Search PubMed⌕ Search

Biomedical subjects

R J Prineas

Publications and source records attributed to R J Prineas.

At least 19 recordsLinked to original sources
PubMed2006

The effect of conjugated equine oestrogen on diabetes incidence: the Women's Health Initiative randomised trial.

AIMS/HYPOTHESIS: Recent clinical trials have found that the combination of conjugated equine oestrogen (CEO) and medroxyprogesterone has a protective effect on the incidence of type 2 diabetes. To determine the effect of CEO alone on the incidence of diabetes mellitus in postmenopausal women, we analysed the results of the Women's Health Initiative oestrogen-alone trial. METHODS: The Women's Health Initiative is a randomised, double-masked trial comparing the effect of daily 0.625 mg CEO with placebo during 7.1 years of follow-up of 10,739 postmenopausal women who were aged 50-79 years and had previously had a hysterectomy. Diabetes incidence was ascertained by self-report of treatment with insulin or oral hypoglycaemic medication. Fasting glucose, insulin and lipoproteins were measured in an 8.6% random sample of study participants, at baseline and at 1, 3 and 6 years. RESULTS: The cumulative incidence of treated diabetes was 8.3% in the oestrogen-alone group and 9.3% in the placebo group (hazard ratio 0.88, 95% CI 0.77-1.01, p=0.072). During the first year of follow-up, a significant fall in insulin resistance (homeostasis model assessment of insulin resistance) in actively treated women compared with the control subjects (Year 1 baseline between-group difference -0.53) was seen. However, there was no difference in insulin resistance at the 3- or 6-year follow-up. CONCLUSIONS/INTERPRETATION: Postmenopausal therapy with oestrogen alone may reduce the incidence of treated diabetes. The effect is smaller than that seen with oestrogen plus progestin. CEO should not, however, be used with the intention of preventing diabetes, as its well-described adverse effects preclude long-term use for primary prevention.

Aged↗
PubMed2006

Tables for the selection of correct blood pressure cuff size based on self-reported height and weight and estimating equations for mid-arm circumference: data from the US National Health and Nutrition Examination Survey.

The purpose of this study was to develop practical prediction equations for estimating adult mid-arm circumference (AC) using self-reported height and weight data from NHANES III 1988-1994 and NHANES 1999-2000. Both surveys used a complex sample design to obtain nationally representative data for the US civilian noninstitutionalized population. The analytic sample consisted of 4801 men and 4854 women in NHANES III and 1960 men and 2180 women from NHANES 1999-2000. Self-reported weight, height, and age data from NHANES III were used for model building, and similar data from NHANES 1999-2000 were used for validation. An all-possible regressions procedure by gender was used to derive the mid-AC prediction equations. The final prediction equations for adult mid-AC are (for self-reported weight in pounds and height in inches) for men: AC (cm) = 32.52145 + 0.10975 x (wt)-0.26057 x (ht)-0.03028 x (age), R2 = 0.76; and for women: AC (cm) = 30.22126 + 0.13534 x (wt)-0.34121 x (ht) + 0.09014 x (age)-0.00082565 x (age2), R2 = 0.81. Based on these equations, tables were created to predict mid-AC using self-reported height and weight. Clinicians can refer to our prediction equations and reference tables to determine mid-AC and proper BP cuff sizes.

Adult↗
PubMed2005

US demographic trends in mid-arm circumference and recommended blood pressure cuffs: 1988-2002.

Mid-arm circumference (AC) measurement is a prerequisite for the selection of properly sized blood pressure (BP) cuffs and accurate BP readings. This study examined trends in the frequency distribution of mid-AC and corresponding recommended BP cuff sizes using National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and NHANES 1999-2002 data. Both surveys used a complex sample design to obtain nationally representative samples of the civilian noninstitutionalized US population. The sample consisted of 7453 men and 8372 women from NHANES III and 4295 men and 4838 women from NHANES 1999-2002. Mean mid-AC (cm) and associated American Heart Association-defined cuff sizes were assessed. Variables were analysed by gender, age, race/ethnicity, and by hypertension or diabetic co-morbidity. Mid-AC increased significantly between surveys for all age groups; the greatest increase in mid-AC occurred in the 20-39 year age group. Data from NHANES 1992-2002 show that among nonHispanic white and nonHispanic black men aged 20-59 years, the mean mid-AC was >34 cm. Among NHB women aged 40 years and above, the mean mid-AC was greater than or equal to 34 cm. In all, 42% of all men and 26% of all women aged 40-59 years required large BP cuffs. In all, 39% of individuals classified as hypertensive and 47% of self-reported diabetics required a BP cuff greater than the standard adult size. In conclusion, mean mid-AC has increased across many demographic subgroups in the US with implications for the accuracy of BP measurement in clinical practice.

Adult↗
PubMed2001

Modeling preclinical cardiovascular risk for use in epidemiologic studies: Miami community health study.

To develop a method for assessing preclinical cardiovascular disease risk, models of resting cardiovascular regulation and of insulin metabolic syndrome were derived from information collected from 1991 to 1996 in a culturally heterogeneous sample of 319 healthy men and women (aged 25-44 years) from Miami-Dade County, Florida. The model of resting cardiovascular regulation used 8 noninvasive measures of autonomic and cardiovascular function. Three factors were derived: 1) parasympathetic, 2) inotropy, and 3) systemic vascular resistance. The model of insulin metabolic syndrome used 12 measures assessing body mass, insulin, glucose, and lipid metabolism. Four factors were derived: 1) body mass and fat distribution, 2) glucose level and regulation, 3) insulin level and regulation, and 4) plasma lipid levels. Analyses of the association of the two models revealed that subjects with lower cardiac contractility had greater body mass, higher fasting and postload insulin and glucose levels, and lower insulin sensitivity. Subjects with greater vascular resistance had greater body mass, higher total cholesterol and triglyceride levels, and lower high density lipoprotein cholesterol levels. These findings indicate that preclinical cardiovascular disease risk may involve pathophysiologic processes in which cardiac inotropic and vasodilatory functions are linked to specific aspects of insulin metabolic syndrome.

Adult↗
PubMed2001

Obtaining event status at the close of the Treatment of Mild Hypertension Study: methods and implication for other trials.

The Treatment of Mild Hypertension Trial was a randomized, double-blind clinical trial conducted from 1986 to 1992 comparing the efficacy of six antihypertensive treatment regimens in 902 participants with stage I hypertension. To satisfy a secondary objective of the study, follow-up information on mortality and cardiovascular morbidity was collected. For this objective the aim was to ascertain the vital and cardiovascular event status as of the last day of the trial. This was accomplished by inviting each participant to attend a closeout visit shortly after the closeout date. In addition to serving as verification of vital status, this visit allowed data collection on nonfatal events that occurred between the last clinic visit and the closeout date. During this visit the patient was unblinded to study medication and given a medical summary of their participation during the trial, as well as a bottle of open-label medication. The advantages of a closeout visit are discussed along with a call for studies to provide clearer definitions of lost to follow-up and censoring times used in life-table analyses, especially when the primary event includes both fatal and nonfatal events. Control Clin Trials 2001;22:56-61

Antihypertensive Agents↗
PubMed2001

Independent risk for cardiovascular disease predicted by modified continuous score electrocardiographic criteria for 6-year incidence and regression of left ventricular hypertrophy among clinically disease free men: 16-year follow-up for the multiple risk factor intervention trial.

Risk prediction for electrocardiographic (ECG) left ventricular hypertrophy related criteria, used in clinical trials, and epidemiologic studies of clinically healthy people, has depended in the past on dichotomous classification of ECG LVH criteria. Recent analyses have shown that more sensitive methods of LVH ECG classification without loss of specificity are needed to improve on dichotomous classification. This was done by relating six year incident significant change in continuous score criteria of ECG LVH to the 16 year (10 year post trial) coronary heart disease (CHD) and cardiovascular disease (CVD) mortality among 12,866 men, free of clinical disease, aged 35 to 57 years at baseline in the Multiple Risk Factor Intervention Trial. It was found that significant change in continuous ECG LVH criteria was a stronger independent predictor of future CHD and CVD mortality than was use of dichotomous classification of the same criteria. It was also demonstrated that increase in continuous ECG LVH indexes, below previous dichotomous thresholds independently (of standard CVD risk factors, including increase in obesity-indicated by an increase in adult BMI) predicted excess CHD and CVD mortality and that combinations of continuous indices increases the specificity and relative risk in clinically disease-free middle-aged men.

Adult↗
PubMed2001

Insulin resistance syndrome in childhood: associations of the euglycemic insulin clamp and fasting insulin with fatness and other risk factors.

OBJECTIVE: Our objective was to describe in children the relation of fatness and insulin resistance to the risk factors associated with the insulin resistance syndrome and to compare fasting insulin with the euglycemic insulin clamp as a measure of insulin resistance in children. STUDY DESIGN: This was a random selection of participants after blood pressure screening of 12,043 students in the fifth through eighth grades. Euglycemic insulin clamp studies with an insulin infusion rate of 1 mU/kg/min and a variable infusion of 20% glucose to maintain euglycemia, that is, plasma glucose at 5.6 mmol/L. Insulin sensitivity (M(lbm)) is defined as the amount of glucose required to maintain euglycemia (milligrams of glucose infused per kilogram lean body mass per minute). RESULTS: Body mass index was significantly correlated with fasting insulin and significantly inversely correlated with M(lbm). Fasting insulin was significantly correlated with systolic blood pressure in both sexes, all lipids, except high-density lipoprotein-cholesterol in males and triglycerides and high-density lipoprotein-cholesterol in females, but after adjustment was done for body mass index, it was significantly related only to triglycerides. M(lbm) was significantly correlated only with triglycerides and high-density lipoprotein-cholesterol, and this did not change after adjustment was done for body mass index. A clustering effect for the risk factors was seen in children in the lowest quartile of M(lbm) (highest degree of insulin resistance) compared with children in the highest quartile of M(lbm) (lowest degree of insulin resistance). CONCLUSIONS: As defined by M(lbm), there is an early association of insulin resistance, independent of body fat, with the risk factors. There is a significant relation between fasting insulin, as an estimate of insulin resistance, and the risk factors, but this is significantly influenced by body fatness. The clustering of risk factors according to level of M(lbm) suggests that adult cardiovascular disease is more likely to develop in children with the greatest degree of insulin resistance.

Adolescent↗
PubMed2000

Associations of general and abdominal obesity with multiple health outcomes in older women: the Iowa Women's Health Study.

BACKGROUND: Recent clinical guidelines on the health risks of obesity use body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) and waist circumference, but the waist-hip ratio may provide independent information. METHODS: To assess the joint and relative associations of BMI, waist circumference, and waist-hip ratio with multiple disease end points, we conducted a prospective cohort study of 31,702 Iowa women, aged 55 to 69 years and free of cancer, heart disease, and diabetes, assembled by random sampling and mail survey in 1986. Study end points were total and cause-specific mortality and incidence of site-specific cancers and self-reported diabetes, hypertension, and hip fracture over 11 to 12 years. RESULTS: The waist-hip ratio was the best anthropometric predictor of total mortality, with the multivariable-adjusted relative risk for quintile 5 vs 1 of 1.2 (95% confidence interval, 1.1-1.4), compared with 0.91 (95% confidence interval, 0.8-1.0) for BMI and 1.1 (95% confidence interval, 1.0-1. 3) for waist circumference. The waist-hip ratio was also associated positively with mortality from coronary heart disease, other cardiovascular diseases, cancer, and other causes. The waist-hip ratio was associated less consistently than BMI or waist circumference with cancer incidence. All anthropometric indexes were associated with incidence of diabetes and hypertension. For example, women simultaneously in the highest quintiles of BMI and waist-hip ratio had a relative risk of diabetes of 29 (95% confidence interval, 18-46) vs. women in the lowest combined quintiles. CONCLUSION: The waist-hip ratio offers additional prognostic information beyond BMI and waist circumference.

Abdomen↗
PubMed2000

Relation of low body mass to death and stroke in the systolic hypertension in the elderly program. The SHEP Cooperative Research Group.

BACKGROUND: There are scant data on the effect of body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) on cardiovascular events and death in older patients with hypertension. OBJECTIVE: To determine if low body mass in older patients with hypertension confers an increased risk of death or stroke. PATIENTS: Participants were 3975 men and women (mean age, 71 years) enrolled in 17 US centers in the Systolic Hypertension in the Elderly Program trial, a randomized, double-blind, placebo-controlled clinical trial of lowdose antihypertensive therapy, with follow-up for 5 years. MAIN OUTCOME MEASURES: Five-year adjusted mortality and stroke rates from Cox proportional hazards analyses. RESULTS: There was no statistically significant relation of death or stroke with BMI in the placebo group (P = .47), and there was a U- or J-shaped relation in the treatment group. The J-shaped relation of death with BMI in the treated group (P = .03) showed that the lowest probability of death for men was associated with a BMI of 26.0 and for women with a BMI of 29.6; the curve was quite flat for women across a wide range of BMIs. For stroke, men and women did not differ, and the BMI nadir for both sexes combined was 29, with risk increasing steeply at BMIs below 24. Those in active treatment, however, had lower death and stroke rates compared with those taking placebo. CONCLUSIONS: Among older patients with hypertension, a wide range of BMIs was associated with a similar risk of death and stroke; a low BMI was associated with increased risk. Lean, older patients with hypertension in treatment should be monitored carefully for additional risk factors.

Aged↗
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

Secular trends of blood pressure and body size in a multi-ethnic adolescent population: 1986 to 1996.

OBJECTIVES: To determine the levels and time trends of blood pressure and body size in a healthy population of youth. STUDY DESIGN: Minneapolis, Minnesota, fifth through eighth grade public school children (aged 10 to 14 years) were surveyed in 1986 and 1996. Blood pressure, height, and weight were measured by technicians trained to the same rigorous protocol at each time period, and comparisons were made between the 2 groups (1986 and 1996). RESULTS: In 1986 and 1996, 8222 and 10,241 children, respectively, were measured with participation rates of over 93%. African American, Hispanic, Native American, Asian, and non-Hispanic white groups were all represented. Systolic blood pressure was significantly higher and diastolic blood pressure lower in 1996 than in 1986 in all ethnic and gender groups. Weight and body mass index (wt/ht2) were significantly higher in all groups in 1996. Adjustment for body size largely eliminated the systolic blood pressure differences but had no effect on measured diastolic blood pressure. CONCLUSIONS: Body size and systolic blood pressure are rising among school children. Weight and body mass index show substantial increases over 10 years (1986-1996). Diastolic blood pressure fell for unclear reasons. These changes may have future health implications for cardiovascular disease, as these youth move into adulthood.

Adolescent↗
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↗
PubMed1999

Is fasting leptin associated with insulin resistance among nondiabetic individuals? The Miami Community Health Study.

OBJECTIVE: Whether serum leptin levels are associated with insulin resistance independent of the effects of hyperinsulinemia and adiposity is an important unanswered question. We examined the relationship between the rate of insulin-mediated glucose uptake and serum leptin concentrations among nondiabetic men and women. RESEARCH DESIGN AND METHODS: A cross-sectional analysis was performed among 49 young to middle-aged men and women who participated in the Miami Community Health Study. All participants had measures of insulin resistance (euglycemic-hyperinsulinemic clamp), postchallenge insulin levels, fasting serum leptin levels, and several measures of adiposity. RESULTS: The rate of insulin-mediated glucose uptake (M in milligrams per kilogram per minute) was significantly associated with leptin concentrations in both men (r = -0.83; P < 0.001) and women (r = -0.59; P < 0.001). M was also inversely related to percent body fat and to the 2-h insulin area under the curve (AUC). After covariate adjustment for sex, percent body fat, and AUC, leptin remained a significant correlate of M (P = 0.04). CONCLUSIONS: Cross-sectionally, leptin was significantly associated with insulin resistance in this nondiabetic sample of men and women. There may be a different physiological mechanism to explain the leptin/insulin resistance association apart from the insulin/adiposity link. Confirmatory evidence awaits the results of clinical trials.

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↗