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Biomedical subjects

R J Jarrett

Publications and source records attributed to R J Jarrett.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Why is insulin tied to the prevalence of cardiovascular diseases without being a risk factor for their incidence?].

Insulin is frequently considered to be a risk factor for atherosclerosis (or for coronary and vascular disease). Furthermore, hyperinsulinaemia is claimed to be the primary cause underlying the other features which make up the insulin resistance syndrome. However, if proof of these assertions is based only on prospective studies, its value is limited. Only two studies, both carried out, surprisingly, in policemen, have shown convincingly that insulin was a coronary risk factor. In one of the studies, the Paris Prospective Study, the insulin-coronary disease correlation was shown to subside with increasing duration of follow-up. The other prospective studies have failed to evidence a correlation between insulinaemia and cardiovascular events, even with univariate analysis. One study even showed a negative correlation between insulinaemia and coronary complications. In view of the fact that insulinaemia has been shown repeatedly to be associated with classic cardiovascular risk factors--systolic hypertension, decrease in HDL cholesterol, increase in triglycerides, and abdominal obesity--it is highly surprising that univariate analysis has not been able to show the same correlation between insulin and cardiovascular complications. In fact, the combination of elevated insulinaemia and classic risk factors may result in protection against the deleterious effects of these factors. Another possibility would be that insulinaemia is associated with unknown protective factors. Both hypotheses would account for the existence of a correlation between insulin and current cardiovascular disease, as well as the absence of correlation between insulin and later onset of cardiovascular disease.

Cardiovascular Diseases↗
PubMed1993

Gestational diabetes: a non-entity?

Screening for gestational diabetes is commonly recommended despite the absence of a common definition of gestational diabetes. Furthermore, there is no consensus about management or treatment. Those who recommend screening do so largely on the basis of fetal morbidity, which seems to be predominantly "macrosomia"--another term without an agreed definition. The implications of macrosomia in terms of actual morbidity are also not clear. R J Jarrett reviews the history of the subject and concludes that gestational diabetes is simply impaired glucose tolerance temporally associated with pregnancy. Its main importance is as a predictor of subsequent non-insulin dependent diabetes, but it fails the major tests for a condition suitable for a screening programme.

Diabetes, Gestational↗
PubMed1992

Prognostic significance of microalbuminuria in insulin-dependent diabetes mellitus: a twenty-three year follow-up study.

A cohort of 63 Type 1 insulin-dependent diabetic patients were first characterized for overnight urinary albumin excretion rate (AER) in 1967. In 1981, seven out of eight (87%) patients with initial AER greater than or equal to 30 less than or equal to 140 micrograms/min (microalbuminuria) developed clinical proteinuria compared to only 2 out of 55 (4%) patients with initial AER less than 30 micrograms/min. The same cohort of patients was reassessed in 1990 after a total follow-up period of 23 years. The aim was to investigate the role of microalbuminuria in the prediction of total/cardiovascular mortality and the development of renal failure, in addition to clinical proteinuria. The initially microalbuminuric patients had a significantly higher risk of developing not only clinical proteinuria (relative risk 9.3, 95% C.I. 1.36 to 3.10, P less than 0.05), but also of dying from a cardiovascular cause (relative risk 2.94, 95% C.I. 1.18 to 7.34, P less than 0.05). The rate of progression to renal failure was higher but not significantly so in the microalbuminuric (2 of 8) compared to the normoalbuminuric (4 of 53) group (relative risk 3.31, 95% C.I. 0.72 to 15.24, NS). In insulin-dependent diabetic patients microalbuminuria is a powerful predictor of clinically overt diabetic renal disease as well as cardiovascular mortality.

Adult↗
PubMed1992

Risk factors for coronary heart disease in diabetes mellitus.

A review of the putative risk factors associated with the development of coronary heart disease in diabetes is presented. Emphasis is given to the effect of nephropathy (persistent proteinuria) and hypertension on cardiovascular mortality in IDDM. Risk factors associated with CHD in NIDDM are also reviewed. Finally, possible reasons to explain the increased incidence of CHD associated with proteinuria in IDDM patients, including lipoprotein abnormalities, increased fibrinogen levels, increased platelet adhesiveness, and altered hemostatic variables, are discussed.

Coronary Disease↗
PubMed1992

Body weight and coronary heart disease mortality: an analysis in relation to age and smoking habit. 15 years follow-up data from the Whitehall Study.

18,403 male civil servants aged 40-64 years were examined in London between 1968 and 1970. Mortality from all causes and specifically from coronary heart disease (CHD) over 15 years of follow-up was initially analysed in relation to deciles of body mass index (BMI = weight/height2) at entry into the study. In older men all causes mortality tended to be higher in those with a low BMI, but this was not so for CHD mortality. The latter was further studied after dividing the population into sub-groups according to age and cigarette smoking. With BMI distribution divided into fifths and five year age groups there were significant positive trends of CHD mortality across the BMI distribution in all age groups except the youngest (40-44 years) and oldest (60-64 years). For analysis by smoking category--never, ex- and current cigarette smoker--three age-specific groups were used: 40-49, 50-59 and 60-64 years. In men aged less than 60 years there were significant positive trends of CHD mortality and BMI in five of the six age and smoking categories, the exception being ex-smokers aged 40-49 years. Associations were strongest in the current smokers. By contrast in men aged 60-64 years there was a significant association between BMI and CHD mortality only in ex-smokers and this was of low order (P = 0.04). The data are compatible with some reports of a lesser association of obesity with mortality risk in older persons and in this data set the observation is not confounded by smoking habit.

Adult↗
PubMed1991

Incidence of macrovascular disease in diabetes mellitus: the London cohort of the WHO Multinational Study of Vascular Disease in Diabetics.

We report on the incidence of new macrovascular disease among the 497 members of the London Cohort of the WHO Multinational Study of Vascular Disease in Diabetics (aged 35-54 years at recruitment) over a mean 8.33 year follow-up period. Overall at the end of the follow-up period the prevalence of macrovascular disease in the cohort was 45%; 43% of the subjects showed evidence of ischaemic heart disease, 4.5% of cerebrovascular disease and 4.2% of peripheral vascular disease. The incidence rates for new disease in those subjects who were free at baseline expressed per 1000 patient years of follow-up were: ischaemic ECG abnormality 23.6 (patients with insulin-dependent diabetes 19.8, patients with non-insulin-dependent diabetes 28.1), myocardial infarction 17.6 (patients with insulin-dependent diabetes 16.5, patients with non-insulin-dependent diabetes 18.8), all ichaemic heart disease 31.7 (patients with insulin-dependent diabetes 30.3, patients with non-insulin-dependent diabetes 33.4), cerebrovascular disease 5.9 and peripheral vascular disease 5.2. Incidence rates were generally similar among men and women except for myocardial infarction in patients with non-insulin-dependent diabetes where men had a significantly higher incidence rate. Macrovascular disease is a major problem in patients with diabetes and in this age group is mainly manifested as ischaemic heart disease.

Adult↗
PubMed1991

Risk factors for macrovascular disease in diabetes mellitus: the London follow-up to the WHO Multinational Study of Vascular Disease in Diabetics.

We have examined the relationship between baseline variables and the incidence of new macrovascular complications amongst the 497 members of the London cohort of the WHO Multinational Study of Vascular Disease in Diabetics over a mean 8.33-year follow-up. In univariate logistic regression analysis the incidence of new ischaemic electrocardiographic abnormality was significantly associated with systolic and diastolic blood pressure, diabetes duration and hypertension in patients with insulin-dependent diabetes, and with smoking in patients with non-insulin-dependent diabetes. New myocardial infarction was associated with systolic blood pressure, plasma cholesterol, proteinuria and smoking in patient with non-insulin-dependent diabetes; there were no significant associations among patients with insulin-dependent diabetes. All new ischaemic heart disease was associated with hypertension in patients with insulin-dependent diabetes, and plasma cholesterol and smoking in patients with non-insulin-dependent diabetes. New cerebrovascular disease was associated with systolic and diastolic blood pressure, ECG abnormality and hypertension. New peripheral vascular disease was associated with smoking. Multivariate analysis showed the following significant associations 1) in patients with insulin-dependent diabetes: ECG abnormality; hypertension, myocardial infarction; smoking, ischaemic heart disease; hypertension, diabetes duration and smoking, 2) in patients with non-insulin-dependent diabetes: ECG abnormality; smoking, myocardial infarction; serum cholesterol, proteinuria and smoking ischaemic heart disease; smoking. For new cerebrovascular disease, proteinuria and ECG abnormality were significant predictors in multivariate analysis. Patients with diabetes share many of the established risk factors for nondiabetic subjects, in addition proteinuria may be of significance in the prediction of macrovascular disease in diabetes.

Adult↗
PubMed1991

Low physical activity and worsening of glucose tolerance: results from a 2-year follow-up of a population sample in Malta.

The relationship between the level of habitual physical activity and glucose intolerance was examined cross-sectionally and during a 2-year follow-up among a sample of 388 subjects in Malta. At baseline, the subjects were classified into three categories of physical activity, which was inversely related to the 2-h post challenge blood glucose (P = 0.02). In a multivariate analysis, age (standardized regression coefficient 0.23; P less than 0.001), family history of diabetes (0.20; P less than 0.001), and physical activity (-0.18; P = 0.002) were the strongest predictors of the 2-h blood glucose at baseline. The age standardized 2-year risk of glucose intolerance, i.e. impaired glucose tolerance or diabetes was consistently and inversely related to the level of physical activity. Among subjects with normal glucose tolerance at baseline (n = 127) those with low physical activity had a 2.7 times higher risk of glucose intolerance during follow-up than those with high physical activity (P = 0.1), and even a 3.7-fold risk of glucose intolerance at baseline (n = 196) when both the subjects with normal and impaired glucose tolerance at baseline were considered together (P = 0.005). Similar trends were observed for the risk of diabetes. The suggested protective effect of physical activity was independent of body mass, a family history of diabetes and gender. Within the limits of this small study we conclude that physical activity may have some importance in the primary prevention of impaired glucose tolerance and, possibly, non-insulin-dependent diabetes mellitus.

Adolescent↗
PubMed1991

Are conventional risk factors for mortality relevant in type 2 diabetes?

One-hundred and ninety-one men with Type 2 (non-insulin-dependent) diabetes mellitus, participants in the Whitehall Survey, were followed for 15 years. Age-adjusted all-cause and ischaemic heart disease (IHD) mortality rates were significantly increased in the diabetic men. Of four putative risk factors for IHD ascertained in the survey (plasma cholesterol, systolic blood pressure, cigarette smoking, body mass index) only blood pressure was a significant predictor in univariate Cox regression analysis. A review of comparable studies revealed lack of consistency in the association of these risk factors (derived from studies in non-diabetic populations) and mortality in individuals with Type 2 diabetes. Given the absence of clinical trial data, risk factor intervention in Type 2 diabetes is currently based upon inference derived from studies in non-diabetic subjects.

Analysis of Variance↗
PubMed1991

Hypertension in glucose intolerance and diabetes.

In insulin-dependent diabetes mellitus, an excess frequency of raised blood pressure occurs in association with increased urinary albumin excretion. It is not known whether the renal disorder causes the raised blood pressure, or whether the two disorders occur concomitantly. In non-insulin-dependent diabetes mellitus, any excess of raised blood pressure is small or non-existent when adjustments are made for obesity. However, raised blood pressure is found in glucose-intolerant individuals, independent of obesity. Reported associations between albumin excretion and blood pressure in non-insulin-dependent diabetes are inconsistent.

Albuminuria↗
PubMed1990

A prospective study of mortality among middle-aged diabetic patients (the London Cohort of the WHO Multinational Study of Vascular Disease in Diabetics) I: Causes and death rates.

The 497 members of the London Cohort of the WHO Multinational Study of Vascular Disease in Diabetics have been followed for mortality from 1975 to 1987. During this period 92 patients died. The most common cause of death was myocardial infarction: 36 (39.1%) deaths, heart disease was responsible for 51.1% of deaths and all cardiovascular disease for 55.4%. Neoplastic disease accounted for 25% of the deaths and diabetic nephropathy for 5.4%. Age-standardised mortality rates were higher in men than in women in both Type 1 (insulin-dependent) diabetes and Type 2 (non-insulin-dependent) diabetes. Standardised mortality ratios for the first and second five year follow-up periods were higher for men than for women in Type 2 diabetes but were higher for women than men in Type 1. The results suggest that the female survival advantage seen in the general population may persist in Type 2 but not in Type 1 diabetes.

Adult↗