Testing for developmental changes in gene expression on resemblance for quantitative traits in kinships of twins: application to height, weight, and blood pressure

Height, weight, and blood pressure measurements on identical and fraternal twins and their families were analyzed to assess the degree to which genetic effects may change with age. The blood pressure data were based on the total sample of 1,767 individuals, while height and weight were available on 1,640 individuals in 204 monozygotic twin kinships. The results of testing alternative hypotheses about developmental changes in gene expression indicate that different mechanisms may be operative for these traits. While there was no evidence that developmental effects are a significant source of the observed variation in systolic or diastolic blood pressure, there was strong evidence that genetically determined developmental changes are an important factor in the determination of body weight. Age-related changes in weight appeared to be best explained by the cumulative developmental effects of a single set of genes, rather than by the expression of new genes at different stages of development.     

Interrelationships between lipids, lipoproteins, and blood pressure in children from kindreds with essential hypertension

The interrelationships of blood pressure and plasma lipoproteins in 154 white children aged 8 through 18 years were investigated. The children came from four very large kindreds, each ascertained by one middle-aged man with essential hypertension. Statistical adjustments by multiple regression methods were made for age and body size effects on blood pressure and lipid-lipoprotein levels and the residuals used in subsequent analyses. Small but consistent and statistically significant positive relationships between fourth or fifth phase diastolic blood pressure and plasma cholesterol, triglyceride, and low-density lipoprotein-cholesterol (C-LDL) levels were identified; higher diastolic blood pressures were associated with higher cholesterol, triglycerides, and C-LDL levels. Only a hint of similar associations with systolic blood pressure was detected. The data suggested a possible inverse relationship between blood pressure and high-density lipoprotein-cholesterol (C-HDL): higher C-HDL levels were associated with lower diastolic blood pressure; however, the associations were not statistically significant at the 0.05 level. A principal components analysis generated blood pressure components arithmetically similar to estimates of mean arterial pressure and pulse pressure; both of these components showed relationships to lipid-lipoprotein levels. Because levels of lipid-lipoproteins and blood pressure show evidence of familial clustering, it is possible these interrelationships result from shared genetic or environmental determinants. The associations may have important health consequences, since evidence exists that the level of blood pressure in childhood sets the pattern for later life.     

Acute effects of whey protein isolate on blood pressure, vascular function and inflammatory markers in overweight postmenopausal women

Previous evidence indicates that chronic consumption of dairy whey proteins has beneficial effects on CVD risk factors. The present study investigated the postprandial effects of whey protein isolate on blood pressure, vascular function and inflammatory markers in overweight and obese postmenopausal women. This was a randomised, three-way cross-over design study where twenty overweight and obese postmenopausal women consumed a breakfast meal in conjunction with one of three supplements: 45 g whey protein isolate, 45 g sodium caseinate or 45 g of a glucose control. Fasting and postprandial blood samples, blood pressure and pulse wave analysis readings were taken for up to 6 h. After consumption of the meal, both systolic and diastolic blood pressure, and augmentation index (AI) decreased initially for all interventions and gradually returned to baseline levels by 6 h. However, there were no significant differences in AI, systolic or diastolic blood pressure within or between the glucose control, casein or whey groups. There were also no significant group effects on plasma inflammatory markers (IL-6, TNF-α and C-reactive protein). The health effects previously seen with chronic whey protein ingestion were not seen in the acute 6 h postprandial period in relation to blood pressure, vascular function or inflammatory markers when compared with casein and a glucose control. This suggests that such effects are better observed from the long-term consumption of whey proteins.     

利用面板数据模型研究血脂对血压的影响

目的 利用面板数据模型,探讨血脂四项指标对血压的影响。 方法 收集社区居民连续5年的血脂、血压及身高、体重、腰围等体检数据,建立以血压为因变量,以血脂四项指标为自变量,以BMI和腰围为控制变量的面板数据模型,分析血脂水平变化对血压的影响。 结果 单因素模型中,影响收缩压的有甘油三酯、低密度脂蛋白;影响舒张压的有总胆固醇、甘油三酯、低密度脂蛋白。多因素模型中,影响收缩压的有高密度脂蛋白与低密度脂蛋白,影响舒张压的是低密度脂蛋白与甘油三酯,总胆固醇未能进入两个方程。 结论 血脂四项中,总胆固醇不能影响血压,甘油三酯增高会导致舒张压上升,高密度脂蛋白增高会降低收缩压,低密度脂蛋白增高会导致收缩压与舒张压的上升。居民膳食指南中,对于胆固醇的摄入,作出不再受限制的简单的建议是不够的,应该综合当前的研究结果,对脂肪的摄入提出更精准的推荐。     

Physical fitness and blood pressure: the role of age

Most epidemiologic studies have shown an inverse relationship between resting blood pressure and usual levels of physical fitness or activity. The inference is that fitness lowers blood pressure. However, maximum oxygen uptake (VO2max--a widely accepted measure of fitness) and blood pressure are both correlated with age; young people usually have lower pressures and higher VO2max (ml X kg-1 X min-1). Systolic and diastolic pressures were measured and maximal oxygen uptake was estimated in 184 men and 227 women aged 18-65 years who were randomly selected as part of a cardiovascular risk factor survey conducted in two New England cities between April 1981 and March 1982. Initially, both measures of blood pressure were strongly and inversely correlated with estimated maximal oxygen uptake. However, when the effects of age were partialed out, the strength of the correlations decreased sharply for both males and females. The proportion of the variance in systolic pressure explained by maximal oxygen uptake decreased from 9.6 to 0.8% for males and 21.2 to 2.3% for females. Similar decreases were demonstrated for diastolic pressure in males (14.4 to 2.9%) and females (20.3 to 2.3%). These data indicate that the frequently observed relationship between fitness and blood pressure is strongly influenced by age. Future research to specifically examine the effects of physical activity and of physical fitness on blood pressure is needed.     

Perspectives on isolated systolic hypertension in elderly patients

Until the mid-20th century, clinicians' concern was directed mainly to the systolic component of blood pressure. Later, however, when systolic blood pressure was found to be elevated with advancing age and decreased compliance of the arterial wall, it began to be considered an inevitable consequence of aging. Based on this belief, physicians often concluded that only the diastolic blood pressure elevation, which reflected peripheral vascular resistance, was harmful, while systolic hypertension was innocuous. Therapeutic intervention was practiced mainly for diastolic hypertension, and research protocols were based on the levels of diastolic blood pressure alone. In the 1950s, even when life insurance companies' actuarial data revealed that systolic and diastolic blood pressure elevations were hazardous to health, few clinicians took heed. In 1962, the World Health Organization also defined hypertension as a blood pressure level of 165/95 mm Hg or higher for intervention purposes. However, until the 1991 Systolic Hypertension in the Elderly Program (SHEP) trial, many physicians were reluctant to pay credence to the need for therapy of elevated systolic blood pressure (vide infra).     

亚甲基四氢叶酸还原酶基因和血压水平的遗传流行病学研究-同胞对连锁分析

目的 探索５，１０－亚甲基四氢叶酸还原酶（ＭＴＨＦＲ）基因与血压水平的连锁关系。方法 研究现场选择在原发性高血压社区综合防治项目农村社区－北京市房山区良各庄村和黄山店村。研究对象为该现场的１４２对同胞对，及可能获得的父母。基因型测量包括血凝块中提取ＤＮＡ，ＰＣＲ扩增目的基因片断，酶切分析ＭＴＨＦＲ基因多态性。表型为血压水平，协变量的测量包括问卷调查、体格指标及血液生化指标的测量。统计分析方法为数量     

Effect of lead on blood pressure in occupationally nonexposed men

To determine if low-level exposure to lead has an effect on arterial blood pressure, demographic and clinical data of a group of 507 males without any occupational exposure to lead were analyzed in a retrospective study. The following variables were included in the analysis: age, height, weight, nicotine consumption, alcohol intake, blood lead, systolic blood pressure, diastolic blood pressure, and erythrocyte count. The effects of the variables age, weight, height, alcohol intake, nicotine consumption, and blood lead on blood pressure were investigated by stepwise linear regression analysis. The diastolic as well as the systolic blood pressure was significantly influenced by Body Mass Index, age, and alcohol. A significant effect of lead could be found only for diastolic blood pressure. None of the possible interactions were significant enough to merit inclusion in the statistical model. Regarding the strength of the effects on diastolic blood pressure we find that lead ranks after age, weight. In conclusion, this study shows that lead has an effect on diastolic arterial blood pressure in a survey of a group of middle-aged, occupationally nonexposed men.     

舟山海岛地区孕妇妊娠期血红蛋白含量与血压的关系

  目的  探讨舟山地区孕妇妊娠期血红蛋白含量与血压的关系，为妊娠期高血压的病因学研究提供科学依据。  方法  采用回顾性调查研究，对2017年1月~2018年6月期间在浙江省舟山市妇幼保健院进行围产保健的1 383名孕妇孕早、中、晚期的血红蛋白含量与血压进行监测，采用多元线性回归分析不同孕期血红蛋白含量与血压之间的关系。  结果  孕早、中、晚期贫血发生率分别为7.74%、25.45%和15.76%；多元线性回归显示，孕期血红蛋白水平对孕早、中、晚期收缩压均有影响，并且呈现出越早期血红蛋白水平对各期的收缩压影响明显。早期的血红蛋白水平的影响最大(β=0.10，P < 0.001)，中期无统计学关联，晚期的影响其次(β=0.04，P=0.027)。血红蛋白水平与舒张压水平的变化趋势类似于其与收缩压之间的关系。  结论  妊娠期血红蛋白水平对孕早、中、晚期血压均有明显的影响，定期测量孕期血红蛋白水平，可以更好地改善孕产妇健康状况。     

Segregation analysis of cardiovascular reactivity to laboratory stressors

To better understand the contribution of major gene influences to individual differences in cardiovascular reactivity, we performed a segregation analysis on blood pressure responses to two laboratory tasks, mental arithmetic and bicycle exercise. The study population consisted of 1,451 adults (age ≥18 years) who were members of 81 Utah pedigrees. Only 864 members performed the bicycle task because persons age 60 years or older or with heart disease were excluded. Blood pressure reactivity to mental arithmetic was defined as change from resting values, and reactivity to the bicycle task was defined as the difference between maximum blood pressure during exercise and resting values adjusted for the individual's workload. Complex segregation analysis and likelihood procedures were used to test for a major gene effect controlling blood pressure reactivity to each task. Two modifiers of the penetrance, age and sex, were considered parameters in these models. We found that diastolic blood pressure (DBP) but not systolic blood pressure reactivities to the mental arithmetic and bicycle exercise tasks were controlled by major gene effects. The best-fitting model, however, differed for the two tasks. For DBP reactivity to mental arithmetic, a major codominant model with gene frequency 0.10 was the best-fitting model; for the bicycle task, the best-fitting model was a mixed recessive model with gene frequency 0.21. Sex differences in DBP reactivity were significant in both tasks; the effect of age was significant only for the mental arithmetic task. These results suggest a significant genetic component for DBP reactivity to laboratory stressors. Genet. Epidemiol. 14:35–49,1997. © 1997 Wiley-Liss, Inc.     

Blood pressure differences between blacks and whites in relation to body size among US children and adolescents

No large national studies of ethnic differences in blood pressure among children accounting for body size differences have been published, to the authors' knowledge. This report details the similarities and differences in systolic and diastolic blood pressures between Black children and White children in the United States and examines the effects of age, sex, and body size on ethnic differences in blood pressure levels. Standardized measurements of seated systolic and diastolic pressures from eight large epidemiologic studies published between 1978 and 1991 that included measurements of 47,196 children on 68,556 occasions for systolic pressure and for 38,184 children on 52,053 occasions for diastolic pressure were used; 51 percent (24,048 children) were boys and 37 percent (17,466 children) were Black. Overall, there appear to be few substantive ethnic differences in either systolic or diastolic pressure during childhood and adolescence. The differences that were observed were small, inconsistent, and often explained by differences in body size. There was an ethnic group-body mass index (BMI) interaction that resulted in these findings that at lower levels of BMI Blacks have higher blood pressure and more hypertension than do Whites, but that at the highest levels of BMI, Whites have more hypertension (systolic or diastolic pressure) than do Blacks.     

Repeatability of automated ambulatory blood pressure measurements.

BACKGROUND. The repeatability of 24-hour automatic ambulatory blood pressure measurements recorded by noninvasive equipment (Del Mar Pressurometer IV) was assessed to determine the intrapatient variability of this test. METHODS. The usual antihypertensive medications of 73 patients with documented essential hypertension (supine diastolic blood pressure of 95 to 119 mm Hg) were withdrawn, and the patients were treated with placebo medication for 6 weeks. At the end of the placebo period, ambulatory blood pressure measurements of each patient were recorded every 15 minutes for 24 hours on two separate occasions 1 week apart. RESULTS. There was no significant difference in either the 24-hour systolic or diastolic blood pressure for the entire group between weeks. A mean difference for individual patients between the first and second recording within 5 mm Hg was observed in 49.3% and 52.1% of patients for 24-hour systolic and diastolic blood pressure, respectively. The correlation coefficient for 24-hour systolic blood pressure was greater than 24-hour diastolic blood pressure (r = .87 vs r = .67). A difference greater than 18.1/14.9 mm Hg for systolic/diastolic blood pressure would be required to assign a significant (P less than .05) change in blood pressure between two recordings in the same patient. CONCLUSIONS. These data quantify the usefulness of 24-hour ambulatory blood pressure measurements for a group of subjects. However, mean 24-hour ambulatory blood pressure varies significantly for individuals. Intrapatient variability may limit the usefulness of a single 24-hour ambulatory recording for an individual patient and suggests the need for more than one measurement to establish a level of blood pressure.     

Alcohol drinking patterns and blood pressure.

BACKGROUND: Although blood pressure tends to increase with average alcohol consumption, little is known about the effects of drinking patterns on blood pressure. Therefore, the effects of average drinks per day and drinking pattern (defined as the independent and interactive effects of quantity and frequency) on blood pressure were compared. METHODS: Data were obtained from a random sample survey of 1,635 household residents in Erie County, New York. Alcohol-blood pressure relationships were examined using multiple regression analyses that controlled for the potentially confounding influence of 13 additional risk factors for elevated blood pressure. RESULTS: Consistent with prior research, a positive relationship was found between average drinks per day and diastolic and systolic blood pressure. Analyses examining the effect of drinking pattern indicated that drinking frequency had a positive effect on both diastolic and systolic blood pressure, whereas drinking quantity did not affect either. Furthermore, there was little evidence that the frequency-by-quantity interaction affected blood pressure. CONCLUSIONS: Low average alcohol intake and low blood pressure were associated with infrequent drinking, rather than with frequent drinking of small amounts of alcohol. Results suggest that the standard practice of averaging alcohol consumption may obscure important effects of drinking frequency on health.     

The G(894)-T(894) polymorphism in the gene for endothelial nitric oxide synthase and blood pressure in lead-exposed workers from Korea

We evaluated whether the G -T polymorphism in exon 7 of the endothelial nitric oxide synthase (eNOS) gene is associated with blood pressure or modifies the relation between lead dose and blood pressure in 803 lead workers in Korea. A total of 84.9% of individuals were homozygous GG, 14.4% heterozygous GT, and 0.8% homozygous TT. The T allele was not significantly associated with systolic or diastolic blood pressure. The prevalence of hypertension did not differ by T status (OR = 0.82; 95% CI = 0.50-1.37). There was no evidence of effect modification by eNOS genotype on relations of lead dose with blood pressure. These data provide no evidence that the T allele is associated with higher blood pressure or modifies the association of lead dose with blood pressure.     

Effects of fiber intake on the blood pressure, lipids, and heart rate in Goto Kakizaki rats

OBJECTIVE: The prevalence of hypertension in individuals with diabetes mellitus is higher than that in individuals without diabetes mellitus. High fiber intake decreases blood glucose and lipids levels. This study investigated the effects of cereal fiber intake on systolic and diastolic blood pressures in a rat model of type 2 diabetes mellitus. METHODS: Thirty male Goto Kakizaki rats were randomly assigned to one of three groups. Each group was fed a barley diet, a white rice diet, or cornstarch diet. The rats were pair fed for 16 wk. Systolic and diastolic blood pressures were measured once every 4 wk by the photoelectric oscillometric tail-cuff method without anesthesia. RESULTS: The barley diet significantly decreased systolic blood pressure from week 12 and decreased the plasma levels of total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol. There were significant positive correlations between plasma lipids levels and systolic blood pressure. CONCLUSIONS: High fiber intake has beneficial effects on systolic blood pressure and blood lipids levels and suggests that fiber intake should be increased in individuals who have diabetes mellitus to prevent complications.     

Reproducibility and predictive values of routine blood pressure measurements in children. Comparison with adult values and implications for screening children for elevated blood pressure

A study of the variability of blood pressure was conducted among a total of 780 Massachusetts children, 335 children in East Boston and 445 children in Brookline, ages 8-18 years. All children had their blood pressure measured with a standard mercury sphygmomanometer in a school setting on four visits one week apart with three measurements per visit. In East Boston, repeat measurements were made for the same children for four consecutive years. A nested random effects model was used to estimate between- and within-visit variance components. For children aged 8-12 years, these were, respectively, 33.1, 12.0 in boys and 31.2, 11.1 in girls for systolic blood pressure and 57.7, 21.3 in boys and 56.6, 22.6 in girls for systolic muffling blood pressure (Korotkoff phase 4). For children aged 13-18 years of age, they were, respectively, 41.1, 11.8 in boys and 35.2, 12.2 in girls for blood pressure and 40.6, 15.5 in boys and 36.1, 11.4 in girls for diastolic blood pressure (Korotkoff phase 5). Within-person variability for systolic pressure was comparable to previously published data for 434 white adults ages 30-49 years not on antihypertensive medications; however, within-person variability for diastolic pressure was considerably higher in the children, accounting for over 75% of total variability among 8-12-year-old children, compared with 27% for adults. No meaningful effects of age, sex, or blood pressure level on variability of systolic pressure were found. However, age and level of blood pressure each had a large and independent inverse association with variability of diastolic pressure; variance components for younger children (ages 8-12 years) and children with low diastolic pressure (less than 60 mmHg) were approximately twice as large as for older children (ages 13-18 years) and children with diastolic pressure greater than or equal to 60 mmHg, respectively. Finally, predictive value estimates of blood pressure are provided for particular age-sex groups to enable one to efficiently identify children whose true mean level of blood pressure exceeds the 90th percentile for their age-sex group with minimum misclassification. Because of the substantial variability of diastolic pressure in young children, resulting in relatively low predictive value estimates, systolic pressure (either alone or in combination with diastolic pressure) may be more useful as the primary tool for screening children under age 13 years for high blood pressure.     

Bone lead levels and blood pressure endpoints: a meta-analysis

BACKGROUND: Previous reviews have shown increases in blood pressure and hypertension associated with increases in lead levels in blood. We performed a meta-analysis of the association of bone lead levels with systolic blood pressure, diastolic blood pressure, and hypertension using published data. METHODS: We searched Medline, Embase, and Toxline for epidemiologic studies on bone lead levels and blood pressure endpoints. We used inverse-variance weighted random-effects models to summarize the association of tibia or patella lead levels with blood pressure endpoints. RESULTS: We summarized data from 3 prospective studies and 5 cross-sectional studies. All studies measured lead levels in tibia bone and 3 studies measured lead levels in patella. For a 10 microg/g increase in tibia lead, the cross-sectional summary increases in blood pressure were 0.26 mm Hg for systolic (95% confidence interval = 0.02 to 0.50) and 0.02 mm Hg for diastolic (-0.15 to 0.19). The summary odds ratio for hypertension was 1.04 (1.01 to 1.07). For a 10 microg/g increase in patella lead, the summary odds ratio for hypertension was 1.04 (0.96 to 1.12). CONCLUSION: Systolic blood pressure and hypertension risk were associated with lead levels in tibia bone, but the magnitude of the summary estimates was small. These summary estimates, however, were based on published data and we could not evaluate nonlinear dose-response relationships, the relative contribution of bone and blood lead levels, or the influence of differences in study populations. A more detailed characterization of the association of bone lead levels and blood pressure endpoints would require a pooled analysis of individual participant data from existing studies.     

Prevalence of high blood pressure among schoolchildren in Cuiabá, Midwestern Brazil

OBJECTIVE: The ways in which basal blood pressure levels are obtained may lead to different prevalence estimates. The objective of the study was to estimate the prevalence of high blood pressure among schoolchildren and to compare systolic and diastolic means obtained from three measurements of arterial pressure. METHODS: This was a cross-sectional study among seven to ten-year-old schoolchildren (N=601) from public and private schools in the urban area of Cuiabá, midwestern Brazil, in 2005. Three different blood pressure measurements at ten-minute intervals were made during a single visit. Children were considered to have high blood pressure when their systolic and/or diastolic blood pressure reached levels greater than or equal to the 95th percentile in the reference table, in accordance with their gender, age and percentile height. To calculate the prevalence, the first and third blood pressure measurements were considered separately. RESULTS: There were statistically significant differences between the systolic and diastolic means from the three measurements of the study. The mean systolic and diastolic pressures from the third measurement of the study were 97.2 mmHg (SD=8.68) and 63.1 mmHg (SD=6.66) respectively. The prevalence of high blood pressure was 8.7% (95% CI: 6.4;10.9) from the first measurement and 2.3% (95% CI: 1.1;3.5) from the third measurement. There was no statistical difference in prevalence in relation to age, sex, skin color and type of school. CONCLUSIONS: In studies with a single visit, blood pressure measurements decrease significantly from the first to the third measurement. The third measurement seems to reveal blood pressure levels closer to the basal levels.     

低浓度混苯对作业人员血压的影响

目的 探讨混苯对作业人员血压的影响,以保护混苯作业人员身体健康,提高防护的有效性。方法 选择接触混苯的作业工人133名（男103名,女30名）作为接触组,另选择169名（男97名,女72名）无尘毒接触史的工人作为对照组。测定工人血压、身高体重等,用统一的调查表询问饮食习惯、生活习惯等项目,并测定作业环境中苯、甲苯、二甲苯的浓度,对所得数据进行单因素方差分析和多元逐步回归分析。结果 接触组高血压检出率高于对照组（P＜0．05）。单因素方差分析结果表明,接触组的收缩压低于对照线（P＜0．01）,而舒张压均高于对照组（P＜0．05）,多元逐步回归的结果显示接触苯的浓度是导致血压升高的主要影响因素之一。结论 长期接触混苯可能导致舒张压升高,因而对该作业人群应定期检测血压,以防止职业因素对人群造成的危害。     

In patients with mild hypertension, does exercise and a gradual rather than abrupt increase in fatty acid and salt intake cause less rise in cardiovascular risk factors?

In a randomised, single blind controlled trial, 58 patients with mild essential hypertension were administered either a normal diet with a gradual increase in salt and fatty acid consumption (Group A, 30 cases), or an abrupt increase (Group B, 28 cases) for a period of 24 weeks. Group A patients also did more physical activity from weeks 12-24 of the study. At entry to the study, age, sex, risk factors, previous drug therapy and nutrient intakes were comparable between the 2 groups. Adherence to nutrient intakes and exercise was assessed by questionnaires. After 12 weeks, a comparison of changes in mean blood pressure and blood lipids in groups A and B showed no significant difference. However, group B patients showed a significant increase in mean total cholesterol, diastolic pressure and heart rate compared to initial levels. There were no such changes in group A. After 24 weeks, while salt, fatty acids and cholesterol intakes were similar in both groups, there were significantly higher levels of mean total cholesterol, triglycerides, serum sodium, systolic and diastolic blood pressure, and heart rate in group B compared with group A. This may have been due to exercise or to a gradual rather than abrupt increase in salt and fatty acids consumption allowing the body to adapt. Increased physical activity appears to have a positive influence on adaptation leading to prevention of the adverse effects induced by fatty acids and salt loading.