Interrelationships among body composition, blood rheology and exercise performance

It is well known that body composition influences blood rheology (higher blood viscosity and RBC aggregation in obese individuals). On the other hand, blood rheology is related to exercise performance (the fitter the athlete the more fluid the blood). The 'paradox of hematocrit' is that most of the time trained athletes have a lower hematocrit while doping aims at increasing it, a situation which seems to challenge physiology and can be explained by the fact that systemic hematocrit may have poor physiological relevance at the microcirculatory level in exercising muscles. However, recent studies dealing with the marked differences among hemorheologic profiles observed in selected sports lead to the concept that the relationships between hemorheology and performance on one hand and body composition and hemorheology on the other hand are more complex and somewhat different according to the variety of exercise and the physiological and/or pathophysiological background. Increased fat mass, but also fat free mass independently of fat mass, are both correlated to impairments of blood fluidity, consistent with the emerging concept that beside increases in fat mass, increases in fat free mass may also be related to metabolic and circulatory disturbances.     

The relationship between nocturnal blood pressure drop and body composition indices among hypertensive patients

Among hypertensive subjects, the lack of physiological blood pressure drop as part of diurnal blood pressure variations is termed as non‐dipper blood pressure. Herein, we investigated the relationship between hypertension character and body composition indices. This study included a total of 104 patients (54 M, mean age: 47.6 ± 12.1 years). Patients' heights, weights, and waist and hip circumferences were measured, and body composition indices were calculated. All patients' office blood pressure measurements and 24‐hour ambulatory blood pressure readings were recorded. A blood pressure drop of at least 10% compared with daytime blood pressure readings is called dipper blood pressure, while a drop of less than 10% is termed as non‐dipper blood pressure. Based on ambulatory blood pressure readings, the patients were grouped into Group 1 (dipper pattern; 51 pts, 34 M, mean age 45.6 ± 12.3) and Group 2 (non‐dipper pattern, 53 pts; 20 M, mean age 49.6 ± 11.6). The proportion of females and smokers were significantly lower in Group 1 than Group 2. BRI, BAI, waist‐to‐height ratio, and waist circumference were significantly higher in Group 2 than Group 1. There were significant positive correlations between body roundness index (BRI), body adiposity index (BAI), waist‐to‐weight ratio, and WC and nocturnal mean systolic and diastolic blood pressure readings. Percent systolic nocturnal drop was significantly correlated with waist‐to‐height ratio, BAI, and BRI. Similarly, percent diastolic nocturnal drop and waist‐to‐height ratio, BAI, and BRI were correlated. In conclusion, the relatively new body composition indices, namely BRI and BAI, are more closely related to nocturnal blood pressure readings among non‐dipper subjects.     

Association between body composition and blood pressure in a contemporary cohort of 9-year-old children

Elevated blood pressure (BP) in children is an early risk factor for cardiovascular disease and is positively associated with body mass index (BMI). However, BMI does not distinguish between fat and lean masses, and the relationship of BP in children to different elements of body composition is not well established. BP, BMI and body composition were measured in 6863 children enrolled in the Avon Longitudinal Study of Parents and Children. Fat mass, lean mass and trunk fat were assessed using dual-energy X-ray absorptiometry. After full adjustment for confounders, total body fat and BMI were positively associated with systolic blood pressure (SBP) (beta=3.29, 95% confidence interval CI 3.02, 3.57 mm Hg/standard deviation (s.d.) and beta=3.97, 95% CI 3.73, 4.21 mm Hg/s.d., respectively) and diastolic blood pressure (DBP) (beta=1.26, 95% CI 1.05, 1.46 mm Hg/s.d. and beta=1.37, 95% CI 1.19, 1.54 mm Hg/s.d., respectively). SBP was also positively associated with lean mass (beta=3.38, 95% CI 2.95, 3.81 mm Hg/s.d.), and weakly associated with trunk fat (beta=1.42, 95% CI -0.06, 2.90 mm Hg/s.d., independent of total fat mass), which was robust in girls only. The association between lean mass and SBP remained even after accounting for fat mass. SBP in 9-year-old children is independently associated with fat mass and lean mass and, to a lesser extent, trunk fat in girls. In this analysis, because both fat and lean masses are associated with BP, BMI predicts BP at least as well as these components of body composition.     

Psychosocial work factors associated to blood pressure and cardiovascular symptoms among Mexican nurses

OBJECTIVE: To determine if job stress, according with Karasek's model, and job insecurity are significantly associated with cardiovascular indicators such as blood pressure (BP) and cardiovascular symptoms (CS), considering traditional risk factors for cardiovascular disease (age, body mass index, smoking, alcohol consumption, among others). MATERIAL AND METHODS: A job content questionnaire (JCQ) and one for cardiovascular symptoms were administered to a sample of 109 nurses from a public hospital in Mexico City during July 2004. A digital monitor was utilized to measure BP at the workplace using a point estimates protocol. RESULTS: A significant association among these variables was found (beta between .20 and .24), even when traditional cardiovascular risk factors were considered. CONCLUSIONS: The relation between job stress and BP is significant in the Mexican population and highlights the association between job insecurity and cardiovascular indicators, indicating its importance in the Mexican work context. Future studies are suggested, as well as the prevention and surveillance of these factors in occupational and public health fields in terms of their role in cardiovascular epidemiology.     

Fasting insulin and leptin serum levels are associated with systolic blood pressure independent of percentage body fat and body mass index.

OBJECTIVE: To examine the relationship between leptin and insulin serum levels and systolic and diastolic blood pressure in young men. SETTING: Kobe University of Mercantile Marine, Kobe, Japan. Participants: One hundred and ninety-eight male students aged 18-20 years (comprising 100% of those eligible). DESIGN AND MEASUREMENTS: A cross-sectional survey of a sample of male college students was performed, with measurements to include anthropometry, blood pressure and blood tests after overnight fasting. RESULTS: Compared with 90 men with an optimal blood pressure, 56 men with high-normal and high blood pressure had an increase in body mass index (23.7 +/- 5.2 versus 20.4 +/- 2.2 kg/m2), percentage body fat (21.7 +/- 8.0 versus 16.3 +/- 4.2%) and serum leptin (3.7 +/- 4.7 versus 1.5 +/- 0.8 ng/ml). In addition, they had greater serum insulin (59 +/- 31 versus 43 +/- 12 pmol/l) despite there being no differences in plasma glucose, resulting in a reduction of the ratio of glucose to insulin (x 10(6)) (107 +/- 43 versus 126 +/-, which is an estimate of insulin sensitivity in a nondiabetic population. Furthermore, the 56 men had higher serum triglyceride levels, although there was no difference in low density lipoprotein-cholesterol and high density lipoprotein-cholesterol between men with optimal and high-normal plus high blood pressure. Similar differences were found between men in a top versus low tertile of systolic and diastolic blood pressure. In multiple regression analysis, both log leptin and log insulin emerged as determinants for systolic blood pressure independent of body mass index and percentage body fat, but an association with diastolic blood pressure was only shown for log leptin. CONCLUSION: Hyperleptinemia and hyperinsulinemia may be regulators of arterial pressure, independent of body mass index or percentage body fat.     

Variants in CXADR and F2RL1 are associated with blood pressure and obesity in African-Americans in regions identified through admixture mapping

OBJECTIVE:: Genetic variants in 296 genes in regions identified through admixture mapping of hypertension, BMI, and lipids were assessed for association with hypertension, blood pressure (BP), BMI, and high-density lipoprotein cholesterol (HDL-C). METHODS:: This study identified coding SNPs identified from HapMap2 data that were located in genes on chromosomes 5, 6, 8, and 21, wherein ancestry association evidence for hypertension, BMI, or HDL-C was identified in previous admixture mapping studies. Genotyping was performed in 1733 unrelated African-Americans from the National Heart, Lung and Blood Institute's Family Blood Pressure Project, and gene-based association analyses were conducted for hypertension, SBP, DBP, BMI, and HDL-C. A gene score based on the number of minor alleles of each SNP in a gene was created and used for gene-based regression analyses, adjusting for age, age, sex, local marker ancestry, and BMI, as applicable. An individual's African ancestry estimated from 2507 ancestry-informative markers was also adjusted for to eliminate any confounding due to population stratification. RESULTS:: CXADR (rs437470) on chromosome 21 was associated with SBP and DBP with or without adjusting for local ancestry (P?相似文献   

Automated office blood pressure measurements obtained with and without preceding rest are associated with awake ambulatory blood pressure

Automated office blood pressure (AOBP) measurement, attended or unattended, eliminates the white coat effect (WCE) showing a strong association with awake ambulatory blood pressure (ABP). This study examined the difference in AOBP readings, with and without 5 minutes of rest prior to three readings recorded at 1‐min intervals. Cross‐sectional data from 100 randomized selected hypertensives, 61 men and 39 women, with a mean age of 52.2 ± 10.8 years, 82% treated, were analyzed. The mean systolic AOBP values without preceding rest were 127.0 ± 18.2 mm Hg, and the mean systolic AOBP values with 5 minutes of preceding rest were 125.7 ± 17.9 mm Hg (P = .05). A significant order effect was observed for the mean systolic BP values when AOBP without 5 minutes of preceding rest was performed as the first measurement (130.0 ± 17.7 vs 126.5 ± 16.2, P = .008). When we used a target systolic AOBP ≥ 130 mm Hg, awake ABP yielded lower readings, while at a target systolic AOBP value of < 130 mm Hg higher awake ABP values were obtained. Our findings indicate that systolic AOBP can be initially checked without any preceding rest and if readings are normal can be accepted. Otherwise, when AOBP is ≥ 130 mm Hg, measurements should be rechecked with 5 minutes of rest.     

Angiotensinogen promoter haplotypes are associated with blood pressure in untreated hypertensives

BACKGROUND: The polymorphic angiotensinogen (AGT) gene is one of the most promising candidates for blood pressure (BP) regulation and essential hypertension. OBJECTIVES: To investigate whether AGT haplotype analysis adds significant information compared to single polymorphism analysis with respect to different BP phenotypes in an untreated hypertensive sample. METHODS: Two hundred and twelve untreated hypertensive subjects of Caucasian origin were genotyped for the AGT polymorphisms C-532T, A-20C, C-18T, and G-6A. RESULTS: In single variant analyses, untreated hypertensives, carrying the AGT -532T or -6A alleles had significantly higher systolic blood pressure (SBP) and diastolic blood pressure (DBP), as well as ambulatory BP values compared to respective non-carriers. In haplotype-based analyses, combining all four AGT promoter variants, we demonstrate that AGT haplotypes containing different allele combinations at positions -532 and -6 were significantly associated with different BP values: (1) -532T and -6A with higher, (2) -532C and -6G with lower, (3) -532C and -6A with intermediate BP values. Since the result for the -532C/-20A/-18C/-6G haplotype was due to differences between non-carriers and carriers of this haplotype on both chromosomes, a recessive inheritance model for BP effects could be assumed. CONCLUSIONS: Our results designate the C-532T and G-6A as the best candidates for functional studies on the AGT gene. Haplotype-based analyses should greatly aid in the dissection of the genetic basis of complex traits, such as BP regulation and hypertension.     

Patient and social environment factors associated with self blood pressure monitoring by male veterans with hypertension

Self blood pressure monitoring (SBPM) can facilitate hypertension management, but determinants of SBPM are understudied. The authors examined the relationship of patient and social environment characteristics to monitor possession and frequency of SBPM in 578 male hypertensive veterans. Measures included possession of a monitor; SBPM frequency; concurrent blood pressure control; and patient demographic, clinical, and psychosocial factors. In logistic regression analyses, older age, diabetes, unemployment, and better mental health status were related to greater likelihood of monitor possession. Ordinal logistic regression showed that among patients with a monitor, having diabetes, being unemployed, and having a shorter duration of hypertension were independently related to greater frequency of SBPM. Monitor possession, but not frequency of SBPM, was related to a decreased likelihood of blood pressure control in adjusted analyses. Our results suggest that patient characteristics may influence SBPM and may represent points of leverage for intervening to increase self-monitoring.     

Eating breakfast and snacks while television viewing are associated with some cardio metabolic risk factors among Iranian children

Aim

We aimed to investigate the association of eating meals while television viewing (TVV) and screen-based behaviors with cardio metabolic risk factors (CRFs) among school-aged children in Shiraz.

Plasma saturated and linoleic fatty acids are independently associated with blood pressure.

The role of individual fatty acids in blood pressure regulation is unclear. We studied the cross-sectional relationship of blood pressure, total plasma phospholipid fatty acid concentrations, and proportions of individual fatty acids among participants in a population study. Blood pressure was measured automatically, and plasma phospholipid fatty acids were determined by gas-liquid chromatography in 4033 healthy men 40 to 42 years old. Significant positive linear associations existed between total fatty acids and saturated fatty acids and blood pressure, whereas polyunsaturated linoleic acid was inversely associated with blood pressure. In multiple regression analyses, a 2-SD increase in total fatty acids was associated with an increase of 6.0 (95% CI, 5.1 to 6.8) mm Hg systolic blood pressure. A 2-SD increase in saturated palmitic acid was associated with 1.4 (95% CI, 0.5 to 2.3) mm Hg increase in systolic blood pressure. In contrast, a 2-SD increase in polyunsaturated linoleic acid was associated with a 1.9 (95% CI, 1.0 to 2.8) mm Hg decrease in systolic blood pressure. We conclude that plasma levels of total fatty acids, saturated fatty acids, and polyunsaturated linoleic acid are independently associated with blood pressure. The present study supports the hypothesis that the composition of dietary fat influences blood pressure.     

Excess mortality associated with increased pulse pressure among middle-aged men and women is explained by high systolic blood pressure

OBJECTIVE: To assess the risk of death from coronary heart disease, stroke, all cardiovascular diseases and all-cause mortality associated with pulse pressure among the middle-aged population. METHODS AND DESIGN: A prospective 15-year follow-up cohort study was conducted of two independent cross-sectional random samples of the population who participated in baseline surveys in 1972 or 1977. Each survey included a self-administered questionnaire with questions on smoking and antihypertensive drug treatment, measurements of height, weight and blood pressure and the determination of the serum cholesterol concentration. Multivariate analyses were performed by using Cox proportional hazard models. SETTING: The provinces of North Karelia and Kuopio in eastern Finland PARTICIPANTS: Men and women aged 45-64 years with no history of myocardial infarction or stroke at the time of the baseline survey were selected. In total 4333 men and 5270 women took part in this follow-up study. RESULTS: The relative risk of coronary heart disease, stroke, cardiovascular disease and all-cause mortality increased with the increasing pulse pressure in individuals aged 45-64 years independent of the diastolic blood pressure level. Only in women with diastolic blood pressure > or = 95 mmHg was the relative risk of fatal stroke not statistically significant. After adjustment for systolic blood pressure, the positive association between mortality and increasing pulse pressure disappeared. CONCLUSION: Increasing pulse pressure is a predictor of death from coronary heart disease, stroke, cardiovascular disease and all causes in men and women aged 45-64 years, but the increase in risk is entirely associated with the increase in systolic blood pressure.