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R B Shekelle

Publications and source records attributed to R B Shekelle.

At least 55 records · Page 3Linked to original sources
PubMed1984

Prevalence of diabetes/hyperglycemia and associated cardiovascular risk factors in blacks and whites: Chicago Heart Association Detection Project in Industry.

Prevalence rates of diabetes, asymptomatic hyperglycemia, and cardiovascular risk factors were examined in an employed population of 28,895 whites and 2607 blacks, ages 25 to 64 years. Diabetes had been previously diagnosed in this population among approximately 3% of the males of both races and 2% of the females. Plasma glucose 1 hour after a 50 gm oral load was highest among white males (141 mg/dl), similar and at intermediary levels among black males (134 mg/dl) and white females (135 mg/dl), and lowest among black females (126 mg/dl). A divergent pattern of obesity was observed, however, with black females being by far the most overweight. Preliminary mortality data for males suggest that both blacks and whites with diabetes have sizably higher death rates than those without diabetes; a black-white differential is not apparent.

Adult↗
PubMed1983

Hostility, risk of coronary heart disease, and mortality.

Level of hostility (Ho) was assessed by a 50-item subscale of the Minnesota Multiphasic Personality Inventory at the initial examination of 1877 employed middle-aged men who were free of coronary heart disease (CHD). Ten-year incidence of major CHD events (myocardial infarction and CHD death) was lowest in the first quintile of the Ho scale's distribution, highest in the middle quintile, and intermediate in the other three quintiles. After adjustment for age, blood pressure, serum cholesterol level, cigarette smoking, and intake of ethanol, the relative odds of a major CHD event was 0.68 for men with Ho scores less than or equal to 10 points in comparison to men with higher scores. The Ho scale was positively associated with crude 20-year mortality from CHD, malignant neoplasms, and causes other than cardiovascular--renal diseases and malignant neoplasms. After adjustment for the risk factors listed above, the Ho scale had a statistically significant, positive, monotonic association with 20-year risk of death from all causes combined. A difference of 23 points on the Ho scale, i.e., the difference between the means of the first and the fifth quintiles, was associated with a 42% increase in the risk of death. These results support the previous findings of Williams et al. with respect to the Ho scale and coronary atherosclerosis, and also suggest that the Ho scale may be associated with factors having broad effects on survival.

Adult↗
PubMed1982

Methodological problems in characterizing an individual's plasma glucose level.

Two methodological problems in characterizing an individual's plasma glucose level are examined in this study. First, how large is the intra-individual variation of an individual's 1-hr post-load glucose level and for this estimated intra-individual variation what are the probabilities of misclassifying individuals based on a one-time measurement only of glucose level? Second, do different tests-i.e. fasting, 1-hr, 2 hr post-load, GTT-yield consistent ranking for the same individual? The first of these was explored with data on subsamples from the Chicago Peoples Gas Company (PG) study and the Chicago Heart Association Detection Project in Industry (CHA) study; the second, with data from the Chicago Coronary Prevention Evaluation Program (CPEP). For both the PG and CHA studies, the estimated ratios of the intra- to inter-individual variances were generally higher for post-load plasma glucose than blood pressure, heart rate, weight and serum uric acid. The conditional probabilities of misclassifying individuals into quintiles or deciles based on one measurement of 1-hr post-load glucose were also estimated from these data. These estimated probabilities indicated that the possible attenuation due to intra-individual variation cannot abolish a strong association; however, it may create some problem if the relationship is not very strong. Furthermore, both rank correlation and quintile classification analyses show that fasting, 1-hr and 2-hr plasma glucose level characterize individuals differently. Thus it is possible that the inconsistent results of previous studies, all using a one-time measure of plasma glucose, are partially due to the large intra-individual variation of this variable, and the use of methods that are not highly consistent in their classification of individuals.

Adult↗
PubMed1982

Pulse pressure-I. Level and associated factors in four Chicago epidemiologic studies.

Because systolic blood pressure rises more sharply than diastolic blood pressure for those middle aged and beyond, leading to an increasing prevalence with advancing age of elevated systolic blood pressure without elevated diastolic pressure, i.e. so-called pure systolic hypertension, the question arises as to whether or not factors that have been shown to be related to blood pressure and hypertension are related to pure systolic hypertension or to 'classical' hypertension, i.e. hypertension defined solely by the level of the diastolic pressure. This question was examined in four Chicago epidemiologic studies by examining the associations between several variables and pulse pressure, with pulse pressure redefined so that the association between a variable and pulse pressure indicated whether the variable was more strongly related to systolic or diastolic blood pressure. In these four studies, glucose, heart rate and cigarette use tended to show a stronger association with systolic pressure, suggesting a possible association with pure systolic hypertension, while hematocrit, serum cholesterol, and uric acid tended to be more strongly associated with diastolic pressure, or equally associated with systolic and diastolic pressure, suggesting an association with 'classical' hypertension. Relative weight tended to be more strongly associated with systolic pressure under the age of 35 and more strongly associated with diastolic pressure after age 45.

Adolescent↗
PubMed1982

Pulse pressure-II. Factors associated with follow-up values in three Chicago epidemiologic studies.

This report, the second in a series on pulse pressure and pure systolic hypertension, examined in prospective analyses the associations between both the initial values of five variables and the changes in these variables and pulse pressure, utilizing data from three Chicago epidemiologic studies, in order to determine whether variables known to be related to blood pressure and hypertension are related to pure systolic hypertension or 'classical' hypertension. In these analyses follow-up pulse pressure, which was measured from 2-5 years after the initial measurement of the other variables, was redefined so that the association between the initial value or change and pulse pressure indicated whether the initial value or change was more strongly related to follow-up systolic or diastolic blood pressure. In these three studies, only the initial value for cigarette use had a consistent positive association with follow-up pulse pressure. Change in heart rate was generally positively related to follow-up pulse pressure, while the initial value was not. For relative weight and serum cholesterol, both the change and the initial tended to be negatively related. For glucose, the association was not consistent for either the initial value or the change. The results from these prospective analyses thus suggest that cigarette use is related to pure systolic hypertension, rather than 'classical' hypertension.

Adult↗
PubMed1982

Pulse pressure-III. Prognostic significance in four Chicago epidemiologic studies.

This report, the third in a series on pulse pressure and pure systolic hypertension, examines the associations between blood pressure and the cardiovascular diseases and coronary heart disease, both cross-sectionally and prospectively, utilizing data from four Chicago epidemiologic studies, in an effort to determine whether or not a widened pulse pressure, or pure systolic hypertension, is an independent risk factor. In these analyses, blood pressure is divided into two components, one related to level and the other to pulse pressure, with pulse pressure redefined so that the association between pulse pressure and the prevalence of ECG abnormalities or mortality, indicates whether the endpoint is more strongly related to systolic or diastolic blood pressure. In these studies, blood pressure level is significantly related to both ECG abnormalities and mortality. In the cross-sectional analyses, pulse pressure is generally positively related to the prevalence of ECG abnormalities, indicating a stronger association for systolic blood pressure, and thus a possible association with pure systolic hypertension. However, in the prospective analyses, pulse pressure is generally not related to mortality, indicating an equal association with mortality for systolic and diastolic blood pressure in these studies. Thus, although the cross-sectional analyses generally support the hypothesis that a widened pulse pressure, or pure systolic hypertension, is an independent risk factor for the cardiovascular diseases and coronary heart disease, the prospective analyses do not.

Adolescent↗
PubMed1982

Relative weight and blood pressure in four Chicago epidemiologic studies.

Because systolic blood pressure rises more sharply with age than diastolic blood pressure, leading to an increasing prevalence with advancing age of elevated systolic blood pressure without elevated diastolic pressure, i.e. so-called pure systolic hypertension, the question arises as to whether or not pure systolic hypertension has its own etiology and pathogenesis. Since pure systolic hypertension is characterized by a widened pulse pressure, the present report examined the association between relative weight and pulse pressure, both cross-sectionally and prospectively, in addition, to the association between relative weight and the level of blood pressure, in four Chicago epidemiologic studies. The positive association between relative weight and the level of blood pressure in these studies, in both cross-sectional and prospective analyses, reaffirms the finding in previous studies of a positive association between weight and blood pressure and the prevalence and incidence of hypertension. However, the results of these studies did not generally support the hypothesis that relative weight is related to pulse pressure, and thus possibly to pure systolic hypertension.

Adolescent↗
PubMed1982

Dietary lipids and serum cholesterol level: change in diet confounds the cross-sectional association.

In the Chicago Western Electric Company study, diet was assessed at the initial examination, in 1957-1958, of 1900 middle-aged men and again at their second examination about one year later. At the first examination, lipid composition of the diet, as summarized by a score based on the formula of Keys, Anderson and Grande (Grande, F. Predicting change in serum cholesterol from change in lipid composition of the diet. In: Lauer RM, Shekelle RB, eds. Childhood Prevention of Atherosclerosis and Hypertension. New York: Raven Press, 1980:145-53), was positively associated with level of serum cholesterol. Between the first and second examinations, however, hypercholesterolemic men were more likely than others to have reduced intake of dietary saturated fatty acids and cholesterol. As a result, at the second examination the cross-sectional linear association between the diet score and serum cholesterol concentration was significantly positive for men with initial levels of serum cholesterol less than 250 mg/dl, significantly negative for men with initial levels of 250 mg/dl or higher and not significantly different from zero for all men together. The bias introduced by change in diet among hypercholesterolemic men differs importantly from bias due to unreliability of measurement and to interindividual differences in intrinsic level of serum cholesterol, because it can produce statistically significant but spurious correlations.

Cholesterol↗
PubMed1981

Dietary vitamin A and risk of cancer in the Western Electric study.

Intake of dietary provitamin A (carotene) was inversely related to the 19-year incidence of lung cancer in a prospective epidemiological study of 1954 middle-aged men. The relative risks of lung cancer in the first (lowest) to fourth quartiles of the distribution of carotene intake were respectively, 7.0, 5.5, 3.0, and 1.0 for all men in the study, and 8.1, 5.6, 3.9, and 1.0 for men who had smoked cigarettes for 30 or more years. Intake of preformed vitamin A (retinol) and intake of other nutrients were not significantly related to the risk of lung cancer. Neither carotene nor retinol intake was significantly related to the risk of other carcinomas grouped together, although for men in whom epidermoid carcinomas of the head and neck subsequently developed, carotene intake tended to be below average. These results support the hypothesis that dietary beta-carotene decreased the risk of lung cancer. However, cigarette smoking also increases the risk of serious diseases other than lung cancer, and there is no evidence that dietary carotenoids affect these other risks in any way.

Adult↗
PubMed1981

Diet, serum cholesterol, and death from coronary heart disease. The Western Electric study.

Over twenty years ago, we evaluated diet, serum cholesterol, and other variables in 1900 middle-aged men and repeated the evaluation one year later. No therapeutic suggestions were made. Vital status was determined at the 20th anniversary of the initial examination. Scores summarizing each participant's dietary intake of cholesterol, saturated fatty acids, and polyunsaturated fatty acids were calculated according to the formulas of Keys and Hegsted and their co-workers. The two scores were highly correlated, and results were similar for both: there was a positive association between diet score and serum cholesterol concentration at the initial examination, a positive association between change in diet score and change in serum cholesterol concentration from the initial to the second examination, and a positive association prospectively between mean base-line diet score and the 19-year risk of death from coronary heart disease. These associations persisted after adjustment for potentially confounding factors. The results support the conclusion that lipid composition of the diet affects serum cholesterol concentration and risk of coronary death in middle-aged American men.

Adult↗
PubMed1981

Risk factors for fatal heart attack in young women.

Deaths of 338 women at ages 15-44 years attributed to myocardial infarction (MI) on death certificates during an 18-month period in five metropolitan areas were investigated. Evidence of recent MI or evidence that death occurred suddenly was obtained for about half (163) from records of hospitals or medical examiners or from relatives. A case-control study (involving one deceased control, and one hospitalized living control) of risk factors for heart attack was then conducted using interviews with relatives and abstracts of records of hospitals and physicians identified by the relatives as sources of medical care. Information was obtained on history of prior MI, other heart disease, diabetes, thromboembolism, stroke, hypertension, high cholesterol, obesity, oophorectomy, oral contraception and cigarette smoking. Data are presented on the prevalence of these potential risk factors for the case group and each control group, and for subsets of cases consisting of those without prior heart disease, definite MI only, sudden death only, and white women only. Multivariate analyses identify somewhat different sets of risk factors and different levels of risk for the various subgroups. In general, the risk factors are those that have been reported for men, despite the major difference in level of mortality.

Adolescent↗
PubMed1981

High blood pressure and 17-year cancer mortality in the Western Electric Health Study.

A positive association between elevated blood pressure and risk of death from cancer has been observed in four long-term prospective studies. In the Western Electric Health Study, the relationship was specific to death from renal cell carcinomas and epidermoid cancers of the head and neck. The relationship with epidermoid head and neck cancer was indirect, resulting from the effects of alcohol consumption on both blood pressure and on risk of this cancer. The relationship with kidney cancer was probably due to effects of abnormal renal cell activity. The association between blood pressure and cancer mortality at other sites was not significant.

Adenocarcinoma↗
PubMed1981

Heart rate: a risk factor for cancer?

The relationship between heart rate and cancer mortality was examined in 3 Chicago epidemiologic studies: 1233 white men originally age 40-59 followed 18 years from the Chicago Peoples Gas Company study; 1899 white men originally age 40-55 followed 17 years from the Chicago Western Electric Company study; 5784 white men originally age 45-64 followed 5 years from the Chicago Heart Association Detection Project in Industry. There was a significant association between heart rate and cancer mortality in both univariate and multivariate analyses in men from the Gas Company study and in men from the Chicago Heart Association study, but there was no association between heart rate and cancer mortality in men from the Western Electric study. The relationship persisted in the Gas Company study but not in the Chicago Heart Association study after eliminating deaths within the first 2 years of follow-up. With cancer deaths broken down by the site, mortality from lung and colon cancer in the Gas Company study and mortality from lung cancer in the Chicago Heart Association study were significantly associated with baseline heart rate on univariate analysis and on bivariate analysis controlling for age. Only colon cancer in the Gas Company, however, remained associated with heart rate when other variables were controlled. Thus, in 2 of the 3 studies examined, heart rate appeared to be an independent risk factor for cancer mortality in men.

Adult↗