Patterns of sodium and potassium excretion and blood pressure in the African Diaspora

24-hour sodium and potassium excretion in the Americas: a systematic review and meta-analysis

Objective

To determine the 24-hour urinary sodium and potassium excretions in the Americas.

Methods

A systematic review and meta-analysis were performed seeking for studies conducted between 1990 and 2021 in adults living in any sovereign state of the Americas in Medline, Embase, Scopus, SciELO, and Lilacs. The search was first run on October 26th, 2020 and was updated on December 15th, 2021. Of 3 941 abstracts reviewed, 74 studies were included from 14 countries, 72 studies reporting urinary sodium (27 387 adults), and 42 studies reporting urinary potassium (19 610 adults) carried out between 1990 and 2020. Data were pooled using a random-effects meta-analysis model.

Results

Mean excretion was 157.29 mmol/24h (95% CI, 151.42-163.16) for sodium and 57.69 mmol/24h (95% CI, 53.35-62.03) for potassium. When only women were considered, mean excretion was 135.81 mmol/24h (95% CI, 130.37-141.25) for sodium and 51.73 mmol/24h (95% CI, 48.77-54.70) for potassium. In men, mean excretion was 169.39 mmol/24h (95% CI, 162.14-176.64) for sodium and 62.67 mmol/24h (95% CI, 55.41-69.93) for potassium. Mean sodium excretion was 150.09 mmol/24h (95% CI, 137.87-162.30) in the 1990s and 159.79 mmol/24h (95% CI, 151.63-167.95) in the 2010s. Mean potassium excretion was 58.64 mmol/24h (95% CI, 52.73-64.55) in the 1990s and 56.33 mmol/24/h (95% CI, 48.65-64.00) in the 2010s.

Conclusions

These findings suggest that sodium excretions are almost double the maximum level recommended by the World Health Organization and potassium excretions are 35% lower than the minimum requirement; therefore, major efforts to reduce sodium and to increase potassium intakes should be implemented.

Association between urinary potassium excretion and blood pressure: A systematic review and meta-analysis of observational studies

Background

The evidence base regarding the association between urinary potassium and blood pressure (BP), or risk of hypertension, is inconsistent. Therefore, we sought to conduct a qualitative and quantitative literature review on the association between potassium excretion and BP.

Materials and Methods

Medline, Scopus, Web of Science, Science Direct, and Google Scholar were searched up to June 2020. All observational studies that reported BP and measured potassium excretion in overnight or 24-h urine samples were included. Correlation coefficients, mean urinary potassium excretion, and odds ratio (ORs) of hypertension were extracted from the included studies. There were no language or publication date restrictions.

Results

Overall, twelve observational studies, including 16,174 subjects, were identified for inclusion in the present meta-analysis, and 21 effect sizes were extracted. Pooled mean potassium excretion was 3.46 mmol/24 h higher in normotensive individuals compared with hypertensive subjects (95% confidence interval [CI]: 0.61, 6.31). High urinary potassium excretion was not associated with the risk of hypertension (OR: 0.95; 95% CI: 0.79, 1.13). The pooled correlation coefficient between BP and urinary potassium was not significant (ES: 0.01; 95% CI: -0.03, 0.05). However, a subgroup analysis by age indicated a significant positive correlation between urinary potassium and systolic BP in children (ES: 0.12; 95% CI: 0.04, 0.19).

Conclusion

24 h urinary potassium excretion was not correlated to BP and risk of hypertension. In contrast, mean urinary potassium excretion was higher in normotensive individuals compared with hypertensive counterparts. Future studies should focus on the association between different sources of dietary potassium and BP.

Urinary sodium excretion and its association with blood pressure in Nigeria: A nationwide population survey

Assessment of level of salt intake in a population is the first step toward planning strategies aimed at salt reduction. As a surrogate of salt intake, we measured a single 24-hour urine sodium (uNa) of free-living 2503 adults in a nationally representative sample of Nigerians drawn from 12 rural and urban communities; and evaluated the community-level association of uNa with blood pressure (BP). Overall, the median (interquartile range (IQR)) of uNa was 99 (105) mmol, ranging from 23.8 (32.4) in rural north-central to 172.8 (131.0) mmol in urban northwestern region. Daily uNa was significantly higher (p < .001) in men compared to women (107.1 vs 93.9 mmol); and urban compared to rural dwellers (114.9 vs 86.0mmol). About one-half of participants excreted uNa in excess of recommended daily maximum value (86mmol). In a model adjusted for age, sex, body mass index (BMI), level of education, place of residence, and use of antihypertensive medication; being a man (odds ratio, OR 1.69, 95% confidence Interval CI, 1.21-2.37, p = .002) and being < 60 years of age (OR 1.74, 95% CI 1.23-2.45, p = .002), were associated with excreting higher than recommended uNa. In a fully adjusted model of the community-level analysis, urinary sodium, potassium, and sodium-to-potassium ratio each showed no significant independent association with both systolic and diastolic BPs. Among adult Nigerians, the median daily uNa excretion was 99 mmol and it had no significant association with blood pressure indices.

Monitoring and implementation of salt reduction initiatives in Africa: A systematic review

This systematic review aims to document salt consumption patterns and the implementation status and potential impact of salt reduction initiatives in Africa, from studies published between January 2009 and November 2019. Studies were sourced using MEDLINE, Embase, Cochrane Library electronic databases, and gray literature. Of the 887 records retrieved, 38 studies conducted in 18 African countries were included. Twelve studies measured population salt intake, 11 examined salt level in foods, 11 assessed consumer knowledge, attitudes, and behaviors, 1 study evaluated a behavior change intervention, and 3 studies modeled potential health gains and cost savings of salt reduction interventions. The population salt intake studies determined by 24‐hour urine collections showed that the mean (SD) salt intake in African adults ranged from 6.8 (2.2) g to 11.3 (5.4) g/d. Salt levels in foods were generally high, and consumer knowledge was fairly high but did not seem to translate into salt lowering behaviors. Modeling studies showed that interventions for reducing dietary sodium would generate large health gains and cost savings for the health system. Despite this evidence, adoption of population salt reduction strategies in Africa has been slow, and dietary consumption of sodium remains high. Only South Africa adopted legislation in 2016 to reduce population salt intake, but success of this intervention has not yet been fully evaluated. Thus, rigorous evaluation of the salt reduction legislation in South Africa and initiation of salt reduction programs in other African countries will be vital to achieving the targeted 30% reduction in salt intake by 2025.

Differences in hypertension phenotypes between Africans and Europeans: role of environment

OBJECTIVES

Hypertension phenotypes differ between Africans and Europeans, with a greater prevalence of low renin salt-sensitive hypertension and greater predisposition to adverse cardiac remodelling in Africans. To elucidate the roles of inheritance and environment in determining hypertension phenotypes in sub-Saharan Africans and white-Europeans, we compared phenotypes in white individuals in the UK (n = 132) and in African individuals in the UK (n = 158) and Nigeria (n = 179).

METHODS

Biochemistry, blood pressure, left ventricular structure (echocardiography) and 24-h urinary collections of sodium and potassium were measured.

RESULTS

Twenty-four-hour urinary sodium/potassium ratio was lower in individuals living in Europe (both African and white: 2.32 ± 0.15 and 2.28 ± 0.17) than in individuals in Nigeria (4.09 ± 0.26, both P < 0.001) reflecting proportionately higher potassium intake in Europeans (African or white) than African residents. Plasma renin was lower in Africans irrespective of residency than white Europeans, but aldosterone was higher in Africans in Europe than those in Africa (466.15 ± 32.95 vs. 258.60 ± 17.42 pmol/l, P < 0.001). Left ventricular mass index adjusted for blood pressure and other confounders was greatest in Africans in Europe (103.27 ± 2.32 g/m) compared with those in Africa (89.28 ± 1.98 g/m) or white Europeans (86.77 ± 2.63 g/m, both P < 0.001).

CONCLUSION

Despite a similar low renin state in African origin individuals living in Europe and Africa, a higher aldosterone level, possibly related to higher potassium intake or other environmental factors, may contribute to greater cardiac remodelling in Africans in Europe.

Diet and Chronic Kidney Disease

Kidney disease affects almost 15% of the US population, and prevalence is anticipated to grow as the population ages and the obesity epidemic continues due to Western dietary practices. The densely caloric Western diet, characterized by high animal protein and low fruit and vegetable content, has fueled the growth of chronic diseases, including chronic kidney disease. The glomerulus or filtering unit of the kidney is very susceptible to barotrauma, and diets high in animal protein impede the glomerulus' ability to protect itself from hemodynamic injury. High animal protein intake combined with low intake of fruits and vegetables also leads to a high net endogenous acid production requiring augmentation of ammonium excretion in order to prevent acidosis. This higher workload of the kidney to maintain a normal serum bicarbonate level may further exacerbate kidney disease progression. This article reviews the potential mechanisms whereby several key characteristics of the typical Western diet may impact kidney disease incidence and progression. Reducing animal protein intake and egg yolk and increasing intake of fruits and vegetables and fiber may prevent or delay end-stage renal disease, but few clinical trials have examined vegetarian diets for management of chronic kidney disease. More research is needed to determine optimal dietary patterns for the prevention of kidney disease and its progression.

Increased urinary sodium excretion is associated with systolic blood pressure in first degree relatives of hypertensive patients in Ibadan, Southwestern Nigeria

INTRODUCTION

Understanding the risk factors of hypertension has led to a better understanding of the pathogenesis, prevention and reduction in morbidity of hypertension. It is well known that offsprings of hypertensive parents have an increased risk of developing hypertension. It is therefore necessary to explore the physiological differences between normotensive patients with and without a positive family history of hypertension with respect to their urinary excretion of sodium.

METHODS

This study was carried out at the University College Hospital, Ibadan Nigeria, to determine if normotensive patients with a positive family history of hypertension are different with respect to their urinary excretion of electrolytes and blood pressure. It examined the relationship between 24-hour urinary excretion of sodium, chloride and potassium, urea and creatinine and blood pressure in subjects with and without family history of hypertension. It was a case-control study of sixty-two subjects: normotensive patients' first degree relatives of primary hypertensive patients and normotensive patients without positive family history.

RESULTS

The mean (SD) systolic blood pressures for subjects with and without family history of hypertension were significantly different: 120.0(22.25) and 105.0(17.50) respectively, (p=0.001). The mean arterial blood pressures were significantly different: 86.4(10.2) mmHg and 80.1(8.1) mmHg respectively (p=0.010). The mean (SD) 24-hour urinary excretion of sodium for normotensive patients with and without positive family history of hypertension were 180.5 (45.50) mEq/L, and 156.0(36.25) mEq/L respectively. Systolic blood pressure and 24-hour urinary excretion of sodium was also higher in normotensive subjects with a positive family history of hypertension.

CONCLUSION

Systolic blood pressure and twenty-four hour urinary excretion of sodium were higher in normotensive subjects with a positive family history of hypertension than in those without a family history of hypertension.

High-sensitivity ion detection at low voltages with current-driven organic electrochemical transistors

Ions dissolved in aqueous media play a fundamental role in plants, animals, and humans. Therefore, the in situ quantification of the ion concentration in aqueous media is gathering relevant interest in several fields including biomedical diagnostics, environmental monitoring, healthcare products, water and food test and control, agriculture industry and security. The fundamental limitation of the state-of-art transistor-based approaches is the intrinsic trade-off between sensitivity, ion concentration range and operating voltage. Here we show a current-driven configuration based on organic electrochemical transistors that overcomes this fundamental limit. The measured ion sensitivity exceeds by one order of magnitude the Nernst limit at an operating voltage of few hundred millivolts. The ion sensitivity normalized to the supply voltage is larger than 1200 mV V⁻¹ dec⁻¹, which is the largest value ever reported for ion-sensitive transistors. The proposed approach is general and can be extended to any transistor technology, thus opening opportunities for high-performance bioelectronics.

The organic electrochemical transistor is a type of transistor that modulates the channel current by the ion concentration and is thus explored for bio-applications. Here Ghittorelli et al. show a current-driven device configuration to increase the sensitivity by ten times than conventional approaches.

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.

Ethnic differences in prevalence and risk factors for hypertension in the Suriname Health Study: a cross sectional population study

BACKGROUND

Limited information is available about the prevalence, ethnic disparities, and risk factors of hypertension within developing countries. We used data from a nationwide study on non-communicable disease (NCD) risk factors to estimate, explore, and compare the prevalence of hypertension overall and in subgroups of risk factors among different ethnic groups in Suriname.

METHOD

The Suriname Health Study used the World Health Organization Steps design to select respondents with a stratified multistage cluster sample of households. The overall and ethnic specific prevalences of hypertension were calculated in general and in subgroups of sex, age, marital status, educational level, income status, employment, smoking status, residence, physical activity, body mass index (BMI), and waist circumference (WC). Differences in the prevalence between ethnic subgroups were assessed using the Chi-square test. We used several adjustment models to explore whether the observed ethnic differences were explained by biological, demographic, lifestyle, or anthropometric risk factors.

RESULTS

The prevalence of hypertension was 26.2 % (95 % confidence interval 25.1 %-27.4 %). Men had higher mean values for systolic and diastolic blood pressure compared to women. Blood pressure increased with age. The prevalence was highest for Creole, Hindustani, and Javanese and lowest for Amerindians, Mixed, and Maroons. Differences between ethnic groups were measured in the prevalence of hypertension in subcategories of sex, marital status, education, income, smoking, physical activity, and BMI. The major difference in association of ethnic groups with hypertension was between Hindustani and Amerindians.

CONCLUSION

The prevalence of hypertension in Suriname was in the range of developing countries. The highest prevalence was found in Creoles, Hindustani, and Javanese. Differences in the prevalence of hypertension were observed between ethnic subgroups with biological, demographic, lifestyle, and anthropometric risk factors. These findings emphasize the need for ethnic-specific research and prevention and intervention programs.

Salt intakes in sub-Saharan Africa: a systematic review and meta-regression

Background

High sodium intake increases the risk of hypertension and cardiovascular diseases. For this reason the World Health Organization recommends a maximum intake of 2 g per day and a 30 % reduction in population sodium intake by 2025. However, in global reviews, data on sodium intake in sub-Saharan Africa have been limited.

Methods

A systematic review was conducted to identify studies reporting sodium intake in sub-Saharan African populations. Meta-regression analyses were used to test the effect of year of data collection and method of data collection (urinary/dietary), as well as any association between sex, urban/rural status or a country’s economic development, and population sodium intake.

Results

We identified 42 papers reporting 67 estimates of adult population sodium intakes and 12 estimates of child population sodium intakes since 1967. Of the 67 adult populations, 54 (81 %) consumed more than 2 g sodium/day, as did four of the 12 (33 %) child populations. Sixty-five adult estimates were included in the meta-regression, which found that urban populations consumed higher amounts of salt than rural populations and that urine collection gave lower estimates of sodium intake than dietary data.

Conclusions

Sodium intake in much of sub-Saharan Africa is above the World Health Organization’s recommended maximum intake and may be set to increase as the continent undergoes considerable urbanization. Few identified studies used stringent measurement criteria or representative population samples. High quality studies will be required to identify where and with whom to intervene, in order to meet the World Health Organization’s target of a 30 % reduction in population sodium intake and to demonstrate progress towards this target.

Seasonal variation in natural abundance of 2H and 18O in urine samples from rural Nigeria

The doubly labeled water (DLW) method is used to measure free-living energy expenditure in humans. Inherent to this technique is the assumption that natural abundances of stable isotopes (2)H and (18)O in body water remain constant over the course of the measurement period and after elimination of the loading dose of DLW will return to the same predose level. To determine variability in the natural abundances of (2)H and (18)O in humans living in a region with seasonal shifts in rain patterns and sources of drinking water, over the course of 12 mo we collected weekly urine samples from four individuals living in southwest Nigeria as well as samples of their drinking water. From ongoing regional studies of hypertension, obesity, and energy expenditure, we estimated average water turnover rate, urine volumes, and sodium and potassium excretion. Results suggest that (2)H and (18)O in urine, mean concentrations of urinary sodium and potassium, urine volume, and total body turnover differed significantly from dry to rainy season. Additionally, seasonal weather variables (mean monthly maximum temperatures, total monthly rainfall, and minimum relative humidity) were all significantly associated with natural abundances in urine. No seasonal difference was observed in drinking water samples. Findings suggest that natural abundances in urine may not remain constant as assumed, and studies incorporating DLW measurements across the transition of seasons should interpret results with caution unless appropriate doses of the tracers are used.

Impact of westernization on fibroblast growth factor 23 levels among individuals of African ancestry

INTRODUCTION

The Western diet is associated with high consumption of processed foods preserved with phosphate. Higher dietary phosphate consumption stimulates production of fibroblast growth factor 23 (FGF23), which heightens risk for cardiovascular disease and mortality. We hypothesized that adults living in a more westernized society have higher levels of FGF23 due to increased phosphate consumption as measured by urinary phosphate excretion.

METHODS

We measured plasma C-terminal FGF23 levels and urinary phosphate and creatinine levels in timed urine collections among 100 African adults living in the rural area of Igbo-Ora, Nigeria (52 women, 48 men), and 100 African Americans (32 women, 68 men) living in Maywood, IL, an urban suburb of Chicago, IL, USA. Among these 200 participants, urine collections were adequate in 76 and 68 of the Maywood and Igbo-Ora participants, respectively.

RESULTS

In the total group, the mean age and body mass index, respectively, were 34.6 ± 8.2 years and 22.1 ± 3.9 kg/m(2) in Igbo-Ora, and 42.8 ± 7.2 years and 25.8 ± 6.5 kg/m(2) in Maywood. Demographic characteristics for each site were very similar after excluding participants without adequate urine collections. Among all 200 participants, the median (interquartile range) FGF23 levels were significantly higher in Maywood versus Igbo-Ora [63.8 (45.0-89.9) versus 12.5 RU/mL (8.5-18.5); P < 0.0001] and these differences did not change substantially after excluding nine women from Maywood with FGF23 levels >400 RU/mL or after excluding participants with inadequate urine collections. Among participants with adequate urine collections, the mean 24-h urinary phosphate excretion was significantly higher in Maywood versus Igbo-Ora (810.6 ± 309.0 versus 347.5 ± 153.1 mg; P < 0.001) and FGF23 levels correlated significantly with total urinary phosphate excretion (r = 0.62; P < 0.001) and urinary phosphate-to-creatinine ratios (r = 0.50; P < 0.001).

CONCLUSIONS

Living in a more westernized society may be associated with greater net phosphate absorption, as reflected by higher urinary phosphate excretion, and higher FGF23 levels.

Difference between 24-h diet recall and urine excretion for assessing population sodium and potassium intake in adults aged 18-39 y

BACKGROUND

Limited data are available on the accuracy of 24-h dietary recalls used to monitor US sodium and potassium intakes.

OBJECTIVE

We examined the difference in usual sodium and potassium intakes estimated from 24-h dietary recalls and urine collections.

DESIGN

We used data from a cross-sectional study in 402 participants aged 18-39 y (∼50% African American) in the Washington, DC, metropolitan area in 2011. We estimated means and percentiles of usual intakes of daily dietary sodium (dNa) and potassium (dK) and 24-h urine excretion of sodium (uNa) and potassium (uK). We examined Spearman's correlations and differences between estimates from dietary and urine measures. Multiple linear regressions were used to evaluate the factors associated with the difference between dietary and urine measures.

RESULTS

Mean differences between diet and urine estimates were higher in men [dNa - uNa (95% CI) = 936.8 (787.1, 1086.5) mg/d and dK - uK = 571.3 (448.3, 694.3) mg/d] than in women [dNa - uNa (95% CI) = 108.3 (11.1, 205.4) mg/d and dK - uK = 163.4 (85.3, 241.5 mg/d)]. Percentile distributions of diet and urine estimates for sodium and potassium differed for men. Spearman's correlations between measures were 0.16 for men and 0.25 for women for sodium and 0.39 for men and 0.29 for women for potassium. Urinary creatinine, total caloric intake, and percentages of nutrient intake from mixed dishes were independently and consistently associated with the differences between diet and urine estimates of sodium and potassium intake. For men, body mass index was also associated. Race was associated with differences in estimates of potassium intake.

CONCLUSIONS

Low correlations and differences between dietary and urinary sodium or potassium may be due to measurement error in one or both estimates. Future analyses using these methods to assess sodium and potassium intake in relation to health outcomes may consider stratifying by factors associated with the differences in estimates from these methods. This trial was registered at clinicaltrials.gov as NCT01631240.

New insights on the risk for cardiovascular disease in African Americans: the role of added sugars

African Americans are at increased risk for cardiovascular and metabolic diseases, including obesity, high BP, diabetes, CKD, myocardial infarction, and stroke. Here we summarize the current risks and provide an overview of the underlying risk factors that may account for these associations. By reviewing the relationship between cardiovascular and renal diseases and the African-American population during the early 20th century, the historic and recent associations of African heritage with cardiovascular disease, and modern population genetics, it is possible to assemble strong hypotheses for the primary underlying mechanisms driving the increased frequency of disease in African Americans. Our studies suggest that underlying genetic mechanisms may be responsible for the increased frequency of high BP and kidney disease in African Americans, with particular emphasis on the role of APOL1 polymorphisms in causing kidney disease. In contrast, the Western diet, particularly the relatively high intake of fructose-containing sugars and sweetened beverages, appears to be the dominant force driving the increased risk of diabetes, obesity, and downstream complications. Given that intake of added sugars is a remediable risk factor, we recommend clinical trials to examine the reduction of sweetened beverages as a primary means for reducing cardiovascular risk in African Americans.

Dietary potassium intake and renal handling, and their impact on the cardiovascular health of normotensive afro-caribbeans

OBJECTIVE

Recent nutritional profiles of dietary intake have indicated a shift from the ancient diet to the Western diet. The ancient diet provided a high potassium and low sodium intake, which in turn leads to sodium conservation and potassium excretion. This change in the dietary intake is expected to affect potassium and sodium handling in the kidneys. Numerous studies have been done to emphasize the importance of sodium handling by the kidneys and its impact on cardiovascular health. This study will investigate potassium intake and handling, and its impact on the cardiovascular health of a sample of normotensive Afro-Caribbeans by the possible modulation of the renin angiotensin aldosterone system (RAAS).

METHODS

A sample of 51 normotensive Afro-Caribbean participants was recruited for the study. Participants were observed over a two-day period in which they were given a 24-hour ambulatory blood pressure monitor and a container to collect blood pressure data and a 24-hour urine sample. Anthropometric measurements were noted. Urinary electrolytes and supine plasma renin activity (PRA) were determined from the 24-hour urine collection and a blood sample. Dietary potassium intake was estimated based on dietary intake observations and calculated based on the urinary potassium excretion. SPSS version 19 was used to analyse the data to make inferences.

RESULTS

The daily potassium intake was observed to be 2.95 g/day and measured intake from the urinary potassium was between 4.95 and 7.32 g/day. Urinary potassium excretion was 3.66 (± 1.40) g/day. The urinary potassium excretion in the Afro-Caribbean sample in Barbados was higher than the other population samples. The averaged PRA of the participants (supine) was 0.778 (± 1.072) ng/mL/hour. The averaged nocturnal systolic blood pressure dip of the participants was 5.97 (± 4.324) %. There was no significant correlation between urinary potassium excretion, blood pressure, nocturnal systolic blood pressure dip and PRA.

CONCLUSIONS

The Afro-Caribbean sample has an inadequate daily potassium intake based on the observed intake and recommended values, with a high urinary excretion of the electrolyte compared to other values in the literature. This high potassium excretion could have been partly due to low plasma renin activity levels in the study participants. As a possible consequence, an increase in the nocturnal peripheral resistance is a likely cause for the diminished systolic dip. The lack of correlations between dietary potassium excretion and the blood pressure parameters does not allow any firm inference of the electrolyte's handling and its impact on cardiovascular health in the normotensive Afro-Caribbean participants. However, further research is needed to get a more accurate daily potassium intake value, and a more statistically robust sample to assess whether potassium handling and blood pressure would be affected by a change in potassium intake.

Race and the insulin resistance syndrome

Type 2 diabetes remains an important cause of morbidity and mortality. The metabolic syndrome affects 25% of the adult US population based on the Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults from the National Cholesterol Education Program. Knowledge on the impact of obesity on metabolic health parameters has increased greatly over the past decade. This review discusses the limitations of the National Cholesterol Education Program metabolic syndrome definition and the racial disparities in the clinical presentation of the insulin resistance syndrome. We also examine the current literature with particular emphasis on albuminuria, nonalcoholic fatty liver disease, and intramyocellular lipid content. This review explores potential environmental and genetic reasons for differences in the manifestation of insulin resistance across racial/ethnic groups and highlights several promising areas for further study.