Article Abstract:
High blood pressure (hypertension) can no longer be viewed by itself. Rather, it must be considered as part of a spectrum of conditions that are closely interrelated. This becomes especially clear when the relationship between hypertension and major disorders becomes apparent. Hypertension is an important risk factor for conditions such as stroke, heart failure, and kidney failure. One of the major causes of illness and death among hypertensive patients is coronary artery disease. However, while successful treatment of hypertension reduces the risk of conditions such as stroke, treatment of high blood pressure does little to reduce the risk of heart attack. Treatment for high blood pressure should coincide with treatment for other risk factors. For example, while high blood pressure and high cholesterol are both independent risk factors for heart disease, they often occur together. Furthermore, these two risk factors seem to be synergistic, that is, the risk of heart attack in a person with both conditions is greater than the sum of the risks for hypertension or high cholesterol separately. The physiological reasons for this are not clear, but evidence does suggest that the maximum benefit for the patient can only be achieved when both hypertension and high cholesterol are treated together. Research has also demonstrated a relation between hypertension and diabetes. Furthermore, even hypertensive patients without diabetes show indications of intolerance to glucose. As many as 50 percent of all hypertensive patients have glucose intolerance, which may actually precede the development of hypertension. These patients also have high levels of insulin, which may contribute to abnormalities of the arteries. These high levels of insulin are actually worsened by some treatments for high blood pressure. While hypertension can damage the kidney, it is also clear that the kidney exerts important influences on hypertension, as well. In studies of children of hypertensive or normal parents, it has been found that the children of the hypertensive parents have a reduced ability to alter kidney function in response to changing conditions such as excess protein. Such differences may indicate a predisposition to the development of hypertension later in life. (Consumer Summary produced by Reliance Medical Information, Inc.)
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Article Abstract:
Half of all deaths in the US result from cardiovascular disease, and the vast majority of these result from coronary heart disease. The risk factors that contribute to coronary heart disease are well known, and include high blood pressure (hypertension), high cholesterol, and smoking. Research is elucidating the complex physiological relationships between insulin, blood sugar, and the other risk factors for coronary heart disease. Hyperinsulinemia is correlated with high blood pressure and increased total cholesterol. At the same time, hyperinsulinemia is correlated with decreases in the fraction of a type of cholesterol associated with reduced risk of coronary heart disease, high density lipoprotein (HDL). Evidence suggests that it is not the hyperinsulinemia alone that contributes to the increase in these risk factors. Rather, both the risk factors and the hyperinsulinemia appear to result from a common cause, the development of insulin resistance in some tissues. In particular, the skeletal muscle is resistant to insulin in patients with hypertension. Fat cells are also resistant to insulin in these individuals, which may explain the association of hypertension and obesity. It is not certain how insulin resistance and hyperinsulinemia affect blood pressure, but several mechanisms might be involved. These include effects on the kidneys, effects on the sympathetic nervous system (which helps regulate many factors influencing blood pressure), and effects on the transport of sodium ions across cell membranes. The relation between insulin, high blood pressure, and coronary heart disease is of direct importance to patients. It is clear that antihypertensive drugs, such as the thiazides and the beta blockers, lower blood pressure without significantly reducing the risk of coronary heart disease. These same drugs alter the insulin sensitivity of body tissues and cause abnormalities in blood cholesterol. Understanding the relationship between these physiological factors may be important in developing new drug therapies, which not only lower the blood pressure, but reduce the risk of heart disease at the same time. (Consumer Summary produced by Reliance Medical Information, Inc.)
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Article Abstract:
Body mass index (BMI) is a measure of obesity and one of the best indicators of whether a person will develop high blood pressure and cardiovascular disease, but the relationship is not simple. Instead of a linear relationship, the BMI may have a J-shaped curve in relation to heart disease. Lean hypertensive persons may be even more prone to ischemic heart disease (in which blood flow to the heart is severely reduced) and death. However, these studies have included middle-aged males almost exclusively, so the results may not apply to women or to older men. To study whether BMI was related to death or serious cardiovascular events among elderly patients and women, and also whether antihypertensive treatment reduced the risk, 840 patients were studied. It was found that the risk of death or major event (such as heart attack) had a U-shaped curve, with the fattest and thinnest persons at greatest risk, whether they were receiving treatment or a placebo. Men and women of average weight did best, and those who were obese and hypertensive did worst. Blood pressure was not related to obesity, and systolic blood pressure was highest in the leanest women. Lean hypertensive men have been found to be at greater risk of heart attack or other heart disease, which is only partly explained by previous coronary artery disease. Smoking has been posed as an explanation, but when smoking was controlled, the high risk remained. The finding that lean hypertensive patients are at greatest risk provokes questions about hypertension management. Those who fared best in this study were slightly above average in weight. The recommendation that obese patients lose weight is clearly supported. Antihypertensive therapy reduces risk equally among all patients, and the effects do not vary with weight. (Consumer Summary produced by Reliance Medical Information, Inc.)
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