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R B Shekelle

Publications and source records attributed to R B Shekelle.

At least 19 recordsLinked to original sources
PubMed1997

Cigarette smoking, weight gain, and coronary mortality: results from the Chicago Western Electric Study.

BACKGROUND: Prospective studies of overweight and coronary heart disease (CHD) have presented inconsistent findings. Previous inconsistencies may be explained by the modifying effect of cigarette smoking on the association between weight gain and coronary mortality. METHODS AND RESULTS: We prospectively studied 1531 men 40 to 59 years of age who were employed at the Hawthorne Works of the Western Electric Company in Chicago, Ill. Information collected at the initial examination in 1958 included recalled weight at age 20, present weight, height, smoking status, and other CHD risk factors. Vital status was known for all men on the 25th anniversary: 257 CHD deaths occurred over 31,644 person-years of experience. Cox regression analysis was used to investigate risk of coronary mortality associated with change in body mass index (deltaBMI) and its modification by smoking status after adjustment for age, major organ system disease, family history of CHD, and BMI at age 20. Adjustment was not performed for blood pressure or serum total cholesterol because these are intervening variables. DeltaBMI was positively associated with risk of coronary mortality in never-smokers but not in current-smokers (P for interaction =.088). For never-smokers with deltaBMI classified as stable, low gain, moderate gain, or high gain, adjusted relative risks of coronary mortality were 1.00, 1.75, 1.75, and 3.07, respectively (P for trend=.010). For current-smokers, the respective adjusted relative risks were 1.00, 0.78, 1.05, and 1.03 (P for trend=.344). CONCLUSIONS: These results support the hypothesis that cigarette smoking modifies the association between weight gain and coronary mortality. Future investigations of weight gain and coronary mortality should account for the modifying effect of cigarette smoking.

Adult↗
PubMed1997

Fish consumption and the 30-year risk of fatal myocardial infarction.

BACKGROUND: Epidemiologic data on the possible benefit of eating fish to reduce the risk of coronary heart disease have been inconsistent. We used data from the Chicago Western Electric Study to examine the relation between base-line fish consumption and the 30-year risk of death from coronary heart disease. METHODS: The study participants were 1822 men who were 40 to 55 years old and free of cardiovascular disease at base line. Fish consumption, as determined from a detailed dietary history, was stratified (0, 1 to 17, 18 to 34, and > or = 35 g per day). Mortality from coronary heart disease, ascertained from death certificates, was classified as death from myocardial infarction (sudden or nonsudden) or death from other coronary causes. RESULTS: During 47,153 person-years of follow-up, there were 430 deaths from coronary heart disease; 293 were due to myocardial infarctions (196 were sudden, 94 were nonsudden, and 3 were not classifiable). Cox proportional-hazards regression showed that for men who consumed 35 g or more of fish daily as compared with those who consumed none, the relative risks of death from coronary heart disease and from sudden or nonsudden myocardial infarction were 0.62 (95 percent confidence interval, 0.40 to 0.94) and 0.56 (95 percent confidence interval, 0.33 to 0.93), respectively, with a graded relation between the relative risks and the strata of fish consumption (P for trend = 0.04 and 0.02, respectively). These findings were accounted for by the relation of fish consumption to nonsudden death from myocardial infarction (relative risk, 0.33; 95 percent confidence interval, 0.12 to 0.91; P for trend= 0.007). CONCLUSIONS: These data show an inverse association between fish consumption and death from coronary heart disease, especially nonsudden death from myocardial infarction.

Adult↗
PubMed1997

Dietary vitamin C, beta-carotene and 30-year risk of stroke: results from the Western Electric Study.

The relations of dietary antioxidants vitamin C and beta-carotene to 30-year risk of stroke incidence and mortality were investigated prospectively in the Chicago Western Electric Study among 1,843 middle-aged men who remained free of cardiovascular disease through their second examination. Stroke mortality was ascertained from death certificates, and nonfatal stroke from records of the Health Care Financing Administration. During 46, 102 person-years of follow-up, 222 strokes occurred; 76 of them were fatal. After adjustment for age, systolic blood pressure, cigarette smoking, body mass index, serum cholesterol, total energy intake, alcohol consumption, and diabetes, relative risks (and 95% confidence intervals) for nonfatal and fatal strokes (n = 222) in highest versus lowest quartiles of dietary beta-carotene and vitamin C intake were 0.84 (0.57-1.24) and 0.71 (0.47-1.05), respectively. Generally similar results were observed for fatal strokes (n = 76). Although there was a modest decrease in risk of stroke with higher intake of beta-carotene and vitamin-C intake, these data do not provide definitive evidence that high intake of antioxidant vitamins decreases risk of stroke.

Adult↗
PubMed1996

Measures of adiposity and coronary heart disease mortality in the Chicago Western Electric Company Study.

Associations of body mass index (BMI), two measures of percent body fat derived from skinfolds, body weight adjusted for height, triceps and subscapular skinfolds, and their sum, with 22-year coronary heart disease (CHD) mortality were compared in 1707 white men ages 40-55 years at baseline (1958) and free of CHD and cancer in 1961 in the Western Electric Study. Because associations of adiposity measures with CHD mortality differed by length of follow-up, analyses were conducted separately for the first 14 years of follow-up and years 15 through 22. In Cox regression analyses, none of the adiposity measures was significantly related to CHD mortality for the first 14 years of follow-up. For years 15-22, all adiposity measures, except triceps skinfold, were significantly related with adjustment for age, as well as eight other covariates. These results indicate that a positive relation of adiposity to CHD risk may not become apparent until several years after the assessment of adiposity.

Adipose Tissue↗
PubMed1996

Fish consumption and stroke in men. 30-year findings of the Chicago Western Electric Study.

BACKGROUND AND PURPOSE: Evidence of a relationship of fish intake to stroke incidence or mortality is weak. This report examines the association of fish consumption with stroke. METHODS: A cohort of 2107 men aged 40 to 55 years from the Chicago Western Electric Study who were free of coronary heart disease and stroke through their first annual reexamination was investigated in relation to baseline fish intake and 30-year risk of fatal and nonfatal stroke. Data on baseline fish intake, categorized into four levels (> or = 35 g/d, 18 to 34 g/d, 1 to 17 g/d, and 0 g/d), were available for 1847 men. Average values of macronutrients and micronutrients from the first two examinations and major coronary and stroke risk factors were assessed in relation to fish consumption. Stroke mortality was ascertained from death certificates and nonfatal stroke from records of the Health Care Financing Administration. RESULTS: During 46,426 person-years of follow-up, 76 stroke deaths occurred. Men consuming > or = 35 g/d of fish (highest level) had a higher age-adjusted death rate from stroke (23.5 per 10,000 person-years) than men in the three other categories of fish consumption. Based on a Cox proportional hazards regression model with adjustment for age, systolic blood pressure, cigarette smoking, serum cholesterol level, diabetes, electrocardiographic abnormalities, and table salt use, hazards ratios (and 95% confidence intervals) for fish consumers compared with nonconsumers were 1.34 (0.53 to 3.41) for > or = 35 g/d, 0.96 (0.41 to 2.21) for 18 to 34 g/d, and 1.00 (0.43 to 2.33) for 1 to 17 g/d. Age-adjusted and multivariate analyses for fatal and nonfatal strokes (n = 222) yielded similar results. CONCLUSIONS: With stroke rates highest in the subgroup reporting highest fish intake, these data do not support the hypothesis of an inverse association of fish consumption with strokes.

Adult↗
PubMed1996

Dietary beta-carotene, vitamin C, and risk of prostate cancer: results from the Western Electric Study.

Dietary factors are likely candidates for important determinants of prostatic cancer risk. Among the most investigated nutritional factors have been antioxidants. We evaluated dietary beta-carotene and vitamin C in relation to subsequent risk of prostate cancer in a prospective study of 1,899 middle-aged men. We combined prostate cancer cases diagnosed in the first 24 years of follow-up with incident cases identified from the Health Care Financing Administration hospitalization and outpatient files during an additional 6-year follow-up period. We obtained death certificates for all decedents. During the 30-year follow-up, prostate cancer developed in 132 men. There was no indication that consumption of beta-carotene or vitamin C was related to increased or decreased risk of prostate cancer. Relative risks for highest vs lowest quartiles of beta-carotene and vitamin C intake were 1.27 [95% confidence interval (CI) = 0.75-2.14] and 1.03 (95% CI = 0.59-1.60), respectively, after adjustment for age, number of cigarettes smoked per day, dietary cholesterol and saturated fat, alcohol consumption, total energy intake, and occupation. Associations between intake of these nutrients and risk of prostate cancer differed depending on whether the cancer was diagnosed during the first 19 years of follow-up or the next 11 years of follow-up. Overall survival over the 30 years of follow-up was positively associated with intake of beta-carotene and vitamin C.

Adult↗
PubMed1994

Impact of the treatment of isolated systolic hypertension on behavioral variables. Results from the systolic hypertension in the elderly program.

BACKGROUND: Little information has been published on the impact of antihypertensive medications on quality of life in older persons. Particular concern has existed that lowering systolic blood pressure in older persons might have adverse consequences on cognition, mood, or leisure activities. METHODS: A multicenter double-blind randomized controlled trial was conducted over an average of 5 years' followup involving 16 academic clinical trial clinics. Participants consisted of 4736 persons (1.06%) selected from 447,921 screenees aged 60 years and older. Systolic blood pressure at baseline ranged from 160 to 219 mm Hg, while diastolic blood pressure was less than 90 mm Hg. Participants were randomized to active antihypertensive drug therapy or matching placebo. Active treatment consisted of 12.5 to 25 mg of chlorthalidone for step 1, while step 2 consisted of 25 to 50 mg of atenolol. If atenolol was contraindicated, 0.05 to 0.10 mg of reserpine could be used for the second-step drug. The impact of drug treatment on measures of cognitive, emotional, and physical function and leisure activities was assessed. RESULTS: Our analyses demonstrate that active treatment of isolated systolic hypertension in the Systolic Hypertension in the Elderly Program cohort had no measured negative effects and, for some measures, a slight positive effect on cognitive, physical, and leisure function. The positive findings in favor of the treatment group were small. There was no effect on measures related to emotional state. Measures of cognitive and emotional function were stable in both groups for the duration of the study. Both treatment groups showed a modest trend toward deterioration of some measures of physical and leisure function over the study period. CONCLUSIONS: The overall study cohort exhibited decline over time in activities of daily living, particularly the more strenuous ones, and some decline in certain leisure activities. However, mood, cognitive function, basic self-care, and moderate leisure activity were remarkably stable for both the active and the placebo groups throughout the entire study. Results of this study support the inference that medical treatment of isolated systolic hypertension does not cause deterioration in measures of cognition, emotional state, physical function, or leisure activities.

Activities of Daily Living↗
PubMed1994

Decision latitude, psychologic demand, job strain, and coronary heart disease in the Western Electric Study.

The hypothesis that low decision latitude and high psychologic demand are associated with an increased risk of the incidence of and mortality from coronary heart disease was investigated in a 25-year follow-up study of 1,683 men aged 38-56 years who participated in the Chicago Western Electric Study (1957-1983). Scores for decision latitude and psychologic demand, which had been linked to the 1960 US Census occupation codes, were assigned to men in the Western Electric cohort based on job title at the initial examination (1957-1958). After adjustment for major coronary risk factors, the relative risk for 25-year coronary death was 0.76 (95% confidence interval (CI) 0.59-1.00) for a 20-point increase in the decision latitude score (approximate difference between tertiles) and was 0.78 (95% CI 0.48-1.26) for a 10-point increase in the psychologic demand score (approximate difference between three groups). For job strain (defined by low decision latitude and high psychologic demand), it was 1.40 (95% CI 0.92-2.14). Controlling for occupational class reduced the magnitude of the relative risks between job characteristics and coronary mortality. Analysis stratified by occupational class indicated that the effect of decision latitude was more pronounced for white-collar than for blue-collar workers. This study provided only limited evidence for associations between job characteristics and coronary heart disease mortality.

Adult↗
PubMed1993

Does body fatness modify the effect of dietary cholesterol on serum cholesterol? Results from the Chicago Western Electric Study.

The hypothesis that lean persons are more responsive than fat persons to the effects of dietary cholesterol was investigated in 1,903 middle-aged employed men who were examined in 1958 and 1959 as participants in the Chicago Western Electric Study. Change in intake of dietary cholesterol was positively associated with change in serum cholesterol for men in the lowest tertile of body mass index (defined as weight (kg)/height (m)2) (< 24.2) but not for men in the highest tertile (> 26.6) after adjustment for change in body mass index and change in intakes of energy and saturated and polyunsaturated fatty acids. A decrease of 150 mg/1,000 kcal in dietary cholesterol was associated with mean changes of -0.46, -0.18, and 0.13 mmol/liter in serum cholesterol for men with body mass indices of < 24.2, 24.2-26.6, and > 26.6, respectively. Body mass index was strongly correlated with subscapular skinfold thickness; thus, these differences in body mass index reflect true differences in adiposity. These results may help to explain inconsistencies that have occurred in feeding experiments with dietary cholesterol, and they suggest that a reduction in dietary cholesterol should have a more favorable effect on the serum cholesterol levels of fat persons after they have lost weight.

Adipose Tissue↗
PubMed1993

Subscapular and triceps skinfold thicknesses, body mass index and cardiovascular risk factors in a cohort of middle-aged employed men.

Associations of indices of adiposity with cardiovascular risk factors were examined in 1860 middle aged men employed by the Western Electric Company in Chicago in 1960 and 1961. Body mass index and subscapular and triceps skinfolds were examined for associations with systolic and diastolic blood pressure, serum cholesterol, and post-load serum glucose. Correlations of study variables measured one year apart suggest that triceps and subscapular skinfold measurements are less reproducible than body mass index, but more reproducible than measurements of systolic and diastolic blood pressure and serum cholesterol. Associations with blood pressure were stronger for body mass index than for skinfolds, and subscapular skinfold was associated with blood pressure independently of triceps skinfold, as well as age, heart rate, alcohol intake, and family history of cardiovascular disease. Body mass index was also generally more strongly related to serum cholesterol than skinfold measurements. Triceps skinfold was more strongly related to serum cholesterol than subscapular skinfold based on average values for the variables in 1960-61, but subscapular skinfold was more strongly related to one-year change in serum cholesterol. Subscapular skinfold was as strongly related to serum glucose as body mass index. This association was also independent of triceps skinfold and other variables. These analyses demonstrate positive associations of subscapular skinfold, an index of central adiposity, with blood pressure and serum glucose levels. Associations of subscapular and triceps skinfolds with serum cholesterol levels were not consistent in the cross-sectional and longitudinal analyses and require further investigation.

Adult↗
PubMed1993

Relationship of baseline major risk factors to coronary and all-cause mortality, and to longevity: findings from long-term follow-up of Chicago cohorts.

The focus here is on relationships between major risk factors and long-term mortality from coronary heart disease (CHD) and all causes, and on longevity, in Chicago cohorts: 25-year follow-up for Peoples Gas (PG) men aged 25-39 (n = 1,119), 30-year follow-up for PG men aged 40-59 (n = 1,235), 24-year follow-up for Western Electric (WE) men aged 40-55 (n = 1,882); also 15-year follow-up for five cohorts of the Chicago Heart Association (CHA) Study: men aged 25-39 (n = 7,873), 40-59 (n = 8,515), 60-74 (n = 1,490), and women aged 40-59 (n = 7,082) and 60-74 (n = 1,243); also 12-year findings for very low risk men (n = 11,098) and other men (n = 350,564) screened for the Multiple Risk Factor Intervention Trial (MRFIT). With a high degree of consistency, multivariate analyses showed independent positive relationships of baseline serum cholesterol, blood pressure and cigarette use to risk of death from CHD and all causes. For the WE cohort, with baseline nutrient data, dietary cholesterol was also independently related to these mortality risks. Combined risk factor impact was strong for both men and women of all baseline ages. Thus, for WE men, favorable compared to observed levels of serum cholesterol, blood pressure, cigarette use and dietary cholesterol were estimated to result in 24-year risk of CHD death 69% lower, all-cause death 42% lower and longevity 9 years greater. For CHA middle-aged and older women, favorable baseline levels of serum cholesterol, blood pressure and cigarette use were estimated to yield 15-year-CHD risk lower by about 60% and longevity greater by about 5 years. For MRFIT, very low risk men (serum cholesterol < 182 mg/dl, systolic/diastolic blood pressure < 120/<80), nonsmokers, nondiabetic, no previous heart attack), compared to all others, observed 12-year death rates were lower by 89% for CHD, 79% for stroke, 86% for all cardiovascular diseases, 30% for cancers, 21% for other causes, 53% for all causes, and longevity was estimated to be more than 9 years longer. These findings indicate great potentials for prevention of the CHD epidemic and for increased longevity with health for men and women, through improved life-styles and consequent lower risk factor levels.

Adult↗
PubMed1992

Serum cholesterol, beta-carotene, and risk of lung cancer.

This paper hypothesizes that beta-carotene mediates the association between low serum cholesterol and increased risk of lung cancer, predicts that the association should be greater in population strata with low intake of beta-carotene than in those with high intake if the hypothesis is correct, and investigates this prediction with data from a 24-year cohort study of 1,960 middle-aged employed men. In the total cohort, serum cholesterol was not related to risk of lung cancer. The relative risk associated with a difference of -1.0 mmol per liter in serum cholesterol was 1.01 (95% confidence interval of 0.80-1.27) after adjustment for cigarette smoking, age, and intake of beta-carotene. In contrast, however, when the study group was restricted to men with intake of beta-carotene less than 5,000 (N = 929) or less than 3,000 IU per day (N = 272), comparable relative risks were 1.10 and 1.21, respectively. Although the 95% confidence intervals for these relative risks were broad and included unity, the result is consistent with expectation. We conclude that the hypothesis warrants further investigation.

Adult↗
PubMed1992

A delicate subject.

Explore the source record for details and available documents.

Epidemiologic Methods↗
PubMed1992

Does body fatness modify the association between dietary cholesterol and risk of coronary death? Results from the Chicago Western Electric Study.

The hypothesis that body fatness modifies the relation between dietary cholesterol and 25-year coronary mortality was examined in a cohort of 1,792 middle-aged men employed by the Western Electric Company in Chicago. Relative risks of coronary death (and 95% confidence intervals) associated with a 225 mg/day greater intake of dietary cholesterol for men with a subscapular skinfold thickness less than or equal to 14, 15-20, and greater than or equal to 21 mm were 1.44 (1.10-1.90), 1.07 (0.84-1.36), and 0.95 (0.76-1.20), respectively, after adjustment for age; serum total cholesterol level; systolic blood pressure; cigarette smoking; family history of cardiovascular disease; evidence of major organ system disease at baseline; and intake of saturated fatty acids, polyunsaturated fatty acids, energy, and ethanol. Adjusted relative risks associated with a 15-mm greater subscapular skinfold thickness for men with a dietary cholesterol intake less than or equal to 649, 650-799, and greater than or equal to 800 mg/day were 1.76 (1.04-2.98), 1.64 (1.04-2.57), and 1.00 (0.69-1.55), respectively. Fatter men apparently did not benefit from a diet lower in cholesterol, while men who ate a diet high in cholesterol apparently did not benefit from leanness. These results support the hypothesis that body fatness modifies the relation between dietary cholesterol and coronary mortality, perhaps because leaner men are more responsive than fatter men to the effects of dietary cholesterol on the concentration of low density lipoprotein cholesterol.

Adipose Tissue↗
PubMed1991

Dietary cholesterol and incidence of lung cancer: the Western Electric Study.

The hypothesis that dietary cholesterol is positively associated with lung cancer was investigated in a 24-year cohort study of 1,878 middle-aged men who were employed in 1958 by the Western Electric Company in Chicago. The relative risk of lung cancer associated with an increment in dietary cholesterol of 500 mg/day was 1.9 (95 percent confidence interval 1.1-3.4) after adjustment for cigarettes, age, and intake of beta-carotene and fat. Results suggested that the association was specific to cholesterol from eggs. Further research is needed to understand the basis for this association.

Adenocarcinoma↗
PubMed1990

Post-load plasma glucose and cancer mortality in middle-aged men and women. 12-year follow-up findings of the Chicago Heart Association Detection Project in Industry.

The relation of post-load plasma glucose to 12-year cancer mortality was studied in 11,521 white men and 8,591 white women aged 35-64 years at entry in the Chicago Heart Association Detection Project in Industry. There were 298 deaths in which cancer was the underlying cause in men and 186 such deaths in women. Plasma glucose levels at baseline measured one hour after a 50 g oral glucose load were positively related to cancer mortality in men but not in women. This increased mortality in men persisted after controlling for age, body mass index, smoking, serum cholesterol, systolic blood pressure, education, and anti-hypertensive treatment. A site-specific analysis of the male cancer deaths demonstrated higher mean plasma glucose levels for decedents for nearly all sites except oral cancers, liver cancer, and other respiratory cancers. For women, elevations existed for those who died of colon, lung, and hematologic/lymphatic tumors, but not for most other sites. The associations between baseline post-load plasma glucose levels and cancer mortality were similar for earlier and later cancer deaths, which indicates that incipient or occult neoplasm at baseline was not responsible for elevated glucose levels in men who subsequently died of cancer. Cancer mortality rates were also higher for those with a clinical diagnosis of diabetes than for those without, but the numbers of persons with diabetes were small as were the numbers of cancer deaths (19 in the men and 10 in the women).

Administration, Oral↗