A Slightly Low Hemoglobin Level Is Beneficially Associated with Arterial Stiffness in Japanese Community-Dwelling Women

Erythroid anion transport, nitric oxide, and blood pressure

Glycophorin A and glycophorin B are structural membrane glycoproteins bound in the band 3 multiprotein complexes on human red blood cells (RBCs). Band 3 is an erythroid-specific anion exchanger (AE1). AE1-mediated HCO3 - transport provides the substrate for the enzyme-catalyzed conversion HCO3 - (aq) ⇌ CO2(g), which takes place inside the RBCs. Bicarbonate transport via AE1 supports intravascular acid-base homeostasis and respiratory excretion of CO2. In the past decade, we conducted several comparative physiology studies on Taiwanese people having the glycophorin variant GPMur RBC type (which accompanies greater AE1 expression). We found that increased anion transport across the erythrocyte membrane not only enhances gas exchange and lung functions but also elevates blood pressure (BP) and reduces nitric oxide (NO)-dependent vasodilation and exhaled NO fraction (FeNO) in healthy individuals with GP.Mur. Notably, in people carrying the GPMur blood type, the BP and NO-dependent, flow-mediated vasodilation (FMD) are both more strongly correlated with individual hemoglobin (Hb) levels. As blood NO and nitrite (NO2 -) are predominantly scavenged by intraerythrocytic Hb, and NO2 - primarily enters RBCs via AE1, could a more monoanion-permeable RBC membrane (i.e., GPMur/increased AE1) enhance NO2 -/NO3 - permeability and Hb scavenging of NO2 - and NO to affect blood pressure? In this perspective, a working model is proposed for the potential role of AE1 in intravascular NO availability, blood pressure, and clinical relevance.

Association between hemoglobin concentration and hypertension risk in native Tibetans at high altitude

Previous studies examining the association between hemoglobin concentration and hypertension have yielded inconsistent results. There is still a lack of evidence regarding the association between hemoglobin concentration and hypertension risk in native Tibetans at high altitude. We performed this cross-sectional study in Luhuo County of Ganzi Tibetan Autonomous Prefecture (average altitude of 3500 m). In this study, we enrolled 1547 native Tibetans. The association between hemoglobin concentration and hypertension risk was examined by multivariate binary logistic regression and smooth curve fitting. Native Tibetans with hypertension had significantly higher hemoglobin concentrations than those without hypertension (165.9 ± 21.5 g/L vs. 157.7 ± 19.2 g/L, P < 0.001). An increase in hemoglobin concentration of 1 g/L was associated with hypertension (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.01-1.02) after confounder adjustment. The highest hemoglobin concentration group (exceeding 173 g/L) was associated with an increased hypertension risk compared with the bottom quartile of hemoglobin concentration (OR 2.39, 95% CI 1.48-3.85). Hemoglobin concentration (per 1 g/L change) exceeding 176 g/L was significantly associated with an increased hypertension risk (OR 1.04, 95% CI 1.03-1.06). Additionally, high-altitude polycythemia significantly increased the hypertension risk compared with a normal hemoglobin concentration (OR 2.92, 95% CI 1.25-6.86). A similar result was observed for mild polycythemia (OR 1.74, 95% CI 1.29-2.34). In conclusion, hemoglobin concentration was associated with hypertension risk in native Tibetans. When the hemoglobin concentration exceeded a certain value (approximately 176 g/L), the risk of hypertension was significantly increased.

Blood Haemoglobin Concentration Is Directly and Independently Related with Pulse Wave Velocity, a Measure of Large Artery Stiffness

High haemoglobin level has been associated with metabolic syndrome, elevated blood pressure (BP), and increased mortality risk. In this cross-sectional study, we investigated the association of blood haemoglobin with haemodynamics in 743 subjects, using whole-body impedance cardiography and pulse wave analysis. The participants were allocated to sex-stratified haemoglobin tertiles with mean values 135, 144, and 154 g/L, respectively. The mean age was similar in all tertiles, while body mass index was higher in the highest versus the lowest haemoglobin tertile. The highest haemoglobin tertile had the highest erythrocyte and leukocyte counts, plasma C-reactive protein, uric acid, renin activity, and aldosterone. The lipid profile was less favourable and insulin sensitivity lower in the highest versus the lowest haemoglobin tertile. Aortic BP, cardiac output, and systemic vascular resistance were similar in all tertiles, while the pulse wave velocity (PWV) was higher in the highest versus the lowest haemoglobin tertile. In linear regression analysis, age (Beta 0.478), mean aortic BP (Beta 0.178), uric acid (Beta 0.150), heart rate (Beta 0.148), and aldosterone-to-renin ratio (Beta 0.123) had the strongest associations with PWV (p < 0.001 for all). Additionally, haemoglobin concentration was an explanatory factory for PWV (Beta 0.070, p = 0.028). To conclude, blood haemoglobin concentration had a small direct and independent association with a measure of large artery stiffness.

The associations between hematological parameters and the incidence of prehypertension and hypertension in children and adolescents: a prospective cohort study

Uncontrolled pediatric hypertension may increase the risk of hypertension in adulthood. Several studies have reported an association between hematological parameters and blood pressure (BP) levels. However, epidemiologic evidence of this association in children and adolescents remains scarce. This study aims to explore the associations between hematological parameters and the incidence of prehypertension and hypertension in children and adolescents. This longitudinal study was conducted with 1368 participants aged 6-8 years from baseline visit to follow-up visit. Compared with participants from the normal blood pressure (BP) group, participants from the elevated BP group had significantly higher baseline red blood cell (RBC) counts, hemoglobin (Hb) counts and hematocrit (Hct) levels (all P < 0.001). A multilevel linear mixed model was conducted to analyze the relationship between hematological parameters and BP levels. The results suggested that SBP, DBP and MAP increased significantly with a quartile increase of levels of hematological parameters (all P < 0.05). Furthermore, a multilevel mixed logistic regression model was used to analyze the risk of per interquartile range increase in hematological parameters on the incidence of prehypertension and hypertension. The risk of prehypertension and hypertension incidence increased by (1.34 (95%CIs: 1.20, 1.50)), (1.38 (95%CIs: 1.24,1.54)), (1.33 (95%CIs: 1.19,1.50)), (1.14 (95%CIs: 1.03,1.26)) fold with a one-quartile increase in levels of RBC, Hb, Hct and Fe, respectively (all P < 0.05). This longitudinal study showed that hematological parameters were positively associated with BP levels in healthy children and adolescents, which excluded the effect of antihypertensive drugs on BP levels that often appeared in adults.

Cardiovascular health and potential cardiovascular risk factors in young athletes

Introduction

Cardiovascular disease remains the most common cause of death worldwide, and early manifestations are increasingly identified in childhood and adolescence. With physical inactivity being the most prevalent modifiable risk factor, the risk for cardiovascular disease is deemed low in people engaging in regular physical exercise. The aim of this study was to investigate early markers and drivers of cardiovascular disease in young athletes pursuing a career in competitive sports.

Methods

One hundred and five athletes (65 males, mean age 15.7 ± 3.7 years) were characterized by measurement of body impedance to estimate body fat, blood pressure (BP), carotid femoral pulse wave velocity (PWV) to evaluate arterial elasticity, ergometry to assess peak power output, echocardiography to calculate left ventricular mass, and blood tests.

Results

Systolic BP was elevated in 12.6% and thereby more than twice as high as expected for the normal population. Similarly, structural vascular and cardiac changes represented by elevated PWV and left ventricular mass were found in 9.5% and 10.3%. Higher PWV was independently associated with higher systolic BP (β = 0.0186, p < 0.0001), which in turn was closely correlated to hemoglobin levels (β = 0.1252, p = 0.0435). In this population, increased left ventricular mass was associated with lower resting heart rate (β = -0.5187, p = 0.0052), higher metabolic equivalent hours (β = 0.1303, p = 0.0002), sport disciplines with high dynamic component (β = 17.45, p = 0.0009), and also higher systolic BP (β = 0.4715, p = 0.0354).

Conclusion

Despite regular physical exercise and in the absence of obesity, we found an unexpected high rate of cardiovascular risk factors. The association of PWV, systolic BP, and hemoglobin suggested a possible link between training-induced raised hemoglobin levels and altered vascular properties. Our results point toward the need for thorough medical examinations in this seemingly healthy cohort of children and young adults. Long-term follow-up of individuals who started excessive physical exercise at a young age seems warranted to further explore the potential adverse effects on vascular health.

Positive Association between Hemoglobin Concentration and Blood Pressure in Adults: A Cross-Sectional Study Based on Rafsanjan Cohort Study

Introduction

Identification of factors associated with blood pressure (BP), including hemoglobin, can be used in diagnosing, controlling, and predicting the prognosis of patients. This study aims to investigate the cross-sectional association between hemoglobin concentration and BP in people aged 35-70 years in a cohort study of Rafsanjan, Iran.

Method

This cross-sectional study was conducted on 9398 urban and rural population of Rafsanjan adult cohort study as a part of the prospective epidemiological research studies in Iran (PERSIAN). Demographic information, medical history, history of smoking and alcohol intake, systolic and diastolic BP, and hemoglobin concentration were collected. A logistic regression test was performed to evaluate the relationship between hemoglobin concentration and BP in 4 unadjusted and adjusted models based on demographic indicators, clinical and laboratory findings using SPSS.24 software and SAS software version 9.2.

Results

The mean age of the participants was 49.78 ± 9.53 years, and 53.2% (5002 people) were women. Adjusted models 3 and 4 showed a positive association between BP and hemoglobin. For each unit increase in hemoglobin, the odds ratio (OR) of BP in the adjusted model 3 was 1.062 (95% CI: 1.005-1.121), and in the adjusted model 4, it was 1.090 (95% CI: 1.031-1.153).

Conclusion

Based on the results, the positive trend of BP and hemoglobin levels may indicate the need to pay more attention to these people as higher-risk groups for hypertension.

Clinical Factors Associated with Arterial Stiffness in Chronic Kidney Disease

BACKGROUND

Arterial stiffness influences the prognosis of patients with end-stage kidney disease; however, the factors that promote arterial stiffness in chronic kidney disease (CKD) patients remain unknown. We aimed to explore the clinical factors associated with arterial stiffness in CKD.

METHODS

Between September 2017 and September 2022, all CKD patients treated at the Department of Nephrology, General Hospital of the Chinese People's Liberation Army, excluding dialysis patients, were screened and their medical records within the last month were collected. Arterial stiffness was measured by the augmentation index (AIx). The correlative clinical factors with arterial stiffness were explored in different linear regression models.

RESULTS

559 patients were included in the study. AIx@75 increased as the deterioration of CKDG1-CKDG5, with values of 1 (-9, 11), 5.5 (-4, 13.25), 9 (0, 16), 12 (1.5, 23.5), and 22 (13, 28), respectively (Z = 63.03, p < 0.001). Multivariate linear regression analysis showed that AIx@75 was positively associated with female sex (β = 8.926, 95% confidence interval (CI) 6.291, 11.562, p < 0.001), age (β = 0. 485, 95% CI 0.39, 0.58, p < 0.001), mean arterial pressure (MAP) (β = 0.255, 95% CI 0.159, 0.35, p < 0.001), and was negatively associated with ACEI/ARB (β = -4.466, 95% CI -6.963, -1.969, p < 0.001) and glucocorticoid (β = -3.163, 95% CI -6.143, -0.183, p = 0.038). Smoking, eGFR, hemoglobin, and cause of disease were associated with AIx@75 in multivariate linear regression models when considering factors partly.

CONCLUSIONS

Female, age, smoking, MAP, eGFR, cause of disease, ACEI/ARB, and glucocorticoid were found to be associated with atherosclerosis in CKD patients.

Cross-Sectional Associations of Body Adiposity, Sedentary Behavior, and Physical Activity with Hemoglobin and White Blood Cell Count

BACKGROUND

This study examined whether hemoglobin (Hb) and white blood cell count (WBC) associate with body adiposity and other cardiometabolic risk factors, as well as accelerometer-measured sedentary behavior (SB) and physical activity (PA), when adjusted for body mass index (BMI).

METHODS

The cross-sectional analysis included 144 participants (42 men) with a mean age of 57.0 years and a mean BMI of 31.7 kg/m². SB and standing time, breaks in sedentary time and PA were measured during four consecutive weeks with hip-worn accelerometers. A fasting blood sample was collected from each participant during the 4-week measurement period and analyzed using Sysmex XN and Cobas 8000 c702 analyzers. Associations of WBC, Hb and other red blood cell markers with cardiometabolic risk factors and physical activity were examined by Pearson's partial correlation coefficient test and with linear mixed regression models.

RESULTS

In sex- and age-adjusted correlation analyses both BMI and waist circumference correlated positively with Hb, WBC, red blood cell count (RBC), and hematocrit. Hb was also positively correlated with systolic blood pressure, insulin resistance scores, liver enzymes, LDL, and triglyceride levels. Sedentary time correlated positively with WBC, whereas standing time correlated negatively with WBC. Lying time correlated positively with WBC, RBC, hematocrit, and Hb. Regarding SB and PA measures, only the association between lying time and RBC remained significant after adjustment for the BMI.

CONCLUSION

We conclude that body adiposity, rather than components of SB or PA, associates with Hb levels and WBC, which cluster with general metabolic derangement.

Integrating Health Data-Driven Machine Learning Algorithms to Evaluate Risk Factors of Early Stage Hypertension at Different Levels of HDL and LDL Cholesterol

Purpose: Cardiovascular disease (CVD) is a major worldwide health burden. As the risk factors of CVD, hypertension, and hyperlipidemia are most mentioned. Early stage hypertension in the population with dyslipidemia is an important public health hazard. This study was the application of data-driven machine learning (ML), demonstrating complex relationships between risk factors and outcomes and promising predictive performance with vast amounts of medical data, aimed to investigate the association between dyslipidemia and the incidence of early stage hypertension in a large cohort with normal blood pressure at baseline. Methods: This study analyzed annual health screening data for 71,108 people from 2005 to 2017, including data for 27 risk-related indicators, sourced from the MJ Group, a major health screening center in Taiwan. We used five machine learning (ML) methods—stochastic gradient boosting (SGB), multivariate adaptive regression splines (MARS), least absolute shrinkage and selection operator regression (Lasso), ridge regression (Ridge), and gradient boosting with categorical features support (CatBoost)—to develop a multi-stage ML algorithm-based prediction scheme and then evaluate important risk factors at the early stage of hypertension, especially for groups with high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels within or out of the reference range. Results: Age, body mass index, waist circumference, waist-to-hip ratio, fasting plasma glucose, and C-reactive protein (CRP) were associated with hypertension. The hemoglobin level was also a positive contributor to blood pressure elevation and it appeared among the top three important risk factors in all LDL-C/HDL-C groups; therefore, these variables may be important in affecting blood pressure in the early stage of hypertension. A residual contribution to blood pressure elevation was found in groups with increased LDL-C. This suggests that LDL-C levels are associated with CPR levels, and that the LDL-C level may be an important factor for predicting the development of hypertension. Conclusion: The five prediction models provided similar classifications of risk factors. The results of this study show that an increase in LDL-C is more important than the start of a drop in HDL-C in health screening of sub-healthy adults. The findings of this study should be of value to health awareness raising about hypertension and further discussion and follow-up research.

Influence of hemoglobin on blood pressure among people with GP.Mur blood type☆

BACKGROUND/PURPOSE

GP.Mur is a clinically important red blood cell (RBC) type. GP.Mur and band 3 interact on the RBCs. We previously observed that healthy adults with GP.Mur type present slightly higher blood pressure (BP). Because band 3 and Hb comodulate nitric oxide (NO)-dependent vasodilation and hemoglobin (Hb) is positively associated with BP, we aimed to test whether these could contribute to higher BP in GP.Mur+ people.

METHODS

We recruited 989 non-elderly adults (21% GP.Mur) free of catastrophic illness and not on cardiovascular or anti-hypertensive medication. Their body indices, blood lab data and lifestyle data were collected for analyses of potential BP-related factors (BMI, age, smoking, Hb, and GP.Mur).

RESULTS

BMI and age remained the most significant contributors to BP. GP.Mur slightly increased systolic BP (SBP). The direct correlation between Hb and BP was only found in Taiwanese non-anemic men, not women. After age and BMI adjusted, we estimated an increase of 1.8 mmHg and 2.6 mmHg of SBP by 1 g/dL Hb among men without and with GP.Mur type, respectively. Hb was generally lower among people expressing GP.Mur, which likely limited their larger impact on BP.

CONCLUSION

GP.Mur contributed to BP in both Hb-dependent and Hb-independent fashion. A pronounced impact of hemoglobin on BP likely requires sufficient Hb, as GP.Mur increased the sensitivity of SBP to Hb only in non-anemic Taiwanese men, and not in Taiwanese women or anemic men. The mechanism through which GP.Mur affected BP independent of Hb is unknown.

Relationship Between Hemoglobin and Blood Pressure Levels in the Context of Chronic Morbidity Among Older Adults Residing in a Developing Country: A Community-Level Comparative Cross-Sectional Study

Objectives: The objective of this study is to assess the association between hemoglobin (Hb) and blood pressure (BP) levels among community-dwelling older adults.

Materials and Methods: This comparative cross-sectional study was conducted in April 2021 in West Bengal, India. Individuals who are receiving treatment for hypertension, or had a history of blood transfusion, or had a history of intake of iron and vitamins were excluded from the study. A total of 81 and 106 individuals were recruited in “Group 1” (no self-reported comorbidity) and “Group 2” (self-reported comorbidity present), respectively.

Results: The mean (SD) age of the participants (n = 187) was 67.4 (7.4) years; 54% (n = 101) were males; and 45.4% (n = 85) were obese. We found a significant association of Hb level with systolic blood pressure (SBP) (r = 0.22, p = 0.04) and mean arterial pressure (MAP) (r = 0.22, p = 0.04) in “Group 1”. The quantum of increases in SBP, diastolic blood pressure (DBP), pulse pressure (PP), and MAP with one gram/dl change in Hb level were 3.24 (95% CI: -0.75 to 7.24) mmHg, 1.17 (95% CI: -0.84 to 3.20) mmHg, 2.06 (95% CI: -0.67 to 4.81) mmHg, and 1.87 (95% CI: -0.65 to 4.39) mmHg, respectively, in “Group 1” after adjustment for age, gender, and body mass index. The findings were inconsistent in “Group 2”, and the changes in Hb level were 0.5 (95% CI: -3.77 to 2.77) mmHg, 0.92 (95% CI: -0.72 to 2.75) mmHg, -1.42 (95% CI: -4.09 to 1.24) mmHg, and 0.45 (95% CI: -1.05 to 2.40) mmHg, respectively.

Conclusion: Hb level has a positive correlation with SBP and MAP only in those without comorbidities.

Hemoglobin and hematocrit levels are positively associated with blood pressure in children and adolescents 10 to 18 years old

To investigate the associations between hemoglobin (Hb) concentration and hematocrit (Hct), and blood pressure (BP) in children and adolescents. The study population consisted of 7950 subjects total (4229 boys and 3721 girls) aged 10-18 years who participated in the Korea National Health and Nutrition Examination Surveys conducted between 2007 and 2017. The prevalence of hypertension was 19.19% (21.51% for boys and 16.5% for girls) among the study population, and the prevalence of obesity was 9.59% (10.5% for boys and 8.6% for girls). Hb count and Hct tended to increase with the degree of obesity and BP elevation. Systolic BP (SBP) and diastolic BP (DBP) positively correlated with Hb count and Hct in both sexes. Following multiple linear regression analysis, Hb count and Hct presented a positive association with SBP and DBP after adjusting for age, BMI SDS, alcohol consumption, smoking status, physical activity, rural residence, household income, diagnosis of T2DM, hypertension, and dyslipidemia. Hb count and Hct were positively associated with SBP and DBP in children and adolescents 10-18 years old.

The levels of hemoglobin are positively associated with arterial stiffness in community-dwelling Chinese adults

BACKGROUND AND AIMS

Hemoglobin (Hb) concentrations are known to be related to cardiovascular diseases. This study investigated the association between Hb levels and arterial stiffness, as assessed by measurement of the brachial-ankle pulse wave velocity (baPWV).

METHODS AND RESULTS

3576 adults (2139 males and 1437 females) from the general Chinese population who had their physical check-ups in the health examination centers of Jiangmen Central Hospital were enrolled into the study. The anthropometrics and laboratory data as well as the baPWV and Hb levels were subsequently obtained. Age-adjusted partial correlation and multivariable stepwise linear regression analyses were used to evaluate the relationships between Hb and baPWV for men and women separately. In both sexes, Hb levels were positively associated with body mass index, total cholesterol, low-density lipoprotein cholesterol, triglycerides, glutamic-pyruvic transaminase, γ-glutamyltranspeptidase, uric acid and baPWV, but negatively correlated with the estimated glomerular filtration rate. Multivariable linear regression analysis showed that Hb was significantly and independently associated with arterial stiffness in men (β = 0.043, 95% CI 0.010-0.077, p < 0.05) and women (β = 0.035, 95% CI 0.001-0.069, P < 0.05), after adjustment for confounding factors.

CONCLUSION

The data indicate that high Hb concentration significantly correlate with increased baPWV in general Chinese population.

Sex-dependent correlates of arterial stiffness in Tanzanian adults

OBJECTIVE

Arterial stiffness is a known indicator for cardiovascular disease. However, the factors that lead to arterial stiffening have primarily been studied in participants from high-income countries. Here, we examine clinical and lifestyle metrics in relation to arterial stiffness in Tanzanian adults.

METHODS

We performed pulse wave velocity (PWV), the gold standard measure of arterial stiffness, on 808 Tanzanian adults (ages 18-65) enrolled in a longitudinal cohort studying trends in blood pressure.

RESULTS

As expected, PWV was strongly associated with age, blood pressure and sex. We controlled for these factors in our statistical analysis. Lifestyle metrics were compared across multiple PWV quantiles. We found that determinants of PWV varied by sex: in female participants, PWV was associated with common obesity metrics and menopause, while in male participants, PWV was associated with HIV status and duration of anti-retroviral therapy (ART). Further clinical and lifestyle factors such as marriage status and type of occupation were also significantly associated with PWV and moderated by sex.

CONCLUSION

Together, our data demonstrate the importance of studying sex-specific causal pathways for arterial stiffness and of including under-represented populations in these studies.

Incidence and risk factors for progression from prehypertension to hypertension: a 12-year Korean Cohort Study

OBJECTIVES

This study evaluated the incidence and risk factors for progression from prehypertension to hypertension among middle-aged and elderly Korean adults.

METHODS

A total of 115 456 participants with prehypertension in 2003-2004 were selected from the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) Program. All participants were followed until 2015. Potential risk factors for progression to hypertension were evaluated using the chi-squared test or t-test. A Cox proportional hazards model was used to predict the risk of progression to hypertension according to sex. The incidence of hypertension in the prehypertension group was evaluated by calculating the incidence density during the entire follow-up period.

RESULTS

During the follow-up period, 48 919 participants experienced progression to hypertension, which corresponded to incidence densities of 45.82/1000 person-years among men and 53.57/1000 person-years among women. Among both men and women, progression to hypertension was predicted by an elevated BMI, family history of hypertension, history of diabetes mellitus, and older age. Among men, progression to hypertension was associated with frequent drinking and high alanine aminotransferase levels. Among women, progression to hypertension was associated with high hemoglobin levels and low household income.

CONCLUSION

This study identified various risk factors for progression from prehypertension to hypertension among middle-aged and elderly Korean adults. This information may help researchers develop comprehensive and effective strategies for managing prehypertension.

The Optimal Haemoglobin Target in Dialysis Patients May Be Determined by Its Contrasting Effects on Arterial Stiffness and Pressure Pulsatility

Introduction

It remains unclear why the optimal haemoglobin target is lower in patients with chronic kidney disease (CKD) than in non-CKD persons. Arteriosclerosis and consequent impaired arterial function comprise a central cardiovascular risk mechanism in CKD. We hypothesized that the optimal haemoglobin target depends on its opposing effects on arterial stiffness and pressure pulsatility in CKD.

Methods

Arterial stiffness (aortic pulse wave velocity), wave reflection (augmentation index, reflected wave pressure and reflection magnitude), and pressure pulsatility (central systolic and pulse pressure, peripheral pulse pressure, pressure amplification and forward wave pressure) were assessed in 48 dialysis patients.

Results

In established confounder and diabetes adjusted linear regression models, haemoglobin levels were directly associated with arterial stiffness (partial R=0.366, p=0.03) and inversely with central systolic pressure (partial R=−0.344, p=0.04), central pulse pressure (partial R=−0.403, p=0.01), peripheral pulse pressure (partial R=−0.521, p=0.001) and forward wave pressure (partial R=−0.544, p=0.001). The presence of heart failure and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers and erythropoietin stimulating agents did not materially alter these relationships upon further adjustment for the respective characteristics in the models, and in sensitivity analyses. In receiver operator characteristic curve analysis, the optimal haemoglobin concentration cut-off values in predicting arterial stiffness and increased central pulse pressure were remarkably similar at 10.95 g/dl and 10.85 g/dl, respectively, and with clinically useful sensitivities, specificities and positive and negative predictive values. In logistic regression models, a haemoglobin value of >10.9 mg/dl was associated with both arterial stiffness (>10 m/sec; OR (95% CI) = 10.48 (1.57–70.08), p=0.02) and normal central pulse pressure (>50 mmHg; OR (95% CI) = 7.55 (1.58–36.03), p=0.01).

Conclusion

This study suggests that the optimal haemoglobin target in dialysis patients is ~11g/dl and determined by its differential and contrasting effects on arterial stiffness and pressure pulsatility.

Blood pressure, T cells, and mortality in people with HIV in Tanzania during the first 2 years of antiretroviral therapy

Cardiovascular disease is now a leading cause of mortality in people with HIV (PWH). High blood pressure is the major driver of cardiovascular disease. Despite this, little is known about blood pressure in PWH during the early years of antiretroviral therapy (ART). In this prospective cohort study in Tanzania, the authors conducted unobserved blood pressure measurements at enrollment, 3, 6, 12, 18, and 24 months in 500 PWH initiating ART and 504 HIV-uninfected adults. The authors excluded measurements taken on antihypertensive medications. Although PWH had a significantly lower blood pressure before ART initiation, they had a significantly greater increase in blood pressure during the first 2 years of ART compared to HIV-uninfected controls. Blood pressure correlates in PWH differed from HIV-uninfected controls. In PWH, lower baseline CD4⁺ T-cell counts were associated with lower blood pressure, and greater increases in CD4⁺ T-cell counts on ART were associated with greater increases in blood pressure, both on average and within individuals. In addition, PWH with a systolic blood pressure (SBP) <90 mm Hg at the time of ART initiation had ~30% mortality in the following 3 months due to occult infections. These patients require careful investigation for occult infections, and those with tuberculosis may benefit from corticosteroids.

Association between hemoglobin variability and incidence of hypertension over 40 years: a Korean national cohort study

Hemoglobin level determines blood viscosity and as hemoglobin level rises, blood pressure rises. However, hemoglobin level in individuals is not fixed and change in hemoglobin is affected by various clinical conditions. The purpose of this study is to investigate whether the hemoglobin variability affects the development of hypertension using Korean cohort database. This study was conducted with 94,798 adults (age ≥ 40 years) who visited the health screening in 2006 or 2007 (index year) and had at least 3 health screenings from 2002 to 2007. Hemoglobin variability was assessed by 3 indices of coefficient of variation (CV), standard deviation, and variability independent of the mean. Cox proportional hazard regression analysis was performed for each index of quartile groups (Q1–Q4). A total of 29,145 participants (30.7%) had the incidence of hypertension during a median follow-up of 7.4 ± 2.5 years. In the multivariable adjusted model, the hazard ratio and 95% confidence interval for incidence of hypertension of Q2, Q3, and Q4 compared with Q1 of hemoglobin variability CV were 1.014 [0.981–1.047], 1.064 [1.030–1.099] and 1.094 [1.059–1.131] respectively. The results were consistent in various sensitivity and subgroup analyses. This study showed that hemoglobin variability could be associated with hypertension development.

Hematocrit, hemoglobin and red blood cells are associated with vascular function and vascular structure in men

High and low hematocrit (Hct) and hemoglobin (Hb) levels are associated with the risk of cardiovascular disease. The purpose of this study was to determine the relationships of Hct, Hb and red blood cells (RBCs) with vascular function and structure. We measured flow-mediated vasodilation (FMD), nitroglycerin-induced vasodilation (NID), brachial intima media thickness (IMT), and brachial-ankle pulse wave velocity (baPWV) in 807 men. The subjects were divided into six groups according to the levels of Hct, Hb and RBCs. NID was highest in the 46.0–48.9% Hct group among the six groups according to Hct levels. Brachial IMT was lowest in the 46.0–48.9% Hct group among the six groups. There were no significant differences in FMD and baPWV among the six groups. We used 46.0–48.9% Hct as a reference to define the lower tertile. The adjusted odds ratio of being in the low tertile of NID was significantly higher in the < 42.9% and ≥ 49.0% Hct groups. Adjusted odds ratio of being in the low tertile of brachial IMT was significantly lower in the < 39.9% Hct groups. Similar results were obtained for Hb and RBCs. Low and high levels of Hct, Hb and RBCs were associated with vascular smooth muscle dysfunction, and low Hct levels were associated with abnormal vascular structure. Increases in the levels of Hct, Hb and RBCs within normal ranges may have beneficial effects on the vasculature.

Hemoglobin and erythrocyte count are independently and positively associated with arterial stiffness in a community-based study

The association of blood hemoglobin (Hb) concentration and red blood cell (RBC) count with arterial stiffness is not well-defined. Herein, we examined the associations of brachial-ankle pulse wave velocity (baPWV) and augmentation index (AI) with Hb level and RBC count from a population cohort in and around Beijing, China. A total of 3994 participants (57.1 ± 8.8 years old) were included in our analysis. Blood routine examination, baPWV, and possible covariates were examined. The mean Hb, RBC count, AI corrected for a heart rate of 75 bpm (AIP75), and baPWV were 131.4 ± 17.1 g/l, 4.2 ± 0.5 10¹²/l, 80.2 ± 12.0%, and 1665.3 ± 377.1 cm/s, respectively, consistent with previously described cohorts. RBC counts and Hb levels were positively associated with baPWV (β for 10¹²/l RBC: 50.08 cm/s, 95% confidence interval [CI]: 30.54-69.63, p < 0.001; β for 10 g/l Hb: 9.05 cm/s, 95% CI: 3.35-14.76, p = 0.002) and AIP75 (β for 10¹²/l RBC: 1.33%, 95% CI: 0.55-2.12, p < 0.001; β for 10 g/l Hb: 0.34%, 95% CI: 0.12-0.57, p = 0.003), despite adjustment for covariates. The average levels of baPWV in the third-fourth quartile RBC groups were higher than in the first quartile (Q1) group (p < 0.001 for all). The average levels of baPWV in the fourth quartile Hb groups were higher than in the Q1 Hb group (p = 0.038). Mean AIP75 levels in the third-fourth RBC and Hb groups were higher than in the Q1 groups (p < 0.05 for all). In conclusion, circulating blood Hb levels and RBC counts are positively associated with arterial stiffness in our community-based study.

Association of Hemoglobin and Blood Pressure in a Chinese Community-Dwelling Population

This study investigated the relationship between hemoglobin (Hb) level and blood pressure in a Chinese community-dwelling population with normal glucose metabolism. Hb, fasting plasma glucose, glycated Hb A1c, hepatic and renal function, lipid, electrolytes, and anthropometric parameters were measured. Hb level was found to be positively correlated with systolic (SBP; r = 0.075, p < 0.001) and diastolic (DBP; r = 0.272, p < 0.001) blood pressure in the cohort. The relationship was not affected by age, BMI, serum creatinine (Cr), and low-density lipoprotein (LDL) in both males and females. Multivariate stepwise regression showed that age (β = 0.556, p < 0.001), BMI (β = 1.107, < 0.001), Hb (β = 0.082, p < 0.001), Cr (β = -0.032, p < 0.001), and LDL (β = 1.023, p < 0.001) were independent factors for SBP, and Hb (β = 0.168, p < 0.001), BMI (β = 0.519, p = 0.001), and LDL (β = 0.331, p < 0.001) for DBP. Hb level is positively associated with both SBP and DBP in a Chinese community-dwelling population with normal glucose metabolism.

Risk factors of pre-hypertension and hypertension among non-pregnant women of reproductive age in northeastern Tanzania: a community based cross-sectional study

OBJECTIVES

To determine risk factors of pre-hypertension and hypertension in a cohort of 1247 rural Tanzanian women before conception.

METHODS

Demographic and socioeconomic data, anthropometric measurements, past medical and obstetric history and other risk factors for pre-hypertension and hypertension were collected using a structured questionnaire. Multiple logistic regression analysis was used to evaluate the associations between anthropometric indices and other risk factors of pre-hypertension and hypertension. The predictive power of different anthropometric indicators for identification of pre-hypertension and hypertension patients was determined by Receiver Operating Characteristic curves (ROC).

RESULTS

The median (range) age was 28.0 (18-40) years. The age-standardised prevalences of pre-hypertension and hypertension were 37.2 (95% CI 34.0-40.6) and 8.5% (95%CI 6.7-10.8), respectively. Of hypertensive patients (n = 98), only 20 (20.4%) were aware of their condition. In multivariate analysis, increasing age, obesity and haemoglobin levels were significantly associated with pre-hypertension and hypertension.

CONCLUSION

Despite a low prevalence of hypertension, over one third of the women had pre-hypertension. This poses a great challenge ahead as pre-hypertensive women may progress into hypertension as they grow older without appropriate interventions. Obesity was the single most important modifiable risk factor for pre-hypertension and hypertension.

High serum leptin levels are associated with central arterial stiffness in geriatric patients on hemodialysis

OBJECTIVE

Central arterial stiffness predicts cardiovascular (CV) mortality in hemodialysis (HD) patients. The aging process transforms lipid distribution and thus alters adipokine secretion. The harmful effects of leptin on CV events may change in the elderly. The purpose of this study was to investigate the relationship between leptin and central arterial stiffness markers through carotid-femoral pulse wave velocity (cfPWV) in geriatric HD patients.

MATERIALS AND METHODS

Patients over 65 years old on chronic HD were recruited. Blood samples were collected, and the cfPWV was measured with the SphygmoCor system. The patients with cfPWV values >10 m/s were defined as the high arterial stiffness group.

RESULTS

In total, 30 (51.7%) of the 58 geriatric patients on chronic HD in this study were in the high arterial stiffness group. The high arterial stiffness group had higher rates of diabetes mellitus (P = 0.019), hypertension (P = 0.019), and higher systolic blood pressure (P = 0.018), pulse pressure (P = 0.019), body mass index (P = 0.018), serum leptin levels (P = 0.008), and hemoglobin levels (P = 0.040) than those in the low arterial stiffness group. Multivariable forward stepwise linear regression analysis showed logarithmically transformed leptin (log-leptin, β =0.408, adjusted R 2 change = 0.164; P = 0.001) and diabetes (β =0.312, adjusted R 2 change = 0.085; P = 0.009) were associated with cfPWV values in geriatric HD patients. Moreover, an increased serum leptin level (odds ratio: 1.053; 95% confidence interval: 1.007-1.100; P = 0.023) was an independent factor for central arterial stiffness among geriatric HD patients after multivariate logistic regression analysis.

CONCLUSION

In this study, a higher serum leptin level was correlated with central arterial stiffness in geriatric HD patients.

Exploring the relationship of peripheral total bilirubin, red blood cell, and hemoglobin with blood pressure during childhood and adolescence

OBJECTIVE

Total bilirubin is beneficial for protecting cardiovascular diseases in adults. The authors aimed to investigate the association of total bilirubin, red blood cell, and hemoglobin levels with the prevalence of high blood pressure in children and adolescents.

METHODS

A total of 3776 students (aged from 6 to 16 years old) were examined using cluster sampling. Pre-high blood pressure and high blood pressure were respectively defined as the point of 90th and 95th percentiles based on the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Both systolic and diastolic blood pressure were standardized into z-scores.

RESULTS

Peripheral total bilirubin, red blood cell and hemoglobin levels were significantly correlated with age, and also varied with gender. Peripheral total bilirubin was negatively correlated with systolic blood pressure in 6- and 9-year-old boys, whilst positively correlated with diastolic blood pressure in the 12-year-old boys and 13- to 15-year-old girls (p<0.05). Higher levels of red blood cell and hemoglobin were observed in pre-high blood pressure and high blood pressure students when compared with their normotensive peers (p<0.01). The increases in red blood cell and hemoglobin were significantly associated with high blood pressure after adjusting for confounding factors. The ORs (95% CI) of each of the increases were 2.44 (1.52-3.92) and 1.04 (1.03-1.06), respectively. No statistical association between total bilirubin and high blood pressure was observed (p>0.05).

CONCLUSION

Total bilirubin could be weakly correlated with both systolic and diastolic blood pressure, as correlations varied with age and gender in children and adolescents; in turn, the increased levels of red blood cell and hemoglobin are proposed to be positively associated with the prevalence of high blood pressure.

Evaluation of lipid profiles and hematological parameters in hypertensive patients: Laboratory-based cross-sectional study

INTRODUCTION

Hypertension and dyslipidemia are the two coexisting and synergizing major risk factors for cardiovascular diseases. The cellular constituents of blood affect the volume and viscosity of blood, thus playing a key role in regulating blood pressure. Overweight and obesity are key determinants of adverse metabolic changes including an increase in blood pressure. The aim of this study was to evaluate lipid profiles and hematological parameters in hypertensive patients at Debre Markos Referral Hospital, Northwest Ethiopia.

METHODS

Laboratory-based cross-sectional study was conducted in 100 eligible hypertensive patients at the hospital. The required amount of blood was withdrawn from the patients by healthcare professionals for immediate automated laboratory analyses. Data were collected on socio-demographic factors, anthropometric measurements, blood pressure, lipid profiles, and hematological parameters.

RESULT

The mean serum levels of triglyceride, total cholesterol, and low-density lipoprotein were significantly higher than their respective cut-off values in the hypertensive patients. Besides, 54%, 52%, 35%, and 11% of the hypertensive patients had abnormal low-density lipoprotein, total cholesterol, triglyceride, and high-density lipoprotein levels, respectively. Higher levels of low-density lipoprotein, hemoglobin, and red blood cell count were observed in the hypertensive patients whose blood pressure had been poorly controlled than the controlled ones (p < 0.05). Waist circumference had a significant positive association with the serum levels of total cholesterol and white blood cell count (p < 0.05).

CONCLUSION

Hypertensive patients had a high prevalence of lipid profile abnormalities and poorly controlled blood pressure which synergize in accelerating other cardiovascular diseases. Some hematological parameters such as red blood cell count are also increased as do the severity of hypertension.

Hemoglobin level and lipoprotein particle size

Background

Alterations in lipoprotein size are associated with increased cardiovascular disease risk. Higher hemoglobin levels may indicate a higher risk of atherosclerosis and was previously associated with obesity, metabolic syndrome, and insulin resistance. No previous studies have investigated an association between hemoglobin concentration and lipoprotein particle size.

Methods

We conducted a population-based, cross-sectional study of 766 Caucasian, middle-aged subjects (341 men and 425 women) born in Pieksämäki, Finland, who were categorized into five age groups. The concentrations and sizes of lipoprotein subclass particles were analyzed by high-throughput nuclear magnetic resonance (NMR) spectroscopy.

Results

Larger very low density lipoprotein (VLDL) particle diameter was associated with higher hemoglobin concentrations in men (p = 0.003). There was a strong relationship between smaller high density lipoprotein (HDL) particle size and higher hemoglobin concentration in both men and women as well as with smaller low density lipoprotein (LDL) particle size and higher hemoglobin concentration in men and women (p < 0.001; p = 0.009, p = 0.008). VLDL particle concentration had a moderate positive correlation with hemoglobin concentration (r = 0.15; p < 0.001). LDL particle concentration showed a statistical trend suggesting increasing particle concentration with increasing hemoglobin levels (r = 0.08; p = 0.05).

Conclusion

Higher hemoglobin levels are associated with larger VLDL, smaller LDL, and smaller HDL particle sizes and increasing amounts of larger VLDL and smaller LDL particles. This suggests that a higher hemoglobin concentration is associated with an unfavorable lipoprotein particle profile that is part of states that increase cardiovascular disease risk like diabetes and metabolic syndrome.

Investigation of causes of sex-related differences in ocular blood flow in healthy eyes determined by laser speckle flowgraphy

Sex-related differences are present in the systemic and ocular blood flow. However, the cause of the sex-related differences has not been determined. We investigated the ocular blood flow, represented by the mean blur rate (MBR), on the optic nerve head (ONH) determined by laser speckle flowgraphy in 138 males (63.9 ± 8.9 years) and 194 females (63.5 ± 9.4 years). The correlations between the MBR on the ONH and the clinical data were determined. The overall ONH-MBR was significantly higher in females than males (P < 0.001). In addition, the levels of the hemoglobin and hematocrit were significantly lower in females than in males (P < 0.001). The ONH-MBR was negatively and significantly correlated with the levels of the hemoglobin and hematocrit (both, P < 0.001). Multiple regression analyses showed that the sex (β = 0.248, P < 0.001) was an independent factor correlated with the ONH-MBR when the clinical examination data were not included in the analyses. However, when the clinical examination data were included, the hemoglobin level (β = −0.295, P < 0.001) was an independent factor that contributed to the ONH-MBR but the sex was not. We conclude that the sex-related differences in the hemoglobin level and the negative correlation between hemoglobin and the ONH-MBR are the causes of the sex-related differences in the ONH-MBR.

Prognostic significance of anaemia in patients with heart failure with preserved and reduced ejection fraction: results from the MAGGIC individual patient data meta-analysis

BACKGROUND

Anaemia is common among patients with heart failure (HF) and is an important prognostic marker.

AIM

We sought to determine the prognostic importance of anaemia in a large multinational pooled dataset of prospectively enrolled HF patients, with the specific aim to determine the prognostic role of anaemia in HF with preserved and reduced ejection fraction (HF-PEF and HF-REF, respectively).

DESIGN

Individual person data meta-analysis.

METHODS

Patients with haemoglobin (Hb) data from the MAGGIC dataset were used. Anaemia was defined as Hb < 120 g/l in women and <130 g/l in men. HF-PEF was defined as EF ≥ 50%; HF-REF was EF < 50%. Cox proportional hazard modelling, with adjustment for clinically relevant variables, was undertaken to investigate factors associated with 3-year all-cause mortality.

RESULTS

Thirteen thousand two hundred and ninety-five patients with HF from 19 studies (9887 with HF-REF and 3408 with HF-PEF). The prevalence of anaemia was similar among those with HF-REF and HF-PEF (42.8 and 41.6% respectively). Compared with patients with normal Hb values, those with anaemia were older, were more likely to have diabetes, ischaemic aetiology, New York Heart Association class IV symptoms, lower estimated glomerular filtration rate and were more likely to be taking diuretic and less likely to be taking a beta-blocker. Patients with anaemia had higher all-cause mortality (adjusted hazard ratio [aHR] 1.38, 95% confidence interval [CI] 1.25-1.51), independent of EF group: aHR 1.67 (1.39-1.99) in HF-PEF and aHR 2.49 (2.13-2.90) in HF-REF.

CONCLUSIONS

Anaemia is an adverse prognostic factor in HF irrespective of EF. The prognostic importance of anaemia was greatest in patients with HF-REF.

Pre-Hypertension in Apparently Healthy Young Adults: Incidence and Influence of Haemoglobin Level

INTRODUCTION

Prehypertension is a precursor of clinical hypertension and consequently of the cardiovascular disease. Recent studies have found positive correlation between Haemoglobin Level (Hb) and Blood Pressure (BP). But the presumed association between Hb and BP has not been investigated in healthy young adults.

AIM

This study aimed to estimate the incidence of prehypertension and the influence of Hb level on BP in healthy young adults.

MATERIALS AND METHODS

This was a cross-sectional study done in 84 apparently healthy undergraduate medical students aged between 18-23 years, of either sex. In study subjects, BP and haemoglobin content was measured. Prehypertension was defined as BP levels of 120 to 139/80 to 89 mm Hg. Statistical analysis was done by unpaired t-test and Pearson correlation Coefficient tests.

RESULTS

Incidence of prehypertension was 50%. In 24% of the study subjects both systolic and diastolic BP was in prehypertensive state. In another 26% of study subjects only systolic BP was above normal. There was positive correlation between systolic BP and Hb level (p = 0.0015).

CONCLUSION

High incidence of prehypertension especially systolic prehypertension prevails inapparently healthy medical undergraduate students. In them, positive correlation between Hb and systolic BP persists.

Hemoglobin levels and blood pressure are associated in rural black africans

OBJECTIVES

The association between blood levels of hemoglobin (B-hgb) and blood pressure (BP) has been widely investigated in Caucasians and Asians but there is a paucity of data in rural black Africans. The objective was to investigate the association between B-hgb and BP in a rural black African population.

METHODS

A cross-sectional study was conducted in three districts in Kenya (Bondo, Kitui, and Transmara) with the inclusion of participants aged ≥17 years. Background information, anthropometry, BP, B-hgb, hepatic insulin resistance (HOMA2-IR), standard lipid profile, and oral glucose tolerance test were obtained in each participant.

RESULTS

Background characteristics among 1,167 participants showed that anemic and non-anemic participants differed significantly from each other as there were more women, lower body mass index and waist circumference (WC), lower degree of hepatic insulin resistance and plasma cholesterols among the anemic participants. Furthermore, anemic participants had significantly lower systolic and diastolic BP (P < 0.01) but not a significantly different prevalence of hypertension (P = 0.08). Multivariate linear regression models adjusted for-age, sex, plasma total-cholesterol, WC, Log2(HOMA2-IR), ethnicity, and smoking status-revealed that B-hgb (per mmol/l increment) was significantly associated with systolic BP (estimate: 1.18 (0.37-1.98)) and diastolic BP (estimate: 1.06 (0.54-1.57)) (P < 0.01).

CONCLUSIONS

B-hgb is associated with BP in rural black Africans.

Hypovolaemia was associated with clustering of major cardiovascular risk factors in general population

Background

Previous studies indicated that the clustering of major cardiovascular disease (CVD) risk factors is common, and multiple unhealthy lifestyles are responsible for the clustering of CVD risk factors. However, little is known about the direct association between the volume load and the clustering of CVD risk factors in general population.

Methods

We investigated the association of the clustering of CVD risk factors (defined as two or more of the following factors: hypertension, diabetes, dyslipidemia and overweight) with volume load, which was evaluated by bioelectrical impedance analysis. Hypovolaemia was defined as extracellular water/total body water (ECW/TBW) at and under the 10th percentile for the normal population.

Results

Among the 7900 adults, only 29.3% were free of any pre-defined CVD risk factors and 40.8% had clustering of CVD risk factors. Hypovolaemia in clustering group was statistically higher than that either in the single or in the none risk factor group, which was 23.7% vs. 17.0% and 10.0%, respectively (P <0.001). As a categorical outcome, the percentage of the lowest quartiles of ECW/TBW and TBW/TBWwatson in clustering group were statistically higher than either those in the single or in the none risk factor group, which were 44.9% vs. 36.9% and 25.1% (P <0.001), 36.2% vs. 32.2% and 25.0%, respectively (P <0.001). After adjusting of potential confounders, hypovolaemia was significantly associated with clustering of CVD risk factors, with an OR of 1.66 (95% CI, 1.45-1.90).

Conclusions

Hypovolaemia was associated with clustering of major CVD risk factors, which further confirms the importance of lifestyle for the development of CVD.

Hemoglobin in normal range, the lower the better?-Evidence from a study from Chinese community-dwelling participants

OBJECTIVE

To examine the association between hemoglobin (Hb) levels and cardiovascular risk factors in a large community-dwelling cohort.

METHODS

A total of 4,186 women and 4,851 men were enrolled in the study. Data on personal history, physical examination and biochemical parameters were collected. Subjects were categorized by gender and divided into different group according to the level of Hb or blood pressure, and the association between Hb levels and cardiovascular risk factors was examined using Pearson's correlation analysis.

RESULTS

In both men and women even with normal Hb level, tertiles of Hb levels were positively associated with body mass index (BMI), total-cholesterol (TC), triglyceride (TG), uric acid (UA), diastolic blood pressures (DBP) and fasting plasma glucose (FPG) (all P=0.000 in men and women). Furthermore, significantly increased incidence of hyperuricemia (P=0.000 both in men and women) and obesity (P=0.000 both in men and women) were observed with the gradually increased Hb level. In addition, Pearson's correlation analysis revealed obvious correlation between Hb level and various cardiovascular risk factors including blood pressure and UA. Binary logistic regression analysis further demonstrated that the level of Hb was an important risk factor for elevated blood pressure (OR =1.216; 95% CI: 1.138-1.293, P=0.000 in men; OR =1.287; 95% CI: 1.229-1.363, P=0.000 in women).

CONCLUSIONS

Increasing Hb levels, even in subjects with normal level were associated with increasing prevalence of cardiovascular risk factors, suggesting that a slightly low Hb level might be beneficial to Chinese community-dwelling individuals.

Association between hemoglobin and diabetes in relation to the triglycerides-to-high-density lipoprotein cholesterol (TG-HDL) ratio in Japanese individuals: the Nagasaki Islands Study

OBJECTIVE

Our previous study reported that categorizing diabetes patients according to the serum triglycerides-to-high-density lipoprotein cholesterol (TG-HDL) ratio is useful for estimating the risk of atherosclerosis, as a high TG-HDL ratio in patients with diabetes constitutes risk factors for atherosclerosis. Another study showed that a high hemoglobin level is associated with the risk of atherosclerosis. However, no previous studies have examined the association between the hemoglobin level and diabetes categorized by the TG-HDL ratio. In order to investigate these associations, we conducted a cross-sectional study of 3,733 (1,299 men and 2,434 women) Japanese participants 30-89 years of age undergoing a general health checkup.

METHODS

We investigated the association between the hemoglobin levels and the incidence of diabetes in all subjects, who were divided into tertiles according to the TG-HDL ratio. Diabetes was defined as an HbA1c (NGSP) level of ≥ 6.5% and/or the initiation of glucose-lowering or insulin therapy.

RESULTS

Of the 265 diabetes patients identified in this study, 116 had a high TG-HDL ratio (high TG-HDL diabetes) and 71 had a low TG-HDL ratio (low TG-HDL diabetes). Independent from classical cardiovascular risk factors, the multivariate odds ratio of a 1 SD (standard deviation) increment in hemoglobin (1.30 g/dL for men, 1.16 g/dL for women) was 1.04 (95% confidence intervals (CI): 0.88-1.22) for all patients with diabetes, 1.44 (95%CI: 1.17-1.77) for the patients with high TG-HDL diabetes and 0.67 (95%CI: 0.54-0.83) for the patients with low TG-HDL diabetes.

CONCLUSION

The hemoglobin level is positively associated with high TG-HDL diabetes and inversely associated with low TG-HDL diabetes. These findings suggest that measuring the hemoglobin level is clinically relevant for estimating the risk of atherosclerosis in patients with diabetes categorized according to the TG-HDL ratio.

Association between the hemoglobin levels and hypertension in relation to the BMI status in a rural Japanese population: the Nagasaki Islands Study

OBJECTIVE

The hemoglobin levels and blood pressure has been reported in a few studies, and a positive association between the hemoglobin levels and the body mass index (BMI) status has also been documented. A higher BMI may therefore affect the association between the hemoglobin levels and hypertension. However, no published studies have examined this association in relation to the BMI status. The primary purpose of this study was to assess the association between the hemoglobin levels and hypertension in relation to the BMI status.

METHODS

A cross-sectional study of 3,203 non-anemic subjects (1,191 men and 2,012 women, 30-79 years old) who were undergoing general health checkups was conducted.

RESULTS

A positive association between the hemoglobin levels and hypertension was established for both men and women. For a one SD (standard deviation) increment in hemoglobin, the multivariable odds ratio (ORs) and 95% confidence interval (CIs) for hypertension were 1.21 (95%CI: 1.05-1.40) for men and 1.25 (95%CI: 1.13-1.39) for women. We also found that a significant association was confined to the participants with a BMI of <25 kg/m(2). Among the participants with a BMI of <25 kg/m(2), the multivariable ORs and 95% CIs for hypertension of a one SD increment in hemoglobin were 1.34 (95%CI: 1.12-1.60) for men and 1.31 (95%CI: 1.16-1.47) for women. Meanwhile, among those with a BMI of ≥25 kg/m(2), the corresponding values were 1.01 (95%CI: 0.79-1.30) and 1.09 (95%CI: 0.87-1.37).

CONCLUSION

An independent positive association between the hemoglobin levels and the risk of hypertension was observed for both non-anemic Japanese men and women, confined to participants with a BMI of <25 kg/m(2).

Hemoglobin level is positively associated with blood pressure in a large cohort of healthy individuals

It has been hypothesized that an increased hemoglobin level elevates blood pressure. The present study investigated the association between hemoglobin level and systolic blood pressure and diastolic blood pressure in healthy persons. The study population was composed of 101 377 whole blood and plasma donors, who made 691 107 visits to the blood bank. At each visit, hemoglobin level and blood pressure were measured as part of the standard procedure before a blood donation. We used repeated measurement analysis to analyze the data. We used generalized estimating equation models to assess the between-person effect and linear mixed models to assess the within-person effect. All of the analyses were done separately for men and women. In the study population, 50% were men. The mean age in men was 49.3 years (±12.5 years), and in women it was 42.4 years (±13.7 years). Hemoglobin level was positively associated with both systolic and diastolic blood pressures. With respect to the between-person effect, regression coefficients for systolic blood pressure were 1.3 mm Hg per millimole per liter increase in hemoglobin level for men and 1.8 mm Hg per millimole per liter increase in hemoglobin level for women. With respect to the within-person effect, regression coefficients for systolic blood pressure were 0.7 mm Hg and 0.9 mm Hg per millimole per liter increase in hemoglobin level, for men and women, respectively. For diastolic blood pressure, results were comparable. The results show that hemoglobin level is positively associated with both systolic and diastolic blood pressures in healthy individuals. We observed consistent effects between persons but also within persons.