Seasonal hematocrit variation and health risks in the adult population of Kinshasa, Democratic Republic of Congo

Hightower, C. Makena; Hightower, Joyce D; Vázquez, Beatriz Y. Salazar; Intaglietta, Marcos

doi:10.2147/vhrm.s8136

Cited by 9 publications

(6 citation statements)

References 22 publications

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“…As reported by Hu Nan [24], we also found that the risk of pre-hypertension is higher in women than men and could be due to the difference in the level of hematocrit or body constitution [25]. We also observed that the association between hematocrit and pre-hypertension was not significant in older individuals aged over 60 years.…”

Section: Discussionsupporting

confidence: 79%

Association of Hematocrit and Pre-hypertension Among Chinese Adults: The CRC Study

Liu

Liang

Qiu

et al. 2014

Cell Biochem Biophys

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Elevated blood pressure is regarded as an independent risk factor for cardiovascular diseases and diabetes. We examined the relation between hematocrit and pre-hypertension as well as the effect of sex, obesity, fasting glucose, and lipids in Chinese adults. The study samples were from a community-based health examination survey in China and included a total of 2,3691 patients with blood pressure in normal range. The odds ratios [ORs, 95 % confidence interval (CI)] of pre-hypertension across increasing quartiles of hematocrit were 1.000, 1.176 (1.050-1.318), 1.213 (1.081-1.363), and 1.364 (1.209-1.540) (P for trend < 0.001), when adjusted for age, sex, body mass index, glutamic-pyruvic transaminase, glutamic-oxalocetie transaminase, serum uric acid, glucose, and lipids. Associations were significant in both men and women, but not in individuals older than 60 years. In addition, low-density lipoprotein cholesterol significantly interacted with hematocrit (P for interaction <0.024). The associations were more evident in patients with low (P < 0.001) and median LDL-C levels (P < 0.013) than those with high glucose levels. Hematocrit was associated with pre-hypertension, and was independent of metabolic risk factors. These associations were not significant in older individuals and low-density lipoprotein cholesterol may modify these associations.

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Section: Discussionsupporting

confidence: 79%

Association of Hematocrit and Pre-hypertension Among Chinese Adults: The CRC Study

Liu

Liang

Qiu

et al. 2014

Cell Biochem Biophys

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“…), individual's factors (exercise, physical activity, diet, etc.) [28][29][30][31][32][33][34]. Of note that is, the rainy season is the favorable time in diseases increase like malaria and other parasitic diseases not screen in this study.…”

Section: Biomed Research Internationalmentioning

confidence: 99%

Haematological and Biochemical Reference Values for Healthy Population of Maferinyah Rural Community in Guinea

Béavogui

Touré

Camara

et al. 2020

BioMed Research International

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Guinea’s reference ranges for biological parameters rely on those of Caucasian values. Variability in reference ranges according to the context is well-documented. We conducted this study for the purpose of future malaria clinical trials that assess the efficacy and safety of malaria drugs. A repeated cross-sectional study was carried out, in an apparently healthy cohort population. Surveys took place in Maferinyah rural community, which is located at 75 km from the capital. The 2.5th and 97.5th percentiles were determined nonparametrically and stood for reference intervals. Reference values were determined separately for males and females according to ranges of age (6-10 years of age; 11-15 years of age; 16-45 years of age). Differences between genders were tested using the Mann-Whitney test, while the Friedman test was performed to test differences within each gender group according to the seasons. A total of 450 volunteers were enrolled. The median age was 13. Males 16-45 years of age had significantly higher hematologic and biochemical values compared to a female of the same age (for hematological parameters: Mean Cell Hemoglobin Concentration MCHC p≤0.001, Platelets p≤0.001, monocytes p=0.0305, eosinophils p=0.0225; for biochemical parameters: Aspartate aminotransferase AST p≤0.001, Alanine Aminotransferase ALT p≤0.001, creatinine p≤0.001). We noticed significant seasonal variations for all the biochemical parameters and some hematologic parameters (Mean Corpuscular Hemoglobin MCH, MCHC, Mean Cell volume). This is the first study establishing hematologic and biochemical parameters in Guinea. These findings provide a useful guide for the clinical researchers and care providers. Studies on large scale and in different settings would be also desirable.

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“…Environmental factors, genetics, nutrition, level of hydration, time in the daily cycle, and seasonal variations (9) cause an additional variability, yielding a dispersion of values that, although not well documented, may be of the order of Ϯ10% of the average for the population grouped according to age and sex.…”

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confidence: 99%

The variability of blood pressure due to small changes of hematocrit

Vázquez

Martini

Tsai

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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Vázquez BY, Martini J, Tsai AG, Johnson PC, Cabrales P, Intaglietta M. The variability of blood pressure due to small changes of hematocrit. Am J Physiol Heart Circ Physiol 299: H863-H867, 2010. First published July 2, 2010; doi:10.1152/ajpheart.00496.2010.-The hematocrit (Hct) of awake hamsters was lowered to 90% of baseline by isovolemic hemodilution using hamster plasma to determine the acute effect of small changes in Hct and blood viscosity on systemic hemodynamics. Mean arterial blood pressure increased, reaching a maximum of about 10% above baseline (8.6 Ϯ 5.5 mmHg) when Hct decreased 8.4 Ϯ 1.9% (P Ͻ 0.005). Cardiac output increased continuously with hemodilution. These conditions were reached at ϳ60 min after exchange transfusion and remained stationary for 1 h. Peripheral vascular resistance was approximately constant up to a decrease of Hct of about 10% and then fell continuously with lowering Hct. Vascular hindrance or vascular resistance independent of blood viscosity increased by about 20% and remained at this level up to an Hct decrease of 20%, indicating that the vasculature constricted with the lowered Hct. The results for the initial 2-h period are opposite but continuous with previous findings with small increases in Hct. In conclusion, limited acute anemic conditions increase mean arterial blood pressure during the initial period of 2 h, an effect that is quantitatively similar but opposite to the acute increase of Hct during the same period. hemodilution; acute anemia; blood viscosity; nitric oxide HEMATOCRIT (Hct) in the healthy population varies primarily as function of age and sex. Environmental factors, genetics, nutrition, level of hydration, time in the daily cycle, and seasonal variations (9) cause an additional variability, yielding a dispersion of values that, although not well documented, may be of the order of Ϯ10% of the average for the population grouped according to age and sex.Hct determines blood viscosity, regulating peripheral vascular resistance (PVR) and therefore, in principle, blood pressure. Increasing the viscosity of a fluid flowing in rigid tubes increases flow resistance and tube wall shear stress. However, this does not necessarily occur in blood vessels where the vessel wall shear stress due to flowing blood modulates the production of vasodilators by mechanotransduction (15,22). Thus, in the circulation, increasing blood viscosity can produce two opposing effects on PVR: a direct effect related to hemodynamic hindrance and an opposite effect due to changes in vessel diameter.Changes in Hct cause hemoconcentration or hemodilution, factors that affect blood viscosity and therefore vascular resistance (VR). Our understanding of these phenomena is based on the work of Richardson and Guyton (18) and Messmer et al. (16), showing how the heart and the circulation respond to changes of Hct and therefore blood viscosity. A common denominator of these studies (12) is that the induced changes of Hct were comparatively large, similar to the Hct perturbations found in hemorrh...

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Seasonal hematocrit variation and health risks in the adult population of Kinshasa, Democratic Republic of Congo

Cited by 9 publications

References 22 publications

Association of Hematocrit and Pre-hypertension Among Chinese Adults: The CRC Study

Association of Hematocrit and Pre-hypertension Among Chinese Adults: The CRC Study

Haematological and Biochemical Reference Values for Healthy Population of Maferinyah Rural Community in Guinea

The variability of blood pressure due to small changes of hematocrit

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