Effects of hunter-gatherer subsistence mode on arterial distensibility in Cameroonian pygmies

A cost-effective, machine learning-driven approach for screening arterial functional aging in a large-scale Chinese population

Introduction

An easily accessible and cost-free machine learning model based on prior probabilities of vascular aging enables an application to pinpoint high-risk populations before physical checks and optimize healthcare investment.

Methods

A dataset containing questionnaire responses and physical measurement parameters from 77,134 adults was extracted from the electronic records of the Health Management Center at the Third Xiangya Hospital. The least absolute shrinkage and selection operator and recursive feature elimination-Lightweight Gradient Elevator were employed to select features from a pool of potential covariates. The participants were randomly divided into training (70%) and test cohorts (30%). Four machine learning algorithms were applied to build the screening models for elevated arterial stiffness (EAS), and the performance of models was evaluated by calculating the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy.

Results

Fourteen easily accessible features were selected to construct the model, including "systolic blood pressure" (SBP), "age," "waist circumference," "history of hypertension," "sex," "exercise," "awareness of normal blood pressure," "eat fruit," "work intensity," "drink milk," "eat bean products," "smoking," "alcohol consumption," and "Irritableness." The extreme gradient boosting (XGBoost) model outperformed the other three models, achieving AUC values of 0.8722 and 0.8710 in the training and test sets, respectively. The most important five features are SBP, age, waist, history of hypertension, and sex.

Conclusion

The XGBoost model ideally assesses the prior probability of the current EAS in the general population. The integration of the model into primary care facilities has the potential to lower medical expenses and enhance the management of arterial aging.

Separate and Joint Associations of Cardiorespiratory Fitness and Healthy Vascular Aging With Subclinical Atherosclerosis in Men

BACKGROUND

Achieving healthy vascular aging (HVA) is important for decelerating age-related cardiovascular disease risk. We evaluated the interplay between HVA, cardiorespiratory fitness (CRF), and subclinical atherosclerosis.

METHODS

We analyzed data on 3722 men who underwent cardiopulmonary exercise testing in a health examination program. HVA was defined as blood pressure <140/90 mm Hg without hypertension and brachial-ankle pulse wave velocity <1266 cm/s. CRF was directly measured by peak oxygen uptake. Subclinical atherosclerosis was defined as coronary artery calcification scores of >0 and ≥100 and a mean carotid artery intima-media thickness (CIMT) >75th percentile for each age group as well as >0.8 mm of CIMT. Separate and joint associations of HVA and CRF with subclinical atherosclerosis were evaluated.

RESULTS

Each 1 metabolic equivalent increment in CRF was associated with 23% higher odds for having HVA. HVA was associated with lower odds of coronary artery calcification but not CIMT. CRF modified the association between HVA and CIMT>0.8 mm (interaction: P=0.01); HVA was associated with lower odds of CIMT>0.8 mm in fit men with no significant association between HVA and CIMT>0.8 mm in unfit men. Compared with no HVA and being unfit, HVA and being fit was associated with lower odds of subclinical atherosclerosis, but there was no significant association between HVA and being unfit with subclinical atherosclerosis.

CONCLUSIONS

HVA and higher CRF are each associated with a lower risk of subclinical atherosclerosis in men. Higher CRF is associated with a higher prevalence of HVA and may modify the association between HVA and subclinical atherosclerosis.

Impact of Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors on Arterial Stiffness and Vascular Aging-What Do We Know So Far? (A Narrative Review)

Vascular aging, early vascular aging or supernormal vascular aging are concepts used for estimating the cardiovascular risk at a certain age. From the famous line of Thomas Sydenham that "a man is as old as his arteries" to the present day, clinical studies in the field of molecular biology of the vasculature have demonstrated the active role of vascular endothelium in the onset of cardiovascular diseases. Arterial stiffness is an important cardiovascular risk factor associated with the occurrence of cardiovascular events and a high risk of morbidity and mortality, especially in the presence of diabetes. Sodium-glucose cotransporter 2 inhibitors decrease arterial stiffness and vascular resistance by decreasing endothelial cell activation, stimulating direct vasorelaxation and ameliorating endothelial dysfunction or expression of pro-atherogenic cells and molecules.

Influencing factors of supernormal vascular aging in Chinese population

OBJECTIVES

Previous studies have analysed the epidemic characteristics of supernormal vascular aging (SUPERNOVA), and found that SUPERNOVA were significantly associated with lower risk of cardiovascular disease. However, the influencing factors of SUPERNOVA are still unclear. The aim of this study was to investigate the characteristics and influencing factors of SUPERNOVA.

METHODS

A total of 42 196 participants of the Kailuan Study were enrolled in the study. SUPERNOVA was defined as the lowest 2.5% of the age-quintile brachial-ankle pulse wave velocity (baPWV), early vascular aging was defined as the highest 2.5% of the age-quintile baPWV. Multivariable logistic regression analysis was applied to investigate the influencing factors of SUPERNOVA.

RESULTS

The population with SUPERNOVA was mostly women, nonsmokers, nondrinkers, and those with higher education. They had lower levels of cardiovascular disease risk factors and healthier lifestyles. The results of logistics regression showed that the influencing factors of SUPERNOVA include age, sex, hypertension, diabetes, resting heart rate, hypersensitive C-reactive protein, and uric acid. However, the effects of these factors were different across age groups. We also observed that in addition to the unalterable factors (age and sex), only resting heart rate above 80 bpm (OR = 0.396, 95% CI: 0.231-0.681) and SBP (OR = 0.945, 95% CI: 0.932-0.958) were significantly associated with odds of SUPERNOVA in participants without cardiovascular risk factors.

CONCLUSION

This study investigated the characteristics of the population with SUPERNOVA and the factors influencing it, which provided a basis for different populations to take preventive measures to slow down the process of vascular aging.

Infection and food combine to cause atherosclerotic coronary heart disease - Review and hypothesis

HYPOTHESIS

It is hypothesised that a combination of childhood and later life infections and excess food consumption, particularly of Western style food, initiates and contributes to atherosclerotic coronary heart disease. To consider this hypothesis we have conducted a brief review of the role of childhood infections, food, and their combined influence on atherosclerosis.

EVIDENCE

(i) Studies of populations with high prevalence of infections and low "hunter gather" like food consumption, have extremely low prevalence of atherosclerosis, (ii) there are consistent associations between infections in childhood and adult atherosclerotic coronary heart disease, (iii) there is an association between increased body weight, (an indication of excess eating), and atherosclerotic heart disease, and (iv) there is evidence that a combination of increased body weight and infections influences the development of atherosclerotic coronary heart disease.Infections do not appear to act independently to cause atherosclerosis. A combination of both food and infection appears to be required to cause atheroma.

CONCLUSION

The hypothesis that infections when combined with excess eating initiates atherosclerosis, is plausible.

ACTION

Action aimed at prevention of atherosclerotic heart disease is possible. There are three safe approaches to prevention (i) encouragement of Mediterranean like diets, (ii) avoidance of overeating and (iii) vigorous control of infections among all age groups. There is a need to monitor patients with a history of serious childhood infections and poor nutrition. In addition, for high risk subjects, cholesterol lowering statins are of proven and safe value.

Vascular aging and its relationship with lifestyles and other risk factors in the general Spanish population: Early Vascular Ageing Study

OBJECTIVES

To describe the prevalence of healthy vascular aging (HVA), normal vascular aging and early vascular aging (EVA) in a sample of Spanish population without cardiovascular disease. The relationship of vascular aging with lifestyle, cardiovascular risk factors, psychological and inflammatory risk factors is also analyzed.

METHODS

A total of 501 participants were recruited (49.70% men, aged 55.90 ± 14.24 years) by random sampling. Vascular aging was defined in three steps: Step 1: participants with vascular damage in carotid arteries or peripheral artery disease were classified as EVA. Step 2: with the percentiles of carotid-to-femoral pulse wave velocity (cfPWV) we used three criteria, first, the 10th and 90th cfPWV percentiles of the population studied by age and sex; second, the 10th and 90th percentiles of the European population reference values and third, the 25th and 75th cfPWV percentiles of the population studied by age and sex. Step 3: participants with hypertension or type 2 diabetes mellitus included in HVA were reclassified as normal vascular aging. Arterial stiffness was assessed with cfPWV using a Sphygmocor device. Physical activity was measured with an accelerometer. Psychological factors, lifestyle and other clinical information were obtained by standard questionnaire.

RESULTS

The global prevalence of HVA was 8 and 14% (men 8 and 10%, women 9 and 18%), and 22 and 18% (men 26 and 23%, women 17 and 12%) for EVA, using criteria a and b, respectively. In the logistic regression analysis, vascular aging maintains positive associations with more sedentary time [odds ratio (OR) = 2.37 and 4.51], having triglycerides above 150 mg/dl (OR = 6.55 and 4.06), abdominal obesity (OR = 2.73 and 2.90), increased uric acid (OR = 4.63 and 2.98) and insulin resistance index homeostatic model assessment (OR = 4.05 and 6.78), and a negative association with less physical activity (OR = 0.29 and 0.28) using criteria a and b, respectively.

CONCLUSION

One in 10 has HVA and one in five EVA. The prevalence of EVA is higher in men. Study results suggest that preventive strategies aimed at increasing physical activity, reducing sedentary time and decreasing obesity and insulin resistance improve vascular aging.

Arterial Stiffness and Cardiovascular Risk in Hypertension

Arterial stiffness, a leading marker of risk in hypertension, can be measured at material or structural levels, with the latter combining effects of the geometry and composition of the wall, including intramural organization. Numerous studies have shown that structural stiffness predicts outcomes in models that adjust for conventional risk factors. Elastic arteries, nearer to the heart, are most sensitive to effects of blood pressure and age, major determinants of stiffness. Stiffness is usually considered as an index of vascular aging, wherein individuals excessively affected by risk factor exposure represent early vascular aging, whereas those resistant to risk factors represent supernormal vascular aging. Stiffness affects the function of the brain and kidneys by increasing pulsatile loads within their microvascular beds, and the heart by increasing left ventricular systolic load; excessive pressure pulsatility also decreases diastolic pressure, necessary for coronary perfusion. Stiffness promotes inward remodeling of small arteries, which increases resistance, blood pressure, and in turn, central artery stiffness, thus creating an insidious feedback loop. Chronic antihypertensive treatments can reduce stiffness beyond passive reductions due to decreased blood pressure. Preventive drugs, such as lipid-lowering drugs and antidiabetic drugs, have additional effects on stiffness, independent of pressure. Newer anti-inflammatory drugs also have blood pressure independent effects. Reduction of stiffness is expected to confer benefit beyond the lowering of pressure, although this hypothesis is not yet proven. We summarize different steps for making arterial stiffness measurement a keystone in hypertension management and cardiovascular prevention as a whole.

Central blood pressure and aortic pulse wave reflection in water-exercised postmenopausal hypertensive women: A cross-sectional study

Exercise training has been associated with the attenuation of cardiovascular impairment after menopause. This study aimed to compare central and peripheral blood pressure and aortic pulse wave reflection in sedentary and trained (aerobic exercise in the water) hypertensive postmenopausal women. Hypertensive postmenopausal women were divided into sedentary (SED, n = 53) and trained groups (TR, n = 31). Self-reporting from the trained group presented a mean of 1.7 ± 0.3 years of exercise practice in the water. Central blood pressure and amplification indexes (AIx) were obtained by the applanation tonometry of radial and aortic arteries. No changes were observed in systolic blood pressure (SBP) in the TR group than the SED group; however, office diastolic blood pressure (DBP) was reduced compared to the SED group. Central blood pressure and augmentation index (AIx@75%) values were similar in the SED and TR groups. These data suggest that self-reported long-term exercise training in the water could not improve central hemodynamic variables in postmenopausal hypertensive women compared to sedentary ones. However, it should be emphasized that DBP levels were reduced in trained subjects, which might reduce cardiovascular outcomes.

Early and Supernormal Vascular Aging: Clinical Characteristics and Association With Incident Cardiovascular Events

Pulse wave velocity is an established marker of early vascular aging but may also help identifying individuals with supernormal vascular aging. We tested the hypothesis that individuals with the largest difference (Δ-age) between chronological and vascular age show the lowest rate of cardiovascular events and may thus be defined as supernormal vascular aging. Vascular age was defined as the predicted age in the best fitting multivariable regression model including classical risk factors and treatment and pulse wave velocity, in a subset of the Reference Values for Arterial Stiffness Collaboration Database (n=3347). Δ-age was then calculated as chronological age minus vascular age, and the 10th and 90th percentiles were used to define early (Δ-age<-5.7 years), normal (Δ-age -5.7 to 6.8 years) and supernormal vascular aging (Δ-age>6.8 years). The risk for fatal and nonfatal cardiovascular events associated with vascular aging categories was investigated in the Malmö Diet and Cancer Study cohort (n=2642). In the Malmö Diet and Cancer Study Cohort (6.6-year follow-up, 286 events), Δ-age was significantly (P<0.01) and inversely associated with cardiovascular events. Compared with normal vascular aging, supernormal vascular aging had lower risk (hazard ratio, 0.59 [95% CI, 0.41-0.85]), whereas early vascular aging had higher risk (hazard ratio, 2.70 [95% CI, 1.55-4.70]) of cardiovascular events, in particular coronary events. There was no significant association with all-cause mortality. This study represents the first validation of the clinical significance of the supernormal vascular aging concept, based on prospective data. Its further characterization may help discovering novel protective molecular pathways and providing preventive strategies for successful vascular aging.

Prevalence and determinants of blood pressure variability in pygmies of Southern region Cameroon

INTRODUCTION

The impact of urbanization and living conditions on the prevalence of hypertension in the Cameroonian population is poorly known.

AIM

To evaluate the prevalence and determinants of blood pressure (BP) in adult Pygmies and Bantus living in urban and rural areas of Southern Cameroon.

PARTICIPANTS AND METHODS

This was a cross-sectional comparative study of 406 adults (96 urban Bantus, 100 urban Pygmies, 111 rural Bantus and 99 tropical rainforest Pygmies with a traditional Pygmies way of life), recruited in Southern Cameroon (mean age 42 ± 17 years; 56.7% women). Sociodemographic, anthropometric and BP parameters were collected. Hypertension was defined as BP at least 140/90 mmHg and/or use of BP-lowering drug(s).

RESULTS

The age-standardized prevalence of hypertension in urban Bantus, rural Bantus, urban Pygmies and traditional Pygmies was 18.0, 13.5, 9.3 and 4.1%, respectively. Mean SBP and DBP differed significantly according to Bantu vs. Pygmy ethnicity, and urban vs. rural residency. After multiple adjustments, mean arterial pressure was significantly associated with age, BMI, Bantu ancestry and urban residency.

CONCLUSION

Bantu ethnicity and urban residency are significantly associated with high-BP among people from Southern Cameroon.

Exploring and comparing definitions of healthy vascular ageing in the population: characteristics and prospective cardiovascular risk

Different methods can be used to define healthy vascular ageing (HVA). In this prospective cohort study, we explored three different definitions in order to provide guidance for which to use. 2718 subjects were included from the Cardiovascular (CV) arm of the Malmö Diet Cancer Study (MDCS; median age 71.9 years, 62.2% females). Three different definitions of HVA were used: HVA-1 (<15th percentile of aortic pulse wave velocity (aPWV) distribution from age-quintiles); HVA-2 (<35th percentile of aPWV+ <35th percentile of carotid Intima-Media Thickness. cIMT); and HVA-3 (aPWV < 7.6 m/s + no hypertension). The HVA-1 and HVA-2 groups were compared with the HVA-3, and to the corresponding groups without HVA (non-HVA), in cross-sectional analyses for baseline characteristics and using Cox regressions for prospective risk, yielding hazard ratios (HRs) adjusted for conventional risk factors. A composite CVD endpoint was used, consisting of myocardial infarctions, ischemic heart disease mortality, and coronary artery procedures. The baseline characteristics were, with minor exceptions, similar across HVA groups. In the fully adjusted model, the HRs (95%CI) were 0.62 (0.41-0.93), 0.45 (0.26-0.76), and 0.56 (0.34-0.91) for HVA-1, HVA-2, and HVA-3, respectively. In summary, this observational study of elderly subjects provides examples of integrating hypertension and cIMT in the definition of HVA, as compared with only using aPWV. As aPWV itself is such a robust marker of HVA, it is demanding to find additional markers which improve the definition. There is a need to create a generally accepted definition of HVA.

Aging Fits the Disease Criteria of the International Classification of Diseases

The disease criteria used by the World Health Organization (WHO) were applied to human biological aging in order to assess whether aging can be classified as a disease. These criteria were developed for the 11th revision of the International Classification of Diseases (ICD) and included disease diagnostics, mechanisms, course and outcomes, known interventions, and linkage to genetic and environmental factors. RESULTS: Biological aging can be diagnosed with frailty indices, functional, blood-based biomarkers. A number of major causal mechanisms of human aging involved in various organs have been described, such as inflammation, replicative cellular senescence, immune senescence, proteostasis failures, mitochondrial dysfunctions, fibrotic propensity, hormonal aging, body composition changes, etc. We identified a number of clinically proven interventions, as well as genetic and environmental factors of aging. Therefore, aging fits the ICD-11 criteria and can be considered a disease. Our proposal was submitted to the ICD-11 Joint Task force, and this led to the inclusion of the extension code for "Ageing-related" (XT9T) into the "Causality" section of the ICD-11. This might lead to greater focus on biological aging in global health policy and might provide for more opportunities for the new therapy developers.

Central Versus Peripheral Artery Stiffening and Cardiovascular Risk

The large elastic arteries fulfill an important role in buffering the cyclical changes in blood pressure, which result from intermittent ventricular ejection. With aging and accrual of cardiovascular risk factors, the elastic arteries stiffen, and this process holds a number of deleterious consequences for the cardiovascular system and major organs. Indeed, arterial stiffness is now recognized as an important, independent determinant of cardiovascular disease risk. Additional, important information concerning the mechanisms underlying arterial stiffening has come from longitudinal studies of arterial stiffness. More recently, attention has focused on the role of peripheral, muscular arteries in cardiovascular disease risk prediction and, in particular, the clinical consequences of reversal of the normal gradient of arterial stiffness between central and peripheral arteries, with aging and disease.

Cross-Sectional Association of Frailty and Arterial Stiffness in Community-Dwelling Older Adults: The Framingham Heart Study

BACKGROUND

Frailty is a risk factor for cardiovascular disease (CVD). Underlying mechanisms to explain the connection between frailty and CVD are unclear. We sought to examine the association between frailty and arterial stiffness, a precursor of hypertension and CVD.

METHODS

We conducted a cross-sectional analysis of community-dwelling Framingham Heart Study Offspring and Omni participants ≥60 years of age examined in 2005-2008. Frailty was defined primarily according to the Fried physical phenotype definition, which identifies nonfrail, prefrail, and frail individuals. Arterial stiffness was assessed using carotid-femoral pulse wave velocity (CFPWV). Generalized linear regression was used to examine the association between frailty level and CFPWV (modeled as -1000/CFPWV in msec/m, then transformed back to the original scale, m/s), adjusted for age, sex, cohort, mean arterial pressure, heart rate, height, and smoking.

RESULTS

Of 2,171 participants (55% women, 91% white), 45% were prefrail and 7% were frail. Mean ages were 67, 70, and 73 years, and adjusted CFPWV least squares means were 10.0 (95% CI, 9.9-10.1), 10.3 (10.2-10.5), and 10.5 m/s (10.1-11.0); p = .0002 for nonfrail, prefrail, and frail groups, respectively. Results were similar using the Rockwood cumulative deficit model of frailty, and in a sensitivity analysis adjusting for prevalent coronary heart disease and diabetes.

CONCLUSIONS

Prefrailty and frailty were associated with higher arterial stiffness in a cohort of community-dwelling older adults. Arterial stiffness may help explain the relationship between frailty and CVD.

Association between healthy vascular aging and the risk of the first stroke in a community-based Chinese cohort

In this study we tested whether vascular aging is associated with the risk of first stroke in the Kailuan cohort, a community-based Chinese cohort. For participants aged ≥ 50 years, healthy vascular aging (HVA) was defined as an absence of hypertension and a brachial-ankle pulse wave velocity < the mean + 2 standard deviations, which was determined from a reference sample of healthy participants aged < 30 years. The primary outcome was first stroke (ischemic or hemorrhagic). In total, 11,474 participants were enrolled. The prevalence of HVA decreased from 36.0% in participants aged 50-59 years to 4.7% in those aged ≥ 70 years. During a median follow-up of 3.3 years, the incidence of first stroke was 0.5% in the HVA group but was 2.6% in the Non-HVA group. After adjusting for confounding variables, HVA was associated with a 0.32-fold lower risk of first stroke compared to the Non-HVA group (95% confidence interval, 0.18-0.56; p < 0.001). It thus appears that HVA reduced the risk of first stroke in a community-based Chinese population. This suggests that evaluation of vascular aging as part of public health screening may be useful for stroke risk assessment.

Polygenic adaptation and convergent evolution on growth and cardiac genetic pathways in African and Asian rainforest hunter-gatherers

Different human populations facing similar environmental challenges have sometimes evolved convergent biological adaptations, for example, hypoxia resistance at high altitudes and depigmented skin in northern latitudes on separate continents. The "pygmy" phenotype (small adult body size), characteristic of hunter-gatherer populations inhabiting both African and Asian tropical rainforests, is often highlighted as another case of convergent adaptation in humans. However, the degree to which phenotypic convergence in this polygenic trait is due to convergent versus population-specific genetic changes is unknown. To address this question, we analyzed high-coverage sequence data from the protein-coding portion of the genomes of two pairs of populations: Batwa rainforest hunter-gatherers and neighboring Bakiga agriculturalists from Uganda and Andamanese rainforest hunter-gatherers and Brahmin agriculturalists from India. We observed signatures of convergent positive selection between the rainforest hunter-gatherers across the set of genes with "growth factor binding" functions ([Formula: see text]). Unexpectedly, for the rainforest groups, we also observed convergent and population-specific signatures of positive selection in pathways related to cardiac development (e.g., "cardiac muscle tissue development"; [Formula: see text]). We hypothesize that the growth hormone subresponsiveness likely underlying the adult small body-size phenotype may have led to compensatory changes in cardiac pathways, in which this hormone also plays an essential role. Importantly, in the agriculturalist populations, we did not observe similar patterns of positive selection on sets of genes associated with growth or cardiac development, indicating our results most likely reflect a history of convergent adaptation to the similar ecology of rainforests rather than a more general evolutionary pattern.

Urbanization as a risk factor for aortic stiffness in a cohort in India

Urbanization is associated with higher prevalence of cardiovascular disease worldwide. Aortic stiffness, as measured by carotid-femoral pulse wave velocity is a validated predictor of cardiovascular disease. Our objective was to determine the association between urbanization and carotid-femoral pulse wave velocity. The analysis included 6166 participants enrolled in an ongoing population-based study (mean age 42 years; 58% female) who live in an 80 × 80 km region of southern India. Multiple measures of urbanization were used and compared: 1) census designations, 2) satellite derived land cover (crops, grass, shrubs or trees as rural; built-up areas as urban), and 3) distance categories based on proximity to an urban center. The association between urbanization and carotid-femoral pulse wave velocity was tested in sex-stratified linear regression models. People residing in urban areas had significantly (p < 0.05) elevated mean carotid-femoral pulse wave velocity compared to non-urban populations after adjustment for other risk factors. There was also an inverse association between distance from the urban center and mean carotid-femoral pulse wave velocity: each 10 km increase in distance was associated with a decrease in mean carotid-femoral pulse wave velocity of 0.07 m/s (95% CI: -0.09, -0.06 m/s). The association was stronger among older participants, among smokers, and among those with other cardiovascular risk factors. Further research is needed to determine which components in the urban environment are associated with higher carotid-femoral pulse wave velocity.

A genome scan for genes underlying adult body size differences between Central African hunter-gatherers and farmers

The evolutionary and biological bases of the Central African "pygmy" phenotype, a characteristic of rainforest hunter-gatherers defined by reduced body size compared with neighboring farmers, remain largely unknown. Here, we perform a joint investigation in Central African hunter-gatherers and farmers of adult standing height, sitting height, leg length, and body mass index (BMI), considering 358 hunter-gatherers and 169 farmers with genotypes for 153,798 SNPs. In addition to reduced standing heights, hunter-gatherers have shorter sitting heights and leg lengths and higher sitting/standing height ratios than farmers and lower BMI for males. Standing height, sitting height, and leg length are strongly correlated with inferred levels of farmer genetic ancestry, whereas BMI is only weakly correlated, perhaps reflecting greater contributions of non-genetic factors to body weight than to height. Single- and multi-marker association tests identify one region and eight genes associated with hunter-gatherer/farmer status, and 24 genes associated with the height-related traits. Many of these genes have putative functions consistent with roles in determining their associated traits and the pygmy phenotype, and they include three associated with standing height in non-Africans (PRKG1, DSCAM, MAGI2). We find evidence that European height-associated SNPs or variants in linkage disequilibrium with them contribute to standing- and sitting-height determination in Central Africans, but not to the differential status of hunter-gatherers and farmers. These findings provide new insights into the biological basis of the pygmy phenotype, and they highlight the potential of cross-population studies for exploring the genetic basis of phenotypes that vary naturally across populations.

Association of urinary sodium excretion with blood pressure and risk factors associated with hypertension among Cameroonian pygmies and bantus: a cross-sectional study

Background

High salt intake increases blood pressure (BP) and hypertension risk. This study aimed to examine association of urinary sodium excretion with BP and hypertension correlates among Cameroonian pygmies under hunter-gatherer subsistence mode and Bantus, living in urban area under unhealthy behavioral habits.

Methods

In this cross-sectional cluster sampling study, we randomly enrolled rural pygmies living in Lolodorf and urban Bantus living in Douala. The World Health Organization steps questionnaire was used to collect socio-demographic and lifestyle data. Height, weight, BP and single overnight spot urine samples were obtained in all participants. BP was measured in triplicate. Urinary sodium and potassium excretion was determined by flame photometry. Data were recorded and analyzed using SPSS 16.0.

Results

We included 150 Pygmies and 150 Bantus aged 38 ± 12 years and 33 ± 11 years, respectively (p <  0.0001). Compare to Bantus, pygmy’s height and weight were respectively: 1.54 ± 0.09 m vs 1.72 ± 0.12 m; and 54.4 ± 9.2 kg vs 77.2 ± 14.8 kg, all p <  0.0001. Age-standardized prevalence of hypertension was 3.3% among Pygmies and 28% among Bantus (p <  0.0001). Age-adjusted systolic and diastolic BP were lower in Pygmies than in Bantus (107 ± 12 vs 119 ± 17 mmHg and 71 ± 11 vs 78 ± 13 mmHg respectively, all P <  0.0001). BP increased with age but to a lesser extent in Pygmies (all p <  0.01). Urinary sodium excretion was lower in Pygmies than in Bantus (46.9 ± 32.4 vs 121.5 ± 61.0 mmol/l, p <  0.0001). Systolic and diastolic BP were positively associated with urinary sodium excretion in Bantus (all p <  0.05). In the two groups, urinary potassium excretion was similar, and was not related to blood pressure. In the total study group and in Bantus taken separately, urinary sodium excretion was higher in hypertensive than in normotensive subjects. Multivariable logistic regression showed that urinary sodium excretion, Bantu status and age emerged as independent determinants of hypertension in the whole study group (OR (95%CI): 1.012 (1.005–1.018); 11.408 (3.599–36.165); 1.095 (1.057–1.135) respectively, p <  0.0001).

Conclusion

Hunter-gatherer pygmies exhibit low level of urinary sodium excretion related to low rate of hypertension and slower BP increase with age. Salt intake was a major driver of hypertension in our study population. Our findings highlight the need of efforts to implement nationwide prevention programs promoting risk factor screening and healthier lifestyles including reduction of dietary salt intake in Cameroonian.

Measurement of Aortic Pulse Wave Velocity With a Connected Bathroom Scale

BACKGROUND

Measurement of arterial stiffness should be more available. Our aim was to show that aortic pulse wave velocity can be reliably measured with a bathroom scale combining the principles of ballistocardiography (BCG) and impedance plethysmography on a single foot.

METHOD

The calibration of the bathroom scale was conducted on a group of 106 individuals. The aortic pulse wave velocity was measured with the SphygmoCor in the supine position. Three consecutive measurements were then performed on the Withings scale in the standing position. This aorta-leg pulse transit time (alPTT) was then converted into a velocity with the additional input of the height of the person. Agreement between the SphygmoCor and the bathroom scale so calibrated is assessed on a separate group of 86 individuals, following the same protocol.

RESULTS

The bias is 0.25 m·s⁻¹ and the SE 1.39 m·s⁻¹. This agreement with Sphygmocor is “acceptable” according to the ARTERY classification. The alPTT correlated well with cfPTT with (Spearman) R = 0.73 in pooled population (cal 0.79, val 0.66). The aorta-leg pulse wave velocity correlated with carotid-femoral pulse wave velocity with R = 0.76 (cal 0.80, val 0.70).

CONCLUSION

Estimation of the aortic pulse wave velocity is feasible with a bathroom scale. Further investigations are needed to improve the repeatability of measurements and to test their accuracy in different populations and conditions.

Prevalence, Correlates, and Prognosis of Healthy Vascular Aging in a Western Community-Dwelling Cohort: The Framingham Heart Study

Hypertension and increased vascular stiffness are viewed as inevitable parts of aging. To elucidate whether the age-related decrease in vascular function is avoidable, we assessed the prevalence, correlates, and prognosis of healthy vascular aging (HVA) in 3196 Framingham Study participants aged ≥50 years. We defined HVA as absence of hypertension and pulse wave velocity <7.6 m/s (mean+2 SD of a reference sample aged <30 years). Overall, 566 (17.7%) individuals had HVA, with prevalence decreasing from 30.3% in people aged 50 to 59 to 1% in those aged ≥70 years. In regression models adjusted for physical activity, caloric intake, and traditional cardiovascular disease (CVD) risk factors, we observed that lower age, female sex, lower body mass index, use of lipid-lowering drugs, and absence of diabetes mellitus were cross-sectionally associated with HVA (P<0.001 for all). A unit increase in a cardiovascular health score (Life's Simple 7) was associated with 1.55-fold (95% confidence interval, 1.38-1.74) age- and sex-adjusted odds of HVA. During a follow-up of 9.6 years, 391 CVD events occurred. In Cox regression models adjusted for traditional CVD risk factors, including blood pressure, HVA was associated with a hazard ratio of 0.45 (95% confidence interval, 0.26-0.77) for CVD relative to absence of HVA. Although HVA is achievable in individuals acculturated to a Western lifestyle, maintaining normal vascular function beyond 70 years of age is challenging. Although our data are observational, our findings support prevention strategies targeting modifiable factors and behaviors and obesity, in particular, to prevent or delay vascular aging and the associated risk of CVD.

Pilot study of risk factors associated with cardiovascular disease in northern and southern Cameroonians

Aim:

The aim of the study was to evaluate whether the risk factors for cardiovascular disease (CVD) are similar in the northern and southern regions of Cameroon.

Methods:

The participants answered a questionnaire concerning their lifestyle. Anthropometric and blood pressure measurements were evaluated in 192 individuals and biochemical parameters in 50 randomly selected volunteers.

Results:

Northerners displayed low alcohol and tobacco consumption, little practice of sport but physically demanding professions, and consumption of soybean, refined palm and other polyunsaturated oils. Southerners consumed alcohol, practiced sport, had intellectually based professions, and consumed crude and refined palm oils. Waist circumference and body mass index were higher in the southerners compared to the northerners. Blood glucose levels, and systolic and diastolic blood pressures were higher among the northerners than the southerners. Among the southerners, there were positive correlations between total cholesterol levels and systolic or diastolic blood pressure, low-density lipoprotein cholesterol and blood glucose levels or diastolic blood pressure, triglyceride levels and systolic blood pressure.

Conclusion:

Providing region-adapted, health-related advice for northern and southern Cameroonians would contribute to reducing risk factors for CVD.

PCSK9 inhibition as an emerging lipid lowering therapy: Unanswered questions

Although statins have been used for the treatment of hypercholesterolemia for more than two decades, cardiovascular disease (CVD), which is related at least in part to high levels of low-density lipoprotein cholesterol (LDL-C), is the number one cause of death in Europe and the USA. Several studies have shown that the reduction in cardiovascular (CV) events is proportional to the absolute LDL-C lowering achieved with statins. In the quest for further reduction in LDL-C and CV events, new drugs that mainly support statin action have emerged. Since 2003, with the discovery of proprotein convertase subtilisin/kexin type 9 (PCSK9), which is a key factor in the LDL clearance pathway, new modalities, mainly in the form of monoclonal antibodies that block this protein (PCSK9 inhibitors), have reached phase III of clinical development with very promising efficacy and safety data. With a mean further reduction of LDL-C levels of ∼60% beyond that achieved with statins, the PCSK9 inhibitors set the bar even lower in terms of LDL-C levels. This review manuscript addresses important questions about the efficacy, safety and clinical use of PCSK9 inhibitors to evaluate the role of these agents in reducing CV risk.

Arteriosclerosis and vascular calcification: causes, clinical assessment and therapy

BACKGROUND

Arteriosclerosis is a pathological, structural (media vascular calcification) and physiological (modified vascular smooth vessel cells; increased arterial stiffness) alteration of the vessel wall. Through improved assessment methods (functional and imaging), it has become a well-known phenomenon in recent decades. However, its clinical importance was underestimated until recently.

MATERIALS AND METHODS

Currently available English-speaking data about conditions/diseases associated with arteriosclerosis, its clinical sequels, available diagnostic procedures and therapeutic modalities were reviewed and summarized.

RESULTS

In recent decades, emerging data have brought about a better understanding of causes and consequences of arteriosclerosis and highlight its growing clinical impact.

CONCLUSION

Although arteriosclerosis showed an independent clinical impact on cardiovascular morbidity and mortality, especially in patients with chronic kidney disease/end-stage renal disease (CKD/ESRD) and diabetes mellitus, convincing clinical therapy concepts are not available until now. The establishment of novel therapeutic strategies derived from basic research is strongly needed.

Age-related remodeling of small arteries is accompanied by increased sphingomyelinase activity and accumulation of long-chain ceramides

The structure and function of large arteries alters with age leading to increased risk of cardiovascular disease. Age‐related large artery remodeling and arteriosclerosis is associated with increased collagen deposition, inflammation, and endothelial dysfunction. Bioactive sphingolipids are known to regulate these processes, and are also involved in aging and cellular senescence. However, less is known about age‐associated alterations in small artery morphology and function or whether changes in arterial sphingolipids occur in aging. We show that mesenteric small arteries from old sheep have increased lumen diameter and media thickness without a change in media to lumen ratio, indicative of outward hypertrophic remodeling. This remodeling occurred without overt changes in blood pressure or pulse pressure indicating it was a consequence of aging per se. There was no age‐associated change in mechanical properties of the arteries despite an increase in total collagen content and deposition of collagen in a thickened intima layer in arteries from old animals. Analysis of the sphingolipid profile showed an increase in long‐chain ceramide (C14–C20), but no change in the levels of sphingosine or sphingosine‐1‐phosphate in arteries from old compared to young animals. This was accompanied by a parallel increase in acid and neutral sphingomyelinase activity in old arteries compared to young. This study demonstrates remodeling of small arteries during aging that is accompanied by accumulation of long‐chain ceramides. This suggests that sphingolipids may be important mediators of vascular aging.

In this study, we have investigated remodeling of small arteries in a large animal model of aging, the sheep. We show that there is age‐related formation of neointima and increased collagen deposition that is accompanied by changes in sphingolipid metabolism resulting in ceramide accumulation in the tissues. These are the first data implicating sphingolipids as important mediators of vascular aging in small arteries. Given that aging is a major risk factor for cardiovascular disease, our study opens a new area for further research into the mechanisms that underlie vascular remodeling in aging.

A multimodal Darwinian strategy for alleviating the atherosclerosis pandemic

The conflict between our 'primitive' genes and 'modern' lifestyle probably lies at the root of several disorders that afflict modern man. Atherosclerosis, which is relatively unknown among contemporary hunter-gatherer populations, has reached pandemic proportions in recent times. Being an evolutionary problem with several inter-related pathologies, current therapeutic strategy for treating atherosclerosis has inherent limitations. Reviewing evolution-linked risk factors suggests that there are four aspects to the etiology of atherosclerosis namely, decreased intestinal parasitism, oversensitivity of evolutionarily redundant mast cells, chronic underactivation of AMPK (cellular energy sensor) and a deficiency of vitamin D. A combination of these four causes appear to have precipitated the atherosclerosis pandemic in modern times. Man and worms co-existed symbiotically in the past. Massive de-worming campaigns could have disrupted this symbiosis, increasing nutritional availability to man (pro-obesity) at the cost of decreased immunotolerance (pro-atherogenicity). A reduction in helminth-induced chronic TH2 activation could also have enhanced TH1 polarization, eventually disrupting the reciprocal regulation of TH1/TH2 balance and resulting in atherosclerosis. The riddance of helminth infestations may have rendered mast cells immunologically redundant, making them oversensitive to inflammatory stimuli, thereby playing a pro-atherogenic role. AMPK activation exerts pleiotropic anti-atherogenic effects, such as suppression of fatty acid, cholesterol, protein synthesis, reduction of vascular smooth muscle proliferation, etc. As energy deficit is the chief stimulus for AMPK activation, the over-nourished modern man appears to be suffering from chronic underactivation of AMPK, legitimising the unrivalled supremacy of metformin, the oldest prescribed antidiabetic drug. The fact that humans evolved in the sunny tropics suggests that humans are selected for high vitamin D levels. Vitamin D deficiency is now linked to several conditions including increased risk of CV disorders, diabetes, etc. The manifold decrease in vitamin D levels in modern man justifies a need for supplementation. We therefore hypothesize that a judicious combination of mast cell stabilization, AMPK activation, vitamin D supplementation, and moderation in hygiene practices could be an evolution-based multimodal strategy for both preventing and mitigating the pandemic of atherosclerosis.

Immunity, atherosclerosis and cardiovascular disease

Atherosclerosis, the major cause of cardiovascular disease (CVD), is a chronic inflammatory condition with immune competent cells in lesions producing mainly pro-inflammatory cytokines. Dead cells and oxidized forms of low density lipoproteins (oxLDL) are abundant. The major direct cause of CVD appears to be rupture of atherosclerotic plaques. oxLDL has proinflammatory and immune-stimulatory properties, causes cell death at higher concentrations and contains inflammatory phospholipids with phosphorylcholine (PC) as an interesting epitope. Antibodies against PC (anti-PC) may be atheroprotective, one mechanism being anti-inflammatory. Bacteria and virus have been discussed, but it has been difficult to find direct evidence, and antibiotic trials have not been successful. Heat shock proteins could be one major target for atherogenic immune reactions. More direct causes of plaque rupture include pro-inflammatory cytokines, chemokines, and lipid mediators. To prove that inflammation is a cause of atherosclerosis and CVD, clinical studies with anti-inflammatory and/or immune-modulatory treatment are needed. The potential causes of immune reactions and inflammation in atherosclerosis and how inflammation can be targeted therapeutically to provide novel treatments for CVD are reviewed.