Organisational factors in relation to control of blood pressure: an observational study

BACKGROUND: Studies show that 60-75% of treated patients with hypertension in general practice, still do not reach the recommended blood pressure targets of <150/90 mmHg. AIM: To investigate aspects of hypertension management in relation to sociodemographic variables, antihypertensive drug treatment, and organisational factors in primary care. DESIGN OF STUDY: Observational study over 3 years. SETTING: Eight general practices in Tayside, UK. METHOD: Participants were 560 randomly selected patients aged 40-79 years receiving treatment for hypertension. The outcome measurement was blood pressure control, expressed in binary form based on the British Hypertension Society audit standard of <150/90 mmHg. RESULTS: Of 536 eligible patients, 261 (49%) were defined as having inadequate blood pressure control at the end of the study period. No significant associations were discovered with sex, age, deprivation score and comorbidity. In those patients with inadequate control, 30% had no modifications to their drug treatment during the study period. Blood pressure control at the end of the study period was not associated with number of antihypertensive drugs taken or number of antihypertensive drug modifications. The mean number of clinician contacts was 11 (standard deviation = 8), and mean continuity in primary care was high, although this was not associated with improved blood pressure control. A higher proportion of hypertension-related consultations were associated with increased odds of having inadequate blood pressure control. CONCLUSION: Achieving adequate blood pressure control continues to represent a substantial health problem in a significant proportion of the hypertensive population. Patient, physician and organisational elements play a role in ensuring effective delivery of hypertension care in the community.     

Twelve-year tracking of blood pressure in Korean school children: the Kangwha Study.

Longitudinal data from different populations have shown different degrees of tracking of blood pressure (BP). To examine BP tracking in Korean school children, 219 of 430 children (100 males, 119 females) who were 6 years old in 1986 in Kangwha County, Korea have been examined annually up to 1997 in the Kangwha Study. BP was measured twice with standard mercury sphygmomanometers and the average of the two measurements was used for the level of BP. Diastolic BP were measured at the fourth Korotkoff sound. Tracking was examined using a time-lag correlation analysis and McMahan's tracking index tau, which indicates the proportion of variation attributable to tracking apart from the natural growth component. As well the jackknife method was used to obtain the confidence interval of tau. Correlation coefficients between systolic BP from age 6 to 17 ranged from 0.39-0.54 for males and 0.44-0.57 for females. Taus for systolic BP were 0.875 (95% CI: 0.803-0.947) and 0.900 (95% CI: 0.809-0.991) in males and females, respectively. Correlation coefficients between diastolic BP from age 6 to 17 ranged from 0.28-0.47 for males and 0.14-0.47 for females. Taus for diastolic BP were 0.983 (95% CI: 0.897-1.000) and 0.800 (95% CI: 0.717-0.883) in males and females, respectively. These findings showed strong evidence for BP tracking in Korean school children from childhood to late adolescence.     

Modeling the effects of nutritional and socioeconomic factors on the growth and morbidity of Kenyan school children

This paper estimates dynamic models for the height, head circumference, weight, and morbidity of approximately 110 Kenyan school children (6–9 years) in a multivariate longitudinal data framework. Dynamic models allow anthropometric dimensions to depend on the respective measurements in the previous period. The system of 4 equations specified for height, head circumference, weight, and morbidity incorporates the inter-relationships among these variables; explanatory variables in the model consist of nutritional, socioeconomic, demographic, and environmental factors. The model parameters are estimated using the principle of maximum-likelihood, while controlling for the unobserved between-children differences. The main findings are, first, that calcium intakes are positively associated with height while protein and energy intakes are associated with weight. Vitamin A intakes are negatively associated with morbidity. Second, socioeconomic status plus the cash income of the household is a significant predictor of height, head circumference, and morbidity. Third, maternal height is positively associated with children's height and maternal body mass index (BMI) is positively associated with children's weight. Fourth, parents' scores on psychological tests, mother's age, and children's hemoglobin concentration are negatively associated with morbidity while mothers' morbidity is positively associated with children's morbidity. Implications of the modeling results are discussed. Am. J. Hum. Biol. 11:317–326, 1999. © 1999 Wiley-Liss, Inc.     

Blood pressure reactions to acute psychological stress and future blood pressure status: a 10-year follow-up of men in the Whitehall II study

OBJECTIVE: The aim of this study was to examine whether blood pressure reactions to mental stress predicted future blood pressure and hypertension. METHODS: Blood pressure was recorded at an initial medical screening examination after which blood pressure reactions to a mental stress task were determined. A follow-up screening assessment of blood pressure and antihypertensive medication status was undertaken 10 years later. Data were available for 796 male public servants, between 35 and 55 years of age upon entry to the study. RESULTS: Systolic blood pressure reactions to mental stress were positively correlated with follow-up screening systolic blood pressure and to a lesser extent, follow-up diastolic pressure. In multivariate tests, by far the strongest predictors of follow-up blood pressures were initial screening blood pressures. In the case of follow-up systolic blood pressure, systolic reactions to stress emerged as an additional predictor of follow-up systolic blood pressure. With regard to follow-up diastolic blood pressure, reactivity did not enter the analogous equations. The same outcomes emerged when the analyses were adjusted for medication status. When hypertension at 10-year follow-up was the focus, both systolic and diastolic reactions to stress were predictive. However, with correction for age and initial screening blood pressure, these associations were no longer statistically significant. CONCLUSIONS: The results of this study provide modest support for the hypothesis that heightened blood pressure reactions to mental stress contribute to the development of high blood pressure. At the same time, they question the clinical utility of stress testing as a prognostic device.     

Relationships between serial childhood adiposity measures and adult blood pressure: The Fels longitudinal study

Objectives: Several studies have shown that causes of adult hypertension arise in childhood, and obesity may be a potential cause or at least a mitigating factor in this development. Body mass index is a well studied obesity metric, yet other potential adiposity measures such as percent body fat and waist circumference have been somewhat less considered. The purpose of this study is to determine associations between these alternative serial childhood adiposity measures and adulthood blood pressure. Methods: Measurements from participants in the Fels Longitudinal Study were used to summarize childhood adiposity, represented by childhood measurements of percent body fat and height‐adjusted waist circumference. These subjects also provided systolic and diastolic blood pressure as adults. Childhood adiposity levels were categorized as high or low as compared to the respective upper quartile, and associations with adult blood pressure were measured using Poisson regression to estimate the number of expected occurrences of elevated adiposity during childhood. Adult lifestyle covariates and adiposity were accounted for using multiple linear regression. Results: Summary indices of the childhood adiposity measures were significantly associated with both adult blood pressure metrics in men and women, though some of these associations were altered or reduced in the presence of adult lifestyle characteristics and adult adiposity measures. Conclusions: Childhood measures of percent body fat and height‐adjusted waist circumference have an effect on adult blood pressure, though the effect can be mitigated by adult lifestyles. Am. J. Hum. Biol., 2010. © 2010 Wiley‐Liss, Inc.     

Contribution of early intervention and early caregiving experiences to resilience in low-birthweight,premature children living in poverty

Examined the Infant Health and Development Program (IHDP) and the quality of care experienced at home by premature, low-birthweight children (LBW) living in poverty. Only 26 of 243 LBW children (11%) who received no intervention were identified as functioning in the normal range for cognitive, social/adaptive, health, and growth parameters at age 3 compared to 59 out of 153 (39%) from the intervention group. LBW children who showed early signs of resiliency differed from nonresilient children in that they were receiving more responsive, accepting, stimulating, organized care in their own homes; and they were living in safer, less crowded homes. Overall, premature, LBW children born into poverty have a very poor prognosis of functioning within normal ranges in all domains of development. However, those reared in a setting with three or more protective factors and those who participated in the IHDP intervention more often showed early signs of resiliency.     

学龄儿童行为问题综合研究(之二)——临床病例对照研究

我们的临床病例对照研究资料表明:儿童行为问题的发生与儿童各个发育阶段很多环节和许多方面因素有关,从发育阶段来看,涉及到母孕期,围产期,婴幼儿期和学龄期四个时期,从影响因素来看,既涉及到生物医学因素也涉及社会和心理因素,而在不同时期的主要危险因素则又有所不同,母孕和围产期以生物学危险因素为主,随着年龄增大,在婴儿期,特别是学龄期社会心理因素所起作用愈来愈大,生物学因素有可能构成了行为儿童的素因。而环境因素,教育因素,社会心理因素构成了行为问题的诱因和调节因素,这些危险因素包括研究之一所发现的因素可能处于一个大的控制系统中。     

Cardiac morphology and blood pressure in the adult zebrafish

Zebrafish has become a popular model for the study of cardiovascular development. We performed morphologic analysis on 3 months postfertilization zebrafish hearts (n > or = 20) with scanning electron microscopy, hematoxylin and eosin staining and Masson's trichrome staining, and morphometric analysis on cell organelles with transmission electron photomicrographs. We measured atrial, ventricular, ventral, and dorsal aortic blood pressures (n > or = 5) with a servonull system. The atrioventricular orifice was positioned on the dorsomedial side of the anterior ventricle, surmounted by the single-chambered atrium. The atrioventricular valve was free of tension apparati but supported by papillary bands to prevent retrograde flow. The ventricle was spanned with fine trabeculae perpendicular to the compact layer and perforated with a subepicardial network of coronary arteries, which originated from the efferent branchial arteries by means of the main coronary vessel. Ventricular myocytes were larger than those in the atrium (P < 0.05) with abundant mitochondria close to the sarcolemmal. Sarcoplasmic reticulum was sparse in zebrafish ventricle. Bulbus arteriosus was located anterior to the ventricle, and functioned as an elastic reservoir to absorb the rapid rise of pressure during ventricular contraction. The dense matrix of collagen interspersed across the entire bulbus arteriosus exemplified the characteristics of vasculature smooth muscle. There were pressure gradients from atrium to ventricle, and from ventral to dorsal aorta, indicating that the valves and the branchial arteries, respectively, were points of resistance to blood flow. These data serve as a framework for structure-function investigations of the zebrafish cardiovascular system.     

Tracking of blood pressure in children and youth

Part of a preventive pediatric strategy against cardiovascular diseases is the early identification of hypertension in childhood. There is a clearly established relationship between blood pressure measured during childhood and at later periods for the same individual. This relationship was investigated in studies of blood pressure tracking in children over the past two decades. This report reviews longitudinal studies that analysed tracking of blood pressure between the ages of 4 and 20 years. The results confirm the existence of tracking, but the statistical relationship seems too weak to justify preventive pediatric strategies based on blood pressure in childhood. However, during adolescence, tracking of blood pressure is affected by the processes of growth and maturation. Methodological problems may have also resulted in underestimation of the amount of tracking. An increase in the number of blood pressure measurements and the use of vertex-corrected blood pressure values would probably improve tracking. It is important to analyse the improvement in tracking coefficients when these new methods are used in order to determine the maximal extent to which blood pressure in childhood can predict future levels. Recently, several studies that were able to relate blood pressure values from childhood to adulthood suggested that tracking seems to persist over this long period. Together with comparable results from future analyses of studies considered in this review, more detailed information will become available about the predictability of blood pressure in children. Although blood pressure is the best single predictor of future blood pressure, results of this review indicate that its predictability is not sufficiently strong for preventive strategies in childhood. Therefore, the development of blood pressure predictors based on more than one parameter is recommended. © 1994 Wiley-Liss, Inc.     

Nutritional status of children from Papua New Guinea: Associations with socioeconomic factors

Growth faltering has been well documented in children from Papua New Guinea, although there is evidence that broad processes of modernization, such as cash cropping, have resulted in increased body size. It is not clear, however, what household socioeconomic factors may be associated with larger body size in populations undergoing early stages of modernization. This cross‐sectional study examined the nutritional status of children between birth and 5 years of age living near Kanabea, Papua New Guinea, a relatively remote outpost in the highland fringe experiencing a limited cash economy. Weight and height were measured on 260 children from 190 households. The mean z‐scores of ?2.26 ± 1.50 (SD) for height‐for‐age, ?2.43 ± 1.25 for weight‐for‐age, and ?1.34 ± 1.49 for weight‐for‐height are suggestive of both acute and chronic malnutrition. Using a cut‐off value of ≤ ?2SD, 68.8% of the children were stunted and/or wasted. These values are similar to those from a 1992–93 survey in the district, revealing that malnutrition remains a problem in the area. In this largely traditional horticultural group, educated mothers and mothers who spoke pidgin and/or English in addition to the local language had children with better z‐scores. Am. J. Hum. Biol. 14:659–668, 2002. © 2002 Wiley‐Liss, Inc.     

Sleep duration and blood pressure: a longitudinal analysis from early to late adolescence

The aim of this study was to evaluate the association between sleep duration and blood pressure using a cross‐sectional and longitudinal approach. As part of a population‐based cohort, 1403 adolescents were evaluated at 13 and 17 years old. Sleep duration was estimated by the difference between self‐reported usual bedtime and wake‐up time. Blood pressure was measured using the auscultatory method. Regression coefficients (β) and respective 95% confidence intervals were computed to evaluate the association between sleep duration and blood pressure, using linear regression models adjusted for practice of sports and body mass index at 17 years old. The mean (standard deviation) sleep duration at 13 years old was 9.0 (0.76) h per day, and on average it decreased by 46 min up to 17 years old. The median (25th–75th) systolic blood pressure at 17 years old was 110.0 (103.5–119.0) mmHg in females and 114.0 (106.0–122.0)mmHg in males (P < 0.001); for diastolic blood pressure the values were 66.0 (60.0–71.0) and 69.0 (62.0–75.0) mmHg, respectively (P < 0.001). In cross‐sectional analysis, at 17 years old, after adjustment, a positive association was found between sleep duration and blood pressure, significant only for systolic blood pressure among females [β = 0.730 (0.005; 1.455)]. In girls, no significant association was found between sleep duration at 13 years old and blood pressure at 17 years old, but in males an inverse association was found between sleep duration at 13 years old and blood pressure at 17 years old significant only for systolic blood pressure [β = ?1.938 (?3.229; ?0.647)]. This study found no association between sleep duration at 13 years old and blood pressure at 17 years old in girls, but among males an inverse association was found.     

Intracranial pressure and biochemical indicators of brain damage: follow-up study

Aim

To investigate the relation between metabolic parameters of the brain tissue, as direct indicators of real metabolic conditions within the brain, and intracranial pressure, as the consequence of pathophysiological changes.

Methods

Twelve patients with closed head injuries were followed up for 24 hours after injury. A Codman parenchymal intracranial pressure and a Neurotrend electrode were inserted within 3 hours after injury to monitor parenchymal intracranial pressure, brain tissue partial oxygen pressure (P_brO₂), brain tissue partial carbon dioxide pressure (P_brCO₂), pH, and brain tissue temperature. Data detected at 8-hourly intervals were compared with repeated measures analysis of variance.

Result

At the initial observation, the mean value of intracranial pressure was 22.2 ± 3.2 mm Hg. Although it increased at the second and decreased at the third measurement, the differences between the measurements were not significant (P = 0.320). The value of P_brCO₂ was increased from the beginning (63.3 ± 6.0 mm Hg), whereas P_brO₂ was within the normal range at the first measurement (38.9 ± 6.9 mm Hg), but significantly decreased after 8 hours (P = 0.004), remaining low at later time points.

Conclusion

After brain injury, changes in P_brCO₂ are visible earlier than those in P_brO₂. Improvement in intracranial pressure values did not necessary mean improvement in the brain tissue oxygenation. In addition to intracranial pressure, P_brO_2, P_brCO₂ and pH should also be monitored, as they directly reflect the real metabolic conditions within brain tissue and may be used in predictions about the outcome and possible therapeutic approaches.In head injuries, the brain is often threatened by various secondary pathophysiological processes leading to hypoxia or ischemia of the brain tissue (1). In the acute phase after head injury, the cerebral blood flow decreases, while the oxygen consumption in the brain tissue markedly increases (2-4). Secondary neurocytotoxic processes cause brain edema and increase the intracranial pressure, which further worsens cerebral metabolism, causing new neurocytotoxic complications. To prevent this vicious circle of pathophysiological processes, it is necessary to maintain adequate oxygenation of the brain tissue, which depends on the cerebral perfusion pressure and cerebral blood flow (5).Cerebral perfusion pressure equals the difference between the mean arterial pressure and intracranial pressure. Continuous measurement of the mean arterial pressure is always possible in intensive care units (ICU), and the treatment of head injuries today routinely includes monitoring of intracranial pressure. A cerebral perfusion pressure of about 70 mm Hg can optimally supply the brain with blood; if the brain tissue partial oxygen pressure is above 35 mm Hg, normal oxygenation of the brain tissue should be assured (5,6). Continuous assessment of brain oxygenation is possible with the use of commercial sensors.It is generally accepted that intracranial pressure is the key parameter in the assessment of patients with brain injuries. Moreover, patient treatment is based on the value of intracranial pressure (7). However, biochemical parameters in the brain tissue, such as the brain tissue partial oxygen pressure (P_brO₂), brain tissue partial carbon dioxide pressure (P_brCO₂), and pH, directly reflect the real metabolic conditions in the brain, whereas intracranial pressure is merely the consequence of pathophysiological changes.In the early phase after the injury, the value of intracranial pressure may still be within the normal range, while biochemical parameters are already pathologically changed. Therefore, these metabolic parameters should be monitored in the acute phase of brain injury. Our hypothesis was that the variations of intracranial pressure values and variations of biochemical parameters were not closely related, even in cases of closed brain injury. To test this, we measured intracranial pressure, brain tissue partial oxygen (P_brO₂) and carbon dioxide (P_brCO₂) pressure, pH, and temperature of the brain tissue at different time points within the first 24 hours after injury. We also investigated the relation between the changes of intracranial pressure values and variations of each of these metabolic parameters.     

Influence of different behavioural factors and obesity status on systolic blood pressure among pre-school children

Aim: The aim of this study was to examine the association between sleeping time (SLT), time spent using screen (ST) and weight status with Systolic Blood Pressure (SBP) among pre-school children.

Subjects and methods: The sample comprised 628 pre-school children (50% female), aged 3–6 years-old. SLT and ST were reported by parents. BMI values were categorized according to IOTF. SBP cut points were based on SBP percentiles for age, sex and height. ST was dichotomized according to the following criteria: ≤1 hour vs >1 hour and SLT: ≤10.5 hours vs >10.5 hours. Participants were then categorized into one of four category profiles: Low ST/High SLT; High ST/Low SLT; Low ST/Low SLT and High ST/High SLT.

Results: Children assigned to the High ST/Low SLT group were 2-times more likely to have high SBP values compared to those who were assigned to the Low ST/High SLT group (OR?=?2.4; 95% CI?=?1.1–5.1). Furthermore, those who were assigned as overweight and obese were more likely to be classified as having elevated BP (OR?=?1.8; 95% CI?=?1.1–3.2 for overweight and OR?=?3.1; 95% CI?=?1.6–5.8 for obese, respectively).

Conclusion: The data showed that high ST exposure time and low SLT are associated with enhanced blood pressure in children at pre-school.     

Contribution to the study of functional architecture of ligamentum venosum in adult man.

Seventeen specimens, removed at necropsy from adult individuals, were submitted to different methods: a) dissection under stereomicroscope; b) 100 mum panorganographic sections stained by Azan, Weigert's resorcin-fucsin; c) total preparations to be examined under polarized light; d) 10 mum thick histological sections stained by Verh?ff-van Gieson; e) silver impregnation after CAJAL-DE CASTRO. The AA. refer the constitution of the ligament as an integration of two opposite directed systems which are made up by collagenous and mioelastic elements disposed like a twisted cord in the middle portion and enlarged like a fan toward more or less extensive areas of the left branch of portal vein and of the ensemble formed by left hepatic vein and inferior vena cava. The bundles are mainly spread by the most external layers of these vessels, and also it has been observed fibrous components that from the vessels directed to the ligament. They call attention for the amount of nerves and nerve fibers in that structure. The AA. remark, on functional bases, taking as probable the participation of the ligament on the control of the changes in the bend made up by portal vein, "pars transversa trunci sinistri" and "pars umbilicalis trunci sinistri".