Diabetes, other risk factors, and 12-yr cardiovascular mortality for men screened in the Multiple Risk Factor Intervention Trial

Gln-Arg192 polymorphism of paraoxonase and coronary heart disease in type 2 diabetes

Paraoxonase is a high-density-lipoprotein-associated enzyme capable of hydrolysing lipid peroxides. Thus it might protect lipoproteins from oxidation. It has two isoforms, which arise from a glutamine (A isoform) to arginine (B isoform) interchange at position 192. The relevance of this polymorphism to coronary heart disease (CHD) in non-insulin-dependent diabetic patients was investigated in case-control study. Of the 434 patients, 171 had confirmed coronary artery disease; the other 263 had no history of such disease. The B allele and AB+BB genotypes were associated with an increased risk of coronary heart disease. Compared with subjects homozygous for the A allele (AA genotype), the odds ratio of CHD for subjects homozygous for the B allele was 2.5 (95% CI 1.2-5.3) and that for those heterozygous for the B allele was 1.6 (95% CI 1.1-2.4), suggesting a codominant effect on cardiovascular risk. When subjected to multivariate analysis, the B allele remained significantly associated with CHD (odds ratio 1.94, p = 0.03). The paraoxonase gene polymorphism is thus an independent cardiovascular risk factor in non-insulin-dependent diabetic patients. A possible explanation for this finding is that activity of the paraoxonase B isotype does not protect well against lipid oxidation, a major atherogenic pathway.

Detection of coronary artery disease in diabetic patients

Coronary artery disease may be difficult to detect in diabetic patients. This study was designed to determine the specificity and sensitivity of three noninvasive tests. Accordingly, the results of 48-h ambulatory electrocardiogram (ECG) monitoring, maximal ECG exercise test, and intravenous dipyridamole myocardial thallium scintigraphy were compared in 59 middle-aged diabetic patients who were consecutively selected for suspected coronary artery disease. All patients also underwent coronary angiography, which was performed regardless of the results of the non-invasive tests. Twenty patients (34%) had significant coronary lesions, i.e. stenosis equal to or greater than 70%, and 16 of these 20 patients (80%) had double or triple vessel disease. Sensitivity and specificity were, respectively, 25% and 88% for ambulatory ECG monitoring, 75% and 77% for the exercise test and 80% and 87% for thallium myocardial scintigraphy. This observation strongly supports the use of non-invasive tests for the detection of coronary artery disease in those diabetic patients at high risk of such disease. As the exercise test is cheaper and more widely available than thallium myocardial scintigraphy it should be used as a first line examination. Dipyridamole myocardial scintigraphy may provide an alternative solution for those patients who cannot perform maximal exercise, or with atypical clinical presentation.

Protocol for a prospective collaborative overview of all current and planned randomized trials of cholesterol treatment regimens. Cholesterol Treatment Trialists' (CTT) Collaboration

The Cholesterol Treatment Trialists' Collaboration aims to provide reliable information about the effects on mortality and morbidity of treatments that modify blood lipid levels for a wide range of patient populations and risk groups. This protocol prospectively defines study eligibility, the main questions to be addressed, and statistical methods to be used. Additionally, by establishing a register of ongoing and planned trials prior to any trial results being known, this systematic overview attempts to avoid the methodologic problems and potential data-dependency of a retrospective project. The collaboration expects to have individual patient data on > 60,000 subjects by the year 2000, including 12,000 women and 20,000 elderly subjects, and should have good power to examine any effects on non-coronary artery disease events. Overall, there should be about 1,900 non-coronary artery disease deaths and > 2,000 total cancer events.

Asymptomatic hyperglycaemia is associated with increased intimal plus medial thickness of the carotid artery

Atherosclerotic changes have not been demonstrated directly in asymptomatic hyperglycaemic non-diabetic subjects, although high mortality due to coronary heart disease has been reported. We measured arterial wall thickness non-invasively, in order to directly demonstrate atherosclerosis of the carotid arteries of hyperglycaemic non-diabetic subjects and to evaluate its risk factors. The thicknesses of the intimal plus medial complex (IMT) of the carotid arteries of 112 asymptomatic hyperglycaemic non-diabetic subjects (aged 22-81, 95 males and 17 females) were compared with those of 55 healthy male subjects and 211 non-insulin-dependent NIDDM male diabetic patients. The subjects were subgrouped into impaired glucose-tolerant (IGT) subjects who had a 2-h glycaemic level of more than 7.8 mmol/l, and non-IGT subjects whose 2-h glycaemic levels were within 6.7-7.7 mmol/l. Non-IGT and IGT subjects showed significantly greater IMTs than age-matched healthy males and showed no significant differences compared to age-matched NIDDM patients. Multivariate analysis demonstrated that the risk factors for IMT of non-IGT and IGT subjects were age and systolic blood pressure. According to data on the accumulation of atherogenic risks (hypertension, dyslipidaemia, and smoking), IMT increased linearly in non-IGT and IGT subjects. However, non-IGT and IGT subjects without hyperlipidaemia, hypertension, or smoking risk still had significantly greater IMT than age-matched normal males (1.019 +/- 0.063 vs 0.770 +/- 0.111 mm, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of the MRFIT screenees: a methodological study

PURPOSE

To review the methods used in the many publications on the MRFIT screenees.

METHOD

Medline was searched for articles mentioning MRFIT screenees. The articles were collected, abstracted, and the method section and some of the result section were scrutinized in detail. The statements in different articles regarding methods used and the presentation of results were compared.

RESULT

The analyses of the MRFIT screenees seem to be retrospective studies of mortality and risk factors, where the underlying data base has been far from complete. Similar data are presented in slightly different fashions in several papers published in different scientific journals at about the same time. The control of the quality of underlying data has been uneven and is not discussed at all in most of the papers published.

CONCLUSION

The often-repeated statement that the MRFIT screenees constitute the largest and most exact data base regarding the relation of risk factors to mortality in the healthy male US population has no foundation.

Does NIDDM increase the risk for coronary heart disease similarly in both low- and high-risk populations?

Finland has marked regional differences in the occurrence of coronary heart disease (CHD). Although the causes for these differences in CHD mortality and morbidity in the Finnish population are unknown, it offers an excellent opportunity to investigate the effects of non-insulin-dependent diabetes mellitus (NIDDM) on CHD risk in two populations differing significantly with respect to the occurrence of CHD. Therefore, we carried out a 7-year prospective population-based study including a large number of patients with NIDDM (East Finland: 253 men and 257 women; West Finland: 328 men, 221 women) and corresponding non-diabetic subjects (East Finland: 313 men, 336 women; West Finland: 325 men, 399 women). In both study populations the presence of NIDDM increased significantly the risk for CHD events (CHD mortality or all CHD events including CHD mortality or non-fatal myocardial infarction). Diabetic men had 3-4 fold higher and diabetic women 8-11-fold higher risk for CHD than corresponding non-diabetic subjects. Both non-diabetic and diabetic subjects had odds ratios (East vs West) for CHD events of about 2 indicating a similar East-West difference in the CHD risk. Regional difference was quite similar in men and women. These results imply that factors related to NIDDM, independently of conventional risk factors and the occurrence of atherothrombosis in the background population, must play a major role in the pathogenesis of atherosclerotic vascular disease in NIDDM diabetes.

Blood pressure changes in diabetes in urban Tanzania

Little is known of the natural history of blood pressure (BP) levels in diabetic patients from sub-Saharan Africa. BP levels were therefore recorded in such patients in Dar es Salaam, Tanzania, over 2, 5, and 7 years. Hypertension was found in 5% of insulin-treated diabetes mellitus (IDDM) and 29.2% of non-insulin-dependent diabetes mellitus (NIDDM) patients at presentation with diabetes. Hypertension developed in a further 2 IDDM (3.7%) and 27 NIDDM (15.6%) patients at 2 years, and in 3 IDDM (13.0%) and 9 NIDDM (9.8%) patients at 5 years. Seven NIDDM (18.4%) patients had developed hypertension by 7 years. In NIDDM patients with normal BP initially, the mean systolic BP rose from 131 to 141 mmHg (P < 0.001) 2 years later (n = 146); from 131 to 138 mmHg (P < 0.001) for those followed for 5 years (n = 82); and from 131 to 138 mmHg (P < 0.05) for those followed for 7 years (n = 31). The mean diastolic BP was 83 mmHg initially and 84 mmHg (NS) for those followed for 2 years (n = 146). There was no observed rise in mean diastolic BP at 5 or 7 years of follow-up. In IDDM patients without hypertension, only the systolic BP rose significantly by 5 years, from 124 to 132 mmHg (P < 0.001; n = 20). These changes were independent of age, sex, body mass index, and proteinuria.(ABSTRACT TRUNCATED AT 250 WORDS)

LDL particle size in mildly hypertriglyceridemic subjects: no relation to insulin resistance or diabetes

We examined 18 Type 2 diabetic and 19 non-diabetic subjects in order to determine the association between insulin resistance and LDL particle size distribution in mildly hypertriglyceridemic and hyperinsulinemic subjects with and without Type 2 diabetes. Insulin sensitivity of the patients was characterized by their insulin-stimulated glucose uptake rate determined by euglycemic clamp technique. LDL particle size distribution was determined by nondenaturing polyacrylamide gradient gel electrophoresis. Type 2 diabetic and non-diabetic subjects had closely similar serum lipid and lipoprotein concentrations as well as the mean particle diameters of the major LDL peak (246 +/- 6 A and 244 +/- 6 A, respectively). To evaluate the effect of insulin resistance on LDL particle size the participants were categorized into two subgroups using the median of their insulin-stimulated glucose uptake rate (14.67 mumol/kg/min) as a cut-off point. Neither lipid and lipoprotein concentrations nor the LDL particle size distributions differed between the more insulin resistant group (nine diabetic and nine non-diabetic subjects) and less insulin resistant group (nine diabetic and ten non-diabetic subjects). LDL particle size was not associated with the insulin-stimulated glucose uptake rate or with the mean 24-h concentration of serum insulin. Mean 24-h concentration of serum triglycerides was the strongest discriminator for LDL particle size (r = -0.44, P < 0.01). In conclusion, neither Type 2 diabetes nor insulin resistance seem to have any direct effect on LDL particle size in mildly hypertriglyceridemic subjects. The fact that LDL particle size was associated with serum triglycerides indicates that the effect of diabetes and insulin resistance on LDL particle size could be explained by the effects of insulin resistance and/or hyperinsulinism on VLDL metabolism.

The Verona diabetes study: a population-based survey on known diabetes mellitus prevalence and 5-year all-cause mortality

This population-based survey aimed to determine the prevalence of known diabetes mellitus on 31 December 1986, and to assess all-cause mortality in the subsequent 5 years (1987-1991) in Verona, Italy. In the study of prevalence, 5996 patients were identified by three independent sources: family physicians, diabetes clinics, and drug prescriptions for diabetes. Mortality was assessed by matching all death certificates of Verona in 1987-1991 with the diabetic cohort. Overall diabetes prevalence was 2.61% (95% confidence interval 2.56-2.67). Prevalence of insulin-dependent and non-insulin-dependent diabetes mellitus was 0.069% (0.059-0.078) and 2.49% (2.43-2.54), respectively. Diabetes prevalence sharply increased after age 35 years up to age 75-79, and finally declined. Prevalence was higher in men up to age 69 years, in women after age 75 years. Of the diabetic cohort 1260 patients (592 men, 668 women) died by 31 December 1991, yielding an overall standardized mortality ratio of 1.46 (CI 1.38-1.54). Even though the differences narrowed with age, mortality rates in the diabetic cohort were higher than in the non-diabetic population at all ages. Women aged 65-74 years showed observed/expected ratio higher than men (2.27, CI 1.92-2.66, vs 1.50, CI 1.30-1.72), while in other age groups the sex-related differences were not significant. Pharmacological treatment of diabetes was associated with an excess mortality, while treatment with diet alone showed an apparent protective effect on mortality (observed/expected ratio 0.73, CI 0.58-0.92).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of diabetes mellitus on early and late outcome after percutaneous transluminal coronary angioplasty

BACKGROUND

Although patients with diabetes mellitus constitute an important segment of the population undergoing coronary angioplasty, the outcome of these patients has not been well characterized.

METHODS AND RESULTS

Data for 1133 diabetic and 9300 nondiabetic patients undergoing elective angioplasty from 1980 to 1990 were analyzed. Diabetics were older and had more cardiovascular comorbidity. Insulin-requiring (IR) diabetics had diabetes for a longer duration and worse renal and ventricular functions compared with non-IR subjects. Angiographic and clinical successes after angioplasty were high and similar in diabetics and nondiabetics. In-hospital major complications were infrequent (3%), with a trend toward higher death or myocardial infarction in IR diabetics. Five-year survival (89% versus 93%) and freedom from infarction (81% versus 89%) were lower, and bypass surgery and additional angioplasty were required more often in diabetics. In diabetics, only 36% survived free of infarction or additional revascularization compared with 53% of nondiabetics, with a marked attrition in the first year after angioplasty, when restenosis is most common. Multivariate correlates of decreased 5-year survival were older age, reduced ejection fraction, history of heart failure, multivessel disease, and diabetes. IR diabetics had worse long-term survival and infarction-free survival than non-IR diabetics.

CONCLUSIONS

Coronary angioplasty in diabetics is associated with high success and low complication rates. Although long-term survival is acceptable, diabetics have a higher rate of infarction and a greater need for additional revascularization procedures, probably because of early restenosis and late progression of coronary disease. The most appropriate treatment for these patients remains to be determined.

Mortality from coronary heart disease and cerebrovascular disease and associated risk factors in diabetic patients in Osaka District, Japan

Mortality from coronary heart disease (CHD) and cerebrovascular disease (CVD), as well as associated risk factors, were examined. The subjects studied were 1939 non-insulin-dependent diabetic (NIDDM) patients and 503 deaths were observed during a mean follow-up period of 9.4 years. Of these deaths, 62 were CHD deaths and 84 were CVD deaths. The mortality rates per 1000 person-years from CHD were 3.95 for males and 2.57 for females and those from CVD were 5.12 and 3.86 for males and females, respectively, showing a higher mortality for males and an increasing trend with age. The baseline factors associated with CHD mortality were age at entry into the study, hypertension, ischemic ECG changes, serum cholesterol level, diabetic retinopathy and albuminuria, while those associated with CVD were age at entry, hypertension, ischemic ECG changes, diabetic retinopathy, albuminuria and therapeutic regimen, all of which were found to be significant by univariate analysis. The relationships were further analyzed by the multiple logistic method. In addition, the baseline characteristics of the patients who died of CHD and CVD were compared with those of patients who died from other causes. The baseline characteristics in cases of deaths from CHD and CVD were significantly different from those of deaths from other causes in terms of obesity, ischemic ECG changes, serum cholesterol level and serum triglycerides level for deaths from CHD and in terms of age at onset, age at death and hypertension for deaths from CVD.

[Diabetes mellitus and atherosclerosis. Physiopathology of diabetic macroangiopathy]

Numerous prospective epidemiological studies point out high mortality prevalence in diabetic subjects. Classical risk factors, especially arterial hypertension and hypertriglyceridaemia, are abnormally associated with diabetes mellitus. However, they don't account for overall surmortality in this disease. Additional markers of cardiovascular risk appeared as albuminuria, abdominal obesity, and the couple insulinoresistance/hyperinsulinism. Physiopathological intrinsic mechanisms inherent to macroangiopathy are multiple and intricate (hemostatic disorders, endothelial impairments, oxidative stress, quantitative and qualitative lipoproteins abnormalities, part of hyperinsulinism and growth factors). Strict normoglycaemia and exacting control of all other risk factors is essential. Use of other therapeutic agents as antioxidants and antiagregants, is discussed.

Mortality in relation to smoking: 40 years' observations on male British doctors

OBJECTIVE

To assess the hazards associated with long term use of tobacco.

DESIGN

Prospective study of mortality in relation to smoking habits assessed in 1951 and again from time to time thereafter, with causes sought of deaths over 40 years (to 1991). Continuation of a study that was last reported after 20 years' follow up (1951-71).

SUBJECTS

34,439 British male doctors who replied to a postal questionnaire in 1951, of whom 10,000 had died during the first 20 years and another 10,000 have died during the second 20 years.

RESULTS

Excess mortality associated with smoking was about twice as extreme during the second half of the study as it had been during the first half. The death rate ratios during 1971-91 (comparing continuing cigarette smokers with life-long non-smokers) were approximately threefold at ages 45-64 and twofold at ages 65-84. The excess mortality was chiefly from diseases that can be caused by smoking. Positive associations with smoking were confirmed for death from cancers of the mouth, oesophagus, pharynx, larynx, lung, pancreas, and bladder; from chronic obstructive pulmonary disease and other respiratory diseases; from vascular diseases; from peptic ulcer; and (perhaps because of confounding by personality and alcohol use) from cirrhosis, suicide, and poisoning. A negative association was confirmed with death from Parkinson's disease. Those who stopped smoking before middle age subsequently avoided almost all of the excess risk that they would otherwise have suffered, but even those who stopped smoking in middle age were subsequently at substantially less risk than those who continued to smoke.

CONCLUSION

Results from the first 20 years of this study, and of other studies at that time, substantially underestimated the hazards of long term use of tobacco. It now seems that about half of all regular cigarette smokers will eventually be killed by their habit.

Mortality in relation to consumption of alcohol: 13 years' observations on male British doctors

OBJECTIVE

To assess the risk of death associated with various patterns of alcohol consumption.

DESIGN

Prospective study of mortality in relation to alcohol drinking habits in 1978, with causes of death sought over the next 13 years (to 1991).

SUBJECTS

12,321 British male doctors born between 1900 and 1930 (mean 1916) who replied to a postal questionnaire in 1978. Those written to in 1978 were the survivors of a long running prospective study of the effects of smoking that had begun in 1951 and was still continuing.

RESULTS

Men were divided on the basis of their response to the 1978 questionnaire into two groups according to whether or not they had ever had any type of vascular disease, diabetes, or "life threatening disease" and into seven groups according to the amount of alcohol they drank. By 1991 almost a third had died. All statistical analyses of mortality were standardised for age, calendar year, and smoking habit. There was a U shaped relation between all cause mortality and the average amount of alcohol reportedly drunk; those who reported drinking 8-14 units of alcohol a week (corresponding to an average of one to two units a day) had the lowest risks. The causes of death were grouped into three main categories: "alcohol augmented" causes (6% of all deaths: cirrhosis, liver cancer, upper aerodigestive (mouth, oesophagus, larynx, and pharynx) cancer, alcoholism, poisoning, or injury), ischaemic heart disease (33% of all deaths), and other causes. The few deaths from alcohol augmented causes showed, at least among regular drinkers, a progressive trend, with the risk increasing with dose. In contrast, the many deaths from ischaemic heart disease showed no significant trend among regular drinkers, but there were significantly lower rates in regular drinkers than in non-drinkers. The aggregate of all other causes showed a U shaped dose-response relation similar to that for all cause mortality. Similar differences persisted irrespective of a history of previous disease, age (under 75 or 75 and older), and period of follow up (first five and last eight years). Some, but apparently not much, of the excess mortality in non-drinkers could be attributed to the inclusion among them of a small proportion of former drinkers.

CONCLUSION

The consumption of alcohol appeared to reduce the risk of ischaemic heart disease, largely irrespective of amount. Among regular drinkers mortality from all causes combined increased progressively with amount drunk above 21 units a week. Among British men in middle or older age the consumption of an average of one or two units of alcohol a day is associated with significantly lower all cause mortality than is the consumption of no alcohol, or the consumption of substantial amounts. Above about three units (two American units) of alcohol a day, progressively greater levels of consumption are associated with progressively higher all cause mortality.

Cholesterol rich apo B containing lipoproteins and smoking are independently associated with macrovascular disease in normotensive NIDDM patients

A cross-sectional study of macrovascular disease (MVD) and associated metabolic and other risk factors was conducted in 87 normotensive NIDDM patients. MVD was assessed by Rose questionnaire, 12 lead resting ECG, duplex scanning of carotid and peripheral vessels, and ankle:brachial systolic blood pressure ratio. Fasting serum total cholesterol, total triglycerides, LDL cholesterol, HDL cholesterol, apolipoproteins AI and B, lipoprotein (a), HbA1, plasma glucose, insulin, and C-peptide responses to a carbohydrate rich meal, body mass index (BMI), waist-hip ratio, urinary albumin excretion rate, blood pressure, smoking and family history were assessed as possible 'risk factors'. Apolipoprotein:lipid ratios were calculated to estimate lipoprotein composition. Thirty-six patients had demonstrable MVD. The presence of MVD was associated with higher total triglycerides (p < 0.05), BMI (p < 0.05), systolic blood pressure (p < 0.01), a lower apo B:non HDL cholesterol ratio (p < 0.001), and smoking (p < 0.005) but no other measures. Multiple regression analysis revealed smoking and a low apo B:non HDL cholesterol to be independently associated with MVD. The low apo B:non HDL cholesterol suggests a high cholesterol content of apo B containing lipoproteins. This lipoprotein abnormality is not a feature of NIDDM, but when present in these patients may be particularly atherogenic.

Impact of cardiovascular disease on health care utilization in a defined diabetic population

We studied the impact on annual medical care utilization and costs in 1988 of cardiovascular disease (CVD) in a population-based sample of 435 diabetic (DM) and 435 matched non-DM members of a Health Maintenance Organization. 58% of DM had at least one diagnosed CVD, compared to 26% of non-DM. 22.7% of outpatient visits, 38.7% of hospital days, and 30% of pharmacy expenditures by those with DM were primarily attributable to CVD. Up to 27% of all CABG recipients in the population had diabetes. In total, CVD directly accounted for at least 24% of total medical care costs among DM, compared to 12% of costs for non-DM. The HMO spent 4.5 times per person more on CVD care in DM than in non-DM members. Treatment with insulin was associated with increased peripheral vascular disease. After adjusting for age, CVD was more prevalent and generated longer hospital stays in DMs with nephropathy. The etiologic association between CVD and DM is well documented but CVD's clinical and economic importance in DM seems underappreciated.

The dyslipoproteinemias of diabetes

Atherosclerosis is the most frequent complication of diabetes. There are many potentially atherogenic factors in diabetes that may underlie this problem. Of these, one is the group of dyslipoproteinemias. In diabetes there are both qualitative and quantitative changes in the plasma lipoproteins. Based on pathophysiological and epidemiological data, these may be among the many factors that can result in early macrovascular disease. Furthermore, at least one of the dyslipoproteinemias--hypertriglyceridemia--is associated with insulin resistance and therefore could aggravate glucose intolerance. Thus, on theoretical grounds it is reasonable to postulate that treating the dyslipoproteinemias of diabetes would reduce atherosclerotic disease. However, to date there have been no intervention studies specifically designed to test this postulate in the diabetic population. One such study, the Diabetes Atherosclerosis Intervention Study, is currently in progress.

Future in lipid and lipoprotein research: from preventing clinical disease to preventing elevated risk factors

The decline in cardiovascular disease has been a major public health success. The relationship between key risk factors such as blood cholesterol levels, smoking, high blood pressure and clinical disease are universally accepted. The approaches to the prevention of cardiovascular disease are changing to a greater emphasis on the prevention of elevated risk factors by better understanding of the relationship between lifestyle and host susceptibility (genetic attributes) and the risk factor changes with age. The development of new methods to measure vascular disease non-invasively in vivo changes the approaches to evaluation of both risk and definition of endpoints in analytical studies and clinical trials. It is possible now to increase the rate of decline in coronary heart disease.

Diabetic dyslipidemia

Diabetes is associated with increased morbidity and mortality from cardiovascular disease in the absence of the major risk factors: cigarette smoking, hypertension, and serum cholesterol concentration. When these risk factors are present, the attributable risk to each factor alone and to the combination of risk factors is higher in diabetics than in nondiabetics. Thus, stringent measures to correct risk factors for cardiovascular disease have been advocated in diabetic patients. In addition to hypercholesterolemia, other lipid and lipoprotein abnormalities collectively referred to as diabetic dyslipidemia are likely to contribute to vascular risk. Hypertriglyceridemia often associated with low high-density lipoprotein cholesterol is common in non-insulin-dependent diabetes mellitus patients and is associated with insulin resistance. Recent information in diabetic patients pointing to the association of hypertriglyceridemia with accumulation of remnant particles and alterations in low-density lipoprotein subfractions helps to explain the strong relationship between hypertriglyceridemia and vascular risk in these individuals. Although there are as yet no intervention trials with lipid-lowering diets or drugs in diabetic patients to judge the impact on vascular disease, national and international bodies have furnished guidelines for the identification and treatment of lipid disorders in diabetes in the hope of reducing the huge toll of vascular disease in these patients.

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

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

Cigarette smoking and diabetes: an update

The article provides an overview of recent scientific information on the role of cigarette smoking in the prognosis of diabetes. Data sources included an English-language MEDLINE search for 1989 through 6/1993, supplemented by manual search of bibliographies of pertinent articles. Only studies of humans were considered. Cigarette smoking is related to the development and progression of diabetic nephropathy. Therefore, smoking status has to be taken into account in clinical studies on the course of nephropathy. The association between smoking and retinopathy is less consistent. Evidence is accumulating that cigarette smoking influences insulin action. Several large prospective cohort studies have shown that the relative risk for all-cause mortality is about twice as high for smoking compared to non-smoking diabetic patients. Strong associations are consistently found between cigarette-pack years and complications. It has been calculated that the theoretical benefit of stopping smoking is the most (cost-)effective risk factor intervention for diabetic patients. However, available programmes to help diabetic patients to stop smoking are unsuccessful.

Insertion/deletion polymorphism of the angiotensin-converting enzyme gene is strongly associated with coronary heart disease in non-insulin-dependent diabetes mellitus

Non-insulin-dependent diabetes mellitus (NIDDM) is considered a model of premature atherosclerosis with a strong genetic component. We have investigated the role of angiotensin-converting enzyme (ACE; EC 3.4.15.1) gene in 316 unrelated NIDDM individuals, 132 who had myocardial infarction or significant coronary stenoses and 184 with no history of coronary heart disease (CHD). A deletion-polymorphism in the ACE gene was recently reported to be associated with myocardial infarction especially in people classified as low risk. Here we report that the D allele of the ACE gene is a strong and independent risk factor for CHD in NIDDM patients. The D allele is associated with early-onset CHD in NIDDM, independently of hypertension and lipid values. A progressively increasing relative risk in individuals heterozygous and homozygous for the D allele was observed (odds ratios of 1.41 and 2.35, respectively; P < 0.007), suggesting a codominant effect on the cardiovascular risk. The percentage of CHD attributable to the ACE deletion allele was 24% in this NIDDM population. Identification of NIDDM patients carrying this putative CHD-susceptibility genotype would help early detection and treatment of CHD.

The role of diabetes mellitus and hypertriglyceridaemia as coronary risk factors in treated hypertension: 15 years of follow-up of antihypertensive treatment in middle-aged men in the Primary Prevention Trial in Göteborg, Sweden

OBJECTIVE

To analyse the importance of diabetes mellitus and hypertriglyceridaemia as potential risk factors for coronary heart disease (CHD) in middle-aged, treated hypertensive men.

DESIGN

A prospective, long-term observational study.

SUBJECTS

Derived from a random population sample--686 hypertensive men aged 47-54 years at entry--followed for 15 years at a special out-patient hypertension clinic.

INTERVENTION AND OUTCOME MEASURES

The patients were mainly treated with beta-adrenoceptor blockers and/or thiazide diuretics. Cardiovascular morbidity was closely monitored during follow-up.

RESULTS

In all, 133 subjects suffered a CHD event during follow-up. The presence of diabetes mellitus at entry more than doubled the CHD risk and a 1 mmol l-1 increment of the serum triglyceride level at entry increased the CHD risk by 21%. In multivariate analyses, smoking, the presence of diabetes mellitus at entry, serum cholesterol and signs or symptoms of hypertensive end organ damage were found to be independent risk factors for CHD. In absolute terms the existence of cardiovascular damage was of much greater prognostic importance than were the presence of various metabolic abnormalities. Of the mean in-study variables, both the average serum cholesterol level and the achieved diastolic blood pressure were significantly associated with CHD. However, new diabetes mellitus which developed during follow-up as well as mean serum triglyceride levels were not associated with CHD.

CONCLUSIONS

Diabetes mellitus and hypertriglyceridaemia present at the start of treatment have a prognostic impact in treated hypertensive men, whereas when such metabolic disorders develop during drug treatment they seem to be of much less importance. Smoking and already existing evidence of hypertensive end organ damage are of utmost importance for the prognosis in this type of patient.

Lipoprotein disorders in diabetes mellitus

In IDDM or NIDDM, the total plasma cholesterol and triglycerides are usually within normal limits when the blood glucose is controlled. Marked hypertriglyceridemia can develop with loss of glycemic control and is often due to superimposed genetic abnormalities in lipoprotein metabolism. Tight control in IDDM usually reduces LDL and VLDL to normal levels and may raise HDL above the normal range. Low HDL cholesterol and mild to moderate elevations of VLDL triglyceride are common in NIDDM if obesity or proteinuria is also present. Both HDL and LDL may be smaller and more dense and may be enriched with triglyceride as compared with cholesterol. These abnormalities may require weight loss for control. The increased incidence of cardiovascular disease in diabetes is unexplained but is amplified by the well-defined cardiovascular risk factors. The new American Diabetes Association guidelines call for treatment of high triglycerides and LDL cholesterol to be aggressively reduced. Triglycerides should be under 200 mg/dL, are considered borderline high between 200 and 400 mg/dL, and high when above 400 mg/dL. Low HDL is defined as less than 35 mg/dL. Control of obesity with diet and exercise and reduced intake of saturated fat and cholesterol are important first steps. If needed, drug therapy is appropriate to reduce LDL to levels below 130 mg/dL in all adult diabetics and below 100 mg/dL in those with cardiovascular disease.

Hypertension and diabetes

Co-presentation of hypertension and diabetes leads to a significantly greater increase of cardiovascular mortality than each disease separately. Hypertension appears to be not only a complication of diabetes but apparently also shares a common pathogenetic mechanism, particularly in non-insulin dependent diabetes. Recent data suggest alterations in the nocturnal decline of blood pressure in diabetics, which together with microalbuminuria, may prove to be a predictor of nephropathy and hypertension. When hypertension occurs in diabetics, it requires a vigorous therapeutic approach. Nevertheless, the presence of diabetes modifies the requirement for first line therapy, particularly with respect to potential alterations of metabolic homeostasis in order to effectively prevent cardiovascular complications.

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)

Risk factors for death from different types of stroke. Multiple Risk Factor Intervention Trial Research Group

The objective of this study was to investigate risk factors for death from different types of stroke among men screened for the Multiple Risk Factor Intervention Trial (MRFIT). A total of 353,340 men were screened by 20 centers for the MRFIT in 1973 to 1975; vital status has been ascertained over an average of 12 years of follow-up (range: 11 to 13 years). Death certificates were coded using the International Classification of Diseases (ICD), ninth revision. Deaths from stroke were classified as death from subarachnoid hemorrhage (ICD code 430), death from intracranial hemorrhage (ICD codes 431 and 432), death from nonhemorrhagic stroke (ICD codes 433 through 438), and death from any type of stroke (ICD codes 430 through 438).

RESULTS

During an average of approximately 12 years of follow-up, 765 deaths from stroke were identified; 139 of these deaths were attributable to subarachnoid hemorrhage; 227, to intracranial hemorrhage; and 399 were classified as nonhemorrhagic stroke. Blood pressure and cigarette smoking were strongly related to each type of stroke. Systolic blood pressure was a stronger predictor than diastolic blood pressure. With the exception of subarachnoid hemorrhage, death rates from each type of stroke increased with age and were higher for black men. The positive association of age and race with subarachnoid hemorrhage was much weaker than for the other types of stroke and was not significant. Income was inversely associated with risk of death from nonhemorrhagic stroke and was not associated with either subarachnoid or intracranial hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)