Is salt intake an independent risk factor of stroke mortality? Demographic analysis by regions in Japan

Relationship between daily eating habits and occurrence of stroke in the O City Cohort I survey: a 26-year follow-up of residents in rural Japan

Objective

This study aimed to elucidate the relationship between daily eating habits and stroke risk factors in O City, Ehime Prefecture, Japan, using stroke registry data collected over a 26-year follow-up period based on standardized national criteria.

Materials and Methods

Overall, 1,793 middle-aged Japanese participants (446 men and 1,347 women) who completed a 33-item Food Frequency Questionnaire (FFQ) and had no history of stroke were matched to those from O City in a stroke registry from 1996 to 2022. Stroke diagnosis for each person was used to determine whether this was their first documented stroke, and we classified strokes as either a cerebral infarction (CI) or a hemorrhagic stroke (HS), the latter which included an intracerebral hemorrhage (ICH) or a subarachnoid hemorrhage (SAH). A Cox proportional hazard regression model was used to examine the association between habitual dietary intake and the occurrence of stroke, using the following covariates: age, body mass index, elevated blood pressure/hypertension, dyslipidemia, prediabetes/diabetes, alcohol consumption, and smoking.

Results

During the 26 years of follow-up, 45 men (10.1%) and 76 women (5.6%) had stroke. The CI rate was 70.2% (n=85; 38 men, 47 women). The HS rate was 29.8% (n=36; 7 men and 29 women); of these patients, 26 and 10 had ICH and SAH, respectively. In men, orange intake showed a significant inverse correlation with CI. In women, fresh fish intake showed a significant inverse correlation with CI, while yogurt intake showed a significant inverse correlation with HS.

Conclusion

Our results indicated that fresh fish intake was significantly associated with the prevention of CI among women in a Japanese cohort survey.

Usefulness of the Reborn Soup for the Reduction of Salt Intake

Aims

The purpose of the present study was to investigate the influence of reborn soup on the perceptions of saltiness and palatability.

Methods

Subjects comprised 103 staff working at Kokura Daiichi Hospital (22 males, 81 females, and mean age: 35 ± 12 years old). They tested soups (commercially available soup with 0.9% NaCl solutions (A), commercially available soup with 0.6% NaCl solutions (B), and reborn soup diluted to 0.6% NaCl solutions (C)). Evaluations of saltiness and palatability for each solution were conducted using a visual analog scale in a double-blinded randomized manner. We estimated 24-hour salt excretion using spot urine samples to estimate salt intake and also assessed blood pressure, the awareness of salt intake using a self-description questionnaire score, and other confounding factors including lifestyle factors.

Results

In all subjects, the average estimated salt intake was 9.0 ± 2.0 g/day, and the rates at which subjects met the established salt intake targets were 15.1% in 73 females without hypertension (<6.5 g/day), 23.5% in 17 males without hypertension (<7.5 g/day), and 0.0% in 13 subjects with hypertension (<6.0 g/day). In both saltiness and palatability, B scored significantly lower than A, but C scored significantly higher than B. Salt intake levels were categorized into tertiles (Q1, lowest; Q3, highest). C scored significantly higher for palatability in the Q1 group than in the Q3 group.

Conclusions

Most participants exceeded the established targets of salt intake. The high-salt-intake group might be able to feel less palatable. Our results indicate that reborn soup may be effective in reducing salt intake without loss of palatability.

Relationship between the behavior change model and salt intake in hypertensive patients: a single non-specialized hypertension clinic prospective observational study

We investigated whether changes in salt reduction readiness are associated with changes in estimated daily salt intake and blood pressure (BP). We divided 86 hypertensive patients into groups with high and low readiness for salt-reducing behavior [an up (UP) and a down (DN) groups, respectively] based on the transtheoretical model (TTM) over a 12-month observation period. We then investigated the relationships between changes in the TTM stage and changes in daily salt intake and BP over 12 months. The patients in the UP group had significantly increased urine potassium concentrations (from 51.2 ± 23.3 mEq/L at baseline to 56.9 ± 25.5 mEq/L at 12 months; P  = 0.048) and significantly decreased estimated 24-h urinary salt excretion (from 9.7 ± 2.9 g/day at baseline to 8.4 ± 2.8 g/day at 12 months; P  = 0.045). In addition, they also had significantly lower changes in urine sodium concentration (-13.1 ± 46.1 vs. -6.6 ± 59.7 mEq/L; P  = 0.048), significantly increased changes in urine potassium concentration (5.7 ± 20.1 vs. -4.8 ± 28.6 mEq/L; P  = 0.030), and significantly decreased changes in estimated 24-h urinary salt excretion (-1.3 ± 2.6 vs. -0.1 ± 2.6 g/day; P  = 0.045) compared with patients in the DN group. However, their home BP did not improve over 12 months. The hypertensive patients who increased their readiness or maintained a high readiness for salt reduction over 12 months showed a significant increase in daily potassium intake and significant decrease in daily salt intake.

Dietary salt intake in Japan - past, present, and future

Salt reduction is the most important lifestyle modification, especially in Japanese individuals who still consume a significant amount of salt. The Dietary Reference Intakes for Japanese 2020, issued by the Ministry of Health, Labour and Welfare, propose a salt intake goal of <7.5 g/day for men and <6.5 g/day for women. Regarding the goal of salt reduction in hypertensive patients, the hypertension guideline by the Japanese Society of Hypertension 2019 (JSH2019) proposes a goal of <6 g/day. Although the average salt intake in Japan gradually decreased in the early 2000s, the declining trend has not been seen in recent years, and thus, it seems difficult to achieve these target salt intake levels. To overcome this challenge, the JSH announced the 'JSH Tokyo Declaration' and pledged to create a specific action plan to achieve the target salt intake level of <6 g/day. The six strategies to achieve the target salt intake level are as follows: (1) educating citizens on the harms of excessive salt intake and the importance of reducing salt intake; (2) recommending the assessment of the salt intake of individuals or populations and proposing adequate methods to reduce salt intake; (3) promoting salt reduction for children as a part of dietary education at school; (4) promoting salt reduction in takeout food, prepared dishes, canteens, and school lunches; (5) encouraging companies to develop and promote low-salt foods; and (6) encouraging the government to take measures to promote salt reduction. Through these activities, a society with a low salt intake will be expected in the near future.

Effect of Monosodium Glutamate on Saltiness and Palatability Ratings of Low-Salt Solutions in Japanese Adults According to Their Early Salt Exposure or Salty Taste Preference

Using umami can help reduce excessive salt intake, which contributes to cardiovascular disease. Differences in salt-exposed environment at birth and preference for the salty taste might affect the sense of taste. Focusing on these two differences, we investigated the effect of monosodium L-glutamate (MSG) on the saltiness and palatability of low-salt solutions. Japanese participants (64 men, 497 women, aged 19–86 years) tasted 0.3%, 0.6%, and 0.9% NaCl solutions with or without 0.3% MSG to evaluate saltiness and palatability. They were also asked about their birthplace, personal salty preference, and family salty preference. Adding MSG enhanced saltiness, especially in the 0.3% NaCl solution, while the effect was attenuated in the 0.6% and 0.9% NaCl solutions. Palatability was rated higher with MSG than without MSG for each NaCl solution, with a peak value for the 0.3% NaCl solution with MSG. There was no difference in the effect of umami ingredients on palatability between the average salt intake by the regional block at birth and salty preference (all p > 0.05). Thus, adding an appropriate amount of umami ingredients can facilitate salt reduction in diet while maintaining palatability regardless of the salt-exposed environment in early childhood or salty preference.

Effect of workplace dietary intervention on salt intake and sodium-to-potassium ratio of Japanese employees: A quasi-experimental study

OBJECTIVES

Excess salt intake is a major risk factor for hypertension and cardiovascular disease. Modifying workplace environments has been recognized to be important for reducing salt intake. However, studies examining the effects of improving the workplace environment regarding salt reduction are limited. This study aimed to evaluate the effects of workplace dietary intervention on employees' salt intake and sodium-to-potassium (Na/K) ratio.

METHODS

A quasi-experimental study was conducted. Two small business establishments in Saitama Prefecture, Japan, were allocated as the intervention (n = 69) and comparison (n = 68) workplaces, respectively. The 1-year intervention involving healthy lunch and nutrition education was implemented in the intervention workplace. Spot urine samples, physical assessments, and self-administered questionnaire data were collected at baseline, 6 months, and 1 year after the start of the intervention. Analysis of covariance was conducted to investigate differences in the salt intake or Na/K ratio between the study workplaces at year 1. Educational status and rotating work schedules were included as covariates.

RESULTS

Salt intake in the intervention workplace decreased significantly from 10.7 to 9.3 g (-1.4 g change; 95% confidence interval [CI]: "-2.4, -0.5"). The adjusted difference in changes in salt intake between workplaces was statistically significant (-3.7 g change; 95% CI: "-5.2, -2.3"). Although no significant change was observed in the Na/K ratio in the intervention workplace (3.37-3.08; -0.29 change; 95% CI: "-0.59, 0.01"), the adjusted difference in changes between the workplaces was statistically significant (-0.60 change; 95% CI: "-1.03, -0.17").

CONCLUSIONS

Providing healthy lunch and nutrition education may be effective approaches to reduce employees' salt intake and Na/K ratio.

Is too much salt harmful? Yes

The contribution of high sodium intake to hypertension and to the severity of immune-mediated diseases is still being heatedly debated in medical literature and in the lay media. This review aims to demonstrate two conflicting views on the topic, with the first part citing the detrimental effects of excessive salt consumption. Sodium plays a central role in volume and blood pressure homeostasis, and the positive correlation between sodium intake and blood pressure has been extensively researched. Despite the fact that the average of global daily salt consumption exceeds recommendations of international associations, health damage from excessive salt intake is still controversial. Individual differences in salt sensitivity are in great part attributed to this contradiction. Patients suffering from certain diseases as well as other vulnerable groups-either minors or individuals of full age-exhibit more pronounced blood pressure reduction when consuming a low-sodium diet. Furthermore, findings from the last two decades give insight into the concept of extrarenal sodium storage; however, the long-term consequences of this phenomenon are lesser known. Evidence of the relationship between sodium and autoimmune diseases are cited in the review, too. Nevertheless, further clinical trials are needed to clarify their interplay. In conclusion, for salt-sensitive risk groups in the population, even stricter limits of sodium consumption should be set than for young, healthy individuals. Therefore, the question raised in the title should be rephrased as follows: "how much salt is harmful" and "for whom is elevated salt intake harmful?"

Association between Cardiovascular Mortality and Economic Development: A Spatio-Temporal Study for Prefectures in Japan

In this paper, we use a bivariate choropleth map to investigate the relationship between mortality from cardiovascular disease (CVD) and gross domestic product (GDP) per capita, by sex, in Japanese prefectures from 1996 to 2015. The overall results show a decline in age-standardized CVD mortality rates in all prefectures, for both men and women, and suggest that GDP per capita has varied over the period. We also observed that the relationship between CVD mortality rates and GDP per capita at the prefecture level does not have an overall pattern of the same or inverse association, but is instead a heterogeneous relationship. We argue that this study provides useful clues to policy makers for establishing effective measures for public health planning and the prevention of deaths from CVD. As demonstrated by this study, mapping of the CVD burden in Japan helps to clarify regional differences in life expectancy and health status across regions and identify prefectures where more targeted policy attention may be needed.

Policy analysis of salt reduction in bread in Iran

Given that average salt intake among Iranians is approximately 10–15 g per day particularly from sodium hidden in bread, cheese, and fast food; lowering this mineral has been followed up seriously in this country for almost 10 years (since 2009). The main objective of the present study was to provide an opportunity to recognize unwanted and unfavorable outcomes of implementing decisions and policies together with associated problems of salt reduction in bread in order to achieve national and global health promotion goals. Thus, this qualitative and retrospective policy analysis was completed to evaluate the policy of salt reduction in bread in Iran. To collect the data, the researchers traveled to six cities in different regions, wherein relevant documents were utilized added to interviews with key actors. Related websites were correspondingly searched to find reports on this policy. Moreover, the researchers referred to some organizations in-person to search documents in this area. Five group discussions were also held to obtain public opinions in this regard. Data analysis was further carried out using framework analysis. The findings revealed that allocation of the highest rates of subsidy to wheat, flour, and bread had led to elimination of competitiveness in wheat, flour, and bread supply chain in Iran. Despite the presence of proper structures as coordinators of other organizations working on public health, there was no intersectoral collaboration in terms of maintaining health of bread products and lowering salt content in this staple food. With regard to changes in priorities of the Iranian Ministry of Health and Medical Education, attempts made to improve bread quality had also failed. In addition, first-line staff (i.e. bakers) had viewed formulation and implementation of the given policy as a top-down one. Given the ambiguities in establishment of new standards, there were similarly contradictions in execution of the policy at various levels. With reference to education provided at a national level, it was concluded that some people had become more sensitive to salt reduction in bread to some extent.

The risk of stroke and associated risk factors in a health examination population: A cross-sectional study

Health examination is an important method for early detection of people with different risk of stroke. This study estimates the risk of stroke and identify risk factors for people who underwent health examinations at the Health Examination Center at West China Hospital, Sichuan University from July 2014 to February 2018.A total of 31,464 people were recruited in this study and divided into 3 groups (low risk, moderate risk, and high risk) according to risk of stroke. We explored possible factors associated with the risk of stroke by using multivariable stepwise logistic regression analysis.Among the participants, 17,959 were at low risk, 11,825 were at moderate risk, and 1680 were at high risk. Age, smoking, alcohol consumption, body mass index, uric acid, diastolic pressure, systolic pressure, triglycerides, low-density lipoprotein cholesterol, glucose, and brachial-ankle pulse wave velocity (baPWV) were independent significant risk factors for stroke, whereas high-density lipoprotein cholesterol was an independent protective factor for stroke. Interestingly, with increasing age, the percentage of people at moderate or high risk of stroke was increased. The percentages of people at moderate and high risk of stroke were also increased with respect to the stages of baPWV.This study showed that >40% of the participants were at moderate or high risk of stroke, especially the older participants. Several factors were related to the risk of stroke, especially baPWV. Some preventive action may be adopted early, and more attention can be paid to the health examination population.

Temporal trend analysis of stroke and salt intake: a 15-year population-based study

Objectives: The aim of this study was to evaluate temporal trends of salt intake with stroke incidence, stroke subtypes, and blood pressure in an adult population.Methods: Data were extracted from Isfahan Salt Study. The stroke incidence rate, average salt intake, systolic and diastolic blood pressure in adults, aged over 18 years were considered from 2000 to 2014. The Average Annual Percent Changes (AAPC), parallelism, and the coincidence of trends were estimated, using a permutation test.Results: The trend of salt intake was increased from 2010 to 2014 (AAPC = +1.59, P-value = 0.004). The trend of the stroke incidence rate was nonlinear with two change points in 2003 and 2009. The overall stroke incidence rate increased by 6.65% per year (95% CI: 1.66, 11.8, P-value = 0.015). The temporal trend changes of stroke incidence rate were steeper in patients who aged 40-45 and over 50 years (+6 to +11.5%) than in patients who aged 19-40 and 45-50 (range: -3.3% to 0). The parallelism hypothesis of longitudinal changes between salt intake and ischemic stroke was accepted in patients, aged <50 years (P-value = 0.871).Conclusions: The average salt intake and its cone-shaped variance over 15 years of the study, indicated that salt intake reduction programs and policies were effective to stop associating intake increase until 2007, however, associated intake was increased since that time, which necessitates performing preventive programs. More importantly, the trend of salt intake and ischemic stroke was similar in patients who aged <50 years, regardless of considering their blood pressure.

High salt intake is associated with a higher risk of cardiovascular events: a 7.2-year evaluation of a cohort of hypertensive patients

BACKGROUND

It is controversial whether high salt intake is directly associated with cardiovascular (CV) events and how far this relation is independent of blood pressure (BP). As Portugal has higher salt consumption and higher mortality by stroke than other European countries, we examined whether salt intake could predict the development of stroke and CV events in a hypertensive population.

METHODS

In a longitudinal retrospective study of a cohort of 608 adult treated hypertensive patients 54.1±14.3 years of age, BMI 29.3±8.3 kg/m, 56.3% women and 17.1% diabetics, we evaluate the long-term prognostic significance of urinary sodium (UNa) excretion measured in 24 h valid samples within the first 3 months after admission along with 24 h ambulatory blood pressure monitoring and pulse wave velocity [(PWV), complior)] measurements.

RESULTS

The mean follow-up duration was 7.2 years (0.5-11.1 years), during which 122 CV events occurred including 80 strokes and 36 coronary events. In 608 patients (group A=507 without events and group B=101 with events: 69 strokes, 26 coronary events, six others), the mean 24 h UNa was 208±79 mmol/day, corresponding to a salt intake of 12.1±4.6 g/day. Twenty-four hours UNa correlated positively with BMI, PWV and systolic blood pressure (SBP) particularly with night-time SBP. Group B versus A showed higher UNa (260+98 vs. 198+71 mmol/day, P<0.001) and higher PWV, BP office, 24 h, daytime and night-time SBP. Logistic regression analysis identified age, night-time SBP and 24 h UNa+ [HR=1.09 (95% CI, 1.06-1.12, P<0.001)] for each 10 mmol increase of UNa+ as the only independent predictors of CV events. UNa+ above the median (189 mmol sodium/day) predicted CV events with HR=2.99 (95% CI, 1.75-5.13, P<0.001) with worse CV event-free survival rates (log rank statistics of 17.44, P<0.001).

CONCLUSION

In a cohort of hypertensive patients, high salt intake independently predicts the occurrence of CV events, particularly of stroke.

Evaluation of Online and In-Person Nutrition Education Related to Salt Knowledge and Behaviors among Special Supplemental Nutrition Program for Women, Infants, and Children Participants

BACKGROUND

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) differs from other federal nutrition programs in that nutrition education is a required component. WIC programs traditionally provide in-person education, but recently some WIC sites have started offering online education. Education focused on reducing salt intake is an important topic for WIC participants because a high-sodium diet has been associated with high blood pressure, and low-income populations are at increased risk.

OBJECTIVE

Our aim was to examine the impacts of traditional in-person and online nutrition education on changes in knowledge, self-efficacy, and behaviors related to reducing salt intake in low-income women enrolled in WIC.

DESIGN

Although a comparison of groups was not the primary focus, a randomized trial examining the impact of online and in-person nutrition education on participant knowledge, self-efficacy, and behaviors related to salt intake was conducted.

PARTICIPANTS/SETTING

Five hundred fourteen WIC participants from three Los Angeles, CA, WIC clinics received either in-person (n=257) or online (n=257) education. Questionnaires assessing salt-related knowledge, self-efficacy, and behaviors were administered at baseline and 2 to 4 months and 9 months later from November 2014 through October 2015.

RESULTS

Positive changes in knowledge and self-efficacy were retained 2 to 4 months and 9 months later for both groups (P<0.05). Both groups reported significant changes in behaviors related to using less salt in cooking (P<0.0001) and eating fewer foods with salt added at the table or during cooking (P<0.001) at 2 to 4 months and 9 months.

CONCLUSIONS

Both online and in-person education resulted in improvements during a 9-month period in knowledge, self-efficacy, and reported behaviors associated with reducing salt intake in a low-income population. Offering an online education option for WIC participants could broaden the reach of nutrition education and lead to long-term positive dietary changes.

Sodium and Its Role in Cardiovascular Disease - The Debate Continues

Guidelines have recommended significant reductions in dietary sodium intake to improve cardiovascular health. However, these dietary sodium intake recommendations have been questioned as emerging evidence has shown that there is a higher risk of cardiovascular disease with a low sodium diet, including in individuals with type 2 diabetes. This may be related to the other pleotropic effects of dietary sodium intake. Therefore, despite recent review of dietary sodium intake guidelines by multiple organizations, including the dietary guidelines for Americans, American Diabetes Association, and American Heart Association, concerns about the impact of the degree of sodium restriction on cardiovascular health continue to be raised. This literature review examines the effects of dietary sodium intake on factors contributing to cardiovascular health, including left ventricular hypertrophy, heart rate, albuminuria, rennin-angiotensin-aldosterone system activation, serum lipids, insulin sensitivity, sympathetic nervous system activation, endothelial function, and immune function. In the last part of this review, the association between dietary sodium intake and cardiovascular outcomes, especially in individuals with diabetes, is explored. Given the increased risk of cardiovascular disease in individuals with diabetes and the increasing incidence of diabetes worldwide, this review is important in summarizing the recent evidence regarding the effects of dietary sodium intake on cardiovascular health, especially in this population.

Regional aging and longevity characteristics in China

The factors that influence the length of human life are complex and longevity remains a controversial topic, particularly in China. This paper demonstrates the spatial patterns and changes of the elderly group (65 years old and over), the oldest old (80 years old and over) and the centenarians in China in the last decade, analyzes the influence of economic development on aging, and in the end, using a case study, explores the characteristics of the centenarians' behavior. The results indicate that high elderly and the oldest old proportions are more common in regions with higher socio-economic development and that have a favorable climate. Centenarian distribution pattern is less influenced by economic but only for few regions. Lifestyle factors, such as sufficient sleep, positive mental state and a light diet are also largely found among the centenarian group.

High salt intake as a multifaceted cardiovascular disease: new support from cellular and molecular evidence

Scientists worldwide have disseminated the idea that increased dietary salt increases blood pressure. Currently, salt intake in the general population is ten times higher than that consumed in the past and at least two times higher than the current recommendation. Indeed, a salt-rich diet increases cardiovascular morbidity and mortality. For a long time, however, the deleterious effects associated with high salt consumption were only related to the effect of salt on blood pressure. Currently, several other effects have been reported. In some cases, the deleterious effects of high salt consumption are independently associated with other common risk factors. In this article, we gather data on the effects of increased salt intake on the cardiovascular system, from infancy to adulthood, to describe the route by which increased salt intake leads to cardiovascular diseases. We have reviewed the cellular and molecular mechanisms through which a high intake of salt acts on the cardiovascular system to lead to the progressive failure of a healthy heart.

Salt, Angiotensin II, Superoxide, and Endothelial Function

Proper function of the vascular endothelium is essential for cardiovascular health, in large part due to its antiproliferative, antihypertrophic, and anti-inflammatory properties. Crucial to the protective role of the endothelium is the production and liberation of nitric oxide (NO), which not only acts as a potent vasodilator, but also reduces levels of reactive oxygen species, including superoxide anion (O2•-). Superoxide anion is highly injurious to the vasculature because it not only scavenges NO molecules, but has other damaging effects, including direct oxidative disruption of normal signaling mechanisms in the endothelium and vascular smooth muscle cells. The renin-angiotensin system plays a crucial role in the maintenance of normal blood pressure. This function is mediated via the peptide hormone angiotensin II (ANG II), which maintains normal blood volume by regulating Na+ excretion. However, elevation of ANG II above normal levels increases O2•- production, promotes oxidative stress and endothelial dysfunction, and plays a major role in multiple disease conditions. Elevated dietary salt intake also leads to oxidant stress and endothelial dysfunction, but these occur in the face of salt-induced ANG II suppression and reduced levels of circulating ANG II. While the effects of abnormally high levels of ANG II have been extensively studied, far less is known regarding the mechanisms of oxidant stress and endothelial dysfunction occurring in response to chronic exposure to abnormally low levels of ANG II. The current article focuses on the mechanisms and consequences of this less well understood relationship among salt, superoxide, and endothelial function.

Reported Amount of Salt Added to Food Is Associated with Increased All-Cause and Cancer-Related Mortality in Older Men in a Prospective Cohort Study

BACKGROUND

The effect of dietary salt intake on important population outcomes such as mortality is controversial. The aim of this study was to examine the association between the dietary habit of adding salt to food and mortality in older men. Design, participants, setting and measurements: A risk factor questionnaire which contained a question about the dietary habit of adding salt to food was completed by 11742 community recruited older men between 1996 and 1999. The men were followed by means of the Western Australia Data Linkage System until November 30th 2010. Deaths due to cardiovascular diseases and cancers were identified using ICD-10 codes in the ranges I00-I99 and C00-D48, respectively. The association between the frequencies of adding salt to food and mortality was assessed using Kaplan Meier estimates and Cox proportional hazard analysis.

RESULTS

Median follow-up for survivors was 12.5 years (inter-quartile range 8.3-13.2 years). A total of 5399 deaths occurred of which the primary cause registered was cancer and cardiovascular disease in 1962 (36.3%) and 1835 (34.0%) men, respectively. The reported frequency of adding salt to food was strongly positively associated with all-cause (p<0.001), cancer-related (p<0.001) but not cardiovascular-related (p=0.649) mortality. Men reporting adding salt to their food always had a 1.12-fold (95% CI 1.05-1.20, p<0.001) and a 1.20-fold (95% CI 1.07-1.34, p=0.001) increased risk of all-cause and cancer-related mortality, respectively, after adjusting for other risk factors. Men reporting adding salt to their food sometimes had a 1.16-fold (95% CI 1.04-1.29, p=0.007) increased risk of cancer-related mortality after adjusting for other risk factors.

CONCLUSION

A history of adding salt to food is associated with increased cancer-related mortality in older men.

Effects of a behavioral intervention that emphasizes spices and herbs on adherence to recommended sodium intake: results of the SPICE randomized clinical trial

BACKGROUND

For decades, dietary sodium intake in the United States has remained high, and few studies have examined strategies for maintaining recommended intakes.

OBJECTIVE

We examined the effects of a behavioral intervention, which emphasized spices and herbs, on the maintenance of sodium intake at the recommended intake of 1500 mg/d in individuals to whom the US Dietary Guidelines for Americans apply.

DESIGN

We conducted a 2-phase study that included adults ≥18 y of age for whom Dietary Guidelines for Americans recommends 1500 mg Na/d. The study was conducted in Baltimore, Maryland, from 2012 to 2014. In phase 1, 55 individuals consumed a low-sodium diet for 4 wk. Participants were provided all foods, snacks, and calorie-containing drinks. In phase 2, 40 participants from phase 1 were randomly assigned to either a behavioral intervention to reduce sodium intake (n = 20) or a self-directed control group (n = 20) for 20 wk. The primary study outcome was the change in mean 24-h urinary sodium excretion during phase 2. Linear regression analyses were used to determine intervention effects on urinary sodium excretion.

RESULTS

Participant characteristics were as follows: women: 65%; African American: 88%; hypertension: 63%; diabetes: 18%; mean age: 61 y; and mean body mass index (in kg/m(2)): 30. At the end of phase 2, mean 24-h sodium excretion was lower in the behavioral intervention than in the self-directed group (mean difference: -956.8 mg/d; 95% CI: -1538.7, -374.9 mg/d) after sodium intake at screening was controlled for (P = 0.002). These findings persisted in sensitivity analyses that excluded potentially incomplete urine collections [Mage's equation mean difference: -1090 mg/d (P = 0.001); Joosens' equation mean difference: -796 mg/d (P = 0.04)].

CONCLUSIONS

A multifactorial behavioral intervention emphasizing spices and herbs significantly reduced sodium intake. Because of the ubiquity of sodium in the US food supply, multilevel strategies addressing individual behaviors and the food supply are needed to improve adherence to recommendations. This trial was registered at clinicaltrials.gov as NCT01615159.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

Vascular biology, endothelial and vascular smooth muscle and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients can prevent, control and treat hypertension through numerous mechanisms related to vascular biology. Oxidative stress, inflammation and autoimmune dysfunction initiate and propagate hypertension and cardiovascular disease. There is a role for the selected use of single and component nutraceutical supplements, vitamins, antioxidants and minerals in the treatment of hypertension based on scientifically controlled studies which complement optimal nutrition, coupled with other lifestyle modifications.

Prevalence, incidence, and mortality of stroke in the chinese island populations: a systematic review

BACKGROUND

In China, there are 2.5 million new stroke cases each year and 7.5 million stroke survivors. However, stroke incidence in some island populations is obviously lower compared with inland regions, perhaps due to differences in diet and lifestyle. As the lifestyle in China has changed significantly, along with dramatic transformations in social, economic and environmental conditions, such changes have also been seen in island regions. Thus, we analyzed stroke in the Chinese island regions over the past 30 years.

METHODS

We conducted a systematic review to identify reliable and comparable epidemiologic evidence about stroke in the Chinese island regions between 1980 and 2013. Two authors independently assessed the eligibility and the quality of the articles and disagreement was resolved by discussion. Owing to the great heterogeneity among individual study estimates, a random-effects or fixed-effects model was used to incorporate the heterogeneity among records into a pooled estimate for age-standardized rates. Age-standardized rates were calculated by the direct method with the 2000 world population if included records provided the necessary information.

RESULTS

During the past three decades, the overall pooled age-standardized prevalence of stroke is 6.17 per 1000 (95% CI 4.56-7.78), an increase from 5.54 per 1000 (95% CI 3.88-7.20) prior to 2000 to 8.34 per 1000 (95% CI 5.98-10.69) after 2000. However, this difference was not found to be statistically significant. The overall pooled age-standardized incidence of stroke is 120.42 per 100,000 person years (95% CI 26.17-214.67). Between 1982 and 2008, the incidence of stroke increased and mortality declined over time.

CONCLUSIONS

Effective intervention and specific policy recommendations on stroke prevention should be required, and formulated in a timely fashion to effectively curb the increased trend of stroke in Chinese island regions.

Recent economic evaluations of interventions to prevent cardiovascular disease by reducing sodium intake

Excess intake of sodium, a common problem worldwide, is associated with hypertension and cardiovascular disease (CVD), and hypertension is a major risk factor for CVD. Population-wide efforts to reduce sodium intake have been identified as a promising strategy for preventing hypertension and CVD, and such initiatives are currently recommended by a variety of scientific and public health organizations. By reviewing the literature published from January 2011 to March 2013, we summarized recent economic analyses of interventions to reduce sodium intake. The evidence, derived from estimates of resultant blood pressure decreases and thus decreases in the incidence of CVD events, supports population-wide interventions for reducing sodium intake. Both lowering the salt content in manufactured foods and conducting mass media campaigns at the national level are estimated to be cost-effective in preventing CVD. Although better data on the cost of interventions are needed for rigorous economic evaluations, population-wide sodium intake reduction can be a promising approach for containing the growing health and economic burden associated with hypertension and its sequelae.

Low birth weight and end-stage renal disease: demographic analysis by region in Japan

BACKGROUND We have previously shown regional differences in the incidence of end-stage renal disease (ESRD)within Japan, which is ethnically homogenous, suggesting that non-genetic factors may contribute to the differences.We examined regional distribution in the incidence of low birth weight (LBW), a surrogate for low nephron number,in our search for an explanation.

METHODS

Each year, the Ministry of Health, Labour and Welfare of Japan and the Japanese Society for Dialysis Therapy report the number of LBW babies and patients initiating maintenance dialysis in each prefecture of Japan,respectively. In this study, we calculated the annual incidences of LBW and ESRD in 11 regions of Japan over a 24-year period from 1984 to 2007.

RESULTS

There were distinct regional differences in the annual incidences of both LBW and ESRD (p<0.0001).These regional distributions persisted despite consistent increases (p<0.0001) in incidences of both LBW and ESRD during the study period. Compared with the reference group consisting of 3 regions with the lowest LBW incidence, the odds ratios for ESRD (95% confidence interval) of the 5 regions with intermediate LBW incidence and the 3 regions with the highest LBW incidence are 1.09(1.05–1.14) and 1.29 (1.22–1.35), respectively. The annual incidence of LBW was positively correlated with annual incidence of ESRD in their regional distribution across 11 regions (r = 0.66, p = 0.03).

CONCLUSIONS

The present study, relating regional distribution between LBW and ESRD dynamics in a nationwide population of Japan, revealed that the marked regional differences in the incidence of ESRD within Japan could be explained by a similar regional distribution in the incidence of LBW.

Factors associated with the incidence of dialysis

BACKGROUND

There are regional differences in the incidence of dialysis, but few studies have investigated the reasons for such differences.

METHODS

We stratified 81 factors by gender for each of the 47 prefectures in Japan using the Japanese Society for Dialysis Therapy database of 102,011 patients who started chronic dialysis during 2004-2006.

RESULTS

The age-adjusted average annual incidence of dialysis was 265.6 ± 38.9 per million population. Among the 81 factors tested, 30 showed significant correlations with the incidence of dialysis among males, and 36 among females by univariate regression analysis. Among those factors, multivariate regression analysis showed that the average duration of hospitalization, the mortality rate from malignancy, a history of leg amputation, and duration of sunshine were extracted as determinants of the incidents of dialysis among males, and a history of acute myocardial infarction, mortality rate from lifestyle-related diseases, vitamin C intake, mortality rate from malignancy, amount of family saving, number of dialysis specialists, birth rate, days of snow, potatoes intake, average annual temperature, average duration of hospitalization, protein intake, and mortality rate from cerebrovascular disease were extracted among females.

CONCLUSION

Many environmental factors were correlated with regional differences in the incidence of dialysis.

Which is a better treatment for hypertensive patients with diabetes: a combination of losartan and hydrochlorothiazide or a maximum dose of losartan?

BACKGROUND

This 12-month study compared the effects of a combination of losartan 50 mg and hydrochlorothiazide 12.5 mg with a maximum dose of losartan (100 mg) in hypertensive patients with diabetes.

METHODS

This was a multicenter randomized open-label study.

RESULTS

A similar reduction in systolic/diastolic blood pressure from baseline to month 3 was observed in both groups. There was also a similar decrease in UACR in both groups. A significant decrease in uric acid was observed in the maximum-dose group only. eGFR decreased in the combination group after 1 year.

CONCLUSIONS

The combination of losartan and a diuretic may be a useful option in such hypertensive patients with diabetes, provided that metabolic parameters are closely monitored. In patients with hyperuricemia and impaired renal function, a maximum dose of losartan may be more beneficial.

Sodium, blood pressure, and cardiovascular disease: further evidence supporting the American Heart Association sodium reduction recommendations

Recent reports of selected observational studies and a meta-analysis have stirred controversy and have become the impetus for calls to abandon recommendations for reduced sodium intake by the US general population. A detailed review of these studies documents substantial methodological concerns that limit the usefulness of these studies in setting, much less reversing, dietary recommendations. Indeed, the evidence base supporting recommendations for reduced sodium intake in the general population remains robust and persuasive. The American Heart Association is committed to improving the health of all Americans through implementation of national goals for health promotion and disease prevention, including its recommendation to reduce dietary sodium intake to <1500 mg/d.

High salt intake and stroke: meta-analysis of the epidemiologic evidence

Research on the potential impact of high salt intake on health has grown rapidly over the last decades. Recent studies have suggested that high salt intake could also be associated with adverse effects on cardiovascular system. The review evaluated the current level of epidemiologic evidence on the association between the level of habitual salt intake and stroke outcome. We also suggest further research direction. There were 21 independent samples from 12 studies, with 225,693 participants (follow-up, 3-19 years) and 8135 stroke events. High salt intake was associated with risk of stroke event (pooled odd ratio [OR], 1.34; 95% confidence interval [CI], 1.19-1.51), stroke death (1.40; 1.21-1.63) and stroke onset (1.11; 1.00-1.24), ischemic stroke death (2.15; 1.57-2.95), not associated with risk of ischemic stroke onset (1.07, 0.95-1.2), with no significant evidence of publication bias. High salt intake is associated with significantly increased risk of stroke event. Further research should be directed toward clarifying and quantifying these possible effects and generating testable hypotheses on plausible biologic mechanisms.

Exploring the impact of climate on human longevity

The purpose of this study was to examine the impact of physical geographic factors and climate conditions on human longevity. The centenarian rate (CR) in 2005 was computed for Japan's 47 prefectures, whose geography and climate vary greatly. Several pathways, such as excess winter mortality, land use and agricultural production, possibly linking physical and climate factors with extreme longevity, were explored. The probability of becoming a centenarian varies significantly among the Japanese prefectures. In particular, the computation of CR(70) demonstrated that the actual probability for individuals 70 years old in 1975 of becoming centenarians in 2005 was 3 times higher, on average, in Okinawa, both for males and females, than in Japan as a whole. About three quarters of the variance in CR(70) for females and half for males is explained by the physical environment and land use, even when variations in the level of socio-economic status between prefectures are controlled. Our analysis highlighted two features which might have played an important role in the longevity observed in Okinawa. First, there is virtually no winter in Okinawa. For instance, the mean winter temperature observed in 2005 was 17.2°C. Second, today, there is almost no rice production in Okinawa compared to other parts of Japan. In the past, however, production was higher in Okinawa. If we consider that long term effects of harsh winters can contribute to the mortality differential in old age and if we consider that food availability in the first part of the 20th century was mainly dependent on local production, early 20th century birth cohorts in Okinawa clearly had different experiences in terms of winter conditions and in terms of food availability compared to their counterparts in other parts of Japan. This work confirms the impact of climate conditions on human longevity, but it fails to demonstrate a strong association between longevity and mountainous regions and/or air quality.