Seasonal modifications in blood pressure are mainly related to interdialytic body weight gain in dialysis patients.

Argiles A, Lorho R, Servel MF, Chong G, Kerr PG, Mourad G.

Laboratoire de Genomique Fonctionelle-CNRS UPR 2580; Department of Nephrology, University Hospital Lapeyronie, Montpellier, France. Angel.Argiles igh.cnrs.fr

BACKGROUND: Longitudinal studies in dialysis patients have identified seasonal variations in blood pressure that may follow climatic parameters such as external temperature and humidity. We aimed to assess the participation of interdialytic body weight gain variations in the seasonal profile of blood pressure. METHODS: Ninety-nine stable patients (40 F/59 M), 52.9 +/- 1.5 years old, dialyzed in a single satellite dialysis unit between January 7, 1991, and September 30, 1998 were studied. Supine systolic and diastolic blood pressure, body weight, and interdialytic body weight gain were determined at every one of the 38,769 dialyses included, and studied along with climatology data obtained from Meteo, France. RESULTS: Blood pressure varied throughout the year, following a cyclic pattern. It increased from the autumn months toward winter, and decreased toward the spring and warmer months. Systolic and diastolic blood pressures were strongly correlated with interdialytic body weight gain (r= 0.925; P < 0.0001 and r= 0.888; P= 0.0001, respectively). Blood pressure was also correlated with the climatic factors: rainfall (r= 0.786; P < 0.003 and r= 0.784; P < 0.003), humidity (r= 0.701; P= 0.011 and r= 0.699; P < 0.012), and day light span (r=-0712; P < 0.01, and r=-0.658; P < 0.02, respectively). Multivariate regression analyses taking blood pressure as a dependent variable retained interdialytic body weight gain as the first variable in the model. CONCLUSION: Our results establish a strong link between blood pressure variations and interdialytic body weight gain, showing the important participation of volume state in modulating blood pressure in this group of patients.

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Patterning of renal cGMP production by the natriuretic peptide receptor type A and blood pressure in spontaneously hypertensive rats.

Woodard GE, Zhao J, Rosado JA, Brown J.

Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK. GeoffreyW intra.niddk.nih.gov

Although important advances have been made over past decades in studying the mechanisms of hypertension, the nature of cellular signaling patterns involved and their relationship remain unclear. High cGMP production rates in isolated renal glomeruli have been presented as a characteristic of spontaneously hypertensive rat (SHR) even before the development of hypertension, which suggests that this event might be a cause of the increase in blood pressure. Using cross-breeding between SHR and WKY parental strains to obtain F1 and F2 hybrids, we have investigated the patterning of high blood pressure and cGMP production rates. We have found that, in the F2 population, the mean blood pressure and both basal and ANP(1-28)-stimulated cGMP production are similar to the parental SHR. In addition, we have found a positive correlation between blood pressure and high cGMP production rates in the F2 population. The higher cGMP production was not a consequence of hypertension, since in DOCA-salt hypertensive rats cGMP production was similar to that observed in normotensive WKY rats. These observations suggest that high cGMP production is a characteristic linked to hypertension. Finally, reciprocal crosses between the SHR and WKY parental strains showed that in the F1 population blood pressure but not cGMP production are associated with the Y chromosome.

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Lead effect on blood pressure in moderately lead-exposed male workers.

Telisman S, Pizent A, Jurasovic J, Cvitkovic P.

Department of Occupational and Environmental Health, Institute for Medical Research and Occupational Health, Zagreb, Croatia. telisman imi.hr

BACKGROUND: The effect of lead (Pb) and potential confounding variables on blood pressure was examined in healthy male industrial workers 20-43 years of age. METHODS: In 100 Pb workers and 51 reference subjects, the following variables were measured: blood Pb (BPb), activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum zinc (SZn), serum copper (SCu), hematocrit (Hct), body mass index (BMI), and blood pressure. The inter-relationship of biomarkers of Pb (BPb, ALAD, EP) and BCd, SZn, SCu, Hct, BMI, age, smoking, and alcohol to systolic and diastolic blood pressure was calculated by forward stepwise multiple regression. RESULTS: There was no significant difference in blood pressure between the two groups, possibly because the reference subjects had relatively high BPb levels and significantly higher BMI (P < 0.05) as compared to the Pb workers. According to the multiple regression results in Pb workers, an increase in systolic blood pressure was significantly associated with increasing EP (P = 0.001) and BMI (P < 0.002), or alternatively with increasing BMI (P < 0.004) and decreasing ALAD (P < 0.04) and BCd (P < 0.05). An increase in diastolic blood pressure was significantly associated with increasing BMI (P < 0.009) and EP (P = 0.05) and decreasing BCd (P < 0.04). With respect to the EP range of 0.73-13.94 micromol/l erythrocytes in 100 Pb workers, an increase of 17 mm Hg in systolic and 6 mm Hg in diastolic blood pressure was found. CONCLUSIONS: Long-term cumulative Pb exposure, which is better reflected by EP than by ALAD or current BPb level, can significantly increase blood pressure in moderately Pb-exposed male workers (long-term average BPb <400 microg/l; exposure duration 2-21 years). Copyright 2004 Wiley-Liss, Inc.

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Hypertensive Encephalopathy.

Williams O, Brust JC.

Department of Neurology.

The term hypertensive encephalopathy should be reserved for patients with diffuse cerebral effects of precipitous and sustained rises in blood pressure that reverse when blood pressure is lowered and are not due to infarction or hemorrhage. The definitive diagnosis of this syndrome depends on accurate exclusion of other causes that may be associated with elevated blood pressure and neurologic deficits. Treatment is aimed at preventing or limiting target organ (brain) damage. Therapy should be individualized but centered on reducing the mean arterial blood pressure within a period of minutes to 2 hours, by no more than 20% to 25% or to a diastolic blood pressure of 100 to 110 mm Hg (whichever is higher), using short-acting intravenous agents. Oral or sublingual agents should generally be avoided in hypertensive encephalopathy because they are more likely to cause precipitous falls in blood pressure.

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Wrist blood pressure overestimates blood pressure measured at the upper arm.

Palatini P, Longo D, Toffanin G, Bertolo O, Zaetta V, Pessina AC.

Department of Clinical and Experimental Medicine, University of Padova, Italy. palatini unipd.it

OBJECTIVE: Whether blood pressure (BP) measured at the wrist differs from blood pressure measured at the arm is not well known. The aim of this study was to compare the BP readings obtained at the arm with those obtained at the forearm and to assess whether the wrist-arm discrepancies were related to subjects' clinical characteristics. METHODS: We measured blood pressure at the forearm and at the upper arm in 85 subjects using conventional sphygmomanometry. Wrist-arm blood pressure discrepancies were assessed in relation to gender, age, body mass index, skin-fold thickness, arm size, blood pressure level, and arterial compliance measured with the HDI/Pulsewave CR-2000. RESULTS: Blood pressure measured at the wrist consistently overestimated blood pressure taken at the arm with a mean (+/-SD) discrepancy of 8.2 +/- 9.7/9.2 +/- 6.4 mmHg. The systolic blood pressure differences were greater in men than in women (p=0.006) and, among the men, varied according to arm adiposity (positive association, p=0.01). In men, diastolic blood pressure differences correlated with diastolic blood pressure level (negative association, p=0.01). Among the women, only age (p=0.04) was a significant positive independent predictor of the wrist-arm diastolic BP differences. CONCLUSIONS: These results indicate that forearm blood pressure measurement markedly overestimates upper arm blood pressure and that the between-site difference may vary from subject to subject. Wrist blood pressure measurement is not a valid alternative to traditional measurement at the arm and its use should be discouraged.

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Blood pressure and rhinitis in adults: results of the MONICA/KORA-study.

Heinrich J, Doring A.

National Research Center for Environment and Health, GSF-Institute of Epidemiology, PO Box 1129, D-85758 Neuherberg, Germany. joachim.heinrich gsf.de

OBJECTIVE: A study of 330 adults reported increased systolic blood pressure and higher hypertension prevalence rates in men with rhinitis. The authors replicated this study. DESIGN: This cross-sectional study analysed data on blood pressure, medication and allergic rhinitis.Setting A random population-based sample was selected from the City of Augsburg, Germany. PARTICIPANTS: Data from a population-based sample of 2613 subjects (response rate 75%), who participated in the MONICA Augsburg Study (Monitoring of Trends and Determinants of Cardiovascular Diseases) and answered the screening questionnaire of the European Respiratory Health Survey (ECRHS) in Augsburg, Germany. METHODS: Rhinitis was assessed by ECRHS screening questionnaire, blood pressure was measured according to the MONICA protocol and subjects were asked about the current use of any high blood pressure medication. RESULTS: After adjustment for age, body mass index, hypercholesterolemia and smoking, neither average systolic (132.3 versus 132.9 mmHg, P = 0.64) nor diastolic blood pressure (83.8 versus 83.8 mmHg, P = 0.97) was statistically significantly different between men with and without rhinitis. The adjusted prevalence rate of hypertension was also not different between males with and without rhinitis (odds ratio 1.02, 95% confidence interval 0.728-1.436, P = 0.74). In addition, no statistically significant associations between rhinitis and confounder-adjusted blood pressure means or hypertension were seen in women. CONCLUSION: The authors could not confirm the conclusion of the previous study that men with rhinitis need special attention for blood pressure control.

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The influence of low job control on ambulatory blood pressure and perceived stress over the working day in men and women from the Whitehall II cohort.

Steptoe A, Willemsen G.

Department of Epidemiology and Public Health, University College London, 1-19 Torrington Place, London WC1E 6BT, UK. a.steptoe ucl.ac.uk

OBJECTIVE: Work stress contributes to risk of coronary heart disease and hypertension. This study tested the influence of job control on ambulatory blood pressure, and ratings of perceived stress and happiness in men and women systematically sampled by socio-economic status from the Whitehall II epidemiological cohort. PARTICIPANTS: A total of 227 men and women aged 47-59 years sampled from higher, intermediate and lower employment grades. OUTCOME MEASURES: Ambulatory blood pressure and ratings of stress, perceived control and happiness. METHODS: Participants completed standard measures of job demands and job control, and undertook ambulatory monitoring with measures of blood pressure and subjective state every 20 min from early in the working day until going to bed. RESULTS: Systolic and diastolic blood pressure were greater in participants reporting low rather than high job control (means 125.7/81.5 versus 122.4/78.6 mmHg, P < 0.05), independently of gender, employment grade, body mass index, age, smoking status, and physical activity. Differences persisted into the evening after work. Job demands and job strain (high demand/low control) were not associated with blood pressure. Participants reporting low job control experienced stress more frequently over the working day than did those with high job control. Higher socio-economic status participants and women were more stressed by low job control than were men and people of lower socio-economic status. CONCLUSIONS: Job control plays an important role in modulating cardiovascular and affective responses over the working day, and these responses may contribute to increased cardiovascular disease risk.

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Blood pressure in relation to three candidate genes in a Chinese population.

Wang JG, Liu L, Zagato L, Xie J, Fagard R, Jin K, Wang J, Li Y, Bianchi G, Staessen JA, Liu L.

Hypertension Division, Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. jiguang.wang med.kuleuven.ac.be

OBJECTIVE: In a prospective analysis of a Caucasian population, we recently found that the genes encoding angiotensin-converting enzyme (ACE, I/D polymorphism), alpha-adducin (Gly460Trp) and aldosterone synthase (-344C/T) jointly influence the incidence of hypertension. We therefore investigated the association between blood pressure and these three genes in a Chinese population. METHODS: We genotyped 479 Han Chinese from 125 nuclear families recruited in northern China via random sampling (approximately 75%) and at specialized hypertension clinics (approximately 25%). We performed population-based and family-based association analyses using generalized estimating equations (GEE) and the quantitative transmission disequilibrium test (QTDT), respectively, while controlling for covariables. RESULTS: The participants included 239 (49.9%) women and 132 (27.6%) hypertensive patients, of whom 77 took antihypertensive drugs. The blood pressure, measured at the subjects' homes, averaged 126/80 mmHg. Mean values of urinary sodium, potassium and Na/K ratio were 226 mmol/day, 37 mmol/day and 6.31, respectively. In adjusted GEE analyses, systolic blood pressure was 9.3 mmHg (95% confidence interval 3.6-15.0 mmHg; P = 0.001) and 14.6 mmHg (95% confidence interval 3.4-25.8 mmHg; P = 0.01) higher in the ACE DD than II subjects among the alpha-adducin TrpTrp (n = 141) and aldosterone synthase CC (n = 33) homozygotes, respectively (P < or =0.05 for interactions of the ACE genotype with the alpha-adducin and aldosterone synthase polymorphisms). Among 40 informative offspring homozygous for the alpha-adducin Trp allele, systolic blood pressure was significantly associated with transmission of the ACE D allele (beta = 5.5 mmHg; P = 0.046). CONCLUSIONS: The ACE I/D, alpha-adducin Gly460Trp and aldosterone synthase -344C/T polymorphisms interact to influence systolic blood pressure in Chinese, suggesting that these genes might indeed predispose to hypertension, especially in an ecogenetic context characterized by a high salt intake.

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