Differential circadian catecholamine and cortisol responses between healthy women with and without a parental history of hypertension.

OBJECTIVES: Previous studies suggest that otherwise healthy individuals who have a parental history of hypertension (PH+) have an accentuated reactive rise in catecholamines and cortisol to laboratory stressors as well as elevated plasma levels when compared with those with no parental history (PH-); however, few, if any, studies have evaluated whether parental history affects the responses of these hormones to changing environmental circumstances in everyday life. The purpose of this study was to compare urinary catecholamine (epinephrine and norepinephrine) and cortisol excretion and ambulatory blood pressures (BPs) across three daily microenvironments between women with and without a parental history of hypertension. METHODS: The women in the study (PH+, N = 62, age = 35.2 ± 9.1; PH-, N = 72, age = 33.8 ± 10.0) worked in clerical, technical, or professional positions at a major medical center in New York City. Urinary hormone excretion rates and ambulatory BP were measured across three daily microenvironments: work (11 am to 3 p.m.), home (approximately 6 p.m. to 10 p.m.), and during sleep (approximately 10 p.m. to 6 a.m.). History group comparisons by microenvironment were made using repeated-measures ANCOVA and ANOVA analyses. RESULTS: The results show that epinephrine excretion among PH+ women was 36% higher than PH- women (P < 0.008) over the entire day and that nocturnal cortisol excretion was also greater among PH+ women (P < 0.045). PH+ women also had statistically significantly higher systolic (4 mm Hg higher; P < 0.01) and diastolic (2 mm Hg higher, P < 0.03) BP when compared with PH- women across all daily microenvironments. CONCLUSION: These findings suggest that there may be genetically linked mechanisms which elevate tonic epinephrine levels and nocturnal cortisol levels that contribute to elevating circadian BP.

Relationships between diurnal changes in blood pressure and catecholamines among Filipino-American and European-American women.

OBJECTIVES: Studies show that diurnal blood pressure (BP) sensitivity to epinephrine (EPI) in African-American women is significantly greater than that of European-American (EA) women. Few if any studies have examined diurnal catecholamine-BP relationships in women of other ethnic groups. The purpose of this study was to compare the effects of diurnal changes in EPI and norepinephrine (NE) on the diurnal changes in BP between Filipino-American (FA) and EA women. METHODS: The subjects included 31 FA and 27 EA nurses and nurses aides and eight FA and 19 EA hotel workers from Hawaii who wore an ambulatory BP monitor and collected timed urine specimens (4 h at work, approx.4 h at home and approx. 8 h overnight) for assay of EPI and NE. Proportional changes in systolic and diastolic BP from sleep to work and sleep to home were examined using ANCOVA models including fixed effect-covariate interactions, with ethnicity as a fixed factor, and BMI and the appropriate proportional change in EPI or NE as covariates. RESULTS: The results show that there was no association between changes in EPI and BP, either overall or by ethnic group; however, overall changes in diastolic BP from sleep to work tended to be smaller among the FAs (P < 0.06). There was also an interactive effect of NE and ethnic group on diastolic BP such that among FAs, as diastolic BP increased, the corresponding NE change decreased (P < 0.039). CONCLUSION: The relationships between diurnal BP and catecholamine variations differ by ethnicity. Further research is needed to better understand the mechanisms behind the differences and to evaluate whether this vascular tonic relationship has been the focus of natural selective processes.

Ambulatory blood pressure and blood lipids in a multiethnic sample of healthy adults.

OBJECTIVES: Elevated blood pressure (BP), elevated serum cholesterol, and aberrant lipoprotein fractions (low levels of high-density lipoprotein (HDL) and high levels of low-density lipoprotein fractions and triglycerides) have all been used as measures that assess the "metabolic syndrome" and more recently in indexes of allostatic load, which are designed to assess the degree of integrated metabolic pathology. While there are ample data regarding the interrelationships of these measures in various pathophysiological settings, there are limited data regarding the interrelationship of ambulatory BP (ABP) and blood lipids in healthy subjects. The present study evaluates ABP-blood lipid relationships in a multiethnic sample of healthy adults. METHODS: The subjects were 37 men (age = 40.9 ± 10.7 years) and 42 women (age = 35.8 ± 10.4 years) who were employed as hotel workers in Hawaii. Each wore an ABP monitor for one midweek workday and had pressures averaged in three daily microenvironments (work, home, and during sleep). They also had fasting blood samples taken for lipid profiling. RESULTS: Multivariate analysis of covariance shows that there was a strong inverse relationship between HDL and both systolic (P < 0.006) and diastolic (P < 0.006) BP, overall and in each microenvironment, but no statistically significant relationships with other lipid measures. CONCLUSION: These results suggest lipids and BP do not act as a group in healthy adults but that higher HDL is associated with lower BP. This latter finding is consistent with research that shows that HDL promotes vasodilation via its effect on endothelial nitric oxide synthase.

The reproducibility of ethnic differences in the proportional awake-sleep blood pressure decline among women.

A growing body of evidence indicates that African Americans (AA), on average, have a smaller proportional decline in blood pressure (BP) from waking to sleep than European Americans (EA), but this difference is largely based on correlational data from a single assessment day. The persistence of this difference over repeated sampling is not well established. The purpose of this study was to evaluate whether ethnic differences in the awake-sleep BP decline between AA and EA persisted over three monthly assessments. The subjects were 47 AA (age = 39.7 +/- 8.7) and 92 EA (age = 37.4 +/- 9.2) normotensive women. Subjects had 24-h ambulatory BP monitoring done on midweek workdays at 1-month intervals for three consecutive months. The proportional decline in BP was calculated as follows: (average awake - average sleep)/average sleep. The persistence of ethnic differences was evaluated using repeated-measures ANCOVA and by examining Bland-Altman plots. The ANCOVA results revealed that overall, the proportional decline of AA women was less than that of EA women for both SBP (P < 0.038) and DBP (P < 0.083), consistent with previous research, and that there were also no significant ethnic differences by monthly assessment. Bland-Altman plots revealed that overall and by ethnicity, the proportional decline in BP among individual subjects over the 3 months was also reproducible. These results suggest that the ethnic difference in awake-sleep BP between AA and EA women persists over time and that the awake-sleep decline in BP among individuals, whether AA or EA, is also reproducible.

Relationship between waking-sleep blood pressure and catecholamine changes in African-American and European-American women.

BACKGROUND: A blunted decline in waking to sleep blood pressure (BP) is more common in African-American (AA) than European-American (EA) women. The causes of reduced BP 'dipping' in AA women are not known, although several factors including ethnic differences in catecholamine sensitivity have been suggested. The purpose of this study was to investigate the possible contribution of catecholamine influences on BP to ethnic differences in BP dipping in a sample of working women. PARTICIPANTS AND METHODS: Healthy female participants wore ambulatory BP monitors over the course of 1 work day and night. Urine samples for assay of epinephrine and norepinephrine were collected at work (approximately 11.00-15.00 h), home (approximately 06.00-22.00 h) and during sleep (approximately 22.00-06.00 h). Analysis of covariance was used to assess the relationships between changes in BP and the catecholamines by ethnicity. RESULTS: AA women (n=51; age=38.9+/-8.5 years) had smaller proportional BP changes from work to sleep and home to sleep than EA women (n=110; age=37.1+/-9.2 years). Overall, the work to sleep change in epinephrine excretion was positively associated with changes in both SBP (P<0.003) and DBP (P<0.001); however, there was an ethnic difference in the epinephrine-BP relationship. For AA women, these associations were highly positive and significant, but for EA women, there was little correlation. Nonetheless, the analysis also revealed that overall, the work to sleep BP changes were not directly related to ethnic differences in catecholamine variation. CONCLUSION: The AA-EA difference in waking-sleep BP changes (dipping) is not directly related to ethnic differences in catecholamine variation; however, AA seem to have a greater BP sensitivity to epinephrine.

Heightened cortisol responses to daily stress in working women at familial risk for breast cancer.

Consistent with animal models and experimental studies with humans facing other 'background' stressors, women at familial risk for breast cancer have been reported to have stronger cortisol responses to laboratory stressors. To explore the relevance of these findings to daily life, we compared work-stress cortisol responses in women with >or=1 first-degree relative with breast cancer (FH+, n = 74) to women without this risk factor (FH-, n = 141). Repeated-measures ANOVA revealed a group by time interaction (p

Serum electrolyte, serum protein, serum fat and renal responses to a dietary sodium challenge: allostasis and allostatic load.

OBJECTIVE: The purpose of this study was to assess, in borderline hypertensive subjects, the homeostatic and allostatic responses of serum electrolytes, proteins, lipids, hematocrit and renal function to an extreme dietary sodium challenge, and to evaluate whether the responses in these clinical parameters were associated with a concomitant response in blood pressure. SUBJECTS AND METHODS: Data from middle-aged adults with a diagnosis of mild, uncomplicated borderline hypertension were collected at the end of 1-month randomized trials of low (24 +/- 13 mmol/day) and high (309 +/- 88 mmol/day) dietary sodium intake. A total of 48 subjects (38 men and 10 women) were examined. RESULTS: Serum sodium increased (p < 0.001), while all other serum electrolytes, except chloride, decreased (p < 0.01) from the low to high sodium diets. Serum proteins (p < 0.05) and hematocit (p < 0.001) also declined among subjects on a high sodium diet. However, creatinine clearance (an indicator of glomerular filtration) increased with sodium intake (p = 0.004). None of these biochemical or renal functional responses was associated with a change in blood pressure. CONCLUSION: There are modest yet significant changes in serum electrolytes associated with changes in dietary sodium intake, suggesting that these ions are under an allostatic control mechanism. Serum proteins also appear to function as allostatic compensatory mechanisms, offsetting the net effect of increased serum salinity. It is speculated that the adaptive allostatic renal response to a high sodium diet (an increase in GFR) may result in loss of the ability to appropriately vary renal filtration if that diet is chronically maintained.