Plasma lipid and lipoprotein concentrations in Chinese males with coronary artery disease, with and without hypertension

Lipoprotein lipase variants associated with an endophenotype of hypertension: hypertension combined with elevated triglycerides

Previously, we observed that young-onset hypertension was independently associated with elevated plasma triglyceride(s) (TG) levels to a greater extent than other metabolic risk factors. Thus, focusing on the endophenotype--hypertension combined with elevated TG--we designed a family-based haplotype association study to explore its genetic connection with novel genetic variants of lipoprotein lipase gene (LPL), which encodes a major lipid metabolizing enzyme. Young-onset hypertension probands and their families were recruited, numbering 1,002 individuals from 345 families. Single-nucleotide polymorphism discovery for LPL, linkage disequilibrium (LD) analysis, transmission disequilibrium tests (TDT), bin construction, haplotype TDT association and logistic regression analysis were performed. We found that the CC- haplotype (i) spanning from intron 2 to intron 4 and the ACATT haplotype (ii) spanning from intron 5 to intron 6 were significantly associated with hypertension-related phenotypes: hypertension (ii, P=0.05), elevated TG (i, P=0.01), and hypertension combined with elevated TG (i, P=0.001; ii, P<0.0001), according to TDT. The risk of this hypertension subtype increased with the number of risk haplotypes in the two loci, using logistic regression model after adjusting within-family correlation. The relationships between LPL variants and hypertension-related disorders were also confirmed by an independent association study. Finally, we showed a trend that individuals with homozygous risk haplotypes had decreased LPL expression after a fatty meal, as opposed to those with protective haplotypes. In conclusion, this study strongly suggests that two LPL intronic variants may be associated with development of the hypertension endophenotype with elevated TG.

Prevalence and association with diabetes and obesity of lipid phenotypes among the hypertensive Chinese rural adults

BACKGROUND

Both dyslipidemia and hypertension are important risk factors for cardiovascular disease. Studies have found that there is a higher risk of dyslipidemia among hypertensive patients. This study was designed to investigate the epidemiologic features of some forms of dyslipidemia in rural hypertensive adults in China.

METHODS

A cross-sectional survey was conducted during 2004 to 2006 through a cluster multistage sampling of a resident group of 6412 hypertensive individuals (2805 men and 3607 women), aged >/= 35 years, in the countryside of Liaoning, China. The cutpoints of lipid phenotypes were based on the 1992 recommendations of the European Atherosclerosis Society.

RESULTS

The most prevalent abnormality was isolated hypercholesterolemia (34.1% for men and 37.3% for women). Mixed dyslipidemias was the second most prevalent abnormality (14.3%). Isolated hypertriglyceridemia was observed in 5.6% of the sample. The prevalence of normotriglyceridemic hypoalphalipoproteinemia and severe dyslipidemia was 2.0% and 3.3%, respectively. Only a few samples had the abnormality of hypertriglyceridemia/hypoalphalipoproteinemia (.8% for men and .3% for women). The prevalence of isolated hypertriglyceridemia, mixed dyslipidemias, and severe dyslipidemia was higher in diabetic patients compared with nondiabetic patients, in either men or women. Compared with those of normal weight, obese men had a higher prevalence of mixed dyslipidemias and hypertriglyceridemia/hypoalphalipoproteinemia, whereas isolated hypertriglyceridemia was prevalent in both genders.

CONCLUSION

The prevalence of lipid phenotypes among these hypertensive patients was relatively high, even in rural China. Diabetes and obesity, the modifiable risk factors, increased the likelihood of having several forms of an atherogenic lipid profile.

Prevalence of dyslipidemia and associated factors among the hypertensive rural chinese population

BACKGROUND

Dyslipidemia plays a crucial rule in the development of cardiovascular disease, which has become the leading cause of death in most developed countries as well as in developing countries. This study was designed to investigate the epidemiological features of dyslipidemia in rural adults with hypertension in China.

METHODS

A cross-sectional survey was conducted during 2004-2006 through a cluster multistage sampling to a resident group of 6,412 individuals (2,805 men, 3,607 women) with hypertension, aged >/=35 years, in the countryside of Liaoning, China. Serum lipids levels were proposed by National Cholesterol Education Program Adult Treatment Panel III.

RESULTS

Of the study population 34.4% had borderline high total cholesterol (TC), 16.9% had high TC, and 8.8% had low high-density lipoprotein cholesterol (HDL-C). The population with borderline high, high, and very high low-density lipoprotein cholesterol (LDL-C) was 15.7, 3.5, and 0.9%, respectively. In addition, 15.9% had borderline high triglycerides (TG), 17.8% had high TG and 2.0% had very high TG. After adjusting for independent variables, TC and TG had the same risk with fasting plasma glucose (FPG) and body mass index. Risk factors of TC and LDL-C were women, age and FPG. Mongolia nationality as a protective factor positively correlated with TC, LDL-C, and TG. Women, age, drinking, and classification of blood pressure were protective factors but Mongolia nationality was a risk factor for HDL-C.

CONCLUSIONS

This study demonstrated that the prevalence of dyslipidemia was relatively high among rural hypertensive patients in China and there were many modifiable risk factors for dyslipidemia such as hypertension, weight, and impaired glucose metabolism. To prevent dyslipidemia and to reduce the increasing burden of cardiovascular disease in rural areas with the undeveloped economy of China, the first aim for us is to reduce these risk factors.

A novel approach to treatment of hypertension in diabetic patients - a multicenter, double-blind, randomized study comparing the efficacy of combination therapy of Eprosartan versus Ramipril with low-dose Hydrochlorothiazide and Moxonidine on blood pressure levels in patients with hypertension and associated diabetes mellitus type 2 - rationale and design [ISRCTN55725285]

Hypertension and diabetes mellitus are closely interrelated and coexist in as many as two-thirds of patients with type 2 diabetes. The consequent risk of such an association is an accelerated development of atherosclerotic cardiovascular disease and nephropathy complications.In choosing an antihypertensive agent, effectiveness needs to be accompanied by favourable metabolic, cardioprotective, and nephroprotective properties. Given the multifactorial nature of hypertension, the approach that has gained widespread agreement is treatment with more than one agent. Agents with different mechanisms of action increase antihypertensive efficacy because of synergistic impacts on the cardiovascular system. Combination therapy allows the use of lower doses of each antihypertensive agent which accounts for the excellent tolerability of combination products.The aim of the present study is to quantify the efficacy of combination therapy of Eprosartan 600 mg respectively Ramipril 5 mg with low-dose Hydrochlorothiazide and Moxonidine on blood pressure levels in patients with essential hypertension and associated diabetes mellitus type 2.The use of monotherapy (Eprosartan or Ramipril) followed by addition of low-dose Hydrochlorothiazide as second agent and of Moxonidine as a third agent will be individualized to the severity of hypertension in the particular patient and to his/her degree of response to current treatment.

Risk Factors for Cardiovascular Disease in the Elderly in Taiwan

The major objective of the present study was to identify biologic and behavioral risk factors of cardiovascular disease (CVD) in the elderly population in Taiwan. It is hypothesized that the selected risk factors are significantly associated with the prevalence of CVD. Data came from a nationwide geriatric survey in 1991. Stratified proportional sampling was used to recruit 2,600 subjects. These were evaluated by family physicians working for the Departments of Family Medicine at four medical centers in four major cities in Taiwan. Univariate and multivariate logistic regression analyses were used to examine the associations between risk factors and the prevalence of CVD. The prevalence of CVD was 38.31%. Patients with CVD consistently had higher values for each selected risk factor except high-density lipoprotein-cholesterol (HDL-C) and glucose concentrations. The findings also indicated that hypertension, hypertriglyceridemia, low HDL-C concentration, ex-drinking status, and overweight were significantly associated with the prevalence of CVD among the elderly in Taiwan. The findings not only confirm the risk factors for CVD, but also invite more attention to be given to the importance of biologic and behavioral risk factors in CVD.

Managing the patient with diabetes mellitus and heart failure: issues and considerations

Heart failure affects nearly 5 million Americans and is associated with high morbidity and mortality rates. It is now recognized that activation of multiple neurohormonal systems is intrinsic in the pathophysiology of heart failure. Patients with diabetes mellitus are at high risk for heart failure, and some of the complications of diabetes (e.g., insulin resistance) contribute to the development and progression of heart failure, partly because of their effects on neurohormonal systems. Pharmacologic intervention directed toward these systems (i.e., angiotensin-converting enzyme [ACE] inhibition, use of aldosterone antagonists, and beta-adrenergic blockade) has been shown to decrease the morbidity and mortality associated with heart failure. Despite this knowledge, ACE inhibitors, aldosterone antagonists, and beta-blockers are grossly underused, and deaths and hospitalizations due to heart failure have steadily increased. Guidelines for the management of heart failure recommend the use of ACE inhibitors and beta-blockers in patients with mild, moderate, or severe disease. Aldosterone antagonists are recommended in severe heart failure, and recent data also support their use in mild to moderate heart failure. Concerns about the increased incidence of hypoglycemia, worsening dyslipidemia, and decreased insulin sensitivity with beta-blocker use may be preventing physicians from prescribing these agents for patients with diabetes with heart failure. Although evidence from earlier clinical trials justifies some of these concerns, newer vasodilating beta-blockers (e.g., carvedilol) have been shown to have a neutral or positive effect on dyslipidemia and insulin resistance. beta-Blockade in conjunction with ACE inhibition should be standard therapy for all patients with diabetes who have heart failure. Furthermore, early in-hospital initiation of neurohormonal intervention can provide earlier benefit to these patients.

Insulin resistance, hypertension, and coronary heart disease

The goals of this review are two-fold: to examine the evidence in support of a role for insulin resistance and compensatory hyperinsulinemia in the pathogenesis of essential hypertension, and to evaluate the hypothesis that insulin resistance and its manifestations play major roles in the development of coronary heart disease in patients with essential hypertension. In both instances, only experimental results in human beings will be considered. Although it remains a scientific issue of great importance, the scope of this review precludes a discussion of the mechanistic link between insulin resistance/hyperinsulinemia and essential hypertension.

Genetic analysis of a polymorphism in the human apoA-V gene: effect on plasma lipids

Recent discovery and characterization of APOAV suggests a role in metabolism of triglyceride (TG)-rich lipoproteins. Previously, variation at the APOAV locus was shown to modestly influence plasma TGs in normolipidemic samples. The aims of this study were to assess the effects of a polymorphism in APOAV (T-1131C) in terms of its frequency among three dyslipidemic populations and a control population, differences of allele frequency across available ethnic groups, and associations with specific lipoprotein TG and cholesterol compartments. We found a striking elevation in the frequency of the rare allele in a Chinese population (P = 0.0002) compared with Hispanic and European populations. The rare allele of the polymorphism was associated with elevated plasma TG (P = 0.012), VLDL cholesterol (P = 0.0007), and VLDL TG (P = 0.012), LDL TG (P = 0.003), and HDL TG (P = 0.016). Linear regression models predict that possession of the rare allele elevates plasma TG by 21 mg/dl (P = 0.009) and VLDL cholesterol by 8 mg/dl (P = 0.0001), and reduces HDL cholesterol by 2 mg/dl (P = 0.017). The association of the polymorphism with altered lipoprotein profiles was observed in combined hyperlipidemia, hypoalphalipoproteinemia, and hyperalphalipoproteinemia, and in controls. These findings indicate that APOAV is an important determinant of plasma TG and lipoprotein cholesterol, and is potentially a risk factor for cardiovascular disease.

High-density lipoprotein cholesterol and left ventricular hypertrophy in essential hypertension

OBJECTIVE

The proportion of left ventricular (LV) mass variability explained by blood pressure in essential hypertension is small, and several non-haemodynamic determinants of LV mass have been identified or hypothesized. This study examines the possible relation between blood lipids and LV mass in hypertension.

DESIGN

Never-treated non-diabetic hypertensive patients.

SETTING

Hospital hypertension outpatient clinics in Umbria, Italy.

PATIENTS

We investigated the association between high-density lipoprotein (HDL)-cholesterol and echocardiographic LV mass in 1306 never-treated subjects with essential hypertension. Subjects with previous cardiovascular events, diabetes and current or previous antihypertensive or lipid-lowering therapy were excluded.

RESULTS

HDL-cholesterol showed an inverse association with LV mass (r = -0.30, P < 0.001). No association was found between LV mass and total or low-density lipoprotein cholesterol. With multiple linear regression analysis we tested the independent contribution of several potential determinants of LV mass in women and in men. Average 24 h blood pressure (both pulse and mean), body mass index, height, stroke volume, age (all P < 0.01) and low HDL-cholesterol (P < 0.0001 in women, P < 0.001 in men) were associated with a greater LV mass in both sexes. Triglycerides showed a weak univariate association with LV mass in women (r = 0.11, P < 0.02), which did not hold in a multivariate analysis.

CONCLUSIONS

Low HDL-cholesterol is an independent predictor of LV mass in untreated hypertensive subjects. Common hormonal and metabolic mechanisms, including insulin resistance, could explain this association, which may contribute to the adverse prognostic significance of low HDL-cholesterol levels.

The rise of the plasma lipid concentration elicited by dietary sodium chloride restriction in Wistar rats is due to an impairment of the plasma triacylglycerol removal rate

Studies in humans have indicated that dietary salt restriction raises plasma levels of total cholesterol (TC) and triacylglycerols (TAG). In order to explain the mechanisms involved, a rat experimental model was developed consisting of chronic feeding ad libitum isocaloric diets with variable sodium chloride contents. Rates of synthesis of plasma TAG were measured either as the increase of plasma TAG after blocking its removal from plasma by the intra-arterial pulse infusion of Triton-WR 1339, or as the plasma rate of incorporation of [(14)C]-oleic acid [(14)C]-TAG. Plasma TAG removal rate was determined by the intra-arterial pulse infusion of a lipid emulsion. Severe salt restriction increased the plasma concentrations of TAG (71%) and of TC (10%). This result was not due to modification of the rate of synthesis of plasma TAG but was attributed to a 55% slower rate of removal of the TAG-containing lipoproteins. An increased plasma non-esterified fatty acid concentration, probably due to a salt restriction-related insulin resistance, may have impaired the activity of the enzyme lipoprotein lipase.

Syndrome X

The manifestations of syndrome X increase the risk of coronary heart disease (CHD) as much, if not more so, than elevated low-density lipoprotein (LDL) cholesterol concentrations. The fundamental abnormality leading to the manifestations that comprise syndrome X is resistance to insulin regulation of muscle glucose uptake and adipose tissue lipolysis. To prevent decompensation of glucose tolerance, patients with syndrome X secrete large amounts of insulin. Treatment should be aimed at 1) increasing insulin sensitivity, 2) attenuating day-long hyperinsulinemia, and 3) pharmacologic treatment of the specific manifestations of syndrome X if lifestyle interventions are not entirely successful. The two major lifestyle modulators of insulin action are body weight and physical fitness--the heavier and the more sedentary a patient is, the greater the degree of insulin resistance and compensatory hyperinsulinemia. In overweight, insulin-resistant patients, the magnitude of insulin resistance is attenuated with weight loss (10 to 15 pounds). Aerobic exercise (30 minutes a session, three to four times a week) is equally effective, irrespective of the presence of obesity. In the absence of associated weight loss, the usually recommended low-fat, high-carbohydrate diet makes the manifestations of syndrome X worse. This is because the more carbohydrates present in the insulin-resistant patient's diet, the greater the insulinogenic stimulus to the pancreas, and hence day-long plasma insulin levels are higher. Replacing saturated fat with monounsaturated and polyunsaturated fat instead of carbohydrates provides the same favorable effect on LDL cholesterol concentrations without the insulin-stimulating effect of low-fat, high-carbohydrate diets. This intervention does not affect insulin resistance, but maintains day-long insulin levels as low as possible. Although lifestyle changes can be very effective in attenuating the manifestations of syndrome X, it may be necessary to initiate pharmacologic treatment aimed at controlling dyslipidemia and hypertension. The major obstacle to reducing the risk of CHD in patients with syndrome X is becoming aware of its manifestations. After this is accomplished, the relatively simple approaches outlined herein are an effective treatment strategy.

Relation between systemic hypertension and blood lipids on the risk of myocardial infarction

We sought to evaluate the potential interactions between systemic hypertension and blood lipids on the risk of myocardial infarction (MI). Recent evidence suggests that hypertension may interact with other risk factors such as dyslipidemia in the development of coronary heart disease. However, the precise nature of that interrelation remains unclear. We selected 340 cases of first MI and an equal number of age-, sex-, and community-matched controls. Data were collected on a large number of coronary risk factors, and fasting blood samples were obtained. Logistic regression was used to calculate the odds ratio (OR) of nonfatal MI. The age- and sex-adjusted OR of MI was 1.61 (95% confidence interval [CI] 1.15 to 2.25) among treated hypertensives compared with nonhypertensives. Further adjustment for coronary risk factors did not materially alter the results (OR 1.67, 95% CI 1.16 to 2.41). To explore the interrelations among hypertension, lipids, and risk of MI, each lipoprotein parameter was individually added to the risk factor-adjusted multivariate model. The apparent risk associated with hypertension was substantially attenuated by the addition of either high-density lipoprotein cholesterol (OR 1.25, 95% CI 0.82 to 1.90) or triglycerides (OR 1.37, 95% CI 0.91 to 2.05). No significant interactions were found between hypertension and any lipoprotein parameter. These data indicate that the risk of MI associated with treated hypertension may have a lipid mechanism involving high-density lipoprotein cholesterol and/or triglycerides.

Plasma and lipoprotein lipid composition and hepatic antioxidant status in spontaneously hypertensive (SHR) and normotensive (WKY) rats

Plasma and lipoprotein lipid composition and endogenous hepatic antioxidant status were investigated in hypertensive, 14-week-old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats fed a standard commercial rat chow. Total plasma calcium and magnesium concentrations were similar between both rat strains; however, systolic blood pressure in SHR was greater than in WKY at 13 weeks of age (197 ± 12 vs. 132 ± 14 mmHg; p <= 0.05), confirming hypertension in SHR. Total plasma cholesterol and triacylglycerol concentrations were lower (p <= 0.05) in SHR compared with WKY. A lower (p < 0.05) HDL cholesterol level in SHR plasma resulted in a higher LDL to HDL cholesterol ratio compared with WKY counterparts. No significant differences in the relative proportion of HDL apolipoprotein A-I fraction were observed between SHR and WKY. Both SHR VLDL and HDL triacylglycerol fractions were lower (p < 0.05) in SHR than WKY. Analysis of liver antioxidant enzyme activities showed no differences in rat liver superoxide dismutase (SOD), but lower (p < 0.05) liver glutathione peroxidase (GSH-Px) activity in SHR. However, liver glutathione (GSH) levels were similar in SHR and WKY counterparts. A possible compensatory effect to the oxidative status of SHR was suggested by the significant (p < 0.05) increase in both liver catalase (CAT) and glutathione reductase (GSSG-Red) activities. Despite these results, in vitro oxidative challenge studies with H2O2demonstrated a greater susceptibility of liver to GSH depletion in the SHR, although no parallel change in thiobarbituric acid reactive substances (TBARS) production was observed. The comparatively lower plasma cholesterol observed in hypertensive SHR paralleled specific differences in liver catalase and glutathione redox antioxidant enzyme activities.Key words: liver antioxidant status, plasma and lipoprotein lipids, spontaneously hypertensive rat.

[Atherosclerotic cardiovascular disease, lipemic disorders, hypertension, obesity and diabetes mellitus in the population of a metropolitan area of southeastern Brazil. II--Lipemic disorders]

This study has sought to characterize the prevalence of lipemic disorders and other risk factors of atheroschlerotic cardiovascular disease in population groups of Cotia county in Greater S. Paulo, Brazil. The population groups were defined on the basis of socio-economic characteristics and geographical location within the county such as provided elements for the delimitation of the "study areas". A sample representative of each of these areas was taken, constituting in all 1,041 individuals. The data related to eating habits were collected from a sub-sample of 568 people. The lipemic disorders diagnosed were as follows: high risk hypercholesterolemias with values approximately 240 mg/dl for total cholesterol and approximately 160 mg/dl for LDL-cholesterol; borderline risk hypercholesterolemias with values > 200 mg/dl and > 130 mg/dl for total cholesterol and LDL-cholesterol respectively; hypertriglyceridemia, with values approximately 250 mg/dl. The following risk factors were included: atherogenic eating habits (consumption of proteins of animal origin, saturated fats and cholesterol), smoking, drinking, sedentary life style, obesity (IMC > 25 kg/m2), hypertension (140/90 mmHg) and diabetes mellitus (glycemia > 120 mg/dl). The results found were the following: 1--the average number of risk factors was significant by greater among men than among women, for the age groups below 50 years of age (p < 0.01): between 50 and 55 years of age they were equal for the two groups, reaching their greatest value at 60 years of age with a sharp reduction after this latter age as regard the men but presenting a constant gradual increase for the women; 2--the average number of risk factors increased with age for both sexes (p < 0.01); 3--the prevalences of high risk hypercholesterolemias together with hypertriglyceridemia (> = 250 mg/dl) were significantly greater in the classes of higher socio-economic level; 4--the lipemic profile associated with lipemic disorders show that these latter rarely occur with just one constituent in isolation; 5--when the high-risk hypercolesterolemias are added to the borderline cases accompanied by two or more risk factors and hypertriglyceridemia they give a total of 39.2% of men and 32.8% of women, that is to say, 35.4% of the sample need immediate clinical-educational intervention.

Plasma lipid profiles and epidemiology of atherosclerotic diseases in Taiwan--a unique experience

Rapid economic growth in Taiwan is accompanied by changing lifestyles, and the mortality pattern has switched from predominantly infectious diseases to chronic diseases. Age-adjusted mortality from heart disease has increased slowly but steadily. However, mortality from heart disease in Taiwan remains low compared with many other countries. Mortality from the cerebrovascular diseases has decreased gradually. Current age- and sex-specific values of blood cholesterol low density lipoprotein cholesterol (LDL-C) and triglyceride (TG) are, in general, higher than values in mainland China, but lower than those in the NHANES III and PROCAM studies. From 1950 to 1987, percent dietary fat increased from 16% to 36% in Taiwan. However, a high polyunsaturated fat/saturated fat (P/S) ratio (1.3) maintained during this period may in part explain the favorable blood lipid status and low mortality from heart disease. Data from prospective studies are scarce. In case-control studies carried out in Chinese, significantly higher values of TG, CHOL LDL-C, but lower high density lipoprotein cholesterol (HDL-C) levels have often been found in coronary artery disease (CAD) patients than in controls. The percent differences in TG and HDL-C values (20%) were much greater than those of CHOL and LDL-C (3%). A few studies have identified the TG level as an independent risk factor for stroke and CAD in Taiwan, where a moderate to high fat diet with an advantageous P/S ratio is consumed.

Prevalence of hypercholesterolaemia and coronary heart disease risk factors among southeast Asian refugees in a primary care clinic

The National Cholesterol Education Program's guidelines for the detection, evaluation, and treatment of high serum cholesterol in adults were employed in screening 155 Southeast Asian refugees in a primary care clinic in Seattle, Washington. In order to determine the need for a therapeutic intervention, information also was collected on the presence of other coronary heart disease (CHD) risk factors. Male gender (39%), cigarette smoking (27%) and hypertension (26%) were the most common CHD risk factors; diabetes mellitus, obesity, a family or prior history of CHD or cerebral/peripheral vascular disease were each noted in less than 10%. The mean serum total cholesterol was 194 mg/dl. Thirty-seven (24%) patients required further lipoprotein analysis based on cholesterol level, history of CHD and risk factors for CHD. Twenty-one (66%) of 32 patients who underwent lipoprotein analysis (14% of all patients) were candidates for a therapeutic intervention for hypercholesterolaemia. Additionally, 14 (44%) patients undergoing lipoprotein analysis had depressed high-density lipoprotein levels (< 35 mg/dl). We conclude that CHD risk factors including hypercholesterolaemia are common in Southeast Asian refugee clinic patients and that in many, a therapeutic intervention may well be justified. Southeast Asian refugees should be routinely screened for hypercholesterolaemia and other CHD risk factors in accordance with the National Cholesterol Education Program's guidelines.

Effect of endogenous organic hyperinsulinaemia on blood pressure and serum triglycerides

Hyperinsulinaemia and insulin resistance have been hypothesized to be the common pathophysiological factor of hypertension, NIDDM and obesity. To evaluate the possible role of hyperinsulinaemia and insulin resistance on hypertension, we studied a group of 37 patients with insulinoma who were admitted to our department in the period from 1966 to 1990. We recorded blood pressure and assayed blood glucose, plasma insulin, plasma triglycerides and serum uric acid levels, before and after surgery, in these patients and in a 37-subject control group. No significant increase in blood pressure and triglyceride plasma levels was recorded in the chronic hyperinsulinaemic hypoglycaemic patients, suggesting the lack of a direct role of hyperinsulinaemia on hypertension.

Hyperinsulinaemia, obesity, and syndrome X

OBJECTIVE

The major aim of this study was to compare various aspects of carbohydrate, insulin, and lipoprotein metabolism, serum uric acid concentration, and blood pressure in normal subjects stratified on the basis of both plasma insulin concentration and degree of obesity. The hypothesis to be tested was that hyperinsulinaemia, per se, was associated with relative glucose intolerance, higher triglyceride and uric acid concentrations, lower high-density lipoprotein cholesterol concentration and higher blood pressure, irrespective of degree of obesity.

DESIGN

This represents a case-control study, in which normal volunteers were subdivided into four equal groups based upon degree of obesity and plasma insulin response to a 74 g oral glucose challenge.

SETTING

The study was performed in the out-patient clinic of a university hospital.

SUBJECTS

Sixty-four individuals were recruited for this study, subdivided into four groups based upon their plasma insulin concentration and body mass index. Subjects were classified as hyperinsulinaemic if their plasma insulin concentrations in response to an oral glucose challenge were more than two standard deviations above the mean of 732 volunteers previously studied [1]. Obesity was defined as a body mass index of > 30 kg m-2, and individuals were classified as non-obese if their body mass index was < 27.0 kg m-2. Based upon these criteria, four experimental groups were created: (i) non-obese hyperinsulinaemic (NOB hyper); (ii) obese hyperinsulinaemic (OB hyper); (iii) non-obese normoinsulinaemic (NOB normo); and (iv) obese normoinsulinaemic (OB normo).

MAIN OUTCOME MEASURES

Subject groups were compared on the basis of the integrated plasma glucose response to a 75 g oral glucose challenge, fasting plasma triglyceride, cholesterol, high-density lipoprotein cholesterol, and uric acid concentrations, and blood pressure.

RESULTS

Mean (+/- standard error of the mean) integrated plasma glucose response area for 2 h following a 75 g oral glucose load was significantly higher (13.4 +/- 0.4 vs. 11.0 +/- 0.4 mmol l-1, P < 0.001) in the hyperinsulinaemic group, as were the fasting triglyceride levels (2.4 +/- 0.2 vs. 1.4 +/- 0.1 mmol l-1, P < 0.001) and uric acid (5.3 +/- 0.2 vs. 4.4 +/- 0.2 mmol l-1, P < 0.05) concentrations. In contrast, high-density lipoprotein concentrations were lower in the hyperinsulinaemic group (1.06.0.05 vs. 1.32 +/- 0.05 mmol l-1, P < 0.001). In addition, blood pressure was higher in the hyperinsulinaemic group (136 +/- 5/87 +/- 2 vs. 123 +/- 2/82 +/- 1 mmHg, P < 0.05). Furthermore, when each of the two groups were divided into obese (n = 16) and non-obese (n = 16) groups, all of the differences outlined above persisted. These changes were independent of age, gender distribution, generalized and abdominal obesity, cigarette smoking, and estimated physical activity.

CONCLUSIONS

The cluster of changes subsumed under the heading of syndrome X are closely associated with hyperinsulinaemia (and presumably insulin resistance), and can be discerned irrespective of degree of obesity.

Insulin resistance and risk factors for coronary heart disease

In this presentation an effort has been made to review the impact of resistance to insulin-mediated glucose uptake and/or hyperinsulinaemia on various metabolic end-points and clinical syndromes. Insulin resistance is present in the great majority of patients with states of glucose intolerance, but frank decompensation of glucose homoeostasis does not occur if individuals can maintain a state of compensatory hyperinsulinaemia. Although compensatory hyperinsulinaemia may prevent the development of NIDDM in insulin-resistant individuals, there is substantial evidence that insulin resistance and/or hyperinsulinaemia is associated with higher plasma concentrations of triglyceride, uric acid and plasminogen activator inhibitor 1 and with lower HDL cholesterol concentrations. Obesity, decreased physical activity and possibly cigarette smoking accentuate the degree of insulin resistance and its manifestations, and a genetic basis is also involved. Resistance to insulin-mediated glucose uptake and/or hyperinsulinaemia have been shown to be associated with high blood pressure, microvascular angina and CHD. Thus, resistance to insulin-mediated glucose uptake is a common phenomenon, which makes a major contribution to the aetiology and clinical course of common and serious diseases. Based on the above considerations, it is difficult to over-emphasize the health-related implication of a defect in insulin-mediated glucose uptake.

Plasma triglycerides and 24 hour urinary sodium excretion in elderly hypertensives. A pathogenetic connection?

Hypertension among the elderly generally represents a salt- sensitive state. However this salt-sensitivity does not appear to result from age-related increase in either sodium or salt intake. Since 20 years new trends seem to relate the role of sodium in the genesis of hypertension to a primary abnormality of electrolyte transport of cell membrane. Lipid abnormalities have also been described in untreated patients with high blood pressure. Plasma triglycerides were considerably higher (p < 0.01) in the hypertensives than in the controls. 24 hour sodium excretion was significantly lower (p < 0.0001) in hypertensives than in the controls. We have found a strong correlation among reduced sodium excretion, higher triglycerides and elevated blood pressure in the elderly. The blood pressure correlated negatively with 24 hour sodium excretion (p < 0.0001 for systolic and p < 0.002 for diastolic) and positively with plasma triglycerides (p < 0.0001 for systolic and p < 0.001 for diastolic). The poor literature regarding an association of these two alterations in human hypertensives makes our results provocative. We speculated that these alterations may be a facet of the insulin resistance commonly detectable in human hypertensives. However, further investigations are required to answer to this intriguing hypothesis.

Lipids, lipoproteins and other coronary risk factors in Chinese male survivors of myocardial infarction

OBJECTIVE

To assess the importance of an abnormal lipid profile as a risk factor in relation to non-biochemical risk factors, and to define the risk levels for lipid, lipoprotein and apolipoprotein in a Chinese population.

PATIENTS AND METHODS

Serum lipids, lipoproteins, apolipoproteins and other cardiovascular risk factors were studied in 89 Chinese men 3 months after acute myocardial infarction and 56 controls.

RESULTS

Cases had higher mean total cholesterol (TC), LDL- and VLDL-cholesterol, triglycerides and apolipoprotein B (Apo B), and lower mean HDL-cholesterol and apolipoprotein AI (Apo AI). Mean BMI was also higher, as was the prevalence of smokers and subjects with a history of hypertension. In univariate analysis, the odds ratios for TG > or = 1.6 mmol/l, LDL-cholesterol > or = 4.1 mmol/l, VLDL-cholesterol > or = 0.73 mmol/l, Apo B > or = 104 mg/dl were of the same order of magnitude as being a current smoker, having a BMI > or = 24.3 kg/m2, and a history of hypertension. High HDL-cholesterol (> or = 1.39 mmol/l) and Apo AI (> or = 139 mg/dl) were protective factors. The odds ratios for successively higher quartile values of cholesterol were not statistically significant. Multiple logistic regression identified smoking habit, history of hypertension, obesity, high Apo B and low Apo AI concentrations as independent risk factors for myocardial infarction.

CONCLUSIONS

In a Chinese population, low serum Apo AI and high Apo B are risk factors for myocardial infarction of a comparable magnitude to smoking, hypertension and obesity.

Genetic and environmental covariance of serum cholesterol and blood pressure in female twins

Blood pressure elevation is frequently associated with elevated cholesterol, triglyceride or low density lipoprotein (LDL-C) or low high density lipoprotein (HDL-C). The relative importance of genetic and environmental factors in these associations is unclear. We examined the relative contribution of genetic and environmental influences to the association between blood pressure and serum lipids in 75 pairs of female twins using path analysis and maximum-likelihood model fitting. Associations between systolic blood pressure and total cholesterol (r = 0.44, P < 0.001), and LDL-C (r = 0.38, P < 0.001), but not HDL-C (r = 0.05, N.S.), remained significant after age and body mass index adjustment. Univariate models suggested genetic effects contributed 60-70% to the variance of total cholesterol, LDL-C, HDL-C and systolic blood pressure. The remaining variance was explained by age and/or unique environmental influences. Using bivariate models, we demonstrated genetic (P = 0.017) and unique environmental covariance (P = 0.011) of cholesterol and systolic blood pressure. Significant genetic covariance (P = 0.038) was observed between LDL-C and systolic blood pressure. The association between blood pressure and total cholesterol in these twins results from shared genetic and similar unique environmental influences. The association between LDL-C and blood pressure is partly due to shared genetic influences. We conclude that both additive genetic and environmental factors unique to the individual are important determinants of the relationships between serum lipids and blood pressure.

Mechanism of hypertriglyceridemia in Dahl rats

Plasma triglyceride concentrations were shown to be higher in hypertensive (153 +/- 2 mm Hg) male Dahl salt-sensitive rats than in control Sprague-Dawley rats (122 +/- 2 mm Hg). These differences in triglyceride concentrations were seen when blood was drawn at 9 AM from unfasted animals (229 +/- 27 versus 111 +/- 8 mg/dL), at 1 PM after a 4-hour fast (186 +/- 13 versus 88 +/- 4 mg/dL), or at 9 AM after a 13-hour fast (151 +/- 6 versus 90 +/- 6 mg/dL), all p < 0.001. Total triglyceride secretion was also compared in groups of rats by determining the increment in plasma triglyceride concentration for 2 hours after blocking triglyceride removal from plasma by injecting Triton. Studies performed at 1 PM and 9 AM, after the 4- and 13-hour fast, demonstrated that total triglyceride secretion was greater (p < 0.05) in Dahl rats only when studied at 1 PM. Direct estimates of hepatic triglyceride secretion at 1 PM also demonstrated a significant (p < 0.02) increase in secretion rate by perfused livers from Dahl rats, due in part to their increased liver size. In addition, removal of prelabeled very low density lipoprotein-triglyceride in the intact rat was significantly (p < 0.05) decreased in Dahl rats. Lipoprotein lipase activity measured in skeletal muscle, heart, and adipose tissue was also significantly decreased at 9 AM and 1 PM (after 0 and 4 hours of fasting) in tissue from Dahl rats. These data confirm that Dahl rats have higher plasma triglyceride concentrations than Sprague-Dawley rats. Since both total and hepatic triglyceride secretion were somewhat greater in Dahl rats, in association with a decrease in both removal of very low density lipoprotein from plasma and decreased muscle and adipose tissue lipoprotein lipase activity, it seems likely that hypertriglyceridemia in Dahl rats results from a combination of increased triglyceride secretion and decreased triglyceride removal.

Dubbo Study of the elderly: hypertension and lipid levels

Untreated hypertension in age groups below 60 years has been shown to be associated with significant elevations in serum cholesterol and triglyceride levels. Drug therapy of hypertension has also been shown to have adverse effects on lipoproteins. We have investigated lipid and lipoprotein levels in a community-based sample of men and women 60 years and older belonging to one of the following groupings: (a) normal blood pressure (n = 1075); (b) untreated hypertension (n = 329); (c) drug-treated hypertension (n = 880). Serum lipid, lipoprotein, apolipoprotein or plasma glucose levels did not vary significantly between untreated hypertensives and normotensives of either sex. In a multiple regression model controlling for possible influences of age, overweight, alcohol and tobacco usage, and presence of coronary heart disease, anti-hypertensive drug therapy significantly predicted increased serum triglycerides (P less than 0.001) and reduced high density lipoprotein (HDL) cholesterol levels (P less than 0.01) in both sexes, reduced apolipoprotein A-I levels in males (P less than 0.001), and increased apolipoprotein B (P less than 0.01) and plasma glucose levels (P less than 0.001) in females. Adjusted triglycerides were 20% higher and HDL cholesterol was 7% lower in the presence of anti-hypertensive drug therapy. These effects were partially consistent with the known actions of thiazide diuretics and beta-blockers which were used by more than 50% and 40% of subjects, respectively.

The role of insulin resistance and hyperinsulinemia in coronary heart disease

Patients with impaired glucose tolerance (IGT) and non-insulin-dependent diabetes mellitus (NIDDM) are more resistant to insulin-stimulated glucose uptake than are individuals with normal glucose tolerance. Evidence has also been published showing that first-degree relatives of patients with NIDDM are insulin resistant when compared with a matched group of relatives of subjects with normal glucose tolerance. In addition, the ability of insulin to stimulate glucose uptake varies approximately fourfold in individuals with normal glucose tolerance, and insulin resistance of a degree comparable to that seen in patients with IGT or with Type II diabetes is present in a significant portion of the normal population. Given a defect in insulin-stimulated glucose uptake, glucose tolerance can only be maintained if insulin-resistant individuals continue to secrete greater than normal amounts of insulin. As a corollary, glucose homeostasis will decompensate when the insulin secretory response begins to decrease, and the greater the decline in insulin secretion, the larger the increase in plasma glucose concentration. Resistance to insulin-stimulated glucose uptake and compensatory hyperinsulinemia seems to represent the basic defect in patients with NIDDM, with failure of beta-cell function and subsequent development of fasting hyperglycemia only occurring later. This general formulation has received considerable support from longitudinal studies of the natural history of NIDDM. The fact that an increase in ambient insulin concentration can prevent gross decompensation of glucose tolerance in an insulin-resistant individual does not mean that this compensatory response is benign.(ABSTRACT TRUNCATED AT 250 WORDS)

The hypertriglyceridemic rat as a genetic model of hypertension and diabetes

Hypertriglyceridemia was demonstrated in untreated hypertensive patients as well as in animals with genetic and experimental hypertension. The main purpose of the present study was to evaluate the possibility to use the hereditary hypertriglyceridemic (HTG) nonobese rats in hypertensive research. Direct measurement of blood pressure demonstrated significantly higher systolic, diastolic and mean arterial pressures in HTG rats in comparison with control Wistar rats. There was significant positive correlation between blood pressure and plasma triglyceride concentration (r = 0.585, n = 40, p less than 0.001). In addition, there were significantly increased plasma norepinephrine and epinephrine concentrations in HTG rats, suggesting that the stimulation of sympathetic nervous system could be one of the pathogenetic mechanisms involved in the increase of blood pressure of HTG rats.

Abnormalities of carbohydrate and lipid metabolism in Dahl rats

Plasma glucose, insulin, and triglyceride concentration, blood pressure, and insulin action on isolated adipocytes were determined in weight-matched Sprague-Dawley, Dahl salt-resistant, and Dahl salt-sensitive rats. Blood pressure and plasma glucose concentrations were not significantly different in the three groups. However, Dahl salt-sensitive rats had significantly higher plasma insulin (39 +/- 2 microunits/ml) and triglyceride (213 +/- 11 mg/dl) concentrations than did Sprague-Dawley rats (27 +/- 2 microunits/ml and 101 +/- 6 mg/dl, respectively). Values for insulin (34 +/- 4 microunits/ml) and triglyceride (159 +/- 11 mg/dl) were intermediate in Dahl salt-resistant rats. In contrast, maximal insulin-stimulated glucose transport was significantly lower in adipocytes isolated from Dahl salt-sensitive as compared with Sprague-Dawley rats (400 +/- 16 versus 523 +/- 14 fl/cell/sec), with Dahl salt-resistant rats again having intermediate values. However, the ability of insulin to maximally inhibit catecholamine-stimulated lipolysis was similar in all three groups, averaging approximately 20% of the activity present in the absence of insulin. All of these differences were seen when the rats were eating conventional chow and did not change in Dahl rats after 2 weeks of an 8% NaCl diet. On the other hand, the predicted rise in blood pressure took place in Dahl salt-sensitive rats, increasing from 147 +/- 4 to 181 +/- 6 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular risk factors among Asian Americans living in northern California

BACKGROUND

Recent substantial immigration has created large population subsets of Asian Americans in the United States. Available data about cardiovascular risk factors in these persons are sparse.

METHODS

This study examined data among 13,031 persons self-classified as 5951 Chinese, 4211 Filipinos, 1703 Japanese, and 1166 other Asians. Covariates in regression analyses were age, smoking, alcohol, education, and marital status.

RESULTS

Chinese men and women had the lowest adjusted mean body mass index. Filipino men and women had the highest prevalence of hypertension. There were no major differences in blood glucose levels. Total cholesterol levels were highest in Japanese men and women. Comparisons of US-born persons and those born in respective countries of origin showed no major cholesterol or glucose differences; more hypertension only in Chinese and other Asian men; higher body mass index in men, but not in women of most ethnicities; and a lower smoking prevalence in men, but a substantially higher one in women.

CONCLUSIONS

These data show important ethnic differences in risk factors among Asian Americans and indicate groups that should be targeted for public health efforts concerned with obesity (Asian-American men), hypertension (Filipino-American men and women), hypercholesteremia (all Asian Americans), and smoking cessation (Asian-American women).

Abnormalities of carbohydrate and lipoprotein metabolism in patients with hypertension. Relationship to obesity

Patients with untreated hypertension have been shown to be resistant to insulin-stimulated glucose uptake and both hyperinsulinemic and hypertriglyceridemic when compared to matched control groups with normal blood pressure. All of these abnormalities would be accentuated in obese individuals. In addition, insulin resistance, hyperinsulinemia, and hypertriglyceridemia have been demonstrated in rat models of hypertension, including rats with spontaneous hypertension and Sprague-Dawley rats fed a fructose-enriched diet, and the defect in insulin-stimulated glucose uptake in these experimental models can also be shown at the cellular level. Furthermore, experimental interventions that prevent insulin resistance and/or hyperinsulinemia from developing in fructose-fed rats also greatly attenuate the increase in blood pressure. Since endogenous hyperinsulinemia and hypertriglyceridemia have been identified as factors that increase the risk of coronary artery disease, it is likely that they contribute to the increased prevalence of ischemic heart disease in patients with high blood pressure. The fact that past antihypertensive treatment has not focused on these metabolic abnormalities, and, indeed, may have exacerbated them, could help explain why it has been difficult to show that lowering blood pressure decreases risk of coronary artery disease. These observations raise the possibility that abnormalities of carbohydrate and lipoprotein metabolism may play a role in both the etiology and the clinical course of hypertension.

Insulin resistance and compensatory hyperinsulinemia: role in hypertension, dyslipidemia, and coronary heart disease

Resistance to insulin-stimulated glucose uptake and hyperinsulinemia may play a central role in the cause and clinical course of patients with non-insulin-dependent diabetes mellitus, high blood pressure, abnormalities of lipoprotein metabolism, and coronary heart disease. This article summarizes the evidence in support of this general hypothesis.

Insulin resistance, hyperinsulinemia, and hypertriglyceridemia in the etiology and clinical course of hypertension

Patients with untreated hypertension have been shown to be resistant to insulin-stimulated glucose uptake and are more hyperinsulinemic and hypertriglyceridemic than matched groups of patients with normal blood pressure. In addition, insulin resistance, hyperinsulinemia, and hypertriglyceridemia have been demonstrated in spontaneous hypertensive rats and in Sprague-Dawley rats fed a fructose-enriched diet. The defect in insulin-stimulated glucose uptake in these experimental models can also be shown at the cellular level. Experimental interventions that prevent insulin resistance or hyperinsulinemia from developing in fructose-fed rats also greatly attenuate the increase in blood pressure. Since endogenous hyperinsulinemia and hypertriglyceridemia have been identified as factors that increase the risk of coronary artery disease (CAD), it is likely that they contribute to the increased prevalence of CAD in hypertensive patients. Antihypertensive treatment may have exacerbated these metabolic abnormalities, which could help explain why it has been difficult to show that lowering blood pressure decreases the risk of CAD. These observations raise the possibility that abnormalities of carbohydrate and lipoprotein metabolism may play a role in both the etiology and clinical course of hypertension.

Relationship of platelet specific proteins and other factors to atherosclerosis in various stages of hypertension

There is considerable evidence from previous studies that platelets play an important role in the development and progression of atherosclerosis in hypertension, more so in relation to the stage of hypertension. Seventy one hypertensive patients (WHO stage I: 39, stage II: 23, stage III: 9) aged 19-84 (mean age: 56, 59 and 62 respectively for each stage) and 37 normal controls (aged 22-72 with a mean age of 52) were involved in this study. Hematocrit, beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), beta-TG/PF4 ratio, total cholesterol (TC), low density lipoprotein-C, and triglycerides were higher in the hypertensive group while platelet count, circulating platelet aggregates, and high density lipoprotein-C were higher in the normotensive group. Among the hypertensives, stage III patients showed the highest beta-TG, PF4, beta-TG/PF4 ratio, triglycerides, and stage I with the least elevation. There were no significant differences noted in the ADP or epinephrine-induced platelet aggregation in both the normal and hypertensive patients. Other parameters such as heart rate, serum sodium, potassium, renal and liver function tests, plasma renin activity, aldosterone, fibrinogen thromboxane B2 and 6-Keto-PGF1 alpha, showed no significant differences in both groups. This study clearly showed that beta-TG/PF4 ratio and triglycerides are closely related to the stage of hypertension and are good indicators of in vivo platelet activation in hypertensives which may account for the acceleration of hypertensive vascular complications secondary to atherogenesis.

Insulin resistance and hypertension

The author has reviewed the development of the concept that insulin resistance is related not only to the hypertensive state but potentially to the initiation and maintenance of high blood pressure. Potential sequelae of insulin resistance and hyperinsulinemia, as they apply to atherogenesis, are also discussed. The impact of present antihypertensive pharmacologic therapy on insulin resistance is addressed, as are future directions in pharmacologic and nonpharmacologic management of hypertension. In addition, the author speculates on possible mechanisms leading to insulin resistance in hypertension.

Insulin and hypertension

Patients with hypertension have been shown to be resistant to insulin-stimulated glucose uptake and hyperinsulinemic when compared to matched control groups with normal blood pressure. In addition, insulin resistance and hyperinsulinemia have been demonstrated in rat models of hypertension-including SHR rats and Sprague-Dawley rats fed a fructose-enriched diet. Furthermore, fructose-induced hypertension can be attenuated by experimental interventions which decrease insulin resistance and/or hyperinsulinemia. These observations raise the possibility that insulin resistance and hyperinsulinemia may play a role in blood pressure regulation. Finally, insulin resistance and hyperinsulinemia increase risk of coronary artery decrease in patients with hypertension, both directly, and indirectly by their influence on very low density and high density lipoprotein metabolism.

Hypertension as a disease of carbohydrate and lipoprotein metabolism

Patients with untreated hypertension have been shown to be resistant to insulin-stimulated glucose uptake and both hyperinsulinemic and hypertriglyceridemic when compared with matched control groups with normal blood pressure. In addition, insulin resistance, hyperinsulinemia, and hypertriglyceridemia have been demonstrated in rat models of hypertension, including spontaneously hypertensive rats and Sprague-Dawley rats fed a fructose-enriched diet, and the defect in insulin-stimulated glucose uptake in these experimental models can also be shown at the cellular level. Furthermore, experimental interventions that prevent insulin resistance and/or hyperinsulinemia from developing in fructose-fed rats also greatly attenuate the increase in blood pressure. Finally, endogenous hyperinsulinemia and hypertriglyceridemia have been identified as factors that increase the risk of coronary artery disease, and may contribute to the increased prevalence of ischemic heart disease in patients with high blood pressure. The fact that past antihypertensive treatment has not focused on these metabolic abnormalities, and, indeed, may have exacerbated them, could help explain why it has been difficult to show that lowering blood pressure decreases risk of coronary artery disease. These observations raise the possibility that abnormalities of carbohydrate and lipoprotein metabolism may play a role in both the etiology and the clinical course of hypertension.

[Dyslipidemia and some risk factors in the population outside of the metropolitan region of São Paulo, SP-Brazil. A pilot study]

A survey of the prevalence of lipemic disorders and some risk factors associated with them (obesity, hypertension and alcoholism), in a representative sample of the population of 20 years of age and over in a locality typical of the peripheral zone of the Greater S. Paulo Region, Brazil, both in terms of the poverty of the population and with regard to the lack of public sources such as sewage, transport and housing, is undertaken. The following results were obtained: a) the prevalence of one risk factor was about 55%, and of two or more associated risk factors was of approximately 9% in the age group from 20 to 39. There was found to be a prevalence of about 51% and 57%, respectively of two or more associated risk factors for the age groups from 40 to 59 and 60 years of age and over; b) the prevalence of lipemic disorders proper was of about 49%, 58% and 57% respectively, for the age groups of 20 to 39, 40 to 59 and 60 years of age and over. In these cases the most prevalent risk factors among men were alcoholism and hypertension, either isolatedly or associated with obesity, and among women the most prevalent was obesity, alone or associated with hypertension; c) the most prevalent lipemic disorder was due to HDL-cholesterol, mainly among the younger people. The prevalence lower-than-normal HDL-cholesterol, was of about 28% and of "other lipemic disorders" was of 22% in the age group between 20 and 39 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a low fat diet on carbohydrate metabolism in patients with hypertension

Plasma glucose and insulin responses to both a 75-g oral glucose challenge and to conventional meals were determined in eight patients with hypertension and compared with values of a control population. The results indicated that patients with hypertension had significantly higher than normal plasma glucose and insulin concentrations in both situations. Furthermore, when dietary carbohydrate was increased by 16% of total calories (with a reciprocal reduction in dietary fat), the hyperglycemia and hyperinsulinemia present in patients with hypertension were accentuated. Since low fat-high carbohydrate diets are usually recommended for patients with hypertension, these data suggest that abnormalities of glucose and insulin metabolism associated with hypertension would be increased if patients with high blood pressure followed conventional dietary advice. Since hyperglycemia and hyperinsulinemia have been shown to be associated with an increased risk of developing coronary artery disease, it may be appropriate to reevaluate the clinical utility of low fat-high carbohydrate diets in the treatment of hypertension.