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Analytical solutions for point and variance estimators of the mediated effect, the ratio of the mediated to the direct effect, and the proportion of the total effect that is mediated were studied with statistical simulations. We compared several approximate solutions based on the multivariate delta method and second order Taylor series expansions to the(More)
Describes (a) the effects of a social-influences-based drug prevention program (the Midwestern Prevention Project) on the mediating variables it was designed to change and (b) the process by which the effects on mediating variables changed use of drugs (tobacco, alcohol, and marijuana). Students in 42 middle schools and junior high schools in Kansas City,(More)
This study applied piecewise latent growth modeling to longitudinal survey data from 2 different samples of adolescents (N=1,002 and N=1,206) to examine the hypothesis that development of sensation seeking in middle school would predict development of substance use (cigarettes, alcohol, and marijuana) in middle school and high school. Results showed that(More)
This article reviews major risk factors for cigarette smoking, alcohol, and other drug abuse and promising community-based approaches to primary prevention. In a longitudinal experimental study, 8 representative Kansas City communities were assigned randomly to program (school, parent, mass media, and community organization) and control (mass media and(More)
BACKGROUND Leukotrienes are inflammatory mediators generated from arachidonic acid (polyunsaturated n-6 fatty acid) by the enzyme 5-lipoxygenase. Since atherosclerosis involves arterial inflammation, we hypothesized that a polymorphism in the 5-lipoxygenase gene promoter could relate to atherosclerosis in humans and that this effect could interact with the(More)
Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin or TCDD) can arise as a contaminant in the production of herbicides. It causes chloracne in those exposed to it but its human carcinogenicity has been a matter of dispute. We report here a mortality follow-up of 1583 workers (1184 men, 399 women) employed in a chemical plant in Germany that produced herbicides,(More)
BACKGROUND Carotenoids are hypothesized to explain some of the protective effects of fruit and vegetable intake on risk of cardiovascular disease. The present study assessed the protective effects of the oxygenated carotenoid lutein against early atherosclerosis. METHODS AND RESULTS EPIDEMIOLOGY Progression of intima-media thickness (IMT) of the common(More)
This study used Monte Carlo simulations to evaluate the performance of alternative models for the analysis of group-randomized trials having more than two time intervals for data collection. The major distinction among the models tested was the sampling variance of the intervention effect. In the mixed-model ANOVA, the sampling variance of the intervention(More)
BACKGROUND Cigarette smoking is an established causal factor for atherosclerosis. However, the smoking effect on different echogenic components of carotid arterial wall measured by ultrasound is not well elucidated. METHODS Middle-aged men and women who had IMT measurement > or = 0.7 mm at baseline and follow-up were included (N = 413, age 40-60 years at(More)
OBJECTIVE To determine the relationship of vitamin c intake from supplements vs food on early atherosclerosis detected by carotid intima media thickness (IMT). BACKGROUND Oxidative stress and endothelial dysfunction play a critical role in the pathogenesis of atherosclerosis. Dietary vitamin C appears to have anti-oxidant properties and beneficial(More)