Previous studies suggest that hemoconcentration may be one mechanism by which acute psychological stress causes elevations of serum total cholesterol and its subfractions. Alternatively, such ...elevations may result from sympathetically mediated changes in lipid metabolism. This study evaluated these two hypotheses by manipulation of sympathetically mediated responses to stress using a nonselective adrenoceptor antagonist, labetalol.
In a 2 x 2 factorial design, 52 healthy male participants were randomly assigned to a stress or no-stress condition and, within each condition, were administered either labetalol or saline. Participants assigned to stress completed three cognitive and evaluative tasks lasting a total of 18 minutes. Indices of hemoconcentration (hematocrit and hemoglobin), heart rate, blood pressure, and serum lipids (total, high-density lipoprotein (HDL), low-density lipoprotein (LDL), free fatty acids, and triglycerides) were assessed at preinfusion and infusion baselines and after mental stress (or rest).
Labetalol reduced sympathetic activation, as shown by a substantial reduction in heart rate elevation during stress, but did not alter changes in blood pressure or in hemoconcentration, as indicated by equivalent increases in hematocrit and hemoglobin in the two stressed groups. Labetalol blocked stress-induced increases in free fatty acid concentrations and lowered triglyceride levels but did not influence rises in total, HDL, or LDL cholesterol among stressed subjects. However, arithmetic correction for hemoconcentration eliminated the increases in total, HDL, and LDL cholesterol.
These findings suggest that elevations in total cholesterol and its HDL and LDL subfractions during acute stress are caused by accompanying hemoconcentration, whereas concomitant rises in free fatty acids and triglycerides result from the direct metabolic effects of sympathetic activation.
Hypertension is virtually absent in very lean rural African populations but is becoming more common in higher-weight urban African populations and is very common in predominantly obese Westernized ...black populations. This implies that there is a threshold above which weight is related to blood pressure. We studied urban Nigerian civil servants, a lean population in transition toward a more Westernized lifestyle. Blood pressure, fat-related measurements, fasting insulin, physical activity, alcohol intake, macronutrient intake, and electrolyte excretion were measured in 500 male and 299 female civil servants in Benin City, Nigeria, in 1992. Median body mass index (BMI) was 21.5 kg/m2 in men and 24.0 kg/m2 in women. Examination of age-adjusted mean blood pressure across quantiles of BMI in men and women suggested a threshold of 21.5 kg/m2 below which blood pressure was not correlated with BMI. Above this threshold blood pressure was correlated with BMI. Comparison of groups above and below the lower BMI threshold found that differences in blood pressure-BMI covariation were not explained by differences in alcohol intake, caloric or macronutrient intake, or electrolyte excretion. Physical activity was higher in men below the threshold. Fasting insulin and waist-hip ratio were strongly correlated with BMI even in this very lean population but neither was independently related to blood pressure. We conclude that there is a threshold below which little relationship between blood pressure and weight is observed. Above this threshold even at levels considered lean in US blacks, weight is a major determinant of blood pressure in this population of African blacks, which shares ancestry with US blacks.
Diet, alcohol intake, and leisure-time physical activity were compared cross-sectionally in middle-aged female smokers, ex-smokers, and never smokers and were reassessed approximately 3 years later. ...At initial contact, there were no group differences in total caloric intake and very few differences in nutrient intake, but alcohol intake of current smokers and ex-smokers was at least 50% greater than that of never smokers, and current smokers reported less physical activity than did ex-smokers and never smokers. Prospective findings were similar: Compared with continuing smokers, ex-smokers did not change their dietary and alcohol intake but significantly increased physical activity. Thus, some adverse behaviors associated with smoking (e.g., alcohol intake) may be due to self-selection to history of smoking, whereas other behaviors (e.g., reduced physical activity) may be more directly related to smoking itself.
Although substantial evidence from experimental animals suggests that augmentation and reduction in serotonergic neurotransmission both affect arterial blood pressure (BP), it is unknown whether ..."tonic" central serotonergic activity is related to resting BP variability in humans. We tested this hypothesis in a community sample by evaluating the relationship between resting BP and a neuropharmacologic index of brain serotonergic activity (the fenfluramine challenge test). Subjects were 270 generally healthy men and women aged 25 to 60 years who were not receiving prescribed antihypertensive or psychotropic medications. The sample included 216 non-Hispanic whites and 47 blacks. Resting systolic BP ranged from 85 to 161 mm Hg and diastolic from 58 to 98 mm Hg. Each subject received 0.55 to 0.65 mg/kg D,L-fenfluramine hydrochloride, and the plasma prolactin concentration was measured over 3.5 hours. Analyses revealed a linear, inverse relationship between the maximum fenfluramine-induced prolactin rise and systolic and diastolic BP in whites: r=-0.36 and r=-0.29, respectively (P<0.001 for both). These relationships were not observed in the black participants. In whites, the prolactin response to fenfluramine remained a significant predictor of systolic and diastolic BPs in multivariate models including age, gender, body mass index, physical activity, smoking, and alcohol consumption (P</=0.001). When compared with subjects in the highest quartile of prolactin response, individuals whose prolactin responses to fenfluramine comprised the lowest quartile were 2.6 times more likely to have a resting systolic/diastolic BP of >135/85 mm Hg. These data reveal that in white but not black adults, fenfluramine-induced prolactin release correlates inversely with BP and may indicate a role of central serotonergic activity in the pathogenesis of hypertension.
In this article, we evaluated the prospective association between measures of trait anger, hostility, and anxiety and indices of carotid atherosclerosis in 200 healthy middle-aged postmenopausal ...women.
Starting in 1983, 541 premenopausal women were evaluated for their levels of standard cardiovascular risk factors and psychosocial attributes, including their scores on Spielberger Trait Anger, Anxiety, and Anger-in, and Public Self-Consciousness. Starting in 1991, the Cook-Medley Hostile Attitudes Scale was also administered. Starting in 1993, 200 women who had been menopausal for at least 5 years were scanned for carotid atherosclerosis using B-mode ultrasound. The scans were scored for average intima-media thickness (IMT) and plaque index.
Women who had high Trait Anger, Anger-In, and Public Self-Consciousness scores had high IMT scores on average 10 years later. Women who had high Cook-Medley scores also had high IMT scores on average 1.5 years later. Multivariate analyses adjusting for the standard cardiovascular risk factors that most highly predicted IMT scores indicated that holding anger in, being self aware, and having hostile attitudes were significant predictors of IMT. Women with higher plaque scores also tended to report holding in their anger.
Anger suppression and hostile attitudes do predict women's carotid IMT in midlife. Ultrasound measures of carotid atherosclerosis can be used to advance our understanding of the early development of atherosclerosis in women.
: In this chapter, we examine the possibility that negative emotions contribute to the relationship between socioeconomic status (SES) and health. A model of the associations among SES, emotion, and ...health is presented first. We then review the evidence for this model, showing associations of SES with depression, hopelessness, anxiety, and hostile affect and cognition, and of these negative emotions with disease. Notably, most of the data supporting the model provide only indirect evidence that negative emotions serve as a key contributor to the proposed associations. We, therefore, conclude with recommendations for longitudinal research, especially in children, that will more directly and comprehensively examine negative emotions as possible mediators of the SES and health relationship.
The objectives of the present study were threefold: (a) to compare the patterns of hemodynamic responding of children and adolescents during behavioral challenges, (b) to examine whether previously ...reported cardiovascular reactivity differences between Black and White children are dependent on pubertal status, and (c) to assess whether gender differences in hemodynamic response reported for adults is similar in children. One hundred fifty‐nine children (ages 8–10 years) and adolescents (ages 15–17 years), equally divided along gender and racial lines, participated in a laboratory protocol consisting of a reaction time task, a mirror tracing task, a cold forehead challenge, and a stress interview. Results indicated that adolescents responded with greater β‐adrenergic activation than did children and that gender differences in reactivity often reported for adults emerged more clearly in the adolescents than in the children. This study failed to replicate prior findings of greater vasoconstrictive responses in Black children as compared with White children.
A long-standing hypothesis is that feelings of anger and anxiety increase the risk for essential hypertension. Most studies examining this hypothesis have been cross-sectional in design or undertaken ...with men only. We tested this hypothesis along with determination of the other behavioral and biological predictors of increases in systolic (SBP) and diastolic (DBP) blood pressure from baseline to a follow-up examination 3 years later in a prospective study of 468 middle-aged women whose blood pressure at the baseline examination was less than 140/90 mmHg. Analyses showed that increases in the Spielberger Trait Anger Scale between the baseline and 3-year follow-up examination, as well as Framingham Tension scores (a measure of anxiety) at baseline, independently predicted an increase in SBP (P less than 0.01). Other factors that independently predicted an increase in SBP were baseline fasting insulin, parental history of hypertension and increases in body mass index and in alcohol intake across the 3 years of follow-up. Increases in the Spielberger Trait Anger Scores independently predicted increases in DBP (P less than 0.02), as did black race, increases in body mass index and hematocrit and decreases in potassium intake. Although menopausal status and hormone replacement therapy were unrelated to changes in blood pressure, postmenopausal women on hormone replacement therapy did show significant increases in DBP in the univariate analysis. Anxiety at baseline, along with parental history of hypertension, baseline fasting insulin and baseline body mass index, predicted a later onset of hypertension, i.e. on pharmacologic treatment for hypertension, in the univariate analysis.
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