Hans Lithell

A Comparison of the Effects of Hydrochlorothiazide and Captopril on Glucose and Lipid Metabolism in Patients with Hypertension

It has been suggested that the metabolic side effects of antihypertensive drugs are responsible for their failure to reduce cardiovascular morbidity in patients with hypertension. Therefore, in 50 patients with essential hypertension, we performed a randomized, double-blind, crossover study comparing the effects of carbohydrate and lipid metabolism of captopril (mean [+/- SD] dose, 81 +/- 24 mg per day) and hydrochlorothiazide (40 +/- 12 mg per day) over two four-month treatment periods. Captopril increased the insulin-mediated disposal of glucose, as compared with placebo, from 5.7 +/- 2.4 to 6.3 +/- 2.5 mg per kilogram of body weight per minute (P less than 0.05), whereas hydrochlorothiazide caused a decrease from 6.4 +/- 2.0 to 5.7 +/- 1.9 (P less than 0.01). Captopril had no effect on the basal insulin concentration, but it decreased the late (30- to 90-minute) insulin response to glucose and increased the early (2- to 6-minute) insulin peak. Hydrochlorothiazide increased the basal insulin concentration and the late insulin response to glucose. These findings may be explained by an increase in insulin sensitivity with captopril and a decrease with hydrochlorothiazide. Little or no change was seen in serum lipid or lipoprotein levels during treatment with captopril, whereas hydrochlorothiazide caused significant increases in serum total (5 percent) and low-density lipoprotein (6 percent) cholesterol levels and total (15 percent) and very-low-density lipoprotein (25 percent) triglyceride levels, as compared with placebo (P less than 0.01 for all comparisons). We conclude that hydrochlorothiazide for the treatment of essential hypertension has adverse effects on glucose and lipid metabolism. It is possible, but not proved in this study, that these changes may contribute to the risk for diabetes mellitus and coronary heart disease. In contrast, captopril appears to have beneficial or no effects on glucose and lipid metabolism.

Reduced fetal growth rate and increased risk of death from ischaemic heart disease: cohort study of 15 000 Swedish men and women born 1915-29.

Abstract Objective: To establish whether fetal growth rate (as distinct from size at birth) is associated with mortality from ischaemic heart disease. Design: Cohort study based on uniquely detailed obstetric records with 97% follow up over the entire life course and linkage to census data in adult life. Subjects: All 14 611 babies delivered at the Uppsala Academic Hospital, Sweden, during 1915-29 followed up to end of 1995. Main outcome measures: Mortality from ischaemic heart disease and other causes. Results: Cardiovascular disease showed an inverse association with birth weight for both men and women, although this was significant only for men. In men a 1000 g increase in birth weight was associated with a proportional reduction in the rate of ischaemic heart disease of 0.77 (95% confidence interval 0.67 to 0.90). Adjustment for socioeconomic circumstances at birth and in adult life led to slight attenuation of this effect. Relative to the lowest fourth of birth weight for gestational age, mortality from ischaemic heart disease in men in the second, third, and fourth fourths was 0.81 (0.66 to 0.98), 0.63 (0.50 to 0.78), and 0.67 (0.54 to 0.82), respectively. The inclusion of birth weight per se and birth weight for gestational age in the same model strengthened the association with birth weight for gestational age but removed the association with birth weight. Conclusions: This study provides by far the most persuasive evidence of a real association between size at birth and mortality from ischaemic heart disease in men, which cannot be explained by methodological artefact or socioeconomic confounding. It strongly suggests that it is variation in fetal growth rate rather than size at birth that is aetiologically important.

Relation of size at birth to non-insulin dependent diabetes and insulin concentrations in men aged 50-60 years

Abstract Objective: To establish whether the relation between size at birth and non-insulin dependent diabetes is mediated through impaired β cell function or insulin resistance. Design: Cohort study. Setting: Uppsala, Sweden. Subjects: 1333 men whose birth records were traced from a cohort of 2322 men born during 1920-4 and resident in Uppsala in 1970. Main outcome measures: Intravenous glucose tolerance test at age 50 years and non-insulin dependent diabetes at age 60 years. Results: There was a weak inverse correlation (r=-0.07, P=0.03) between ponderal index at birth and 60 minute insulin concentrations in the intravenous glucose tolerance test at age 50 years. This association was stronger (r=-0.19, P=0.001) in the highest third of the distribution of body mass index than in the other two thirds (P=0.01 for the interaction between ponderal index and body mass index). Prevalence of diabetes at age 60 years was 8% in men whose birth weight was less than 3250 g compared with 5% in men with birth weight 3250 g or more (P=0.08; 95% confidence interval for difference −0.3% to 6.8%). There was a stronger association between diabetes and ponderal index: prevalence of diabetes was 12% in the lowest fifth of ponderal index compared with 4% in the other four fifths (P=0.001; 3.0% to 12.6%). Conclusion: These results confirm that reduced fetal growth is associated with increased risk of diabetes and suggest a specific association with thinness at birth. This relation seems to be mediated through insulin resistance rather than through impaired β cell function and to depend on an interaction with obesity in adult life.

Insulin resistance is a characteristic feature of primary hypertension independent of obesity

The relationship between abnormalities in carbohydrate metabolism and hypertension was studied in 143 newly detected hypertensive patients (59% obese) of both sexes (90 males, 53 females) and compared with 51 normotensive controls. Insulin-mediated glucose disposal assessed with the euglycemic insulin clamp technique was significantly decreased in both non-obese (7.2 +/- 2.1 mg/kg/min; P less than .05) and obese hypertensives (5.1 +/- 2.1 mg/kg/min; P less than .01) compared with the controls (8.4 +/- 1.8 mg/kg/min). The decrease in insulin sensitivity and increase in basal insulin as well as a decreased rate of glucose disposal after an intravenous glucose tolerance test (IVGTT) were verified also after statistical adjustment for sex, age, body mass index, and waist-hip ratio. The insulin index (ratio between peak and basal insulin) during IVGTT was significantly decreased in the hypertensive patients (P less than .001). After the statistical adjustment for the factors mentioned the following lipid abnormalities were still significant: total cholesterol (6.25 +/- 1.12 mmol/L non-obese; 6.06 +/- 1.20 mmol/L obese; 5.41 +/- 1.02 mmol/L controls), triglycerides (1.70 +/- 0.74 mmol/L nonobese; 2.26 +/- 1.13 mmol/L obese; 1.24 +/- 0.53 mmol/L controls) and free fatty acids (0.57 +/- 0.20 mmol/L nonobese; 0.59 +/- 0.20 mmol/L obese; 0.48 +/- 0.15 mmol/L controls). This study shows that after correction for a series of probable confounding variables, hypertension emerges as part of a syndrome characterized by major abnormalities of carbohydrate, insulin, and lipid metabolism, which independently or in concert may act as important risk factors for cardiovascular disease.

Failure to realise growth potential in utero and adult obesity in relation to blood pressure in 50 year old Swedish men

Abstract Objectives: To clarify the type of fetal growth impairment associated with increased blood pressure in adult life, and to establish whether this association is influenced by obesity and is mediated through impairment of insulin action. Design: Cross sectional survey with retrospective ascertainment of size at birth from obstetric archives. Subjects: 1333 men resident in Uppsala, Sweden, who took part in a 1970 study of coronary risk factors at age 50 and for whom birth weight was traced. Main outcome measures: Systolic and diastolic blood pressure at age 50. Results: In the full study population for a 1000 g increase in birth weight there was a small change in systolic blood pressure of −2.2 mm Hg (95% confidence interval −4.2 to −0.3 mm Hg) and in diastolic blood pressure of −1.0 mm Hg (−2.2 to 0.1 mm Hg). Much stronger effects were observed among men who were born at term and were in the top third of body mass index at age 50, for whom a 1000 g increase in birth weight was associated with a change of −9.1 mm Hg (−16.4 to −1.9 mm Hg) systolic and −4.2 mm Hg (−8.3 to −0.1 mm Hg) diastolic blood pressure. Men who were light at birth (<3250 g) but were of above median adult height had particularly high blood pressure. Adjustment for insulin concentrations reduced the associations of birth weight with systolic and diastolic blood pressure. Conclusions: A failure to realise growth potential in utero (as indicated by being light at birth but tall as an adult) is associated with raised adult blood pressure. Impaired fetal growth may lead to substantial increases in adult blood pressure among only those who become obese. Metabolic disturbances, possibly related to insulin resistance, may provide a pathway through which fetal growth affects blood pressure.

Clinical value of the metabolic syndrome for long term prediction of total and cardiovascular mortality : prospective, population based cohort study

Abstract Objectives To find out if the presence of the metabolic syndrome increases the risk of subsequent total and cardiovascular mortality, taking into account established risk factors for cardiovascular disease. Design Prospective cohort study. Setting General population. Participants A community based sample of 2322 men followed since 1970 for a maximum of 32.7 years, investigated at ages 50 and 70. Main outcome measures The relations of the metabolic syndrome defined by the national cholesterol education programme (NCEP) of the US National Heart, Lung, and Blood Institute or criteria of the World Health Organization (WHO) to subsequent total and cardiovascular mortality. Results When adding the metabolic syndrome to models with established risk factors for cardiovascular disease (smoking, diabetes, hypertension, and serum cholesterol) at age 50, presence of the metabolic syndrome as defined in the NCEP significantly predicted total and cardiovascular mortality (Cox proportional hazard ratios 1.36, 95% confidence interval 1.17 to 1.58; and 1.59, 1.29 to 1.95, respectively). The metabolic syndrome added prognostic information to that of the established risk factors for cardiovascular disease (likelihood ratio tests, P < 0.0001 for both outcomes). Similar results were obtained in a subsample without diabetes or manifest cardiovascular disease. Conclusions In a large, community based sample of middle aged men, the presence of the metabolic syndrome according to the definition of the NCEP gave long term prognostic information regarding total and cardiovascular mortality if the status of established risk factors for cardiovascular disease was known. If confirmed this may indicate clinical value in diagnosing the metabolic syndrome.

Isolated ambulatory hypertension predicts cardiovascular morbidity in elderly men.

Background—Little is known about isolated ambulatory hypertension, a state with elevated ambulatory but normal office blood pressure (BP). This study aimed to investigate the prognostic significance of isolated ambulatory hypertension for cardiovascular morbidity in a population of elderly men. Methods and Results—At baseline, 24-hour ambulatory BP and metabolic and cardiac risk profiles were evaluated in 578 untreated 70-year-old men, participants of a population-based cohort. Subjects with isolated ambulatory hypertension (office BP <140/90 and daytime BP ≥135/85) and sustained hypertension (office BP ≥140/90 and daytime BP ≥135/85) had increased plasma glucose, body mass index, and echocardiographically determined left ventricular relative wall thickness compared with normotensive subjects (office BP <140/90 and daytime BP <135/85). Seventy-two cardiovascular morbid events (2.37 per 100 person-years at risk) occurred over 8.4 years of follow-up. The prognostic value of isolated ambulatory and sustained hypertension was assessed with Cox proportional hazard regression. Multivariate models adjusting for serum cholesterol, smoking, and diabetes demonstrated that both isolated ambulatory hypertension (hazard ratio [HR], 2.77; 95% CI, 1.15 to 6.68) and sustained hypertension (HR, 2.94; 95% CI, 1.49 to 5.82) were independent predictors of cardiovascular morbidity. In a multivariate model with continuous BP variables, ambulatory daytime systolic BP (HR for 1 SD increase, 1.47; 95% CI, 1.09 to 1.97) was associated with an adverse outcome independently of office systolic BP. Conclusions—In the present study, isolated ambulatory hypertension as well as sustained hypertension predicted cardiovascular morbidity. The findings suggest that 24-hour ambulatory BP monitoring may disclose important prognostic information also in subjects characterized as normotensive according to office BP.

Insulin sensitivity is related to the fatty acid composition of serum lipids and skeletal muscle phospholipids in 70-year-old men.

SummaryRecent data indicate that peripheral insulin sensitivity may be influenced by dietary fat quality and skeletal muscle phospholipid fatty acid composition. During a health survey of 70-year-old men insulin sensitivity was measured by the euglycaemic hyperinsulinaemic clamp technique and the fatty acid composition of the serum cholesterol esters was determined (n=215) by gas liquid chromatography. In a subsample the fatty acids of the skeletal muscle phospholipids and triglycerides were determined after fine needle biopsy from m. vastus lateralis (n=39). The peripheral insulin sensitivity was significantly and negatively correlated to the proportion of palmitic (r=−0.31, p<0.001), palmitoleic (r=−0.25, p<0.001) and di-homo-γ-linolenic (r=−0.33, p<0.001) acids and positively to the content of linoleic (r=0.28, p<0.001) acid in the serum cholesterol esters. There was an even stronger negative relationship to the proportion of palmitic acid in the skeletal muscle phospholipds (r=−0.45, p<0.004). The fatty acid composition was also significantly related to insulin sensitivity in a stepwise multiple regression analysis in the presence of other clinical variables, which were associated with insulin action in univariate analysis. Thus, more than 51% of the variation of the insulin sensitivity was explained by an equation containing body mass index, serum triglyceride concentration and the content of palmitic acid in the skeletal muscle phospholipids. It is concluded that the fatty acid composition in serum and of the phospholipids of skeletal muscle may influence insulin action in elderly men.

Effect of Antihypertensive Drugs on Insulin, Glucose, and Lipid Metabolism

The close relationship between diabetes and hypertension has been recognized for decades. New information indicates that resistance to insulin action on glucose uptake in peripheral tissues is a common underlying mechanism in hypertension and diabetes. In prospective trials, the effects of antihypertensive agents on insulin sensitivity and lipoprotein metabolism have been evaluated. Both β-blockers and thiazide diuretics worsen insulin resistance and deteriorate lipoprotein metabolism. Angiotensin-converting enzyme (ACE) inhibitors, Ca2+ -channel blockers, and α-blockers are neutral or improve these factors. These data may explain the unexpectedly high incidence of the development of diabetes among treated hypertensives and the poor effect on risk for coronary heart disease in intervention trials.

Application of prazosin is associated with an increase of insulin sensitivity in obese patients with hypertension

SummaryThe aim of this study was to determine whether insulin sensitivity measured by the euglycaemic insulin clamp technique is lower in patients with primary hypertension than in matched healthy control subjects, and whether this sensitivity was affected after 12 weeks of antihypertensive treatment with the alpha 1-adrenoceptor blocking drug prazosin. Twelve moderately obese normoglycaemic patients (four men), with hypertension not previously treated with pharmacological agents and diastolic blood pressure above 100 mm Hg, and 12 healthy matched control subjects participated. Supine blood pressure decreased 12/5 mmHg (p<0.01) and standing blood pressure 14/9 mmHg (p=0.001) during prazosin treatment (mean dosage 5.3±1.6 mg/day (SD)). During euglycaemic insulin clamp studies the control subjects showed a higher mean glucose uptake than the untreated hypertensive patients (7.5±1.0 and 5.8±1.9 mg·kg b.w.−1·min−1, respectively, p<0.01). During prazosin treatment there was no significant difference between the hypertensive patients and the control subjects in this respect (6.6±2.8 and 7.5±1.0, respectively, p=0.21). During prazosin treatment, however, the disappearance rate of glucose decreased during the intravenous glucose tolerance test (from 1.7±0.9 to 1.3±0.6, p<0.02) and the area under the glucose concentration-time curve decreased by 38% (from 473±119 to 294±99, p<0.001). The peak insulin concentration decreased from 55±35 to 46±32 mU/l (p<0.006) and the area under the insulin concentration-time curve was suppressed by 38% (from 2368±1597 to 1479±940, p<0.01). This study shows that treatment of moderately obese hypertensive patients with prazosin is associated with an increase of the insulin-mediated glucose disposal and a decrease of the insulin response to an intravenous glucose load.