Biomedical subjects
D R Jacobs
Publications and source records attributed to D R Jacobs.
Blood lipids and lipoproteins in a Minnesota urban population.
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Ventricular premature beats: screening and induction tests in normal men.
Effective future research on the significance of ventricular premature beats (VPB) and their therapeutic suppression require improved and simpler methods for arrhythmia detection, characterization, and measurement. This study considers the comparative yield, repeatability, and validity of several methods of VPB detection and induction in a sample of the general population of middle-aged men. Isometric exercise inducers VPB. Treadmill exercise both induces and suppresses VPB. Cartotid sinus pressure and cold stress provide a small extra yield of VPB.
Scoring systems for evaluating dietary pattern effect on serum cholesterol.
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Preventive cardiology in practice: a device for risk estimation and counseling in coronary disease.
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Diet and serum cholesterol: do zero correlations negate the relationship?
The confounding that results from the uncontrolled conditions under which most epidemiologic observations are made is sufficient to undermine their validity with respect to investigation of the relationship between diet and serum cholesterol. In this paper, the authors show, using both a mathematical model and referring to empirical data, that if certain variances are sufficiently great, even when there is cause and effect, correlation coefficients close to zero would be expected from the actual data of a cross-sectional study. Cross-sectional designs are therefore not suitable for studying this relationship.
A questionnaire for the assessment of leisure time physical activities.
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Natriuretic activity of 16-alpha-hydroxyprogesterone in man.
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Isolated analdosteronism. 3. The ability of aldosterone antagonists to alter electrolyte balance in the absence of a potent mineralocorticoid.
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Epidemiology of low total plasma cholesterol concentration among young adults: the CARDIA study. Coronary Artery Risk Development in Young Adults.
BACKGROUND: Data on stability of plasma total cholesterol levels and its determinants among young adults are lacking. Knowledge of factors associated with low levels of plasma total cholesterol during young adulthood may help clarify the nature of associations between hypocholesterolemia and health or illness. METHODS: Tracking of plasma total cholesterol was investigated using data from the baseline (1985-1986), Year 5 (1990-1991), and Year 7 (1992-1993) examinations of the Coronary Artery Risk Development in Young Adults Study. Lifestyle (including dietary), physiological, medical, and psychological correlates of plasma total cholesterol were examined cross-sectionally at baseline using ANCOVA and multivariate logistic regression. The attributes of participants with persistently low plasma total cholesterol level after 7 years (i.e., remaining below the 10th percentile of sex- and race-specific distributions) were also examined. RESULTS: The cohort in this analysis comprised 720 black men, 922 white men, 899 black women, and 944 white women who were between the ages of 18 and 30 years at baseline. Between 44 and 52% of those with plasma total cholesterol levels below the 10th percentile remained below the same percentile 7 years later. Among black men, a difference of 1 SD in age [3.7 years; odds ratio (OR) = 0.69; 95% CI = 0.52-0.91] and a difference of 1 SD in systolic blood pressure (10.5 mm Hg; OR = 0.73; 95% CI = 0.54-0.97) were independently associated with lower odds, respectively, of being in the lowest 10th percentile of the plasma total cholesterol distribution. Also among black men, current smoking and more calories from carbohydrates were associated with nonsignificantly higher odds of low total cholesterol level. Among white men, a 1 SD older age (3.4 years; OR = 0.78; 95% CI = 0.61-1.00) and a 1 SD higher physical fitness (118 sec; OR = 1.41; 95% CI = 1.09-1.82) predicted lower and higher odds, respectively, of low plasma total cholesterol. Among black women, a 1 SD difference in albumin (0.3 g/dL; OR = 0.80; 95% CI = 0.63-1.03) was related to lower odds of low plasma total cholesterol. Among white women, the factors independently associated with low plasma total cholesterol were body mass index (OR for a difference in 4.0 kg/m2 = 0.73; 95% CI = 0.54-1.00) and gamma-glutamyl transferase (OR for an increase in 9.6 IU/L = 0.41; 95% CI = 0.18-0.93). The independent predictive factors of stably low total cholesterol levels were age and uric acid among black men (both inversely related) and age, Framingham Type A Behavior (inversely), and calories from carbohydrates (positively related) among white men. CONCLUSION: Young adults with low plasma total cholesterol level have characteristics generally associated with good cardiovascular health. However, adverse attributes such as current cigarette smoking (notably among black men) may confound future associations between low total cholesterol and disease.
Case report. Mini-epidemic of thyrotoxicosis occurring in physicians.
This report describes the appearance of thyrotoxicosis over the past eight years in three male physicians working in the Division of Endocrinology at The Mount Sinai Hospital. Since no other instances of hyperthyroidism developed among the hospital medical or dental attending staff, to the authors' knowledge, during the years of 1953-1973, this incidence appears to indicate an unusual occurrence. (Information regarding other possible instances of thyrotoxicosis was obtained by questioning all of the physicians in the Division of Endocrinology at The Mount Sinai Hospital, members of the Division of Endocrinology at the other major institutions in the city and, finally, inquiry of the physicians in the Department of Medicine at The Mount Sinai Hospital.)
Assessment of behavioral risk for coronary disease by voice characteristics.
Behavior characterization is increasingly used and studied in the pathogenesis and management of coronary disease. A specific behavior pattern called Type A has been found to be independently associated with fatal and nonfatal coronary disease. The assessment of Type A is made without quantitative guidelines based on verbal and nonverbal behaviors in a standardized interview. This study has attempted to make this classification solely on the basis of quantifiable verbal behaviors. Two naive persons were trained to code speech behaviors from tape recorded behavior pattern interviews on which Type A had previously been assessed. Intercoder and intracoder reliability was acceptable. Using regression analysis 87% of the interviews were classified in agreement with the previous, standard assessment. Volume of voice and speed of speech were found to make the greatest predictive contribution. Other verbal characteristics including plosiveness were also important. It is concluded that Type A can be validly and repeatably measured by verbal behaviors in the standardized interview.
Psychosocial factors and plasma lipids in black and white young adults: the Coronary Artery Risk Development in Young Adults Study data.
These analyses examined the relationship between fasting plasma lipids and several psychosocial factors in a healthy cohort of 5115 black and white men and women between the ages of 18 and 30. Primary analyses were performed within race/gender subgroups and were supplemented with analyses examining consistency of associations across these groups. After controlling for age, high density lipoprotein (HDL) decreased, triglycerides increased, low density lipoprotein (LDL) increased, and the total cholesterol/HDL cholesterol ratio increased with increasing level of education in black men. This pattern is, in general, opposite to that found in other groups, particularly white women, whose lipid profile was found to be less atherogenic the higher the education. These associations were strongly confounded with health behaviors. There was also a positive association between hostility and triglycerides in women but not in men. No significant association with any plasma lipid for either race or gender was found for Type A behavior, social support, or life events. Despite a narrow plasma lipid range in these young adults, these data support the conclusion that increasing education is associated with a less atherogenic plasma lipid profile, except in black men, for whom education is associated with a less favorable plasma lipid profile. Among other psychosocial factors, the only consistent finding was an inverse association between hostility and triglycerides in women.
Social support and health behavior in hostile black and white men and women in CARDIA. Coronary Artery Risk Development in Young Adults.
OBJECTIVE: These cross-sectional analyses of the Coronary Artery Risk Development in Young Adults (CARDIA) data were stimulated by previous CARDIA analyses that showed an adverse association between hostility and several health behaviors: physical activity, cigarette smoking, alcohol consumption, and caloric intake, in both black and white men and women, such that the higher the hostility, the worse the health behavior profile. The current study investigated whether high social support was associated with better health behavior than low social support in individuals with high hostility scores. METHODS: The subjects were 5115 healthy black and white men and women ranging in age from 18 to 30 years. The hypothesis was that the association between hostility and certain adverse health behaviors would be diminished in the presence of high social support. Race-gender specific median cutpoints of the Cook-Medley Hostility scale and an index of social support defined levels of high and low hostility and social support. RESULTS: After controlling for age and body mass index (BMI), support was positively associated with more exercise in all groups except black women, but when coupled with high hostility, this positive association between support and exercise remained only in men. White women with high support were less often smokers but this association did not hold when examined only in the high-hostile group. Black men and white women with high support in the presence of high hostility consumed more alcohol, but the amount was moderate. CONCLUSIONS: We conclude that social support in the presence of high hostility only sometimes reduces the association of hostility to adverse health behaviors and that these effects are complex. Additional research investigating types of social support on health behavior in different race-gender groups is advocated.
Ability of the Caltrac accelerometer to assess daily physical activity levels.
PURPOSE: The purpose of this study was to determine the ability of the Caltrac accelerometer to assess habitual daily physical activity levels. METHODS: The ability of the Caltrac accelerometer to assess 24-hour physical activity (PA) levels was studied in 28 men and 50 women, age 20 to 59 years, with varying levels of self-reported PA. Twelve days of Caltrac readings obtained over 1 year's duration were compared to simultaneously recorded 48-hour PA records. Additionally, 28 days of Caltrac readings obtained over 1 year's duration were compared to mean values of the following validation measures assessed repeatedly over a 1-year period: a 4-week version of the Minnesota Leisure Time Physical Activity Questionnaire (FWH); VO2peak; and percent body fat. RESULTS: The Caltrac measurements of movement (in MET minutes per day-1) were significantly associated with the following: PA record indices of total (r = .51) and heavy (r = .34) and PA; FWH indices of total (r = .30), heavy R = .36) and moderate (r = .23) PA;, and VO2peak (r = .24). However, the Caltrac measurements of caloric PA record and FWH indices of PA, although there were directly associated with percent body fat (r = .50) and inversely associated with VO2peak (r = -.26). CONCLUSIONS: Caltrac measurements of movement exhibited a moderate associated with several criterion measures related to habitual PA, whereas Caltrac measurements of total energy expenditure, were not reflective of varying levels of PA.
Association of fasting insulin with blood pressure and lipids in young adults. The CARDIA study.
The association of insulin with cardiovascular disease (CVD) may be mediated in part by the associations of insulin with CVD risk factors, particularly blood pressure and serum lipids. These associations were examined in 4576 black and white young adults in the CARDIA Study. Fasting insulin level was correlated in univariate analysis with systolic blood pressure (r = 0.16), diastolic blood pressure (r = 0.13), triglycerides (r = 0.27), total cholesterol (r = 0.10), high density lipoprotein (HDL) cholesterol (r = -0.25), and low density lipoprotein (LDL) cholesterol (r = 0.14), and with age, sex, race, glucose, body mass index, alcohol intake, cigarette use, physical activity, and treadmill duration (all p less than 0.0001). After adjustment for these covariates, insulin remained positively associated with blood pressure, triglycerides, total and LDL cholesterol, and apolipoprotein B and was negatively associated with HDL, HDL2 and HDL3 cholesterol, and apolipoprotein A-I in all four race-sex groups. Higher levels of fasting insulin are associated with unfavorable levels of CVD risk factors in young adults; these associations, though relatively small, can be expected to increase the risk of atherosclerosis. Demonstration of these relationships in a large, racially diverse, healthy population suggests that insulin may be an important intermediate risk factor for CVD in a broad segment of the U.S. population.
Variability in individual serum cholesterol response to change in diet.
Few systematic data are available on the range of individual blood lipid responsiveness to specific diet changes. Multiple, carefully standardized total serum cholesterol (TC) measurements were made in 58 men under a variety of controlled dietary conditions. Responsiveness was defined for each individual as the change in mean TC per unit change in Diet Score based on the Keys-Minnesota equation. Only 3% were potentially "nonresponders," and even these probably evidenced some response. Of the group, 64% responded within 30% of prediction. We classed 9% as hyporesponders, while in another 9% responsiveness exceeded 1.5 times expectation. We conclude that in metabolically normal individuals the variation in short-term response to dietary change is normally distributed but that nonresponse to diet change is rare. Because metabolic, intrinsic hyporesponsiveness of TC to change in diet composition is uncommon, assessment of the real effectiveness of a dietary regimen in an individual is best based on observed dietary changes. TC changes among individuals under treatment should be based on multiple determinations and interpreted with caution.
Distribution of lipoproteins and apolipoproteins in young adults The CARDIA Study.
While there are many studies of the distribution of coronary heart disease risk factors in children, adolescents, and middle-aged adults, little information is available on this topic in young adults. The Coronary Artery Risk Development in Young Adults Study (CARDIA) examined 4858 men and women who fasted 10 or more hours, were ages 18 to 30, and were representative of black and white residents of four U.S. communities. Compared with white men, black men had higher age-adjusted mean levels of high density lipoprotein cholesterol (HDL-C) (6.7 mg/dl, p less than 0.001) and apolipoprotein A-l (apo A-l) (9.1 mg/dl, p less than 0.001) and lower concentrations of triglycerides (-19.7 mg/dl, p less than 0.001) and apolipoprotein B (apo B) (-3.3 mg/dl, p less than 0.001). Compared with white women, black women displayed higher concentrations of low density lipoprotein cholesterol (LDL-C) (5.7 mg/dl, p less than 0.001), apo A-l (2.6 mg/dl, p = 0.001), and apo B (3.0 mg/dl, p less than 0.001), but lower triglycerides (-5.8 mg/dl, p=0.001). Gender differences were more pronounced among whites: white men displayed lower mean levels of HDL-C and apo A-l (-9.2 and -7.3 mg/dl, p less than 0.001) and higher concentrations of LDL-C, triglycerides, and apo B (5.2 20.3, and 5.3 mg/dl, p less than 0.001) than white women. Attained level of education was significantly associated with a favorable lipoprotein/apolipoprotein profile, particularly among white women. These data indicate substantial variation in the distribution of lipoproteins and apolipoproteins in young adults, which may be important determinants of future coronary disease risk.