Biomedical subjects

R J Prineas

Publications and source records attributed to R J Prineas.

At least 19 recordsLinked to original sources

PubMed1999

Relation of weight and rate of increase in weight during childhood and adolescence to body size, blood pressure, fasting insulin, and lipids in young adults. The Minneapolis Children's Blood Pressure Study.

BACKGROUND: Weight gain is of concern during early development because adult obesity and its cardiovascular consequences appear to have their origins during childhood. Insulin resistance is known to be related to obesity. Thus, weight gain beginning in childhood may influence the development of insulin-induced cardiovascular risk during adulthood. METHODS AND RESULTS: We monitored 679 individuals from 7.7+/-0.1 years of age with repeated measures of height, weight, and systolic blood pressure (SBP) until 23.6+/-0.2 years of age, when blood samples were obtained for measurements of insulin and lipids. Initial childhood weight, body mass index (BMI), and height were significantly correlated with young adult weight, BMI, and height and with fasting insulin, lipids, and SBP. The increases in weight and BMI but not height during childhood were significantly related to the young adult levels of insulin, lipids, and SBP. CONCLUSIONS: These data suggest that weight gain in excess of normal growth during childhood is a determinant of adult cardiovascular risk. The finding in multiple linear regression analysis that weight gain during childhood rather than the childhood weight at 7.7 years of age is significantly related to young adult risk factors suggests that a reduction in weight gain could reduce subsequent levels of cardiovascular risk.

Adolescent↗

PubMed1999

Association of nonspecific minor ST-T abnormalities with cardiovascular mortality: the Chicago Western Electric Study.

CONTEXT: Minor electrocardiographic (ECG) ST-T abnormalities are common, but their prognostic importance has not been fully determined. OBJECTIVE: To examine associations of single (1 time only) and multiple (2 times only and > or =3 times) nonspecific minor ST-T abnormalities in 5 years with long-term mortality due to myocardial infarction (MI), coronary heart disease (CHD), cardiovascular disease (CVD), and all causes in middle-aged men. DESIGN: Prospective cohort study (29-year follow-up after 5 annual examinations). SETTING AND PARTICIPANTS: A total of 1673 men employed at the Western Electric Company in Chicago, III, aged 40 to 55 years at entry, with no evidence of CHD and no major ECG abnormalities throughout the first 5-year period. MAIN OUTCOME MEASURES: Minor ST-T abnormalities identified from annual resting ECGs and mortality ascertained from death certificates. RESULTS: Of the 1673 men, 173 had evidence of isolated nonspecific minor ST-T segment abnormalities. During the follow-up period, there were 234 deaths due to MI, 352 deaths due to CHD, 463 deaths due to CVD, and 889 deaths due to all causes. For men with 3 or more annual recordings of minor ST-T abnormalities, risk of death due to MI, CHD, CVD, and all causes was significantly greater than for those with normal ECG findings. For men with 3 or more ECGs with minor ST-T abnormalities, relative risks (and 95% confidence intervals) adjusted for cardiovascular and other risk factors were 2.28 (1.16-4.49), 2.39 (1.39-4.12), 2.30 (1.44-3.68), and 1.60 (1.06-2.42), respectively, with a graded relationship between frequency of occurrence of ST-T abnormalities and mortality risk (linear trend, P< or =.007). CONCLUSIONS: Persistent, minor, nonspecific ST-T abnormalities are associated with increased long-term risk of mortality due to MI, CHD, CVD, and all causes; the higher the frequency of occurrence of minor ST-T abnormalities, the greater the risk. These data underscore the potential value of including nonspecific ECG findings in the overall assessment of cardiovascular risk.

Adult↗

PubMed1999

Cigarette smoking, alcohol use, and physical activity in relation to serum leptin levels in a multiethnic population: The Miami Community Health Study.

PURPOSE: To examine the correlates of plasma leptin, including fasting insulin, adiposity, and several health habits and behaviors among a nondiabetic multiethnic population. METHODS: A cross-sectional study was conducted among 25-44 year old African-Americans (n = 126), Cuban-Americans (n = 107), and non-Hispanic whites (n = 189) randomly selected from Dade County Florida. Fasting leptin levels were correlated with fasting insulin, percent body fat, smoking, alcohol use, and physical activity within each sex. Multiple linear regression and analysis of covariance were used to estimate the independent determinants of plasma leptin concentration separately among men and women. RESULTS: Stepwise linear regression analyses revealed statistically significant associations of leptin with percent body fat, fasting insulin, cigarette smoking, and physical activity (both inversely) among men (p < 0.05 for each). Among women, percent body fat, fasting insulin (both positively), cigarette smoking, and alcohol use (inversely) were independent predictors of leptin levels explaining over 70% of the variance. Analyses of covariance revealed that women had higher adjusted mean leptin levels than men (13.1 ng/ml vs. 5.9 ng/ml; p < 0.001), whereas no separate effect of ethnicity was noted. CONCLUSIONS: Although adiposity was the strongest correlate of leptin levels, fasting insulin and several health habits and behaviors were independently associated with leptin. After adjustment for these factors, women had significantly higher mean leptin levels than men. The independent association among leptin and insulin levels is intriguing and suggests additional avenues for epidemiologic research.

Adult↗

PubMed1998

The relation of fasting insulin to blood pressure in a multiethnic population: the Miami Community Health Study.

PURPOSE: The aim of this study was to examine the associations among fasting insulin, adiposity, waist girth, and blood pressure among a nondiabetic multiethnic population. METHODS: A cross-sectional study was performed among 25-44-year-old African-Americans (n = 159), Cuban-Americans (n = 128), and non-Hispanic whites (n = 207) selected from Dade County, Florida. Fasting insulin levels were correlated with resting blood pressure level within each ethnic group. The separate effects of percentage body fat and waist girth on the association between blood pressure and insulin were analyzed in multiple linear regression and analysis of covariance. RESULTS: Fasting insulin was positively associated with systolic (r = 0.26-0.39; P < 0.01) and diastolic blood pressure (r = 0.19-0.30; P = 0.10 to P < 0.001) among women of all ethnic groups and among non-Hispanic white men (r = 0.27; P < 0.05). Stepwise linear regression analyses revealed statistically significant associations between systolic and diastolic blood pressure and fasting insulin level in non-Hispanic whites independent of other covariates, including sex and percentage body fat (P < 0.001). Fasting insulin was also independently and significantly related to systolic blood pressure among African-Americans (P = 0.02). Among Cuban-Americans, sex and percentage body fat were the main correlates of blood pressure level. Analysis of covariance revealed a relationship between insulin and blood pressure that was independent of waist girth among men and women. CONCLUSIONS: Fasting insulin level and blood pressure were positively associated among African-Americans and non-Hispanic whites. This association was not entirely due to the common association with percentage body fat or waist girth.

Adipose Tissue↗

PubMed1998

Findings from the American College of Epidemiology's survey on Ethics guidelines. The American College of Epidemiology Ethics and Standards of Practice Committee.

PURPOSE: A survey to establish both the need and subject areas for a possible new set of ethics guidelines for epidemiologists was conducted among a random sample of 300 North American (Canada, Mexico, and United States) members of three major United States-based professional epidemiology organizations. METHODS: An 88% response rate revealed wide agreement on topics to be included in any new set of guidelines, but uncertainty prevailed about the need for new guidelines; 41% agreed that there was a need to develop a new set, 43% had no opinion, and 16% disagreed. RESULTS: There was almost no difference in preferences between men and women for topics to be included in a new set of guidelines, or between those aware or unaware of extant ethics guidelines in epidemiology. Fifty-four percent were aware of such guidelines and only 29% of these said they could describe the content of the guidelines. CONCLUSION: More needs to be done to evaluate the utility of ethics codes in epidemiology.

Data Collection↗

PubMed1998

Reduction of cardiovascular disease: what is the role of the pediatrician?

It is apparent from the results of the 1995 and 1998 surveys reported by Kimm et al in this issue of Pediatrics that pediatricians are interested in blood pressure and lipids but uncertain about the management of these coronary heart disease (CHD) risk factors. Data from longitudinal epidemiologic studies initiated in pediatric cohorts support the important role for pediatricians in the detection of children at risk for CHD, and detection should be followed by effective intervention/treatment programs. However, the latter may be difficult in most office practices, because of the intensive effort by specialized personnel required to successfully reduce CHD risk.

Cardiovascular Diseases↗

PubMed1997

Heart rate adjustment of exercise-induced ST-segment depression identifies men who benefit from a risk factor reduction program.

BACKGROUND: Whether subjects identified as being at increased risk of coronary heart disease (CHD) death by heart rate adjustment of exercise-induced ST-segment depression will benefit from therapy aimed at reducing risk factors has not been examined. METHODS AND RESULTS: Exercise ECGs were performed in 11,880 men from the Usual Care (UC) and Special Intervention (SI) groups of the Multiple Risk Factor Intervention Trial. UC men were referred to customary sources of care in the community; SI men received counseling on smoking cessation and dietary reduction of cholesterol, and stepped-care therapy for hypertension. An abnormal ST-segment response to exercise was defined according to standard criteria as > or = 100 microV of additional horizontal or downsloping ST-segment depression and by an ST-segment/heart rate (ST/HR) index >1.60 microV/bpm. After 7 years of follow-up, CHD mortality was significantly lower in SI than UC men with an abnormal ST/HR index (2.4%, 19/786 versus 5.3%, 39/729, P=.005) but was comparable in SI and UC men with a normal ST/HR index (1.6%, 84/5154 versus 1.3%, 70/5211, P=NS). Risk reduction in SI men with an abnormal ST/HR index was independent of age and other cardiac risk factors. In contrast, there was no significant difference in CHD death rate between the smaller groups of SI and UC men with an abnormal test by standard criteria (3.6%, 7/192 versus 2.7%, 5/186, P=NS). CONCLUSIONS: An abnormal ST/HR index identifies men in whom therapy aimed at reducing CHD risk factors reduces the risk of CHD death by 61%. These findings support the application of heart rate adjustment of ST depression for screening of asymptomatic subjects at increased risk of CHD to identify those who will benefit most from risk factor-reduction programs.

Adult↗

PubMed1997

Prognostic associations of Minnesota Code serial electrocardiographic change classification with coronary heart disease mortality in the Multiple Risk Factor Intervention Trial.

A central requirement for epidemiologic studies and clinical trials is a bias-free, objective determination of cardiac incidence rates between comparison groups. Epidemiologic studies and clinical trials frequently use changes in the Minnesota Code to document incident ischemic events. An electrocardiographic (ECG) classification system was developed to document significant ECG pattern change using objective comparison rules for side-by-side annual ECG comparison. Previously, we showed that major evolving Q waves were strongly and independently associated with total and coronary disease mortality. Using baseline-to-annual ECG comparisons in the Multiple Risk Factor Intervention Trial, we evaluated major evolving Q waves, minor evolving Q waves combined with major evolving ST-T waves and major evolving ST-T waves alone for their prognostic associations with coronary, cardiovascular, and total mortality during 16 years of follow-up. The 16-year coronary mortality rate in men with evolving minor Q waves plus evolving ST-T waves had an average adjusted relative risk of 4, equivalent to that of a major evolving Q wave. These risk ratios held whether a clinical infarction had occurred. Silent evolving ST-T waves without Q-wave change had an average adjusted relative coronary mortality risk of 1.6. Serial comparison methodology documents additional incident ischemic ECG events beyond the traditional major Minnesota Q-code change used in older epidemiologic studies. The procedure is standardized, quantitative, and repeatable. It is applicable for any study, present or past, that used Minnesota coding. The method is also well suited for incorporation in computer analysis programs.

Adult↗

PubMed1997

Relationships of quality-of-life measures to long-term lifestyle and drug treatment in the Treatment of Mild Hypertension Study.

OBJECTIVES: To compare 5 antihypertensive drugs and placebo for changes in quality of life (QL). To assess the relationship of lifestyle factors and change in lifestyle factors to QL in participants with stage I diastolic hypertension. METHODS: The Treatment of Mild Hypertension Study (TOMHS) was a randomized, double-blind, placebo-controlled clinical trial with minimum participant follow-up of 4 years. It was conducted at 4 hypertension screening and treatment academic centers in the United States. The cohort consisted of 902 men and women with hypertension, aged 45 to 69 years, with diastolic blood pressures less than 100 mm Hg. Informed consent was obtained from each participant after the nature of the procedures had been fully explained. Sustained nutritional-hygienic intervention was administered to all participants to reduce weight, to reduce dietary sodium and alcohol intake, and to increase physical activity. Participants were randomized to take (1) acebutolol (n = 132); (2) amlodipine maleate (n = 131); (3) chlorthalidone (n = 126); (4) doxazosin mesylate (n = 134); (5) enalapril maleate (n = 135); or placebo (n = 234). Changes in 7 QL indexes were assessed based on a 35-item questionnaire: (1) general health; (2) energy or fatigue; (3) mental health; (4) general functioning; (5) satisfaction with physical abilities; (6) social functioning; and (7) social contacts. RESULTS: At baseline, higher QL was associated with older age, more physical activity, lower obesity level, male gender, non-African American race, and higher educational level. Improvements in QL were observed in all randomized groups, including the placebo group during follow-up; greater improvements were observed in the acebutolol and chlorthalidone groups and were evident throughout follow-up. The amount of weight loss, increase in physical activity, and level of attained blood pressure control during follow-up were related to greater improvements in QL. CONCLUSIONS: In patients with stage I hypertension, antihypertensive treatment with any of 5 agents used in TOMHS does not impair QL. The diuretic chlorthali-done and the cardioselective beta-blocker acebutolol appear to improve QL the most. Success with lifestyle changes affecting weight loss and increase in physical activity relate to greater improvements in QL and show that these interventions, in addition to contributing to blood pressure control, have positive effects on the general well-being of the individual.

Aged↗

PubMed1997

Nutrition and other risk factors for renal cell carcinoma in postmenopausal women.

Among 35,192 postmenopausal, predominantly white women in Iowa age 55-69 years and free of cancer, we collected baseline history, dietary information, and anthropometric data by mail in 1986. We ascertained the 8-year incidence (62 new cases) of renal cell carcinoma using the Iowa Surveillance, Epidemiology, and End Results (SEER) register, the National Death Index, and mail follow-up. Risk factors for renal cell carcinoma included increasing age, increasing weight (either current, maximum adult weight, or weight at ages 18, 30, or 50 years), greater waist-to-hip ratio, and a history of blood transfusion. Total dietary calcium was associated independently with a reduced risk of renal cell carcinoma. No other dietary micro- or macronutrients or food groups were predictive of the development of renal cell carcinoma. Other previously identified risk factors were not confirmed: most notably, there was no increased risk from a history of hypertension, after adjustment for diuretic use. History of ever-use of diuretics was associated with a twofold increased risk of renal cancer, although the strength of association was markedly reduced after adjustment for age, weight, waist-to-hip ratio, and calcium intake.

Adult↗

PubMed1997

Does insulin resistance unite the separate components of the insulin resistance syndrome? Evidence from the Miami Community Health Study.

A number of coronary heart disease risk factors have been identified that often cluster together to increase the risk of macrovascular disease. This cluster is referred to as the insulin resistance syndrome, and the risk factors commonly include dyslipidemia, elevated blood pressure, an android pattern of body fat distribution, and glucose intolerance. Whether hyperinsulinemia or insulin resistance per se provides a common pathway for these metabolic abnormalities is unclear. The authors studied 50 nondiabetic persons who had completed a euglycemic hyperinsulinemic clamp protocol in addition to a 75-g oral glucose tolerance test and other measures of the coronary risk profile. Using principal-component analysis, we reduced nine coronary risk factors to two uncorrelated factors that explained 54.5% of the variance. Factor 1 consisted of positive loadings for uric acid, systolic and diastolic blood pressure, triglyceride concentration, and waist girth and negative loadings for HDL cholesterol and the rate of insulin-mediated glucose disposal (M, in milligrams per kilogram of body weight per minute). M also loaded on factor 2, along with fasting insulin and glucose concentrations, diastolic blood pressure, and waist girth. The observation that M loaded on both factors suggests that a resistance to insulin action may provide the mechanism uniting the features of the insulin resistance syndrome. Hyperinsulinemia with concomitant insulin resistance may be necessary to produce this metabolic derangement, as well as the increased risk of macrovascular complications.

Adult↗

PubMed1997

Long-term effects on sexual function of five antihypertensive drugs and nutritional hygienic treatment in hypertensive men and women. Treatment of Mild Hypertension Study (TOMHS)

Problems with sexual function have been a long-standing concern in the treatment of hypertension and may influence the choice of treatment regimens and decisions to discontinue drugs. The Treatment of Mild Hypertension Study (TOMHS) provides an excellent opportunity for examination of sexual function and effects of treatment on sexual function in men and women with stage I diastolic hypertension because of the number of drug classes studied, the double-blind study design, and the long-term follow-up. TOMHS was a double-blind, randomized controlled trial of 902 hypertensive individuals (557 men, 345 women), aged 45 to 69 years, treated with placebo or one of five active drugs (acebutolol, amlodipine maleate, chlorthalidone, doxazosin maleate, or enalapril maleate). All participants received intensive lifestyle counseling regarding weight loss, dietary sodium reduction, alcohol reduction (for current drinkers), and increased physical activity. Sexual function was ascertained by physician interviews at baseline and annually during follow-up. At baseline, 14.4% of men and 4.9% of women reported a problems with sexual function. In men, 12.2% had problems obtaining and/or maintaining an erection; 2.0% of women reported a problem having an orgasm. Erection problems in men at baseline were positively related to age, systolic pressure, and previous antihypertensive drug use. The incidences of erection dysfunction during follow-up in men were 9.5% and 14.7% through 24 and 48 months, respectively, and were related to type of antihypertensive therapy. Participants randomized to chlorthalidone reported a significantly higher incidence of erection problems through 24 months than participants randomized to placebo (17.1% versus 8.1%, P = .025). Incidence rates through 48 months were more similar among treatment groups than at 24 months, with nonsignificant differences between the chlorthalidone and placebo groups. Incidence was lowest in the doxazosin group but was not significantly different from the placebo group. Incidence for acebutolol, amlodipine, and enalapril groups was similar to that in the placebo group. In many cases, erection dysfunction did not require withdrawal of medication. Disappearance of erection problems among men with problems at baseline was common in all groups but greatest in the doxazosin group. Incidence of reported sexual problems in women was low in all treatment groups. In conclusion, long-term incidence of erection problems in treated hypertensive men is relatively low but is higher with chlorthalidone treatment. Effects of erection dysfunction with chlorthalidone appear relatively early and are often tolerable, and new occurrences after 2 years are unlikely. The rate of reported sexual problems in hypertensive women is low and does not appear to differ by type of drug. Similar incidence rates of erection dysfunction in placebo and most active drug groups caution against routine attribution of erection problems to antihypertensive medication.

Acebutolol↗

PubMed1997

Relation of fasting insulin to blood pressure and lipids in adolescents and parents.

This study was intended to clarify the relation between fasting insulin, lipids, and blood pressure in adolescents before the onset of hypertension and to examine the association of these data with similar data obtained in their parents. The participants in this study were 183 adolescents 14 to 18 years old (96 girls) completing a 4-year intervention trial and their parents (164 mothers, 122 fathers). Blood pressure was measured twice on the right arm in a seated position using a random-zero sphygmomanometer. Fasting blood samples were obtained for lipid and insulin analyses. Fasting insulin was significantly correlated with systolic blood pressure in the adolescents and also in the parents before and after adjustment for body mass index. Fasting insulin was correlated significantly with levels of cholesterol, triglycerides, and HDL and LDL cholesterol in the adolescents. It was correlated only with triglycerides and HDL-cholesterol in mothers and fathers. After adjustment for body mass index, the correlations between fasting insulin and lipids in the children were not significant. A significant relation was shown between children's systolic blood pressure and mothers' fasting insulin and systolic blood pressure. Significant correlations were found between the children's and fathers' triglycerides and HDL-cholesterol, whereas significant correlations were found for fasting insulin and all lipids between mothers and children, and these remained significant after adjustment for body mass index. These results show (1) a significant relation between fasting insulin and both lipids and systolic blood pressure in adolescents and (2) a significant relation for these factors between adolescents and their parents. Although weight appears to play an important role in this relation during adolescence, genetic and environmental factors other than those mediated via weight may control insulin metabolism within families. The data support a role for studies during early biological development to address these issues.

Adolescent↗

PubMed1997

Insulin response in a triethnic population: effects of sex, ethnic origin, and body fat. Miami Community Health Study.

OBJECTIVE: To assess sex and ethnic differences in hyperinsulinemia/insulin resistance and to examine the impact of percent body fat on such differences. RESEARCH DESIGN AND METHODS: A cross-sectional epidemiological study was performed in a normoglycemic population of African-Americans (n = 159), Cuban Americans (n = 128), and non-Hispanic whites (n = 207) who resided in Dade County, Florida, from 1990 to 1995. The insulin area under the curve (AUC) in response to a standard 75-g oral glucose tolerance test (OGTT) was used as an indicator of hyperinsulinemia/insulin resistance. Analysis of covariance was performed to compare sex and ethnic differences in the insulin AUC. Multiple linear regression was used to evaluate the independent correlates of the insulin AUC. RESULTS: After covariate adjustment for percent body fat, men displayed a significantly higher insulin AUC than did women (P < 0.001). African-Americans and Cuban-Americans each had a significantly higher insulin AUC than did non-Hispanic white participants (P = 0.01). Alcohol consumption was inversely related to AUC (P = 0.04). CONCLUSIONS: Despite the greater percentage of body fat in women, the insulin AUC was similar in women and men. After adjustment for the sex difference in percent body fat, women displayed a lower insulin AUC than did men, indicating enhanced insulin sensitivity. These differences by sex and ethnicity in insulin resistance are consistent with established differences in heart-disease risk (i.e., higher in men and African-Americans) and suggest that hyperinsulinemia/insulin resistance may partly underlie such differences.

Adult↗

PubMed1996

Dietary antioxidant vitamins and death from coronary heart disease in postmenopausal women.

BACKGROUND: The role of dietary antioxidant vitamins in preventing coronary heart disease has aroused considerable interest because of the knowledge that oxidative modification of low-density lipoprotein may promote atherosclerosis. METHODS: We studied 34,486 postmenopausal women with no cardiovascular disease who in early 1986 completed a questionnaire that assessed, among other factors, their intake of vitamins A, E, and C from food sources and supplements. During approximately seven years of follow-up (ending December 31, 1992), 242 of the women died of coronary heart disease. RESULTS: In analyses adjusted for age and dietary energy intake, vitamin E consumption appeared to be inversely associated with the risk of death from coronary heart disease. This association was particularly striking in the subgroup of 21,809 women who did not consume vitamin supplements (relative risks from lowest to highest quintile of vitamin E intake, 1.0, 0.68, 0.71, 0.42, and 0.42; P for trend 0.008). After adjustment for possible confounding variables, this inverse association remained (relative risks from lowest to highest quintile, 1.0, 0.70, 0.76, 0.32, and 0.38; P for trend, 0.004). There was little evidence that the intake of vitamin E from supplements was associated with a decreased risk of death from coronary heart disease, but the effects of high-dose supplementation and the duration of supplement use could not be definitely addressed. Intake of vitamins A and C did not appear to be associated with the risk of death form coronary heart disease. CONCLUSIONS: These results suggest that in postmenopausal women the intake of vitamin E from food is inversely associated with the risk of death from coronary heart disease and that such women can lower their risk without using vitamin supplements. By contrast, the intake of vitamins A and C was not associated with lower risks of dying from coronary disease.

Aged↗

PubMed1996

Type A behavior pattern and change in blood pressure from childhood to adolescence. The Minneapolis Children's Blood Pressure Study.

The association of the Type A behavior pattern with change in blood pressure was examined in a multiethnic sample of schoolchildren. Blood pressure was assessed in 1978 (mean age = 8 years) and approximately biannually thereafter through 1987-1990, when a post-high school screening was completed. The Matthews Youth Test for Health (MYTH) was completed by the teachers of a sample of participants in 1982 (n = 502). The Jenkins Activity Survey (JAS) was completed by all adolescents who participated in the post-high school screening (n = 816). Males were more likely to be classified as Type A than were females by the JAS and the MYTH. Type A status was not associated cross-sectionally with elevated blood pressure. JAS-assessed Type B males had significantly higher mean post-high school fourth- and fifth-phase diastolic blood pressures than did Type A males (70.2 mmHg vs. 68.2 mmHg, p < 0.05; 68.1 mmHg vs. 65.2 mmHg, p < 0.01). JAS-assessed Type A/B status was not associated with 10-year change in blood pressure. MYTH-determined Type B females tended to have higher diastolic blood pressures than MYTH-determined Type A females throughout the 10-year study period. Results from this study did not confirm the hypothesis that Type A participants would have significantly higher blood pressures than Type B participants at the time of Type A assessment; nor did they confirm the hypothesis that Type A participants would exhibit greater increases in blood pressure than Type B participants over a 10-year period.

Adolescent↗

PubMed1996

Prognostic value of heart rate adjustment of exercise-induced ST segment depression in the multiple risk factor intervention trial.

OBJECTIVES: We sought to assess the effect of heart rate adjustment of ST segment depression on risk stratification for the prediction of death from coronary artery disease. BACKGROUND: Standard analysis of the ST segment response to exercise based on a fixed magnitude of horizontal or downsloping ST segment depression has demonstrated only limited diagnostic sensitivity for the detection of coronary artery disease and has variable test performance in predicting coronary artery disease mortality. Heart rate adjustment of the magnitude of ST segment depression has been proposed as an alternative approach to increase the diagnostic and prognostic accuracy of the exercise electrocardiogram (ECG). METHODS: Exercise ECGs were performed in 5,940 men from the Usual Care Group of the Multiple Risk Factor Intervention Trial at entry into the study. An abnormal ST segment response to exercise was defined according to standard criteria as > or = 100 micro V of additional horizontal or downsloping ST segment depression at peak exercise. The ST segment/heart rate index was calculated by dividing the change in ST segment depression from rest to peak exercise by the exercise-induced change in heart rate. An abnormal ST segment/heart rate index was defined as >1.60 micro V/beats per min. RESULTS: After a mean follow-up of 7 years there were 109 coronary artery disease deaths. Using a Cox proportional hazards model, a positive exercise ECG by standard criteria was not predictive of coronary mortality (age-adjusted relative risk [RR] 1.5, 95% confidence interval [CI] 0.6 to 3.6, p = 0.39). In contrast, an abnormal ST segment/heart rate index significantly increased the risk of death from coronary artery disease (age-adjusted RR 4.1, 95% CI 2.7 to 6.0, p < 0.0001). Excess risk of death was confined to the highest quintile of ST segment/heart rate index values, and within this quintile, risk was directly related to the magnitude of test abnormality. After multivariate adjustment for age, diastolic blood pressure, serum cholesterol and cigarettes smoked per day, the ST segment/heart rate index remained a significant independent predictor of coronary death (RR 3.6, 95% CI 2.4 to 5.4, p < 0.001). CONCLUSIONS: Simple heart rate adjustment of the magnitude of ST segment depression improves the prediction of death from coronary artery disease in relatively high risk, asymptomatic men. These findings strongly support the use of heart rate-adjusted indexes of ST segment depression to improve the predictive value of the exercise ECG.

Coronary Disease↗

PubMed1996

Insulin sensitivity and blood pressure in a biethnic sample: the Miami Community Health Study.

An association between blood pressure and insulin sensitivity among normotensive African-Americans has not been demonstrated consistently in epidemiologic studies. Part of the discrepancy may be due to studying persons with profound obesity-an insulin-resistant state itself. The association between insulin-mediated glucose uptake (i.e., insulin sensitivity) and blood pressure was examined among 25 nondiabetic African-American and 28 white non-Hispanic persons aged 25-44 years who ranged from normal weight to obese, using the hyperinsulinemic euglycemic clamp technique. In bivariate analyses, insulin sensitivity was inversely related to systolic (p < 0.01) and diastolic blood pressure (p = 0.08) among African-American persons and to diastolic blood pressure among white non-Hispanic subjects (p < 0.05). Covariate adjustment for age and sex had only a marginal effect on these results. When the data were pooled and further adjusted for ethnicity, insulin sensitivity remained significantly associated with both systolic and diastolic blood pressure (p < 0.01 for each). To consider the effect of obesity, body mass index (BMI) was divided at the sample median (26.5 kg/m2) and the analyses were repeated within each stratum. Among those whose BMI was below the median value, each increment in insulin sensitivity was associated with a 2-mmHg decrease in systolic blood pressure (p = 0.02). These results suggest that ethnicity was not a strong effect modifier in this sample and indicated that insulin sensitivity was inversely related to blood pressure level in these normotensive African-American and white, non-Hispanic participants.

Adult↗