24-h urinary sodium to potassium ratio and its association with obesity in children and adolescents

Sex difference in the relationship between 24-h sodium-potassium ratio and prevalence of metabolic syndromes: a cross-sectional study

Maintaining a balanced ratio between sodium and potassium intake is one of the most important dietary and lifestyle factors in the development of metabolic syndrome (MetS), but available evidence is still limited, particularly when using urine samples to estimate this ratio. We aim to evaluate the associations between the 24-h urinary sodium-potassium ratio (24hUNa/KE) and MetS risk through a large health check-up program in China. This cross-sectional study analyzed health check-up data from 59,292 participants at the Third Xiangya Hospital's Department of Health Management in Changsha, China, from 2018 to 2021. Each participant gave one fasting urine sample to analyze sodium, potassium, and creatinine levels during the check-up. The Kawasaki formula estimated 24-h urinary sodium (24hUNaE) and potassium excretion (24hUKE), with the 24hUNa/KE ratio calculated by dividing 24hUNaE by 24hUKE. The prevalence of MetS was found to be 19.27%. Notably, the overall MetS prevalence was higher in men (28.08%) than in women (7.83%). In women, MetS prevalence increased from 6.35 to 10.30% across the lowest to highest 24hUNa/KE quartiles. A significant increase in MetS prevalence was associated with each standard deviation increase in 24hUNa/KE (adjusted odds ratio [AOR], 1.03; 95% confidence interval [CI] 1.01-1.06), particularly for central obesity (AOR, 1.04; 95% CI 1.02-1.06) and elevated blood pressure (AOR, 1.20; 95% CI 1.17-1.22). In women, a one standard deviation increase in the 24hUNa/KE ratio raised the risk of MetS by 9% (AOR, 1.09; 95% CI 1.05-1.14), but no significant link was found in men. A strong positive link exists between 24hUNa/KE and MetS and its components, especially central obesity and high blood pressure, with a more significant effect in women.

Metabolic risk factors, blood pressure and atherogenic indices of cardiovascular disease across different quartiles of dietary sodium to potassium ratio among young semi-professional athletes with overweight or obesity

BACKGROUND

Previous studies have revealed the role of the dietary sodium-to-potassium ratio in predicting cardiovascular and total mortality. However, a limited number of studies have investigated the association between the dietary sodium-to-potassium ratio and individual biomarkers of metabolic disease in athletes. In this study, we aimed to compare metabolic, atherogenic, and anthropometric risk factors for cardiovascular disease across different quartiles of the dietary sodium-to-potassium ratio among young semi-professional athletes with overweight or obesity.

METHODS

In this cross-sectional study, 637 young semi-professional athletes, aged 20-40 years, were selected from active athletic and fitness clubs. Anthropometric measurements were performed, and fasting blood sugar, serum lipids, and lipoprotein (a) [Lp(a)] were measured. Atherogenic indices, including the atherogenic index of plasma (AIP), Castelli risk index (CRI)-I, CRI-II, and lipid tetrad index (LTI), were calculated.

RESULTS

Participants in the highest quartile of the dietary sodium-to-potassium ratio were younger and had a higher waist-to-hip ratio (WHR) compared to those in the lowest quartile. Additionally, those in the highest quartile showed significantly higher serum total cholesterol and Lp(a) concentrations after adjusting for confounding factors (P < 0.05).

CONCLUSION

Our findings suggest that individuals in the higher quartiles of the dietary sodium-to-potassium ratio exhibit less favorable serum lipid profiles. Further longitudinal and interventional studies are needed to clarify the potential therapeutic role of reducing the dietary sodium-to-potassium ratio in managing cardiovascular disease risk factors.

Urinary sodium-potassium ratio as a genetic predictor of myocardial infarction

BACKGROUND

The relationship between the urinary sodium-potassium ratio (USPR) and risk factors for heart disease has been observed over time. We evaluated the relationship between USPR and myocardial infarction (MI).

METHODS

Causal relationships were estimated based on USPR and MI data from genome-wide association studies. The main analysis method for bidirectional two-sample Mendelian randomization was inverse-variance weighting (IVW), with four other supplementary methods used.

RESULTS

The IVW method indicated a positive correlation between USPR levels and MI (IVW, odds ratio = 1.504, 95% confidence interval: 1.108-2.041, P = 0.009). In contrast, the inverse analysis provided evidence suggesting that MI affected USPR (P > 0.05). The Cochran Q test showed heterogeneity, while the intercept test revealed no horizontal pleiotropy, and the leave-one-out analysis demonstrated that the analyses were reliable.

CONCLUSIONS

This study provides evidence for the causal effect of the USPR on MI; however, this was not the case in the opposite situation. It is plausible that the USPR serves as a promoting factor for MI.

Community-level dietary intake of sodium, potassium, and sodium-to-potassium ratio as a global public health problem: a systematic review and meta-analysis

Background

Widespread adoption of a westernized diet represents a major lifestyle change characterized by substantially higher sodium consumption and lower potassium intake, which is related to cardiovascular morbidity.

Methods

We performed a systematic review and meta-analysis over published studies in accordance with quantifying the dietary intake of sodium and potassium of the universal population across the world. The PubMed, EMBASE, Cochrane Library, and Google Scholar databases were used to find research that pronounced 24-hour urinary sodium or potassium excretion (reference period: 2014-2021). The effect size was estimated using the fixed-effect model; sub-group analysis become accomplished to determine urinary sodium and potassium excretion disaggregated by geographical location. Publication bias became evaluated the usage of graphical funnel plot. Data analysis was performed using STATA 16.

Results

Forty-three studies (n= 62,940) qualified the selection criteria. The mean urinary excretion of sodium and potassium was 156.73 mmol/24h [95% confidence interval (CI), 148.98-164.47] and 48.89 mmol/24 h (95% CI, 43.61-54.17), respectively; the mean urinary sodium/potassium ratio was 3.68 (95% CI, 2.96-4.40).

Conclusions

This updated systematic review highlights excessively high dietary intake of sodium and low intake of potassium at the community level in most parts of the world. The urinary Na/K ratio exceeded the level recommended by the WHO guidelines.

Is there a relationship between 24-hour urinary sodium and potassium and mental health in migraine patients?: A cross-sectional study

There is a lack of evidence and consensus in terms of the association between dietary intake of sodium (Na) and potassium (K) with mental health. By using 24-hours urinary samples as the gold standard method, we conducted a study to explore the association between dietary intake of Na and K with parameters of mental health including depression, anxiety, and stress among an Iranian population diagnosed with migraine. In the present study, 262 subjects (20-50 years old), with a confirmed diagnosis of migraine were enrolled. Mental health was investigated by the Depression, Anxiety, and Stress Scales (DASS-21) questionnaire. Dietary intake of Na and K was estimated by means of a 24-hour urine sample. Multinomial logistic regression analysis was implemented and odds ratio (OR) with 95% confidence interval (CI) was stated. After controlling for potential confounders, the 24-hour urinary Na was associated significantly with the risk of depression (OR = 0.55, 95% CI: 0.30, 1.00; P = .053). After adjustment for confounders, those in the highest tertile of the 24-hour urinary Na/K ratio had lower odds for having depression (OR = 0.54, 95% CI: 0.31, 0.93; P = .027), and marginally significantly lower risk of anxiety (OR = 0.58, 95% CI: 0.31, 1.06; P = .079) and stress (OR = 0.56, 95% CI: 0.31, 1.02; P = .061). In conclusion, higher 24-hour urine Na was associated with a significantly lower risk of depression. Moreover, the 24-hour Na/K ratio was significantly associated with lower risk of depression, anxiety, and stress.

Analysis of spot urine biomarkers and association with body weight in Japanese elementary schoolchildren

Childhood obesity is rapidly increasing worldwide and is largely the consequence of adoption of unhealthy diets excessive in calories and salt (NaCl) as well as devoid in pivotal micronutrients such as potassium (K) and magnesium (Mg). Education-based programs aiming to encourage healthy food knowledge and behaviors are crucial at a young age, and for this purpose, convenient ways to assess daily dietary intake are warranted. We therefore attempted to evaluate the dietary intake of Okinawan schoolchildren in Japan by analyzing a series of biomarkers in morning spot urine samples and explore whether these biomarkers correlate with body weight and a series of metabolic parameters. We enrolled 98 third-grade elementary schoolchildren in Okinawa, Japan. Morning spot urine samples were collected and analyzed using high-performance liquid chromatography (HPLC) to assess dietary intake. We found that estimated daily NaCl intake was higher in obese/overweight children as compared to healthy-weight children (p = 0.0001). There was also a significant positive correlation between body mass index (BMI) and NaCl intake (Spearman) (ρ = 0.45, p < 0.0001) and a negative correlation between BMI and Mg/Cr (ρ =  -0.27, p = 0.01). Furthermore, Na/K ratio was higher in samples collected on Monday (weekend) as compared to samples collected on Thursday or Friday (weekday) (p < 0.0001).

CONCLUSION

Via the use of morning spot urine analyses, our results show that NaCl intake was associated with obesity, and Mg excretion negatively correlated with BMI in Japanese schoolchildren, highlighting the potential role of these micronutrients in maintaining a healthy body weight.

WHAT IS KNOWN

•Overweight and obesity are largely due to excessive consumption of calories and positively correlated with salt (NaCl) intake. •Spot urine methods are convenient for assessing the nutritional needs and targeting prevention programs in children.

WHAT IS NEW

•Utilizing morning spot urine analyses, estimated NaCl intake is positively correlated and Mg/Cr negatively correlated with BMI in Okinawan schoolchildren. •As estimated via morning spot urine samples, a greater proportion of children likely exceeds the recommended NaCl intake on the weekend as compared to weekday.

The Role of Mineral Deficiencies in Insulin Resistance and Obesity

Minerals are critical for maintaining overall health. These tiny chemical compounds are responsible for enzymatic activation, maintaining healthy teeth and bones, regulating energy metabolism, enhancing immunity, and aiding muscle and brain function. However, mineral deficiency in the form of inadequate or under nourished intake affects millions of people throughout the world, with well-documented adverse health consequences of malnutrition. Conversely, mineral deficiency may also be a risk factor for Insulin Resistance (IR) and obesity. This review focuses on another, more "less discussed" form of malnutrition, namely mineral deficiency and its contribution to metabolic disorders. At the cellular level, minerals maintain not only molecular communication but also trigger several key biochemical pathways. Disturbances in these processes due to mineral insufficiency may gradually lead to metabolic disorders such as insulin resistance, pre-diabetes, and central obesity, which might lead to renal failure, cardiac arrest, hepatic carcinoma, and various neurodegenerative diseases. Here we discuss the burden of disease promoted by mineral deficiencies and the medical, social, and economic consequences. Mineral deficiency-mediated IR and obesity have a considerable negative impact on individual well-being, physical consideration, and economic productivity. We discuss possible molecular mechanisms of mineral deficiency that may lead to IR and obesity and suggest strategies to counter these metabolic disorders. To protect mankind from mineral nutrient deficiencies, the key is to take a variety of foods in reasonable quantities, such as organic and pasture-raised eggs, low fat dairy, and grass-fed and finished meats, insecticide, and pesticide-free vegetables and fruits.

Necessity of salt intake reduction education beginning in youth: a cross-sectional survey of sodium-to-potassium ratios in mothers and their preschool children

Urinary sodium-to-potassium ratios are known to be high in preschoolers, but there are no reports comparing these ratios with those of the children's mothers. The aim of this study was to investigate the association between the urinary sodium-to-potassium ratios of mothers and their preschool children under the hypothesis that the ratio is equivalent between the two. We evaluated 297 preschoolers aged four to five attending six kindergartens (four in northern Japan, two in southern Japan), and we also evaluated the children's mothers. We asked the participants to take morning first urine samples for 2 consecutive days in the spring and autumn of the same year (four samples per participant) and to fill out a dietary questionnaire. There was a correlation between the urinary sodium-to-potassium ratios of preschoolers and those of their mothers. However, in a comparison between the preschoolers and their mothers overall, higher values were found in the preschoolers [preschoolers: 4.6 (3.5-6.3) mmol/L/g·Cr; mothers: 4.3 (3.9-4.7) mmol/L/g·Cr, p = 0.003]. These results correlated with the urinary sodium-to-potassium ratios estimated from the dietary questionnaire. The preschoolers showed high sodium and low potassium intake consumption compared to the mothers. Interestingly, these were found to differ by region and gender. In conclusion, the urinary sodium-to-potassium ratio in Japanese preschoolers is related to and higher than that of their mothers. It is important to educate children, their parents, childcare professionals, and society as a whole about proper salt restriction and potassium supplementation, as well as to improve the food environment.

Sodium Intake Is Associated With Renal Resistive Index in an Adult Population-Based Study

Renal resistive index (RRI) has been associated with adverse renal and cardiovascular outcomes. Although traditionally considered a marker of intrinsic renal damage, RRI could also reflect systemic vascular dysfunction. As sodium intake was linked to alterations in vascular properties, we wished to characterize the association of salt consumption with RRI in the general adult population. Participants were recruited in a population-based study in Switzerland. RRI was measured by ultrasound in 3 segmental arteries. Sodium intake (UNa; mmol/24 h) was estimated on 24-hour urine samples. Carotido-femoral pulse wave velocity was obtained by applanation tonometry. Mixed multivariate regression models were used with RRI or pulse wave velocity as independent variables and UNa as dependent variable, adjusting for possible confounders. We included 1002 patients in the analyses with 528 (52.7%) women and mean age of 47.2±17.4. Mean values of UNa and RRI were 141.8±61.1 mmol/24 h and 63.8±5.5%, respectively. In multivariate analysis, UNa was positively associated with RRI (P=0.002) but not with pulse wave velocity (P=0.344). Plasma renin activity and aldosterone did not modify the relationship between UNa and RRI (P=0.087 for interaction). UNa/urinary potassium ratio was positively associated with pulse wave velocity ≥12 m/s (P=0.033). Our results suggest that dietary salt consumption has a direct impact on renal hemodynamic in the adult general population. Alterations in vascular properties likely explain those findings, but inadequate renal vaso-motor response is also possible. Sodium intake could thus potentially be linked to underlying structural systemic damages affecting this population.

Further evidence that methods based on spot urine samples should not be used to examine sodium-disease relationships from the Science of Salt: A regularly updated systematic review of salt and health outcomes (November 2018 to August 2019)

The aim of this eighth Science of Salt outcomes review is to identify, summarize, and critically appraise studies on dietary sodium and health outcomes published between November 1, 2018, and August 31, 2019, to extend this series published in the Journal since 2016. The standardized Science of Salt search strategy was conducted. Studies were screened based on a priori defined criteria to identify publications eligible for detailed critical appraisal. The search strategy resulted in 2621 citations with 27 studies on dietary sodium and health outcomes identified. Two studies met the criteria for detailed critical appraisal and commentary. We report more evidence that high sodium intake has detrimental health effects. A post hoc analysis of the Dietary Approaches to Stop Hypertension (DASH) sodium trial showed that lightheadedness occurred at a greater frequency with a high sodium DASH diet compared to a low sodium DASH diet. In addition, evidence from a post-trial analysis of the Trials of Hypertension (TOHP) I and II cohorts showed that estimates of sodium intake from methods based on spot urine samples are inaccurate and this method alters the linearity of the sodium-mortality association. Compared to measurement of 24-hour sodium excretion using three to seven 24-hour urine collections, estimation of average 24-hour sodium excretion with the Kawasaki equation appeared to change the mortality association from linear to J-shaped. Only two high-quality studies were identified during the review period, both were secondary analyses of previously conducted trials, highlighting the lack of new methodologically sound studies examining sodium and health outcomes.

The Impact of Maternal Overweight on Hair Essential Trace Element and Mineral Content in Pregnant Women and Their Children

The aim of the present study was to investigate hair essential trace elements and mineral levels in 105 pregnant normal-weight (control) and 55 overweight and obese women in the third trimester of pregnancy, as well as in their children at the age of 9 months. The hair essential trace elements and mineral levels were assessed using inductively coupled plasma mass-spectrometry. Overweight pregnant women had significantly reduced Cr (- 24%; p = 0.047) and Zn (- 13%; p = 0.008) content, as well as elevated hair Na and K levels as compared to the controls. Children from overweight and obese mothers had lower hair Mo (- 18%; p = 0.017), Se (- 8%; p = 0.043), and V (- 24%; p = 0.028) levels, as well as elevated Sr content (19%; p = 0.025). Correlation analysis revealed a significant relationship between maternal and child hair levels of Co (r = 0.170; p = 0.038), Cu (r = 0.513; p < 0.001), Mn (r = 0.240; p = 0.003), and Na (r = 0.181; p = 0.027) in the whole sample. Pre-pregnancy maternal body mass index (BMI) positively correlated with maternal hair K (r = 0.336; p < 0.001) and Na (r = 0.212; p = 0.008) and negatively correlated with V (r = - 0.204; p = 0.011) and Zn (r = - 0.162; p = 0.045) levels. The results indicate that impaired trace element and mineral metabolism may play a role in the link between maternal obesity, complications of pregnancy and child's postnatal development. Hypothetically, dietary improvement may be used as a tool to reduce these risks. However, further experimental and clinical studies are required to investigate the relationship between obesity and trace element metabolism in pregnancy.

Comparison of 24-h Diet Records, 24-h Urine, and Duplicate Diets for Estimating Dietary Intakes of Potassium, Sodium, and Iodine in Children

Accurately estimating nutrient intake can be challenging, yet it is important for informing policy. This cross-sectional validation study compared the use of three methods for estimating the intake of sodium, potassium, and iodine in children aged 9–11 years in New Zealand. Over the same 24 hour period, participants collected duplicate diets (n = 37), weighed food records (n = 84), and 24 hour urine samples (n = 82). Important differences were found between dietary estimates of sodium, potassium, and iodine using the three methods of dietary assessment, suggesting that different methods of assessment have specific limitations for the measurement of these nutrients in children. Bland Altman plots show relatively wide limits of agreement for all measures and nutrients. These results support the World Health Organization’s (WHOs) recommendations to use urinary assessment to measure population sodium and iodine intake, while dietary assessment appears to be more accurate for estimating potassium intake. Compared to reference values, our results suggest that the children in this study consume inadequate iodine, inadequate potassium, and excess dietary sodium. Public health measures to reduce sodium intake, increase intake of fruit and vegetables, and iodine-rich foods are warranted in New Zealand.