Hypertension and non-insulin dependent diabetes

Health Consequences of Obesity in Youth: Childhood Predictors of Adult Disease

Obesity now affects one in five children in the United States. Discrimination against overweight children begins early in childhood and becomes progressively institutionalized. Because obese children tend to be taller than their nonoverweight peers, they are apt to be viewed as more mature. The inappropriate expectations that result may have an adverse effect on their socialization. Many of the cardiovascular consequences that characterize adult-onset obesity are preceded by abnormalities that begin in childhood. Hyperlipidemia, hypertension, and abnormal glucose tolerance occur with increased frequency in obese children and adolescents. The relationship of cardiovascular risk factors to visceral fat independent of total body fat remains unclear. Sleep apnea, pseudotumor cerebri, and Blount's disease represent major sources of morbidity for which rapid and sustained weight reduction is essential. Although several periods of increased risk appear in childhood, it is not clear whether obesity with onset early in childhood carries a greater risk of adult morbidity and mortality.

Obesity is now the most prevalent nutritional disease of children and adolescents in the United States. Although obesity-associated morbidities occur more frequently in adults, significant consequences of obesity as well as the antecedents of adult disease occur in obese children and adolescents. In this review, I consider the adverse effects of obesity in children and adolescents and attempt to outline areas for future research. I refer to obesity as a body mass index greater than the 95th percentile for children of the same age and gender.

Diabetes mellitus and raised serum triglyceride concentration in treated hypertension--are they of prognostic importance? Observational study

OBJECTIVE

To analyse whether metabolic changes during long term treatment with antihypertensive drugs are associated with an increased risk of coronary heart disease.

DESIGN

Observational study.

SETTING

Gothenburg, Sweden.

SUBJECTS

686 middle aged hypertensive men, recruited after screening of a random population sample, and followed for 15 years during treatment with predominantly beta adrenoceptor blockers or thiazide diuretics, or both. Coronary heart disease and diabetes mellitus were registered at yearly patient examinations. Entry characteristics, as well as within study serum concentrations of cholesterol and triglycerides and the development of diabetes mellitus, were related to the incidence of coronary heart disease in a time dependent Cox's regression analysis.

MAIN OUTCOME VARIABLE

Coronary heart disease morbidity.

RESULTS

Diabetes mellitus, raised serum cholesterol and triglyceride concentrations present at the beginning of the study were all significantly predictive of coronary heart disease in univariate analysis. The relative risk of diabetes mellitus and of a 1 mmol/l increase in the cholesterol and triglyceride concentrations was 2.12 (95% confidence interval 1.11 to 4.07), 1.21 (1.05 to 1.39), and 1.21 (1.03 to 1.43) respectively. However, when the within study metabolic variables were analysed, only the serum cholesterol concentration was significantly and independently associated with coronary heart disease (relative risk 1.07 (1.02 to 1.13)). Although the triglyceride concentrations increased slightly during the follow up, the within study serum triglyceride concentrations were not associated with the incidence of coronary heart disease (1.04 (0.96 to 1.10)). New diabetes mellitus-that is, onset during follow up-was not significantly associated with an increased risk for coronary heart disease (1.48 (0.37 to 6.00)).

CONCLUSIONS

Metabolic disturbances such as diabetes mellitus and hyperlipidaemia presenting before the start of antihypertensive treatment have a prognostic impact in middle aged, treated hypertensive men. Moreover, while within study cholesterol concentration was an independent predictor of coronary heart disease, drug related diabetes mellitus and raised serum triglyceride concentrations that are associated with treatment do not seem to have any major impact on the coronary heart disease prognosis in this category of patients.

Drug-induced disorders of glucose metabolism. Mechanisms and management

Glucose homeostasis is maintained by a balance between the release and action of insulin, and the counterregulatory responses mediated principally by glucagon, catecholamines, growth hormone and cortisol. Hence, the effects of a drug on glucose metabolism may be mediated by any of these agents singly or in combination. Host factors, such as inherent glucoregulatory mechanisms, concurrent diseases, organ function and concomitant medications also increase the risk of drug-induced disturbances of glucose homeostasis in susceptible individuals. By far the most important agents causing hypoglycaemia are insulin and the sulphonylureas. Alcohol (ethanol), over-zealous glycaemic control, hypoglycaemic unawareness, detective counterregulation especially in insulin-dependent diabetes mellitus (IDDM), and renal and liver impairment are all important predisposing factors. Although antihyperglycaemic agents such as metformin and alpha-glucosidase inhibitors do not cause hypoglycaemia alone, they may enhance the hypoglycaemic effects of potent hypoglycaemic agents such as insulin and sulphonylureas. On the other hand, the potential hypoglycaemic effects of ACE inhibitors, alpha-blockers, lipid-lowering agents and recombinant human insulin-like growth factor demonstrated in experimental settings, are of potential therapeutic interest. Iatrogenic hypoglycaemia and intensive insulin treatment are associated with hypoglycaemic unawareness which may be obviated by meticulous avoidance of hypoglycaemia. Effective patient education remains an important preventive measure. Oral glucose is used to treat mild hypoglycaemic episodes while more severe episodes are treated by intravenous glucose or glucagon. Nasal glucagon and theophylline are other experimental measures to improve recovery from hypoglycaemia. In refractory hypoglycaemia due to hyperinsulinaemia such as during sulphonylurea overdosage or quinine treatment, the long-acting somatostatin, octreotide, may suppress insulin release and restore euglycaemia. Diuretics, beta-blockers, sympathomimetics, corticosteroids and sex hormones are commonly prescribed drugs which may have adverse effects on carbohydrate metabolism especially in patients with diabetes mellitus or those who are at risk of developing glucose intolerance. Pentamidine was frequently associated with dysglycaemia due to its pancreatic beta-cell cytotoxic effects but is now used less often to treat Pneumocystis carinii pneumonia in immunosuppressed patients. Despite the large number of anecdotal reports of drug-induced disturbances of glucose metabolism, many of the so-called adverse drug reactions were either idiosyncratic or coincidental. Nevertheless, they emphasise the complex nature of glucose homeostasis and its potential interactions with drugs, host factors and disease states. An understanding of these relationships may allow more critical interpretation of these clinical observations, better prediction of drug induced adverse effects on carbohydrate metabolism and the implementation of more rational therapy. Hence, the hypoglycaemic effects of a drug may be turned to a therapeutic advantage in patients with glucose intolerance. Similarly, the hyperglycaemic effect of a drug may help to treat refractory hypoglycaemia.

Thinness at birth and insulin resistance in adult life

Type 2 (non-insulin-dependent) diabetes mellitus may originate through impaired development in fetal life. Both insulin deficiency and resistance to the action of insulin are thought to be important in its pathogenesis. Although there is evidence that impaired fetal development may result in insulin deficiency, it is not known whether insulin resistance could also be a consequence of reduced early growth. Insulin resistance was therefore measured in 81 normoglycaemic subjects, and 22 subjects with impaired glucose tolerance, who were born in Preston, UK, between 1935 and 1943. Their birth measurements had been recorded in detail. Insulin resistance was measured by the insulin tolerance test which uses the rate of fall in blood glucose concentrations after intravenous injection of insulin as an index of insulin resistance. Men and women who were thin at birth, as measured by a low ponderal index, were more insulin resistant. The association was statistically significant (p = 0.01) and independent of duration of gestation, adult body mass index and waist to hip ratio and of confounding variables including social class at birth or currently. Thinness at birth and in adult life has opposing effects such that resistance fell with increasing ponderal index at birth but rose with increasing adult body mass index. It is concluded that insulin resistance is associated with impaired development in fetal life.

Effect of aging on glucose tolerance in spontaneously hypertensive rats

We studied the age-related changes of glucose tolerance in female spontaneously hypertensive rats (SHR) that did not become obese with aging. Oral glucose tolerance test was performed in young (3 months), middle-aged (6 to 11 months), and aged (26 months) SHR. Fasting plasma glucose was significantly lower in aged SHR than in young SHR. The increase in plasma glucose after glucose administration over fasting level was significantly higher in aged SHR than in middle-aged SHR, but did not differ between young and aged rats. Pancreatic islet size and pancreatic immunoreactive insulin content were similar between young and aged SHR. The present study demonstrated that glucose tolerance did not deteriorate in SHR with aging, while genetic hypertension persisted. This suggests that the persistence of hypertension per se may not affect glucose tolerance in SHR.

How can we best prolong life? Benefits of coronary risk factor reduction in non-diabetic and diabetic subjects

OBJECTIVE

To compare the theoretical benefits of different approaches to reduce risk factors for coronary heart disease in subjects at risk.

DESIGN

The results of findings from meta-analyses of intervention studies on cause specific mortality and of observational studies on smokers and ex-smokers were applied to observational data on 10 year cause specific mortality derived from the multiple risk factor intervention trial. Lifetable analyses were used to estimate gains in life expectancy.

SUBJECTS

Diabetic and non-diabetic men initially 35-57 years of age.

MAIN OUTCOME MEASURES

10 year mortality from coronary heart disease, 10 year total mortality, man years of intervention to prevent one death and one death from coronary heart disease, gain in life expectancy, and drug costs per year of additional life in diabetic and non-diabetic men of 45.

RESULTS

In non-diabetic men a 10 year mortality from coronary heart disease of 14.4 per 1000 would be reduced by a mean of 0.58, 0.82, 2.64, and 2.74 per 1000 by antihypertensive treatment, lowering cholesterol concentration, taking aspirin, and stopping smoking respectively; a 10 year total mortality of 44.1 per 1000 would fall by a mean of 1.06, 5.16, and 8.65 per 1000 with antihypertensive and aspirin treatment and stopping smoking respectively and increased by a mean of 0.07 per 1000 with the lowering of cholesterol concentration. In diabetic men the reductions in mortality from coronary heart disease would be between three and five times greater, and total mortality would show mean reductions of 5.81, 0.56, 16.17, and 20.84 per 1000 respectively, with all interventions of significant benefit except the lowering of cholesterol concentration. Between 2400 and 3800 man years of pharmacological intervention were calculated as being necessary to prevent one death from coronary heart disease in a non-diabetic man, and between 800 and 1200 man years in a diabetic man. The loss of life expectancy associated with smoking and hypertension is greater than that accruing from hypercholesterolaemia, but stopping smoking would prolong life by a mean of around four years in a 45 year old non-diabetic man and three years in a diabetic man, whereas aspirin and antihypertensive treatment would provide approximately one year of additional life expectancy in both categories.

CONCLUSIONS

Studies to date have shown little impact of drugs that lower cholesterol concentration and blood pressure on either coronary heart disease or total mortality. Although new treatments for hypercholesterolaemia and hypertension might help prevent coronary heart disease, other approaches to reduce the burden of premature death are required.

Cardiovascular risk factors in treated hypertensives--a nation-wide, cross-sectional study in Sweden

Hypertensive patients still face a considerable risk of cardiovascular disease in spite of drug treatment in many studies. This may partly be explained by metabolic disturbances, both primarily linked to hypertension but also secondarily influenced by anti-hypertensive drugs themselves. In order to evaluate residual cardiovascular risk factors we investigated 1915 treated hypertensives (912 males, 1003 females) attending 128 health centres from all parts of Sweden. Mean blood pressure was 148/91 mmHg for males and 151/90 for females, but a substantial proportion of all patients were not well controlled, having a diastolic blood pressures > or = 100 mmHg (17% males, 12% females). Total cholesterol and HDL-cholesterol were 6.03 and 1.25 mmol l-1 for males, and 6.40 and 1.50 for females. The corresponding figures for serum triglycerides were 2.03 and 1.72 mmol l-1, respectively. In all, 38% of the hypertensives had hypercholesterolaemia (> or = 6.5 mmol l-1) and 27% hypertriglyceridaemia (> or = 2.3 mmol l-1). The lipid/lipoprotein findings may also be influenced by the various anti-hypertensive drugs used in Sweden. The prevalence of smoking and diabetes mellitus were 25% and 11% for men, and for women 24% and 9%. In conclusion, Swedish hypertensives show evidence of significant residual cardiovascular risk factors in spite of treatment. This may be of importance for future relative and absolute cardiovascular risk. It is time to re-evaluate the effectiveness of our management and care of hypertensive patients.

Type 2 (non-insulin-dependent) diabetes mellitus, hypertension and hyperlipidaemia (syndrome X): relation to reduced fetal growth

Two follow-up studies were carried out to determine whether lower birthweight is related to the occurrence of syndrome X-Type 2 (non-insulin-dependent) diabetes mellitus, hypertension and hyperlipidaemia. The first study included 407 men born in Hertfordshire, England between 1920 and 1930 whose weights at birth and at 1 year of age had been recorded by health visitors. The second study included 266 men and women born in Preston, UK, between 1935 and 1943 whose size at birth had been measured in detail. The prevalence of syndrome X fell progressively in both men and women, from those who had the lowest to those who had the highest birthweights. Of 64-year-old men whose birthweights were 2.95 kg (6.5 pounds) or less, 22% had syndrome X. Their risk of developing syndrome X was more than 10 times greater than that of men whose birthweights were more than 4.31 kg (9.5 pounds). The association between syndrome X and low birthweight was independent of duration of gestation and of possible confounding variables including cigarette smoking, alcohol consumption and social class currently or at birth. In addition to low birthweight, subjects with syndrome X had small head circumference and low ponderal index at birth, and low weight and below-average dental eruption at 1 year of age. It is concluded that Type 2 diabetes and hypertension have a common origin in sub-optimal development in utero, and that syndrome X should perhaps be re-named "the small-baby syndrome".