Differing Relations to Early Atherosclerosis between Vitamin C from Supplements vs. Food in the Los Angeles Atherosclerosis Study: A Prospective Cohort Study.

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 relations to endothelial function, yet vitamin C taken as a vitamin supplement does not appear to protect from cardiovascular events.

Sex differences in the relation of HDL cholesterol to progression of carotid intima-media thickness: the Los Angeles Atherosclerosis Study.

Epidemiologic studies have revealed that the protective association of high-density lipoprotein cholesterol (HDL-C) with CHD is stronger in older men and younger women. We aimed to investigate sex differences in the relation of HDL-C to progression of carotid intima-media thickness (IMT) (an indicator of subclinical atherosclerosis) in middle age. IMT progression and serum HDL-C were determined for a cohort of 500 women and men aged 40-60 years over three examinations (1.

Smoking status and common carotid artery intima-medial thickness among middle-aged men and women based on ultrasound measurement: a cohort study.

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.

Effects of a randomized controlled trial of transcendental meditation on components of the metabolic syndrome in subjects with coronary heart disease.

Background: The metabolic syndrome is thought to be a contributor to coronary heart disease (CHD), and components of the syndrome have been identified as possible therapeutic targets. Previous data implicate neurohumoral activation related to psychosocial stress as a contributor to the metabolic syndrome. The aim of this study was to evaluate the efficacy of transcendental meditation (TM) on components of the metabolic syndrome and CHD.

Arachidonate 5-lipoxygenase promoter genotype, dietary arachidonic acid, and atherosclerosis.

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 dietary intake of competing 5-lipoxygenase substrates.

Methods: We determined 5-lipoxygenase genotypes, carotid-artery intima-media thickness, and markers of inflammation in a randomly sampled cohort of 470 healthy, middle-aged women and men from the Los Angeles Atherosclerosis Study.

Dietary fiber and progression of atherosclerosis: the Los Angeles Atherosclerosis Study.

Background: Several epidemiologic studies found weak protective relations between dietary fiber intake and the risk of cardiovascular disease events. However, few of the studies addressed possible mechanisms of the effect.

Objective: In the present study, we estimated relations between the progression of atherosclerosis and the intake of selective dietary fiber fractions.

Progression of carotid intima-media thickness and plasma antioxidants: the Los Angeles Atherosclerosis Study.

Objective: Recent epidemiologic and animal model data suggest that oxygenated carotenoids are protective against early atherosclerosis. We assessed the association between atherosclerotic progression, measured by carotid intima-media thickness (IMT), and plasma levels of oxygenated and hydrocarbon carotenoids, tocopherols, retinol, and ascorbic acid.

Methods And Results: Participants were from an occupational cohort of 573 middle-aged women and men who were free of symptomatic cardiovascular disease at baseline.

Parallel developmental trajectories of sensation seeking and regular substance use in adolescents.

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 sensation seeking had strong predictive value for both concurrent and distal marijuana and alcohol use in both samples; however, initial level of sensation seeking predicted initial level of cigarette use during high school in 1 sample only. White participants scored consistently higher on both initial level and rate of increase in sensation seeking than did participants of other ethnicities.

Leisure time physical activity and early atherosclerosis: the Los Angeles Atherosclerosis Study.

Purpose: Some studies of leisure time physical activity find a cardiovascular benefit for moderate activity, whereas others find benefit only for regular vigorous activity. We examined the relation between physical activity and 3-year progression of carotid atherosclerosis.

Methods: Baseline examinations were conducted during 1995 to 1996 with two follow-up examinations at 1.

Carotid wall thickness and years since bilateral oophorectomy: the Los Angeles Atherosclerosis Study.

Evidence that coronary heart disease risk increases with surgical menopause is consistent. However, findings concerning atherosclerosis and surgical menopause are inconsistent. The Los Angeles Atherosclerosis Study (1995-1996) assessed the cross-sectional relation at baseline between years since bilateral oophorectomy and common carotid artery intima-media thickness (IMT).

Isoflavone supplementation and endothelial function in menopausal women.

Objective: Despite strong observational evidence for a beneficial role of oestrogen in cardiovascular disease, recent trial results suggest that hormone replacement therapy (HRT) may have adverse effects in menopausal women with established coronary heart disease. Isoflavones are oestrogen analogues found in plants with oestrogen-like properties and, because of a favourable side-effect profile, may be ideal alternatives to HRT with respect to cardiovascular benefits. Endothelial function is a marker of cardiovascular health.

A Simulation Study of Mediated Effect Measures.

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 empirical standard deviation of each estimator and theoretical standard error when available. The simulations consisted of 500 replications of three normally distributed variables for eight sample sizes (N = 10, 25, 50, 100, 500, 1000, and 5000) and 64 parameter value combinations.