type 2 diabetes) and the degree of coronary atherosclerosis or the risk of clinically evident coronary heart disease (CHD). Furthermore, an increased risk of CHD, similar to that in previously diagnosed diabetic subjects, has been demonstrated in persons with impaired glucose tolerance. These observations suggest that an increased risk of CHD is not a consequence of the development of diabetes (i.e. persistent hyperglycaemia). It is more likely that diabetes develops in individuals who already possess characteristics which increase the risk of CHD in addition to the risk of developing diabetes.

Relationship of body fat topography to insulin sensitivity and metabolic profiles in premenopausal women

The relationship of body fat distribution to metabolic profiles was determined in 80 healthy premenopausal white women of a wide range of obesity levels [percentage of ideal body weight (% IBW) 92-251]. Distribution of fat between the upper and lower body was assessed from the waist/hips girth ratio (WHR), which varied from 0.64 to 1.02. In 23 women, in vivo insulin sensitivity was also determined from the steady-state plasma glucose (SSPG) level at comparable insulin levels of approximately 100 microU/mL attained by the intravenous infusion of somatostatin, glucose, and insulin. Increasing WHR was accompanied by progressively increasing fasting plasma insulin levels (r = 0.47, P less than 0.001), insulin and glucose areas after glucose challenge (r = 0.53, P less than 0.001; r = 0.50, P less than 0.001, respectively) and fasting plasma triglyceride concentrations (r = 0.48, P less than 0.001). Obesity level was similarly correlated with these metabolic indices. Partial and multiple regression analysis and analysis of variance with a linear contrast model revealed that the effects of body fat topography were independent of, and additive to, those of obesity level. Within obese subjects alone (%IBW: 130), %IBW had no predictive value, but WHR remained a significant predictor of plasma glucose, insulin, and triglyceride concentrations. The WHR also correlated with the plasma cholesterol level, but this association was largely dependent on its relationship to %IBW. Both WHR and %IBW correlated with the insulin resistance index, SSPG (r = 0.60, P less than 0.01; r = 0.61, P less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Low density lipoprotein metabolism by cultured skin fibroblasts from atherosclerotic patients

The aim of this study was to determine whether an abnormality in low density lipoprotein (LDL) metabolism could be demonstrated in fibroblasts cultured from normolipidaemic subjects with atherosclerosis. Seventeen male subjects aged 30-55 years with normal plasma lipid concentrations were divided into 2 groups on the basis of the presence or absence of proven coronary artery and/or peripheral vascular disease. LDL metabolism was assessed in cultured fibroblasts obtained from each of these subjects. After 6 h incubation with 125I-labelled LDL, it was found that binding, uptake and degradation of the lipoprotein were all significantly higher in cells from the atherosclerotic group of subjects than the controls. Variations in cellular LDL metabolism were also correlated with 4 risk factors for cardiovascular disease. Plasma LDL concentration in the atherosclerotic subjects was found to be inversely related to LDL binding and degradation. Subject age was inversely related to LDL degradation in both groups of subjects. No association was demonstrated in either group of subjects between LDL metabolism and glucose intolerance, or between LDL metabolism and cigarette smoking. It is concluded from these results that cellular LDL binding may constitute a factor in determining the rate of atheroma formation, which is independent of other cardiovascular risk factors.

The Bedford survey: ten year mortality rates in newly diagnosed diabetics, borderline diabetics and normoglycaemic controls and risk indices for coronary heart disease in borderline diabetics

Mortality rates from coronary heart disease and from all causes have been ascertained over ten years in three groups of people participating in the Bedford Survey--newly-diagnosed diabetics, borderline diabetics and control subjects with normal glucose tolerance. Age corrected mortality rates, from all causes and coronary heart disease, were highest in the diabetics and intermediate in the borderline diabetics and in both groups were similar in men and women. When statistical allowance was made for baseline differences in age, blood pressure and obesity, female borderline diabetics still had a significantly increased risk over their controls of death from 'all causes'. Much of the difference appeared to be due to a relative excess of deaths due to coronary heart disease. It is concluded that borderline diabetes (or impaired glucose tolerance) is associated with a relatively greater increase in mortality risk in women than men. During the 10-year follow-up of the Bedford borderline diabetics, coronary heart disease morbidity and mortality rates were similar in men and women. Age at entry to the study was the major independent and significant predictor of mortality from all causes. The level of systolic blood pressure and current cigarette smoking at baseline were statistically significant predictors only of mortality due to coronary heart disease.

Glucose intolerance and nine-year mortality in Japanese men in Hawaii

The relationship between glucose intolerance and nine-year mortality was examined in a cohort of approximately 8,000 men of Japanese ancestry living in Hawaii who were 45 to 68 years of age at baseline examination. Age-adjusted mortality for death from all causes, cardiovascular disease, coronary heart disease and causes other than cardiovascular disease and cancer were significantly higher in men with glucose intolerance, defined by either medication for diabetes or 1-hour post-load serum glucose levels above the 90th percentile cut-point (225 mg/dl) at baseline examination, than in normoglycemic men. Although many cardiovascular risk factors were found to be associated with glucose intolerance, both post-load serum glucose level and medication for diabetes remained significant as risk factors for overall, cardiovascular and coronary death in multivariate logistic analysis in which confounding effects of age, blood pressure, serum cholesterol, body mass index and other important risk factors were taken into account.

Blood glucose and risk of coronary heart disease

Health status of 1877 Tecumseh Study subjects aged 35-64 years was ascertained in 1977. They represented 77% of the persons in this age range who were apparently healthy and had participated in comprehensive examinations of nearly the entire population of the community in 1959-1960 and 1962-1965. Subjects who developed coronary heart disease had a significantly higher mean blood glucose concentration than other members of the cohort, even after exclusion of diabetics. Similarly, when examined as single variables, age, sex, serum cholesterol, systolic blood pressure, number of cigarettes smoked per day, and relative weight were significantly related to incidence of coronary events. In the multiple logistic function, however, age, cigarette smoking, blood pressure, and blood glucose were the only significant variables. In a two-way interaction model, glucose and cholesterol were a highly predictive pair. After exclusion of diagnosed diabetics, glucose by itself or in interaction with other variables was not significant in the multiple logistic functions.

Fasting and two-hour post-load glucose levels for the diagnosis of diabetes. The relationship between glucose levels and complications of diabetes in the Pima Indians

The frequency distributions of both the fasting and two-hour post-load plasma glucose levels were bimodal in the Pima Indian population aged 25 years and over. The hyperglycaemic component of this distribution represents those with diabetes mellitus, as some 30 percent of this group had evidence of the specific vascular complications of the disease, whereas these abnormalities were virtually absent in those with lower glucose levels. The bimodal characteristics of the frequency distributions were utilized to define optimal criteria to separate those with and without diabetes. The sensitivity and specificity of these criteria for fasting and two-hour glucose levels were compared and were found to be similar. The fasting glucose determination, however, was more reproducible and stable, as well as being easier to obtain, indicating that it is the better measurement for diagnostic purposes. The optimal level for diagnosis of 7.5 mmol/l (136 mg/dl) for the fasting glucose and the equivalent two-hour value of 14 mmol/l (250 mg/dl), were higher than many previously recommended diagnostic levels. Nevertheless, there was no evidence that subjects with lower levels were at appreciable risk of developing the specific complications of diabetes. Subjects with impaired glucose tolerance (IGT), but without fasting hyperglycaemia, should not be diagnosed as having diabetes mellitus.

Intermittent claudication: prevalence and risk factors

Risk factors for intermittent claudication (IC) were studied in 54 patients--that is, all patients with IC on the lists of two general practices--and 108 controls. Smoking was the factor most strongly associated with the development of IC, but systolic and diastolic blood pressures and concentrations of triglyceride, urate, and fibrinogen were all significantly higher among the patients with IC than the controls. The presence of more than one factor appeared to be associated with a multiplicative increase in risk. Cholesterol, an important risk factor for ischaemic heart disease, was not associated with an increased risk of IC. IC was present in about 2% of the men and 1% of the women, who were aged 45-69 years. These findings suggest that IC, a common and disabling manifestation of atheroslcerosis, may be largely preventable.

Bile acid pool changes and regulation of cholate synthesis in experimental diabetes

The effect of alloxan-diabetes and insulin treatment in bile acid pool size and composition, bile acid secretion and cholic acid synthesis was investigated in the rat. The size of the cholate pool was significantly increased 4 days after diabetes induction. It reached a constant size three times that of control animals after 2 weeks of diabetes. Changes in bile acid pool size and secretion were directly dependent of the insulin deficiency state since they were reversed by insulin treatment and were not influenced by the caloric intake of the animal nor the pharmacologic effect of alloxan. Biliary cholate secretion was also 3-fold increased in diabetic rats and it accounted for more than 80% of the total bile acids compared to 60% in the control group. The calculated daily rate of cholate synthesis was increased in diabetic rats and the circadian rhythm of cholate synthesis was abolished in this condition. Therefore, it was shown that the negative feedback mechanism that regulates bile acid snythesis was deleted in diabetes. This mechanism was partially restored after 2 weeks of insulin treatment. These studies demonstrated that bile acid metabolism was profoundly changed in alloxan-diabetic rats and suggested that insulin may play an important role in the regulation of bile acid snythesis and intestinal absorption.

Early arterial lesions in maturity onset diabetes mellitus detected by an ultrasonic technique

Using an ultrasonic technique preclinical atheroma was studied in maturity onset diabetics. The elasticity of the leg arteries was measured as the elastic modulus in 32 patients and a normal range was established in 13 controls. The elastic modulus was higher (i.e. the arteries were stiffer) in diabetics than controls and this was associated with a higher mean blood pressure in the diabetics. Nine phenformin and 10 chlorpropamide treated diabetics had evidence of more severe arterial disease than 13 diet treated patients. This could not be accounted for by other factors known to influence arterial disease.