A comparison of two automated monitors in the measurement of blood pressure reactivity. Trials of Hypertension Prevention Collaborative Research Group

Relationship of John Henryism to cardiovascular functioning at rest and during stress in youth

John Henryism, a coping style characterized by a strong predisposition to confront daily psychosocial stressors in an active and effortful manner, has been associated with cardiovascular (CV) disease risk in adults. This study examined the relationship of John Henryism to CV functioning at rest and during laboratory stressors (i.e. forehead cold stimulation, postural change, and treadmill exercise) in 173 normotensive 10-to 17-year-old African-American and White children. High John Henry scores were associated with higher blood pressure, higher total peripheral resistance, and lower cardiac index at rest. These relationships were qualified by an interaction with socioeconomic status (SES) such that those from lower SES backgrounds who were high on John Henryism had particularly high levels of resting CV measures. No significant associations were observed with CV reactivity to the stressors. Findings are discussed in terms of possible impact of coping styles to environmental stress upon physiological functioning and health.

Impact of a Pharmaceutical Care Intervention on Blood Pressure Control in a Chain Pharmacy Practice

BACKGROUND

Hypertension affects over 50 million Americans, with only 50% of patients being adequately controlled. Several pharmacist counseling and pharmacist-physician comanagement studies have documented that community pharmacist interventions improve blood pressure (BP) management.

OBJECTIVE

To determine whether community pharmacists can improve clinical endpoints including hypertension control, drug therapy dosing, adherence to prescribed regimens, adverse drug reaction incidence, patient understanding, response to therapy, and quality-of-life.

METHODS

The program included the education and training of a group of 18 chain community pharmacists in hypertension therapies, monitoring, and management. Protocols and documentation tools were based on nationally accepted clinical practice guidelines for hypertension in place at the time of the study. Pharmaceutical care (PC) was then compared with usual care (UC) over a 12-month period.

RESULTS

The study initially enrolled 180 PC and 196 UC patients, with 44% (PC) and 32% (UC) of the patients reporting a final BP measurement. A larger proportion (50%) of PC patients who had poorly controlled hypertension at baseline (>140/90 mm Hg) were controlled compared with UC patients (22%). The average reduction in systolic BP was 9.9 mm Hg in PC patients compared with 2.8 mm Hg in UC patients (p < 0.05). Changes in diastolic BP were similar in the PC and UC groups. Based on patient self-report, PC patients were more likely to say that they take their medicines as prescribed compared with UC patients (p < 0.05). The 1- to 6-month antihypertensive adherence rate was higher in PC patients (0.91 ± 0.15) compared to UC patients (0.78 ± 0.30) (p = 0.02); there was no significant difference in adherence rate during the 7- to 12-month period.

CONCLUSIONS

Community pharmacists can positively affect patient medication adherence during the 6-month period following counseling by a pharmacist along with an improvement in patient BP. However, there is much room for improvement in PC programs and in the number of patients who properly adhere to their medications.

Blood pressure rise with swimming versus walking in older women: the Sedentary Women Exercise Adherence Trial 2 (SWEAT 2)

OBJECTIVE

Swimming is often recommended in the prevention and treatment of hypertension. Few studies have investigated the effect of swimming training on blood pressure (BP). Our objective was to evaluate 6 months of supervised moderate swimming or walking on BP in previously sedentary, normotensive, older women.

DESIGN

Women aged 50-70 years (n = 116) were randomly assigned to a supervised 6-month swimming or walking programme. They were further randomized to receive usual care or a behavioural intervention package.

METHODS

Exercise comprised 3 sessions/week with a warm-up, cool down, and 30-min of moderate intensity walking or swimming. BP was recorded for 20 min supine, and 5 min standing. Assessments were made at 0 and 6 months.

RESULTS

At baseline, mean supine BP (+/- SD) was 115.7 +/- 1.3/66.8 +/- 0.7 mmHg. Swimming improved swim distance by 78.1 m (29.3%) [95% confidence interval (CI); 66.7, 89.4] and walk time by 0.58 min (3.8%) (0.41, 0.74). Walking decreased walk time by 1.0 min (6.5%) (0.81, 1.19). After adjustment for initial BP, age, hypertension treatment status and change in weight, swimming increased supine and standing systolic BP relative to walking by 4.4 mmHg (1.2, 7.5) (P = 0.008) and 6.0 mmHg (2.6, 9.5) (P = 0.001), respectively. Supine and standing diastolic BP increased by 1.4 mmHg (-0.14, 3.0) (P = 0.07) and 1.8 mmHg (-0.02, 3.5) (P = 0.05), respectively.

CONCLUSION

Relative to moderately paced walking, regular swimming significantly elevates BP in previously sedentary, normotensive, older women. This finding may have important implications for exercise prescription in older subjects.

Interactive effects of anger expression and ET-1 Lys198Asn polymorphism on vasoconstriction reactivity to behavioral stress

BACKGROUND

Ineffective anger expression has been associated with essential hypertension (EH) and with blood pressure (BP) reactivity to stress. The ET-1/Lys198Asn polymorphism has been associated with increased resting BP and exaggerated vasoconstrictive mediated BP reactivity. African Americans (AAs) are at particular risk for development of EH, report greater anger difficulties, and exhibit greater vasoconstrictive reactivity than their European American (EA) counterparts.

PURPOSE

The objective is to investigate a gene-environment model of stress reactivity in which anger expression, particularly in combination with ET-1 T allele carrier status and AA ethnicity, would be associated with the greatest vasoconstrictive reactivity in response to a behavioral stressor.

METHODS

One hundred ninety-one AA and 197 EA normotensive young adults (M age=18.8+/-2.5 years) participated in the study. Total peripheral resistance index (TPRI) reactivity was assessed during a 10-min video game challenge. Anger expression was measured using Spielberger's Anger Expression Scale.

RESULTS

A multiple regression model with TPRI reactivity as the dependent variable revealed a three-way interaction effect for anger management (i.e., AM=anger control minus anger out scores), ethnicity, and ET-1 polymorphism. Specifically, AA carriers of the ET-1 polymorphism with poor AM skills exhibited the greatest TPRI reactivity.

CONCLUSIONS

Individuals with a genetic predisposition for exaggerated vasoconstriction who also display low AM skills may be at particular risk for development of stress-induced EH. Such individuals may particularly benefit from anger management training.

Endothelin-1 gene Lys198Asn polymorphism and blood pressure reactivity

The Lys198Asn polymorphism of the endothelin-1 gene has been associated with increased blood pressure levels in several studies involving European and Australian adults. The purpose of the present study was to examine the potential moderating influence of ethnicity, obesity, and socioeconomic status on associations between the ET-1/Lys198Asn polymorphism and hemodynamic function at rest and during two laboratory stressors (video game, forehead cold) in a sample of 161 black and 213 white American normotensive young adults (mean age, 18.5+/-2.7 years). Carrier status of the T allele was not associated with resting blood pressure or total peripheral resistance index. However, carriers of the T allele showed greater diastolic blood pressure increases to the video game (P<0.04), particularly among those who were obese (P<0.02). Carrier status also interacted with socioeconomic status such that T allele carriers who came from lower socioeconomic status backgrounds exhibited the greatest increases in systolic blood pressure to the video game challenge (P<0.05). In conclusion, the findings point out the importance of examining the impact of genetic polymorphisms on blood pressure control phenotypes within the context of potentiating environmental factors.

Impact of Transcendental Meditation on cardiovascular function at rest and during acute stress in adolescents with high normal blood pressure

OBJECTIVE

This study examined the impact of the Transcendental Meditation (TM) program on cardiovascular (CV) reactivity in adolescents with high normal BP.

METHOD

Thirty-five adolescents [34 African Americans (AAs), 1 Caucasian American (CA); ages 15-18 years] with resting systolic blood pressure (SBP) between the 85th and 95th percentile for their age and gender on three consecutive occasions, were randomly assigned to either TM (n=17) or health education control (CTL, n=18) groups. The TM group engaged in 15-min meditation twice each day for 2 months including sessions during school lunch break. Primary CV outcome measures were changes in blood pressure (BP), heart rate (HR), and cardiac output (CO) at rest and in response to two laboratory stressors, a simulated car driving stressor and an interpersonal social stressor interview.

RESULTS

The TM group exhibited greater decreases in resting SBP (P<.03) from pre- to postintervention, compared to the CTL group. The TM group exhibited greater decreases from pre- to postintervention in SBP, HR, and CO reactivity (P's<.03) to the simulated car driving stressor, and in SBP reactivity (P<.03) to the social stressor interview.

CONCLUSION

The TM program appears to have a beneficial impact upon CV functioning at rest and during acute laboratory stress in adolescents at-risk for hypertension.

Cardiovascular (CV) responsivity and recovery to acute stress and future CV functioning in youth with family histories of CV disease: a 4-year longitudinal study

Blood pressure (BP) and heart rate (HR) data obtained during supine rest, in response to and recovery from four laboratory stressors in a baseline year were used to predict supine resting BP and HR values obtained during each of four consecutive annual follow-up evaluations. Subjects were 385 normotensive youth [95 African American (AA) males, 106 AA females, 92 European American (EA) males, 92 EA females] (mean age 12.7+/-2.6 at baseline year) with a positive family history of cardiovascular disease (CVD). During the baseline evaluation subjects were presented with four laboratory stressors (namely, postural change, video game challenge, social competence interview, and parent--child conflict discussion). The BP and HR values taken during each of the laboratory stressors and during the post stressor recovery periods were converted to z-scores which were averaged to yield aggregate measures for systolic and diastolic BP and HR responsivity and recovery. The data obtained during the baseline evaluation were subsequently used to predict the follow-up values of supine resting BP and HR. The prediction models were fairly consistent across each of the 4 follow-up years. Responsivity or recovery accounted for up to 6% of the total variance after accounting for baseline values. Within the prediction models responsivity or recovery accounted for 4--56% of the variance. The predictive value of the derived models did not decline from one annual evaluation to the next over the length of the study. CV recovery may supplement resting and responsivity in the prediction of future development of CVD

The effects of life events on cardiovascular reactivity to behavioral stressors as a function of socioeconomic status, ethnicity, and sex

OBJECTIVE

The purposes of this study were 1) to examine the effects of stressful life events on cardiovascular reactivity to acute laboratory stressors in youth and 2) to determine whether these effects varied as a function of socioeconomic status, ethnicity, and/or sex.

METHODS

Four hundred eighty-three youths (mean age = 16.7 years; 249 Caucasian Americans [126 males, 123 females] and 234 African Americans [109 males, 125 females]) completed the Adolescent Resources Challenge Scale (ARCS), a measure of stressful life events, and underwent two laboratory stressors (a car-driving simulation and the Social Competence Interview) during which blood pressure, heart rate, cardiac output, and total peripheral resistance were assessed.

RESULTS

Youths who reported high levels of stressful life events showed smaller increases in blood pressure (both systolic and diastolic) and heart rate to the car-driving simulation but larger increases in cardiac output in response to the Social Competence Interview than did youths who reported low levels of stressful life events. The effect of stressful life events on cardiovascular reactivity was not moderated by sex, ethnicity, or socioeconomic status. Higher family socioeconomic status was associated with greater blood pressure, heart rate, and cardiac output increases in response to the Social Competence Interview.

CONCLUSIONS

The attenuating effects of stressful life events on cardiovascular reactivity in response to car-driving simulation in youths are consistent with an inoculation effect, whereas the potentiating impact of stressful life events on reactivity observed during the social stressor interview is compatible with a possible cost of coping effect.

Effects of race, sex, and socioeconomic status upon cardiovascular stress responsivity and recovery in youth

Cardiovascular (CV) responsivity to and recovery from acute laboratory stressors, as derived from aggregate scores of CV functioning during and after postural change, video game challenge, social competence interview, and parent-child conflict discussion, were evaluated in 272 youths [mean age 13.5 +/- 2.6 years; 162 Blacks (77 males, 85 females), 110 Whites (60 males, 50 females)], all with a positive family history of essential hypertension. Blacks demonstrated greater systolic and diastolic blood pressure (SBP, DBP) and lower heart rate responsivity compared to Whites (all P values < 0.05). A race by neighborhood socioeconomic status (SES) interaction for SBP responsivity was also observed where low SES Whites and high SES Blacks had the greatest responsivity compared to their same race cohorts. Additionally, upper SES Whites had the lowest total peripheral resistance responsivity. For recovery, Blacks and males exhibited higher SBP during recovery compared to Whites and females, respectively. These findings extend previous studies and provide further support for the hypothesis that recovery from stress is a potentially informative component of the contribution of stress responsivity to cardiovascular disease.

Central adiposity and hemodynamic functioning at rest and during stress in adolescents

OBJECTIVE

To examine the impact of central adiposity upon hemodynamic functioning at rest and during stress in adolescents.

DESIGN

Cross-sectional, correlational study.

SUBJECTS

46 White and 49 Black normotensive adolescents with family histories of essential hypertension.

MEASUREMENTS

Systolic and diastolic blood pressure (SBP, DBP), cardiac output and total peripheral resistance responses were assessed at rest, during postural change, video game challenge and forehead cold stimulation. Specific lower and higher waist-to-hip ratio (WHR) tertiles were created for each gender and then integrated for analyses. This resulted in a lower WHR tertile of 11 Whites and 21 Blacks and an upper WHR tertile of 15 Whites and 17 Blacks.

RESULTS

No differences in age, gender or ethnicity proportions were found between tertile groups (all P > 0.21). The upper WHR group showed greater body weight, waist and hip circumferences, body mass index (BMI), triceps skinfold and body surface area (all P < 0.001). Controlling for peripheral (that is, triceps skinfold) and overall (that is, BMI) adiposity, the upper WHR group exhibited greater SBP (that is, peak response minus mean pre-stressor level) to all three stressors and greater DBP reactivity to postural change and cold pressor (all P < 0.05).

CONCLUSION

Central adiposity appears to adversely influence hemodynamic functioning during adolescence. Underlying mechanisms responsible for these associations require exploration.

Prediction of left ventricular mass in youth with family histories of essential hypertension

To determine predictors of left ventricular mass (LVM) and hypertrophy (LVH), 56 black and 30 white normotensive healthy youths (mean age 12.6 +/- 2.3 years at initial visit) were studied twice, 2.5 years apart. During the initial visit, anthropometric variables and hemodynamics were measured at rest and before, during, and after 4 physical and behavioral stressors. 2-D directed M-mode echocardiography was performed to derive LVM. Hierarchical multiple regression analyses indicated that follow-up LVM was predicted by initial LVM, weight, height (ht), and gender (males > females; total model R2 = 0.77, P < 0.0001). Predictors of LVM/ht2.7 were initial LVM/ht2.7, weight, ethnicity (blacks > whites), and the aggregate index of blood pressure reactivity (total model R2 = 0.66, P < 0.0001). Youth with LVH at follow-up were taller, heavier, and exhibited greater blood pressure reactivity at initial evaluation. These findings are important since interventional strategies can be developed that target obesity and exaggerated reactivity to stress.

Determinants of endothelium-dependent femoral artery vasodilation in youth

OBJECTIVE

Decreased endothelium-dependent arterial dilation to reactive hyperemia has been shown in adults to be associated with various manifestations of cardiovascular diseases and cardiovascular risk factors. In a sample of children, we examined the relationships between flow-mediated femoral artery dilation and anthropometric, demographic, cardiovascular, and serum lipid variables that have been associated with cardiovascular diseases.

METHOD

Thirty-three asymptomatic, healthy 11 to 14 years olds were randomly selected from participants in a longitudinal cardiovascular health study. There were 17 boys and 16 girls; 21 whites and 12 blacks. Sixteen had documented family history of premature myocardial infarction (ie, < or = 55 years of age) in first-degree relatives and 17 did not. Measurements included fasting lipids, anthropometrics, blood pressure and heart rate at rest and during supine exercise, postural change, and forehead cold stimulation. Femoral artery dilation to reactive hyperemia was measured via high resolution ultrasound.

RESULTS

Bivariate analyses indicated flow-mediated dilation was negatively correlated with systolic pressure increases to postural change, forehead cold stimulation and dynamic exercise, greater average skinfold thickness, and body fat via dual x-ray absorptiometry and positively correlated with cardiovascular fitness (all ps < .05). Stepwise multiple regression revealed that cardiovascular fitness and systolic pressure reactivity to exercise significantly predicted flow-mediated dilation accounting for 31% of the variance (p < .01).

CONCLUSIONS

Decreased flow-mediated dilation is associated with decreased cardiovascular fitness, increased systolic pressure reactivity to various stressors, and increased indices of body fatness in asymptomatic youth. Further research is warranted to better understand early relationships between this noninvasive measure of endothelial function and cardiovascular risk factors in youth.

Prediction of resting cardiovascular functioning in youth with family histories of essential hypertension: a 5-year follow-up

Two hundred forty-six children (96 Whites, of whom 51 were males; 150 African- Americans, of whom 69 were males) with a familial history of essential hypertension (EH) were re-evaluated 5 years after an initial evaluation. During the initial visit anthropometric, demographic, and resting cardiovascular (CV) parameters (designated initial baseline levels) were assessed. These CV parameters (systolic and diastolic blood pressure [BP], heart rate, cardiac output index [CI], and total peripheral resistance index [TPRI] were also measured during postural challenge, a video game challenge, and a cold pressor task. At follow-up, resting CV parameters were again evaluated, and designated as follow-up resting levels. Moderate temporal stability (r range = .43-.56) was observed for all resting CV parameters. Mean stress responses for each CV parameter for all 3 stressors during the initial visit were positively related to the respective CV follow-up resting level. BP stress responses to postural change and video game challenge to be significant independent predictors of future resting BP after controlling for standard EH risk factors. Follow-up resting CI was not predicted by any stress responses, whereas follow-up resting TPRI was predicted by TPRI responses to the video game after controlling for standard Eh risk factors. These results contrast with those from an earlier 1-year follow-up, where stress responses for neither CI nor TPRI predicted follow-up resting levels. It appears that, as children get older, TPRI stress responses play a stronger role in vasoconstrictive function.

Anthropometric, demographic, and cardiovascular predictors of left ventricular mass in young children

Left ventricular (LV) mass is a strong independent predictor of cardiovascular morbidity and mortality. Few longitudinal studies have examined predictors of LV mass in children. This study assessed the contributions of anthropometric, demographic, and cardiovascular parameters (at rest and after exposure to laboratory stressors) as predictors of LV mass 3.6 years after the initial examination in a sample of 68 Caucasian and African-American children 7.9 +/- 0.7 years old. At the initial examination, all subjects had standard anthropometrics measured and hemodynamics assessed at rest and during 3 stressors: postural change, forehead cold stimulation, and treadmill exercise. On the follow-up examination 3 to 4 years later, echocardiographic evaluations were conducted to estimate LV mass and related LV geometry. LV mass and LV internal diameter in diastole were adjusted for linear growth (LV mass/height2.7 and LV internal dimension during diastole/height0.80, respectively). Hierarchical stepwise multiple regression analyses were conducted using parameters significant in univariate comparisons (p < 0.05). Initial weight (R2 = 0.38), height (R2 = 0.42), and cardiac output reactivity to standing and treadmill exercise (final model R2 = 0.55) were significant predictors of LV mass, whereas LV mass/height2.7 was predicted by initial adiposity (R2 = 0.07) and cardiac output and systolic pressure reactivity to postural change (final model R2 = 0.25). Follow-up relative wall thickness was significantly predicted by ethnicity (African-Americans greater than Caucasians, R2 = 0.15), adiposity (R2 = 0.20), and systolic pressure reactivity to postural change (final model R2 = 0.28). These findings suggest the potential benefit of weight control in childhood as a primary prevention for later onset of cardiovascular disease.

Effect of acute ethanol ingestion on orthostatic vital signs

STUDY OBJECTIVE

To determine the effect of acute ethanol intoxication on the results of orthostatic tilt testing.

DESIGN

Prospective, randomized crossover study. Subjects received ethanol (1.1 gm/kg) or an equal volume of water added to nonalcoholic beer. Orthostatic vital signs, ethanol concentration, and relative volume status were checked initially and hourly for 8 hours.

PARTICIPANTS

Twenty healthy human volunteers, 10 men, and 10 women.

RESULTS

Peak ethanol concentration was 116 +/- 18 mg/dL (mean +/- SD) 1 hour after ingestion. ANOVA for repeated measures revealed a significant difference in orthostatic pulse change and relative volume deficit between the ethanol and placebo groups (P < .05). Post hoc testing revealed significant differences between the two groups at two, five, seven and eight hours post ingestion for pulse change, and two to eight hours for volume status (Bonferroni's corrected t test, P < .0055). At 2 and 5 to 8 hours, there were significantly more positive tilt tests (+/- 30 beat/minute increase) in the ethanol group than in the placebo group (P < .05). Starting at 2 hours, the ethanol group had a statistically significant relative fluid deficit averaging .5 L by 3 hours. There was no difference in postural blood pressure changes between the two groups.

CONCLUSION

In healthy volunteers, ethanol intoxication resulted in exaggerated postural pulse changes and in a greater proportion of positive orthostatic tilt test results than in a placebo group. These changes were accompanied by significant relative fluid deficits.

When to measure resting values in studies of children's cardiovascular reactivity

Investigations suggesting that the order of obtaining resting and cardiovascular reactivity measurements moderates values have provided inconsistent results and have not analyzed data from children; the generalizability of results is uncertain. In this investigation, all children enrolled in the eighth-grade classrooms of the public schools of an entire county (n = 451) participated in standardized reactivity assessments. The order of resting and reactivity measurements was randomized by examination day (a total of 19 days). Analyses indicated that all comparisons of order effects on mean resting blood pressure and heart rate, as well as reactivity (both change from resting and absolute values and both mean and maximal values), were nonsignificant. Results indicate that measurement order is not always a necessary consideration in studies of reactivity; the conditions under which measurement order is a consideration requires clarification.

Pressor reactivity, ethnicity, and 24-hour ambulatory monitoring in children from hypertensive families

We assessed blood pressure responses of a multiethnic (Black and White) sample of 120 children of hypertensive families to orthostasis, video game, forehead cold, and dynamic exercise, and monitored the children's ambulatory pressure 24 hours later. Thirteen children were studied twice (1-year stability). The Black children exhibited higher 24-hour ambulatory systolic and diastolic pressures than the White children. Regardless of ethnicity, peak and mean systolic pressures during each task were generally positively correlated with mean systolic pressure while the children were awake and asleep. Associations between diastolic pressor responses and ambulatory measurements were somewhat dependent upon ethnicity and task. Relatively few reactivity-ambulatory correlations were significant, using pressor reactivity change scores. The children who participated twice exhibited significant 1-year stability for most ambulatory and pressor measurements. Children's pressor responses to laboratory tasks may generalize to the natural environment.

Consistency of ethnic differences in children's pressor reactivity. 1987 to 1992

In this prospective investigation, all children enrolled in the public third-grade classrooms of an entire county (n = 474) had blood pressure measured both at rest and during a stressful television video game. Examinations were repeated in 4 subsequent years when cohort children as well as newly enrolled children were in grades 4, 5, 7, and 8. Both cross-sectional and longitudinal analyses indicated that black children demonstrated significantly greater systolic and diastolic pressor reactivity than white children. These data suggest that ethnic differences in children's pressor reactivity presage ethnic differences in adulthood hypertension.

Validity of physicians' self-reports of cardiovascular disease risk factors

To determine the accuracy of self-reported risk factors in 78 physicians, self-reported information was compared to findings on a standardized examination. Measured weight (r = 0.98), height (r = 0.95), body mass index (r = 0.96), systolic blood pressure (SBP) (r = 0.72), and diastolic blood pressure (DBP) (r = 0.60) were highly correlated with self-reported values (all P < 0.0001). Mean self-reported SBP and DBP did not differ from measured values; measured weight was 1.5 kg greater and measured height 1.4 cm less than self-reported values (both p < 0.0001). Regression of measured on self-reported values indicated excellent agreement except for DBP and heart rate. Differences between measured and self-reported values were not associated with a variety of variables except for a greater difference in SBP at higher levels of SBP. None of the 60 self-reported nonsmokers had expired carbon monoxide levels greater than 10 ppm. These results indicate that physicians' self-reports of height, body mass index, SBP, and smoking are extremely accurate and suitable for research purposes.

Relationship between family environment and children's hemodynamic responses to stress: a longitudinal evaluation

Because interpersonal relationships may have an impact on the risk of developing cardiovascular disease, the authors examined the prospective relationship of family functioning upon hemodynamic stress responses in 87 6- to 8-year-old children. The parents completed the cohesion, conflict, expressiveness, and control subscales of the Family Environment Scale; 2 years later, the authors assessed the children's hemodynamic responses to postural change, forehead cold stimulation, and treadmill exercise. Maternal reports of greater cohesion and expressiveness were related to less increases in systolic pressure and systemic vascular resistance in response to the forehead cold. Mothers' reports of expressiveness were related to lower systolic pressure and cardiac index reactivity to postural change. Fathers' reports of greater control were associated with greater diastolic pressure and vascular resistance increases to forehead cold and to greater vascular resistance responses to exercise. Paternal reports of greater conflict were associated with greater systemic vascular resistance increases and with lower cardiac index increases to exercise. Results suggest family functioning may predict later hemodynamic reactivity to stress. The findings are discussed in terms of previous research on parent-child interaction patterns and children's cardiovascular health.

Ethnicity, pressor reactivity, and children's blood pressure. Five years of observations

During the 5 years of this investigation, resting blood pressure and pressor reactivity were measured in 292 white children and 46 black children in 1987, 1988, 1989, and 1991. In 1987, all children were in the third grade; in 1991, the children were in the seventh grade. Reactivity was assessed with a standardized psychological stressor, a television video game. Children displayed significant stability of absolute blood pressure and heart rate reactivity between grades 3 and 7. At all examinations, black children demonstrated blood pressure reactivity that was significantly greater in magnitude (both absolute level and change from resting measurements) than that of white children. Black children exhibited significantly greater heart rate reactivity only when defined as change from the resting measurements; absolute levels of heart rate reactivity were comparable for blacks and whites. For black children, blood pressure reactivity in 1987 was the strongest predictor of resting blood pressure (both systolic and diastolic) in 1991. Among white children, resting blood pressure was the strongest predictor of future resting blood pressure. Further research is needed to determine if ethnic differences in children's pressor reactivity are associated with ethnic differences in the prevalence of hypertension.

Baseline characteristics of participants in phase I of the Trials of Hypertension Prevention

Phase I of the Trials of Hypertension Prevention was designed to test the effectiveness and safety of three life-style (weight loss, sodium restriction, and stress management) and four nutrition supplement (calcium, magnesium, potassium, and fish oil) interventions in reducing diastolic blood pressure (DBP) in persons with a high-normal blood pressure. A total of 2182 persons with a DBP between 80 and 89 mm Hg met the eligibility criteria for participation in phase I and were randomized to one of the active intervention or control treatment groups. Most were white (82%), male (70%), married (76%), nonsmoking (88%), college graduate (53%), full-time employees (91%). The average blood pressure prior to entry into the trial was 124.9 mm Hg systolic and 83.8 mm Hg diastolic. A variety of baseline observations, including sociodemographic characteristics, personal and family medical history, health habits, diet, and biologic measurements, were documented before randomization and compared among the seven active intervention and control groups. As might be expected in a randomized trial of this sample size, the distribution of measured baseline characteristics was virtually identical in the treated and control groups. Based on this finding and the knowledge that randomization procedures were implemented without deviation from the phase I protocol, it is probable that unknown potential confounders were also equally distributed at entry into the study. Given the achievement of high rates of follow-up, subsequent differences in blood pressure are unlikely to have been due to baseline differences between the active treatment and control groups, and can probably be attributed to effects of the active interventions.