Socioeconomic inequalities, modifiable lifestyle risk factors, and retinal vessel calibers: The African-PREDICT Study.

OBJECTIVE: Lifestyle risk factors vary between socioeconomic status (SES) groups and may influence cardiovascular function differently. The retinal microvasculature allows for monitoring early changes in cardiovascular health, and therefore, we investigated whether retinal vessel calibers associate differently with modifiable risk factors in different SES groups. METHODS: We included 1064 young adults (aged 20-30 years) grouped by low and high SES. The central retinal artery and vein equivalents (CRAE, CRVE) were determined from fundus images captured using the Dynamic Retinal Vessel Analyzer (Imedos Systems GmbH, Jena, Germany). We collected anthropometry, self-reported alcohol consumption, and biochemical data. RESULTS: Retinal vessel calibers did not differ between SES groups (p ≥ .80) after adjusting for sex and ethnicity. Unique independent associations were observed in the low SES group, where CRAE (ß = 0.08, p = .042) and CRVE (ß = .14, p = .001) associated positively with cotinine and body mass index, respectively. In the high SES group, CRAE (ß = -0.09, p = .027) associated negatively with alcohol consumption. CONCLUSION: At young ages, retinal vessel calibers associated differently with modifiable lifestyle risk factors within each SES group. Our data highlight the importance of detecting adverse lifestyle risk factors among young adults from diverse socioeconomic settings to improve prevention of cardiovascular disease.

Leptin and the Retinal Microvasculature in Young Black and White Adults: The African-PREDICT Study.

BACKGROUND: Leptin is a vasoactive peptide that has been linked to diseases associated with macrovascular deterioration. What is still uncertain is its involvement in the microvasculature. Since microvascular changes are presumed to precede macrovascular deterioration, we examined whether measures of the retinal microvasculature are associated with leptin in healthy, young Black and White individuals. METHOD: We included 283 Black and 289 White men and women (aged 20-30 years). We determined serum leptin, calculated central retinal artery and vein equivalents and arterio-venous ratio. We also measured retinal vessel responses to light flicker provocation. RESULTS: Black men were leaner and had lower leptin than White men, whereas Black women had increased adiposity and leptin compared to White women (all p<0.001). Black groups had narrower retinal arteries, and greater maximum arteriolar and venular dilations in response to light flicker than the White groups (p<0.001). Arterio-venous ratio associated negatively with leptin (all p≤0.044) in all groups (except Black women), but was lost upon adjustment for body mass index and other covariates. We found an inverse association between maximal venular dilation and leptin only in Black men in single and multiple regression analyses (Std ß= -0.22; R2=0.05; p=0.035). No associations were found between other retinal measures with leptin in the other groups. CONCLUSION: We found an independent, negative association between retinal vein dilation with leptin in healthy, young Black men, suggesting a potential detrimental role for leptin in regulating microvascular responses in a population group known to be at greater risk of cardiovascular disease development.

Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies.

BACKGROUND: Several studies reported a U-shaped association between urinary sodium excretion and cardiovascular disease events and mortality. Whether these associations vary between those individuals with and without hypertension is uncertain. We aimed to explore whether the association between sodium intake and cardiovascular disease events and all-cause mortality is modified by hypertension status. METHODS: In this pooled analysis, we studied 133,118 individuals (63,559 with hypertension and 69,559 without hypertension), median age of 55 years (IQR 45-63), from 49 countries in four large prospective studies and estimated 24-h urinary sodium excretion (as group-level measure of intake). We related this to the composite outcome of death and major cardiovascular disease events over a median of 4.2 years (IQR 3.0-5.0) and blood pressure. FINDINGS: Increased sodium intake was associated with greater increases in systolic blood pressure in individuals with hypertension (2.08 mm Hg change per g sodium increase) compared with individuals without hypertension (1.22 mm Hg change per g; pinteraction<0.0001). In those individuals with hypertension (6835 events), sodium excretion of 7 g/day or more (7060 [11%] of population with hypertension: hazard ratio [HR] 1.23 [95% CI 1.11-1.37]; p<0.0001) and less than 3 g/day (7006 [11%] of population with hypertension: 1.34 [1.23-1.47]; p<0.0001) were both associated with increased risk compared with sodium excretion of 4-5 g/day (reference 25% of the population with hypertension). In those individuals without hypertension (3021 events), compared with 4-5 g/day (18,508 [27%] of the population without hypertension), higher sodium excretion was not associated with risk of the primary composite outcome (≥ 7 g/day in 6271 [9%] of the population without hypertension; HR 0.90 [95% CI 0.76-1.08]; p=0.2547), whereas an excretion of less than 3 g/day was associated with a significantly increased risk (7547 [11%] of the population without hypertension; HR 1.26 [95% CI 1.10-1.45]; p=0.0009). INTERPRETATION: Compared with moderate sodium intake, high sodium intake is associated with an increased risk of cardiovascular events and death in hypertensive populations (no association in normotensive population), while the association of low sodium intake with increased risk of cardiovascular events and death is observed in those with or without hypertension. These data suggest that lowering sodium intake is best targeted at populations with hypertension who consume high sodium diets. FUNDING: Full funding sources listed at end of paper (see Acknowledgments).

Psychosocial stress but not hypertensive status associated with angiogenesis in Africans.

AIM: Increased angiogenic factors [vascular endothelial growth factor-A (VEGF-A) and angiopoietin-2 (Ang-2)] have been associated with vascular dysfunction and hypertension. Black Africans undergoing rapid urbanization present with elevated blood pressure (BP) and we aimed to determine whether angiogenic factors are elevated in urban versus rural Africans with normal and elevated BP. METHODS AND MATERIALS: Africans (n = 272), matched for gender and age, were recruited from rural and urban communities in South Africa. Omron HEM-757 BP data were obtained and angiogenic markers in plasma and serum were determined. RESULTS: Urban African men displayed a higher (43.90%) hypertension prevalence compared with their rural counterparts (18.52%) and disturbed angiongenic factors. Adjusted VEGF-A concentrations were higher in urban men and women compared with their rural counterparts. Similar VEGF-A levels were observed in rural and urban hypertensives. Logistic regression analysis demonstrated that VEGF-A and Ang-2 levels were associated with psychosocial stress but not with hypertensive status in Africans [odds ratios 1.01-1.09 (95% CI 1.01-1.15), p ≤ 0.05]. CONCLUSION: Psychosocial stress per se was associated with disturbed VEGF-A and Ang-2. We suggest that hyperkinetic BP may act as compensatory mechanism when chronic psychosocial stress prevails, affecting vascular functioning and subsequent increased cardiovascular disease risk.

Stressful life events, neighbourhood characteristics, and systolic blood pressure in South Africa.

The relationship between negative events, neighbourhood characteristics, and systolic blood pressure in developing countries is not well-documented, particularly using longitudinal data. To explore this relationship, we analysed panel data from the first three waves of the South African National Income Dynamics Study using a correlated random effects model adjusted for confounding risk factors. Our sample comprised of 15,631 respondents in 2008, 14,443 respondents in 2010/2011, and 14,418 respondents in 2012, all aged above 15 years. The prevalence of at least one negative household event across the three waves was approximately 30%. In any of the three waves, the adjusted prevalence of hypertension was 23.84%. This share was 21.75% in 2008 (95% CI 18.06-25.44), 23.16% in 2010/11 (95% CI 19.18-27.14), and 18.39% in 2012 (95% CI 16.03-20.75). In our adjusted correlated random effects model, we found that systolic blood pressure was significantly higher among respondents from households that reported death of a household member (0.85 mmHg; p = 0.02) and a reduction in grant income and remittances (2.14 mm Hg; p = 0.01). We also found no significant association between systolic blood pressure and neighbourhood income level. In a country with social and economic challenges, our results indicate that grief and negative financial events are adversely associated with blood pressure, which may explain in part the significant burden of hypertension in low- and middle-income countries.

The usefulness of γ-glutamyltransferase as a marker of cardiovascular function in Africans and Caucasians: the SABPA study.

AIM: Serum γ-glutamyltransferase (GGT) is increasingly regarded as a marker of vascular function. However, the usefulness of this marker is in dispute. Gender and ethnic differences, as well as the serum level range where correlations with vascular function will emerge, may complicate the usefulness of GGT. The aim is to compare correlations with markers of vascular function between African and Caucasian groups. METHODS: This cross-sectional target population study involved four groups of African and Caucasian men and women of 100 participants each. Fasting lipids, GGT, C-reactive protein (CRP), reactive oxygen species, and glycosylated hemoglobin (HbA1c) were determined as well as blood pressure, carotid intima-media thickness (CIMT), and left ventricular hypertrophy. RESULTS: γ-Glutamyltransferase levels were significantly higher in Africans compared with Caucasians and also higher in men than in women. γ-Glutamyltransferase correlated with triglycerides in all four groups and after adjusting the correlations sustained in the male groups but disappeared in women. Correlations existed between GGT and blood pressure, except for the African women. After adjustments, CIMT correlated with GGT in Caucasian men (r = 0.29; P < .01). Glycosylated hemoglobin was associated with GGT in Caucasian women (r = 0.26; P = .01) as well as CRP (r = 0.36; P < .01). When the groups were divided into low and high GGT groups by median split, most of the correlations disappeared in the high GGT groups. CONCLUSIONS: Gender and ethnic-specific associations occurred regarding GGT and variables associated with cardiovascular function. With high levels of GGT the correlations diminished. The usefulness of GGT as a marker of vascular dysfunction seems limited.

Health trends, inequalities and opportunities in South Africa's provinces, 1990-2019: findings from the Global Burden of Disease 2019 Study.

BACKGROUND: Over the last 30 years, South Africa has experienced four 'colliding epidemics' of HIV and tuberculosis, chronic illness and mental health, injury and violence, and maternal, neonatal, and child mortality, which have had substantial effects on health and well-being. Using data from the 2019 Global Burden of Diseases, Injuries and Risk Factors Study (GBD 2019), we evaluated national and provincial health trends and progress towards important Sustainable Development Goal targets from 1990 to 2019. METHODS: We analysed GBD 2019 estimates of mortality, non-fatal health loss, summary health measures and risk factor burden, comparing trends over 1990-2007 and 2007-2019. Additionally, we decomposed changes in life expectancy by cause of death and assessed healthcare system performance. RESULTS: Across the nine provinces, inequalities in mortality and life expectancy increased over 1990-2007, largely due to differences in HIV/AIDS, then decreased over 2007-2019. Demographic change and increases in non-communicable diseases nearly doubled the number of years lived with disability between 1990 and 2019. From 1990 to 2019, risk factor burdens generally shifted from communicable and nutritional disease risks to non-communicable disease and injury risks; unsafe sex remained the top risk factor. Despite widespread improvements in healthcare system performance, the greatest gains were generally in economically advantaged provinces. CONCLUSIONS: Reductions in HIV/AIDS and related conditions have led to improved health since 2007, though most provinces still lag in key areas. To achieve health targets, provincial governments should enhance health investments and exchange of knowledge, resources and best practices alongside populations that have been left behind, especially following the COVID-19 pandemic.

Correcting for Intra-Individual Variability in Sodium Excretion in Spot Urine Samples Does Not Improve the Ability to Predict 24 h Urinary Sodium Excretion.

Given a global focus on salt reduction efforts to reduce cardiovascular risk, it is important to obtain accurate measures of salt intake on a population level. This study determined firstly whether adjustment for intra-individual variation in urinary sodium (Na) excretion using three repeated 24 h collections affects daily estimates and whether the use of repeated spot urine samples results in better prediction of 24 h Na compared to a single collection. Twenty three community-dwelling men and women from South Africa (mean age 59.7 years (SD = 15.6)) participating in the World Health Organization Study on global AGEing and adult health (WHO-SAGE) Wave 3 study collected 24 h and spot early morning urine samples over three consecutive days to assess urinary Na excretion. INTERSALT, Tanaka, and Kawasaki prediction equations, with either average or adjusted spot Na values, were used to estimate 24 h Na and compared these against measured 24 h urinary Na. Adjustment was performed by using the ratio of between-person (sb) and total (sobs) variability obtained from repeated measures analysis of variance. Sensitivity of the equations to predict daily urinary Na values below 5 g salt equivalent was calculated. The sb/sobs for urinary Na using three repeated samples for spot and 24 h samples were 0.706 and 0.798, respectively. Correction using analysis of variance for 3 × 24 h collections resulted in contraction of the upper end of the distribution curve (90th centile: 157 to 136 mmoL/day; 95th centile: 220 to 178 mmoL/day). All three prediction equations grossly over-estimated 24 h urinary Na excretion, regardless of whether a single spot urine or repeated collections corrected for intra-individual variation were used. Sensitivity of equations to detect salt intake equivalent values of ≤5 g/day was 13% for INTERSALT, while the other two equations had zero sensitivity. Correcting for intra-individual variability in Na excretion using three 24 h urine collections contracted the distribution curve for high intakes. Repeated collection of spot samples for urinary Na analysis does not improve the accuracy of predicting 24 h Na excretion. Spot urine samples are not appropriate to detect participants with salt intakes below the recommended 5 g/day.

Direct Comparison of Home Versus Ambulatory Defined Nocturnal Hypertension for Predicting Cardiovascular Events: The Japan Morning Surge-Home Blood Pressure (J-HOP) Study.

The home blood pressure monitoring (HBPM) method that measures blood pressure during sleep hours was reported to be comparable to ambulatory blood pressure monitoring (ABPM) in measuring nighttime blood pressure and detecting nocturnal hypertension. The aim of this study was to directly compare the prognostic power of nocturnal hypertension detected by HBPM versus ABPM for predicting future cardiovascular events. We analyzed nighttime blood pressure (measured by HBPM and ABPM) data of 1005 participants who were included in the J-HOP study (Japan Morning Surge-Home Blood Pressure). During a follow-up period of 7.6±3.4 years, 80 cardiovascular disease events occurred. The majority (91.8%) of our study population were hypertensive, and 80.7% of participants were using antihypertensive medication. Nighttime home systolic blood pressure (SBP) was higher compared to nighttime ambulatory SBP (123.0±14.6 versus 120.3±14.4 mm Hg, P<0.001). Nocturnal hypertension was defined as nighttime home or ambulatory SBP of ≥120 mm Hg. The number of participants with nocturnal hypertension defined by HBPM and ABPM was 564 (56.1%) and 469 (46.7%), respectively. Nocturnal hypertension defined by HBPM was associated with increased risk of future cardiovascular events: total cardiovascular events (coronary artery disease and stroke events; 1.78 [1.00-3.15]) and stroke (2.65 [1.14-6.20]), independent of office SBP. These results were absent with nocturnal hypertension defined by ABPM. This is the first comparison prospective study illustrating that uncontrolled nocturnal hypertension defined by HBPM (independent of office SBP) is a predictor of future cardiovascular events.

The Exercise, Arterial Modulation and Nutrition in Youth South Africa Study (ExAMIN Youth SA).

Background: The impact of a sedentary and unhealthy lifestyle on cardiovascular health is well-documented, however the current obesity and hypertension trends among children is concerning. The ExAMIN Youth SA study aims to investigate the impact of lifestyle behaviors (physical fitness/activity, dietary intake and psychosocial factors) involved in early vascular aging among South African children. Methods: This study is an analytical, multidisciplinary, observational cohort study in a school-based setting. We aim to phenotype a cohort of ~1,000 primary school children (black and white boys and girls between ages 5-9 years) based on current clinical childhood conditions including hypertension and obesity. The primary phenotype is large artery stiffness and retinal microvascular diameters, both biomarkers of early vascular aging. The risk factors and mediators of early vascular aging and also responsible for the clinical conditions include physical inactivity, unhealthy diet, and life stress. Additionally, urinalysis and salivary analyses will be performed to identify biomarkers related to the pathophysiology of early vascular aging. Discussion: In line with the growing prevalence of obesity and hypertension responsible for the development of early vascular aging from childhood to adulthood, this study will address the critical areas in which we observe unfavorable arterial modulation related to dietary behaviors, physical inactivity, and early life stress. Implementation of novel biological markers may further contribute to our understanding of early cardiovascular adaptations in childhood, and aid in the development of primary prevention programs. Trial registration: The study was retrospectively registered on ClinicalTrials.gov on 15 August 2019 (NCT04056377).

A 10-year follow-up study of demographic and cardiometabolic factors in HIV-infected South Africans.

OBJECTIVES: Understanding of the interplay between human immunodeficiency virus (HIV) and cardiovascular disease, especially in Africa, is limited to evidence from longitudinal studies. Therefore the demographic profile and cardiometabolic, renal and liver function of an HIV-infected South African population were profiled from 2005 to 2015. METHODS: The study included 117 HIV-infected and 131 uninfected controls that were examined at baseline, five and 10 years. RESULTS: Mortality rate declined from 24% (2005-2010) to 0% (2010-2015) after the introduction of ART. Longitudinal increases in C-reactive protein (p = 0.002), alanine transaminase (p = 0.006) and gamma-glutamyl transferase (p = 0.046) levels and estimated glomerular filtration rate (p < 0.001) were seen only in the HIV-infected group. This group also showed increased high-density lipoprotein cholesterol (HDL-C) (p < 0.001) and total cholesterol (p < 0.001) levels and decreased triglyceride:HDL-C (p = 0.011) levels. Low-density lipoprotein cholesterol decreased in both groups (p < 0.001). CONCLUSIONS: Despite trajectories of deranged lipid and inflammatory profiles, the cardiometabolic disease risk seems stable in HIV-infected South Africans. Inflammation and renal and liver function warrant regular monitoring.

Correction: Morning blood pressure surge in young black and white adults: The African-PREDICT Study.

In the article "Morning blood pressure surge in young black and white adults: The African-PREDICT Study" by Gontse Gratitude Mokwatsi, Aletta Elisabeth Schutte, Catharina Martha Cornelia Mels and Ruan Kruger which appeared in 'Journal of Human Hypertension' (2018) volume 32, DOI 10.1038/s41371-018-0089-3, the authors regret that they mentioned erroneously that none of their study participants had an exaggerated morning blood pressure surge. They would like to point out that 40 participants in their study population had an exaggerated sleep-trough surge whereas 128 had an exaggerated dynamic surge.

Morning blood pressure surge in young black and white adults: The African-PREDICT Study.

An exaggerated morning blood pressure surge (MBPS) has independent predictive value for cardiovascular mortality and is suggested to be prevalent in elderly hypertensive patients: men and white populations. To better understand the MBPS profile in a young and normotensive population, we evaluated the MBPS in young adults and explored associations with demographic, cardiovascular and health behaviour measurements. We included 845 black (n = 439) and white (n = 406) men and women aged between 20 and 30 years. We calculated the sleep-trough and dynamic morning surge, and compared demographic data, health behaviours and ambulatory blood pressure according to MBPS quartiles. In the total group, higher waist circumference, socioeconomic score, lean mass, ambulatory blood pressure (24-h, daytime blood pressure) and increased night-time dipping (all p < 0.05) were found in the highest sleep-trough and dynamic morning surge quartiles. In the total white group, particularly men, both sleep-trough and dynamic morning surge were higher than the black group (all p < 0.013). More black participants were non-dippers than whites (44% vs 34%; p = 0.004). In multivariable adjusted regression in the total group, we found no consistent associations of MBPS with demographic and health behaviour measurements. MBPS related independently and positively with night-time percentage dipping in all ethnic groups (all p < 0.01). Ethnic differences in MBPS is evident in young adults, with a higher, but normal MBPS in white men. A non-dipping night-time pattern in young black adults (with reduced MBPS) and a higher MBPS (observed in dippers) may serve as potential risk factors for cardiovascular disease.

Predictors of hypertension awareness, treatment and control in South Africa: results from the WHO-SAGE population survey (Wave 2).

South Africa has one of the highest levels of hypertension globally, coupled with poor rates of diagnosis, treatment and control. Risk factors that predict hypertension in high income countries may perform differently in the African context, where communicable disease, obesity and malnutrition co-exist. This study investigated traditional risk factors alongside other health and sociodemographic indicators to determine predictors of hypertension prevalence and management. Participants were recruited from households across South Africa as part of WHO's Study on global AGEing and adult health (WHO SAGE) Wave 2 (2015). Blood pressure (BP) was measured in triplicate and sociodemographic and health data collected by survey (n = 1847; 30% 18-39 years, 39% 40-59 years, 31% 60 years+; median age 51 years; 68% female). Of all adults, 43% were hypertensive (n = 802), of which 58% (n = 398) were unaware, 33% (n = 267) were on medication, with only 18% (n = 141) controlled on medication (BP < 140/90 mmHg). Multivariate logistic regression showed waist-to-height ratio > 0.5 and diabetes comorbidity were the most significant predictors of hypertension presence, awareness and treatment. Individuals with diabetes were twice as likely to have hypertension, 7.0 times more likely to be aware, 3.3 times more likely to be on antihypertensive medication, and 2.4 times more likely to be controlled on medication. Women and individuals reporting lower salt use were more likely to be aware and treated for hypertension. Applying the 2017 AHA/ACC hypertension guidelines showed only 1 in 4 adults had normal BP. As with HIV, similarly intensive efforts are now needed in the region to improve non-communicable disease diagnosis and management.

Aging influences the level and functions of fasting plasma ghrelin levels: the POWIRS-Study.

OBJECTIVE: Ghrelin, known for its orexigenic activity, also have functions such as vasodilation and a growth hormone releasing action. It is uncertain whether these functions change with increasing age. This study aimed to determine whether ghrelin levels differ between young and older women with different levels of obesity; and secondly whether the associations of ghrelin with metabolic syndrome (MS) components, adipocytokines, coagulation factors, and cortisol change with increasing age. METHODS AND RESULTS: Caucasian women (N=107) were divided into young (19-29 years) and older groups (30-56 years). Fasting ghrelin, leptin, adiponectin, glucose, insulin, cortisol, fibrinogen and plasminogen activator inhibitor-1 (PAI-1) levels were determined. Blood pressure (BP), body mass index and waist circumferences were measured. Older lean women showed lower levels of ghrelin (p<0.05) than young lean women, with no differences regarding BP, obesity, lipids, adipokines or insulin resistance (IR). Ghrelin levels of older women remained constant with increasing obesity, but younger women showed significantly reduced ghrelin levels in obese groups. Only younger women showed significant correlations between ghrelin and leptin, adiponectin, fibrinogen and PAI-1 (adjusted for age, obesity and menstrual phase), whereas both age groups showed significant correlations with IR. In younger women factor analysis grouped ghrelin with coagulation factors and all MS components. In older women ghrelin was absent from the MS cluster, but was associated with lower BP, cortisol and IR. CONCLUSIONS: Ghrelin levels were not significantly elevated in lean older women, and did not change with increased obesity in older women--as were observed in younger women. The functions of ghrelin also seem to change with increased age since only in young women ghrelin was associated with obesity, coagulation factors and leptin.

Specific coping strategies of Africans during urbanization: comparing cardiovascular responses and perception of health data.

Specific coping mechanisms of Africans during urbanization were compared to and correlated with cardiovascular responses and perception of health data. Subjects included men (N=286) and women (N=360). The COPE questionnaire classified subjects as active (AC) or passive (PC) copers and the General Health Questionnaire measured subjective perception of health. The Finapres recorded blood pressure continuously before and during application of a handgrip test. Analyses adjusting for age, body mass index and resting cardiovascular data revealed that AC rural subjects showed predominantly cardiac responses and PC rural subjects predominantly vascular responses. All urbanized African men and women showed higher resting blood pressure, vascular responsiveness and hypertension prevalences than their rural counterparts. All rural AC subjects, especially women, and all urban PC subjects, especially men, reported a poorer perception of health. In conclusion, subjects with a PC style showed a predominantly vascular response in rural and urban areas whereas subjects with an AC style seem to shift from a predominant cardiac output response to a predominant vascular resistance response when moving from a rural to an urban area.

Coping mechanisms, perception of health and cardiovascular dysfunction in Africans.

The purpose of this study was to compare active and passive coping strategies of Africans with perception of own health and cardiovascular data. The subjects included 236 apparently healthy Africans (men=109; women=127). The COPE questionnaire was adapted, translated and validated for Africans. Scores on reliable sub-scales were used to classify men and women into more active coping (AC) and more passive coping (PC) subgroups. The General Health Questionnaire measured subjective perception of health. Blood pressure was recorded before and during application of the handgrip test, using the Finapres, a continuous non-invasive blood pressure monitor. Plasma renin activity (PRA) values, measured with radio immuno assay, were compared to blood pressure variables. Analyses of co-variance, adjusted for resting values and age, indicated that PC men responded with a larger increase in total peripheral resistance (TPR) (p=0.006), larger decrease in stroke volume (p=0.07), smaller increase in cardiac output (p=0.09) and larger increases in PRA resting (p=0.04) and reactivity (p< or =0.05) values. PC subjects reported a more negative perception of health than AC subjects. Young PC women presented greater hypertension prevalence rates (p< or =0.01) than AC women. In conclusion, all AC and PC subjects reacted with increased vascular reactivity on the handgrip test. PC men presented enhanced vascular reactivity, PRA and perception of poorer health values.

A comparison of the cardiometabolic profile of black South Africans with suspected non-alcoholic fatty liver disease (NAFLD) and excessive alcohol use.

Excessive alcohol use and non-alcoholic fatty liver disease (NAFLD) are putative cardiovascular disease risk factors. In order to ease the identification of these conditions on primary health care level, we aimed to determine and compare the demographic and cardiometabolic characteristics of excessive alcohol users and those with suspected NAFLD in black South Africans. In the Prospective Urban Rural Epidemiology study (North West Province, South Africa, N = 2021, collected in 2005) we selected 338 participants, namely: 1) alcohol users (N = 143) reporting 'yes' to alcohol intake, with high gamma-glutamyl transferase (GGT) ≥80 U/L and a percentage carbohydrate deficient transferrin (%CDT) ≥2%; 2) non-alcohol users (N = 127) self-reporting 'no' to alcohol intake with GGT ≤30 U/L and %CDT ≤2%; and 3) NAFLD group (N = 68) who were non-drinkers with GGT levels ≥60 U/L and %CDT ≤ 2%. The demographics indicated that the alcohol users were mostly men (73%) with a body mass index (BMI) of 19.8 (15.2-27.3) kg/m(2), 90% of which were smokers. Systolic blood pressure (SBP) of alcohol users significantly correlated with high-density lipoprotein cholesterol (HDL-C) (ß = 0.24; p = 0.003) and waist circumference (WC) (ß = 0.22; p = 0.006). Non-alcohol users were mostly women (84%) with a BMI of 26.0 (18.0-39.2) kg/m(2) and blood pressure in this group related positively with triglycerides. The NAFLD group were also mostly women (72%) with a comparatively larger WC (p < 0.001) and an adverse metabolic profile (total cholesterol: 5.55 ± 1.69 mmol/L; glycosylated hemoglobin: 6.03 (4.70-9.40) %). Diastolic blood pressure in the NAFLD group associated positively with WC (ß = 0.27; p = 0.018). We therefore found disparate gender and cardiometabolic profiles of black South Africans with suspected NAFLD and excessive alcohol use. The described profiles may aid health care practitioners in low resource settings when using these crude screening measures of gender, obesity indices (and self-reported alcohol use) to identify individuals at risk.

Revisiting the relationship between blood pressure and insulin-like growth factor-1.

Conflicting evidence exists on the relationship between blood pressure (BP) and insulin-like growth factor-1 (IGF-1). We reviewed available articles and pooled extrapolated regression coefficients for the association between BP and total IGF-1 as reported in the literature and included additional data from 912 individuals from the general population. We identified 20 studies including 11 704 subjects. We also measured total IGF-1, insulin-like binding protein-3, and BP in 912 black and white men and women from South Africa (aged 20-70 years). When plotting positive and negative weighed regression coefficients (29 data points) against IGF-1, we found a significant positive relationship (r=0.31; P<0.001; n=11 704) intercepting the 0 point at 191 ng/mL IGF-1, suggesting an inverse BP/IGF-1 relationship in low IGF-1 conditions, and a positive relationship in overtly high IGF-1 conditions. In conclusion, our findings suggest that the relationship between BP and IGF-1 is dependent on, or related to, IGF-1 concentrations, as an expression of direct or reverse causality. Low IGF-1 bioavailability (associated with aging and vascular deterioration), resistance to IGF-1, and the complex interplay between IGF-1 and other vasoactive hormones could mask the vasoprotective functions of IGF-1 in cross-sectional studies or could modify their functions in prospective studies.