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Biomedical subjects

R J Jarrett

Publications and source records attributed to R J Jarrett.

At least 19 recordsLinked to original sources
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↗
PubMed1979

Haemostatic variables associated with diabetes and its complications.

To study the possible role of an "increased thrombotic tendency" in the vascular complications of diabetes several tests of haemostatic function were carried out on 91 men and 63 women with diabetes aged 35-54 years and the results compared with findings in 686 men and 393 women of the same age in the Northwick Park Heart Study. Mean values for factors VII and X, fibrinogen, and platelet adhesiveness were higher in the diabetics, but mean fibrinolytic activity and whole blood platelet counts were lower. Antithrombin III values were also higher in the diabetics, which may have constituted a protective response to other changes favouring the onset of vascular disease. Diabetics with retinopathy had higher factor VII and antithrombin III values, and those with proteinuria had higher values for factor VII, fibrinogen, and platelet adhesiveness than those without these complications. These findings suggest a potentially important association between a thrombogenic tendency and vascular disease in diabetes. Nevertheless, prospective data are needed to clarify whether the haemostatic abnormalities precede the onset of clinically manifest vascular complications or are a consequence of them.

Adult↗
PubMed1979

Does the nephrotic syndrome increase the risk of cardiovascular disease?

Cardiovascular mortality and morbidity were assessed, after a mean follow-up period of 5 years, in an unselected series of 159 adults presenting with the nephrotic syndrome between 1972 and 1975. 60% of the deaths were attributed to terminal renal failure, and the incidence of deaths from ischaemic heart-disease (IHD) was not significantly above normal. The proportion of patients experiencing angina and intermittent claudication and the prevalence of ischaemic electrocardiographic changes did not differ significantly from those of a London control population. At follow-up, hypertension was significantly more common (p less than 0.001) in male nephrotic patients than in controls. Earlier reports of a greatly increased incidence of IHD in unselected patients with the nephrotic syndrome were not confirmed. Routine treatment of hyperlipidaemia in the nephrotic syndrome is not, therefore, recommended.

Adolescent↗
PubMed1979

Oral glucose-tolerance tests and the diagnosis of diabetes: results of a prospective study based on the Whitehall survey.

Men who participated in the Whitehall survey and were found to be glucose intolerant have been studied 6--8 years later, together with a control group of men with normal screening blood-sugar levels. Ophthalmoscopically visible microvascular retinal disease was confined to men diagnosed as probably diabetic after the survey because their 2 h blood-sugar level (after a 50 g oral glucose load) in the survey examination or during a subsequent standard oral glucose-tolerance test was greater than or equal to 200 mg/dl (11.1 mmol/l). The lowest blood-sugar in a "diabetic" subsequently found to have retinopathy was 229 mg/dl. Men with lesser degrees of glucose intolerance, including 34 who had "worsened to diabetes", did not have visible retinovascular disease at follow-up. If diabetes implies a risk of specific microvascular complications in the medium term, then the findings in this study support proposals for the revision of diagnostic criteria based on glucose-tolerance tests.

Aged↗
PubMed1979

Effect of control of blood glucose on urinary excretion of albumin and beta2 microglobulin in insulin-dependent diabetes.

To study the effects of improved control of blood glucose on markers of renal glomerular and tubular function, we initially determined, by radioimmunoassay technics, urinary excretion rates of albumin and beta2 microglobulin in 17 nondiabetic subjects and in 43 insulin-dependent, clinically nonproteinuric diabetic patients. Duration of diabetes ranged from six months to 39 years, and the patients were studied while receiving conventional therapy. Mean urinary albumin excretion was significantly elevated in the diabetics, but beta2-microglobulin excretion rates were not different from those of the controls, suggesting that the increased albumin excretion was due to increased transglomerular loss of albumin. Seven patients with long-term diabetes (duration of six to 33 years), selected because of elevated albumin excretion, were studied before and during a continuous, subcutaneous insulin infusion for a period of one to three days. Urinary albumin excretion was significantly reduced during the insulin infusion, but mean beta2-microglobulin excretion did not change. Strict control of blood glucose, even in the short term, may reverse a functional renal abnormality in long-duration, insulin-dependent diabetes.

Adult↗
PubMed1979

Nutrient intake, adiposity, and diabetes.

To study the role of nutritional factors in the genesis of diabetes, estimations of blood sugar concentration, food intake, and adiposity (as body mass index; BMI) were carried out on three normal population samples--namely, 961 employees of Beecham Ltd, 1005 employees of the Greater London Council, and 1488 middle-aged male civil servants (Whitehall study). Blood sugar concentrations and indices of glucose tolerance correlated positively with the degree of adiposity but tended to be negatively correlated with total food energy intake and its component nutrients (total carbohydrate, sucrose, and fat). This inverse trend was largely accounted for by highly significant inverse correlations between food energy intake and adiposity, a relation found in both sexes and in all three population samples and which extended across the whole range of nutrient intake and BMI. These findings suggest that greater degrees of adiposity are associated with lower than average food energy intakes and hence lower total energy expenditures. The association of increased adiposity with low food energy consumption may indicate an underlying "low energy throughput" state, and it may be the mechanisms of this, as well as the obesity, that are responsible for disease.

Adipose Tissue↗
PubMed1979

Worsening to diabetes in men with impaired glucose tolerance ("borderline diabetes").

Two hundred and four men with impaired glucose tolerance (borderline diabetes) discovered in a screening examination have been observed for five years and repeated tests of glucose tolerance performed. By pre-determined criteria 27 men 'worsened to diabetes' and this metabolic deterioration was not significantly influenced by treatment with carbohydrate restriction with or without a daily dose of 50 mg phenformin. Of the baseline variables measured prior to treatment allocation only the blood glucose values were significantly predictive of ultimate worsening to diabetes.

Blood Glucose↗
PubMed1979

Fluorescein angiography in borderline diabetics.

Fluorescein angiography was performed in twenty three men with impaired oral glucose tolerance (borderline diabetics) and sixteen matched, normoglycaemic controls. Retinal abnormalities (microaneurysms and leakage of dye) were observed in 18.7% of the controls, 41.6% of sustained borderline diabetics and 54.4% of initially borderline diabetics who subsequently "worsened to diabetes". Qualitatively the abnormalities were similar in each group. Although the difference in frequency between the sustained borderline diabetics and the controls does not achieve conventional statistical significance, other studies quoted support the conclusion that moderate impairment of glucose tolerance is associated with a raised frequency of minor retinal abnormalities. The significance of these remains to be determined.

Blood Pressure↗
PubMed1978

Does "afternoon diabetes" predict diabetes?

Twenty-eight men were given morning and afternoon oral glucose tolerance tests in 1969 and again in 1975. According to British Diabetic Association criteria all 28 had normal morning values in 1969 but seven had "afternoon diabetes". Four men had diabetic values in the morning in 1975 but only two of these had had afternoon diabetes in 1969. Better prediction of subsequent diabetes was obtained by calculating the area under the morning glucose tolerance curve in 1969. All four men who progressed to diabetes had areas exceeding 1000 units, which distinguished them absolutely from the other 24. They also tended to be more obese, but this was less predictive of subsequent diabetes.

Blood Glucose↗
PubMed1978

Increased glomerular permeability to albumin induced by exercise in diabetic subjects.

The urinary excretion of albumin was measured in insulin-dependent diabetics under ordinary conditions of life and in response to exercise. Possible mechanisms of exercise induced albuminuria in diabetics were also investigated. Under ordinary conditions of life the insulin-treated diabetics, as a group, had a higher mean urinary albumin excretion than normal controls; however, half of the diabetics had albumin excretion rates within the control range. A given exercise load (600 kpm/min for 20 min) produced an exaggerated albumin excretion in diabetics, particularly evident in the post-exercise period. The elevated urinary albumin excretion was due to an increased transglomerular passage of albumin, not to reduced tubular reabsorption. The increase was not associated with differences in blood pressure or urine flow between controls and diabetics. This exercise test has proved to be a suitable provocation test to unmask abnormalities in the glomerular handling of albumin that might not be recognisable at rest.

Albuminuria↗
PubMed1978

Glucose tolerance and blood pressure in two population samples: their relation to diabetes mellitus and hypertension.

The relationship between blood pressure and the blood sugar concentration measured two hours after a 50 g oral glucose load has been examined in two population surveys-the Whitehall and Bedford Surveys. In the Whitehall Survey, which was conducted in men above the age of 40, there was a positive, significant correlation between blood sugar and blood pressure (systolic and diastolic) which was independent of common associations with age, body mass index (BMI) and heart rate. In the Bedford Survey, systolic blood pressures were significantly higher in newly detected diabetics and borderline diabetics, both men and women, than in normoglycaemic controls after adjustment of blood pressures for age and BMI. However, in the stratified random sample of the cooperating Bedford population, only amongst women was the blood sugar significantly and independently correlated with the systolic blood pressure. Evidence is presented and discussed that autonomic, neurohumoral factors may play some part in the pathogenesis of maturity onset diabetes.

Adult↗