Comparison of a salt check sheet with 24-h urinary salt excretion measurement in local residents

Effects of salt reduction education from a salt questionnaire on inter-dialysis weight gain in patients on hemodialysis

BACKGROUND

Heart failure is the leading cause of death in patients undergoing hemodialysis (HD), with fluid overload being the most common cause. Therefore, it is important for patients undergoing HD to reduce salt intake. We recently developed a highly accurate and simple self-administered salt questionnaire. Using this salt questionnaire, we aimed to determine whether salt intake and inter-HD weight gain decrease when patients with HD are instructed to reduce their salt intake.

METHODS

Seventy-eight outpatients at a maintenance HD facility were assessed for dietary salt intake using a salt questionnaire. After one month of dietary guidance, salt intake was assessed again using the salt questionnaire.

RESULTS

The mean age of the patients was 72.2 ± 11.9 years; 47 (60.3%) were men, 23 had diabetic nephropathy as the primary disease, and the median HD vintage was 74 months. Salt intake significantly decreased from 8.41 ± 2.43 g/day before the salt questionnaire intervention to 7.67 ± 2.60 g/day after the intervention (p = 0.010). Changes in salt intake before and after the intervention were significantly positively correlated with changes in weight gain before the start of HD sessions with an interval of 2 days (r = 0.24, p = 0.037). Furthermore, changes in salt intake significantly and positively correlated with changes in weight gain after adjusting for age, sex, and dry weight.

CONCLUSION

The salt questionnaire may be an effective tool for reducing salt intake and controlling weight gain during HD.

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.

Exploratory study on the relationship between urinary sodium/potassium ratio, salt intake, and the antihypertensive effect of esaxerenone: the ENaK Study

Excessive salt intake is one of the causes of hypertension, and reducing salt intake is important for managing the risk of hypertension and subsequent cardiovascular events. Esaxerenone, a mineralocorticoid receptor blocker, has the potential to exert an antihypertensive effect in hypertensive patients with excessive salt intake, but evidence is still lacking, especially in clinical settings. We aimed to determine if baseline sodium/potassium ratio and baseline estimated 24-h urinary sodium excretion can predict the antihypertensive effect of esaxerenone in patients with essential hypertension inadequately controlled with an angiotensin receptor blocker (ARB) or a calcium channel blocker (CCB). This was an exploratory, open-label, interventional study with a 4-week observation period and a 12-week treatment period. Esaxerenone was orally administered once daily in accordance with the Japanese package insert. In total, 126 patients met the eligibility criteria and were enrolled (ARB subcohort, 67; CCB subcohort, 59); all were included in the full analysis set (FAS) and safety analysis. In the FAS, morning home systolic blood pressure (SBP)/diastolic blood pressure (DBP) significantly decreased from baseline to end of treatment (primary efficacy endpoint) (-11.9 ± 10.9/ - 6.4 ± 6.8 mmHg, both p < 0.001); a similar trend was observed in both subcohorts. Significant reductions were also shown in bedtime home and office SBP/DBP (all p < 0.001). Each BP change was consistent regardless of the urinary sodium/potassium ratio or estimated 24-h urinary sodium excretion at baseline. The urinary albumin-creatinine ratio (UACR) and N-terminal pro-brain natriuretic peptide (NT-proBNP) significantly decreased from baseline to Week 12 in the total population and both subcohorts. No new safety concerns were raised. Esaxerenone significantly decreased morning home, bedtime home, and office BP; UACR; and NT-proBNP in this patient population, regardless of concomitant ARB or CCB use. The antihypertensive effect of esaxerenone was independent of the urinary sodium/potassium ratio and estimated 24-h urinary sodium excretion at baseline.

Achievement rate of target blood pressure in patients with hypertension treated by hypertension specialists and non-specialists in a real-world setting

Hypertension remains a major global healthcare issue. Considering that most Japanese patients with hypertension are managed by general practitioners, hypertension specialists should be involved in actual clinical practice. We investigated the blood pressure (BP), guidelines recommended for achievement rate of the target BP, and clinical variables of patients with hypertension treated by hypertension specialists and those treated by non-specialists in a real-world setting. Factors associated with the target BP achievement in this population were also investigated. Outpatients with hypertension from 12 medical facilities in Okinawa Prefecture were enrolled (n = 1469 [specialist group, 794; non-specialist group, 675]; mean age, 64.2 years; females, 45.8%). For all patients, BP and rate of the target BP achievement were 129.0 ± 15.5/74.6 ± 10.6 mmHg, and 51.8%, respectively. BP and the rate of target of BP achievement were 128.0 ± 15.1/73.4 ± 10.4 mmHg and 56.7% in the specialist group, and they were 130.1 ± 15.9/76.0 ± 10.8 mmHg and 46.1% in the non-specialist group. The urinary salt excretion and obesity rates were comparable between the specialist and non-specialist groups. Multivariable logistic analyses indicated that hypertension specialists and good medication adherence were positive factors, whereas obesity, chronic kidney disease, diabetes mellitus, and urinary salt excretion were inverse factors associated with target BP achievement in this population. Initiatives for salt reduction, medication adherence, and proper obesity management are crucial to improving BP management in patients with hypertension. Hypertension specialists are expected to play an essential role in them. For all patients, the target blood pressure (BP) achievement rate were 51.8%. Hypertension specialists and good medication adherence were positive factors in achieving target BP; conversely, obesity, diabetes mellitus, chronic kidney disease, and high urinary salt excretion were inverse factors in achieving target BP among patients with hypertension.

Home blood pressure-lowering effect of digital therapeutics in hypertension: impact of body weight and salt intake

Lifestyle modifications, including body weight reduction and salt restriction, help reduce blood pressure (BP). This study investigated the effects of body mass index (BMI) and salt intake on home BP reductions in unmedicated patients with hypertension receiving guideline-based lifestyle modification from doctors (control group) or with the addition of a digital therapeutics intervention. Data from the HERB Digital Hypertension 1 (HERB-DH1) pivotal trial were analyzed. Home BP was measured for 7 days before each study visit (baseline, and 4/8/12 weeks). Body weight was measured at each visit and salt intake questionnaire was answered at baseline and 12 weeks. This analysis included 302 patients with sufficient home BP monitoring data (digital therapeutics: 156; control group: 146). The reduction in morning home SBP from baseline to 12 weeks was significantly greater in the digital therapeutics vs. control group for patients with baseline BMI ≥ 25 kg/m² and higher salt intake group (self-reported salt intake score ≥ 14) (-5.1 mmHg, p < 0.01). Patients in the digital therapeutics group who experienced a reduction in BMI and an improvement in salt intake score during the 12-week study also had a significantly greater reduction in morning home SBP compared with patients in the control group (-7.2 mmHg, p < 0.01). The digital therapeutic intervention reduced home BP the most in unmedicated patients with hypertension with high baseline BMI and salt intake score. Those with improvements in both BMI and salt intake during the digital therapeutics intervention achieved the greatest reduction in home BP vs. control.Clinical trial registration: Japan Registry of Clinical Trials (jRCT2032190148).

Association between Indoor Temperature in Winter and Serum Cholesterol: A Cross-Sectional Analysis of the Smart Wellness Housing Survey in Japan

AIM

Issuance of the WHO Housing and health guidelines has paralleled growing interest in the housing environment. Despite accumulating evidence of an association between outdoor temperature and serum cholesterol, indoor temperature has not been well investigated. This study examined the association between indoor temperature and serum cholesterol.

METHODS

We collected valid health checkup data of 2004 participants (1333 households), measured the indoor temperature for 2 weeks in winter, and divided participants according to whether they lived in a warm (average bedroom temperature ≥ 18℃), slightly cold (12-18℃) or cold house (＜12˚C). The relationship between bedroom temperature and serum cholesterol was analyzed using multivariate logistic regression models, adjusting for demographics, lifestyle habits and the season in which the health checkup was conducted, with a random effect of climate areas in Japan.

RESULTS

The sample sizes for warm, slightly cold, and cold houses were 206, 940, and 858, respectively. Compared to those in warm houses, the odds ratio of total cholesterol exceeding 220 mg/dL was 1.83 (95%CI: 1.23-2.71, p=0.003) for participants in slightly cold houses and 1.87 (95%CI: 1.25-2.80, p=0.002) in cold houses. Similarly, the odds ratio of LDL/non-HDL cholesterol exceeding the standard range was 1.49 (p=0.056)/1.67 (p=0.035) for those in slightly cold houses and 1.64 (p=0.020)/1.77 (p=0.021) in cold houses. HDL cholesterol and triglycerides were not significantly associated with bedroom temperature.

CONCLUSION

Besides lifestyle modification, improving indoor thermal environment through strategies such as installing high thermal insulation and appropriate use of heating devices may contribute to better serum cholesterol condition.

Relationship between salt reduction readiness and salt intake in hypertensive patients: a single nonspecialized hypertension clinic case study

This is the first report about the association of readiness for salt reduction with daily salt intake or the salt check sheet score in hypertensive patients at a nonspecialized hypertension clinic. We investigated whether salt reduction readiness as evaluated based on the transtheoretical model (TTM) is associated with estimated daily salt intake or the salt check sheet score. The TTM allows evaluators to easily assess a subject's level of readiness for health-related according to five stages. There was no significant relationship between the TTM stages and estimated daily salt intake. A significant correlation was found between the TTM stages and salt check sheet scores (ρ = -0.409; P  < 0.001). When providing salt reduction guidance to hypertensive patients, it is effective for healthcare professionals to use repeated urine tests and salt check sheets to take a salt reduction approach according to the level of readiness of the patients.

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.

A Randomized Trial of Home Blood-Pressure Reduction by Alcohol Guidance During Outpatient Visits: OSAKE Study

BACKGROUND

To evaluate the effectiveness of the nurse-led alcohol guidance to control home blood pressure (HBP) in the morning among male patients with hypertension during outpatient visits.

METHODS

We enrolled 53 male patients with an HBP of ≥135/85 mm Hg with excessive drinking (alcohol ≥210 g/week or ≥60 g/day habitually) among outpatients in a randomized trial. Patients were assigned to a nurse-led alcohol guidance intervention or to the control. The primary outcomes were the mean HBP of 5 consecutive days at 6 months and alcohol consumption.

RESULTS

Twenty-eight and 25 patients were randomized to intervention and control groups, respectively (mean age; 62.7 years old and 64.5, respectively). At baseline, the groups were well balanced across most characteristics. At 6 months, the mean HBP was 131/82 mm Hg in the intervention group vs. 145/87 mm Hg in the control group (SBP <0.001, DBP = 0.09). An HBP level of less than 135/85 mm Hg was achieved among 55.6% of the participants in the intervention group vs. 16.7% in the control group (P = 0.004). The alcohol consumption at 6 months was 256 ± 206 g/w vs. 413 ± 260 g/w, respectively (P = 0.020).

CONCLUSIONS

We confirmed the effectiveness of the nurse-led alcohol guidance to control the HBP in male patients with hypertension during outpatient visits.

PUBLIC TRIALS REGISTRY NUMBER

UMIN000017454 (UMIN Clinical Trials Registry).

Efficacy of a digital therapeutics system in the management of essential hypertension: the HERB-DH1 pivotal trial

Aims

Digital therapeutics is a new approach to facilitate the non-pharmacological treatment of hypertension using software programmes such as smartphone applications and/or device algorithms. Based on promising findings from a small pilot trial, the HERB Digital Hypertension 1 (HERB-DH1) pivotal trial investigated the efficacy of digital therapeutics in patients with hypertension not receiving antihypertensive medication.

Methods and results

This prospective, open-label, randomized controlled study was performed at 12 sites in Japan. Patients with hypertension [office systolic blood pressure (SBP) 140 to <180 mmHg and 24 h SBP ≥130 mmHg] were randomly assigned 1:1 to the digital therapeutics group (HERB system + standard lifestyle modification) or control group (standard lifestyle modification alone). The primary efficacy endpoint was the mean change in 24 h ambulatory SBP from baseline to 12 weeks; key secondary efficacy endpoints were mean changes in office and home blood pressure (BP) from baseline to 12 weeks. All analyses were conducted in the full analysis set population. Between December 2019 and June 2020, 390 patients were randomly assigned to the digital therapeutics group (n = 199) or control (n = 191) group. Between-group differences in 24-h ambulatory, home, and office SBPs at 12 weeks were −2.4 (95% confidence interval −4.5 to −0.3), −4.3 (−6.7 to −1.9), and −3.6 (−6.2 to −1.0) mmHg, respectively. No major programme-related safety events occurred up to 24 weeks.

Conclusion

The HERB-DH1 pivotal study showed the superiority of digital therapeutics compared with standard lifestyle modification alone to reduce 24-h ambulatory, home, and office BPs in the absence of antihypertensive medications.

Electrocardiogram abnormalities in residents in cold homes: a cross-sectional analysis of the nationwide Smart Wellness Housing survey in Japan

Background

Excess winter mortality caused by cardiovascular disease is particularly profound in cold houses. Consistent with this, accumulating evidence indicates that low indoor temperatures at home increase blood pressure. However, it remains unclear whether low indoor temperatures affect other cardiovascular biomarkers. In its latest list of priority medical devices for management of cardiovascular diseases, the World Health Organization (WHO) included electrocardiography systems as capital medical devices. We therefore examined the association between indoor temperature and electrocardiogram findings.

Methods

We collected electrocardiogram data from 1480 participants during health checkups. We also measured the indoor temperature in the living room and bedroom for 2 weeks in winter, and divided participants into those living in warm houses (average exposure temperature ≥ 18 °C), slightly cold houses (12–18 °C), and cold houses (< 12 °C) in accordance with guidelines issued by the WHO and United Kingdom. The association between indoor temperature (warm vs. slightly cold vs. cold houses) and electrocardiogram findings was analyzed using multivariate logistic regression models, with adjustment for confounders such as demographics (e.g., age, sex, body mass index, household income), lifestyle (e.g., eating habit, exercise, smoking, alcohol drinking), and region.

Results

The average temperature at home was 14.7 °C, and 238, 924, and 318 participants lived in warm, slightly cold, and cold houses, respectively. Electrocardiogram abnormalities were observed in 17.6%, 25.4%, and 30.2% of participants living in warm, slightly cold, and cold houses, respectively (p = 0.003, chi-squared test). Compared to participants living in warm houses, the odds ratio of having electrocardiogram abnormalities was 1.79 (95% confidence interval: 1.14–2.81, p = 0.011) for those living in slightly cold houses and 2.18 (95% confidence interval: 1.27–3.75, p = 0.005) for those living in cold houses.

Conclusions

In addition to blood pressure, living in cold houses may have adverse effects on electrocardiogram. Conversely, keeping the indoor thermal environment within an appropriate range through a combination of living in highly thermal insulated houses and appropriate use of heating devices may contribute to good cardiovascular health.

Trial registration

The trial was retrospectively registered on 27 Dec 2017 to the University hospital Medical Information Network Clinical Trials Registry (UMIN-CTR, https://www.umin.ac.jp/ctr/, registration identifier number UMIN000030601).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-021-01024-1.

Salt and potassium intake evaluated with spot urine and brief questionnaires in combination with blood pressure control status in hypertensive outpatients in a real-world setting

Reducing salt and increasing potassium intake are recommended lifestyle modifications for patients with hypertension. The estimated 24-h urinary salt excretion value from spot urine using Tanaka's formula and the salt check-sheet scores, questionnaire-based scores of salt intake, are practical indices of daily salt intake. However, few studies have evaluated salt intake with these methods in hypertensive outpatients. We examined salt and potassium intake with the spot urine method and the salt check-sheet scores of hypertensive outpatients in a multi-facility, real-world setting and examined whether the salt or potassium intake evaluated with these methods related to inadequate blood pressure control. Hypertensive outpatients from 12 medical facilities in the Okinawa prefecture were enrolled from November 2011 to April 2014 (n = 1559, mean age 63.9 years, 46% women). The mean blood pressure, urinary salt excretion value, urinary potassium excretion value, and total score on the salt check-sheet were 129/75 mmHg, 8.7 g/day, 1.6 g/day, and 10.4 points, respectively. The urinary salt excretion value and total score on the salt check-sheet but not urinary potassium excretion value were associated with inadequate blood pressure control (≥140/90 mmHg). Higher body mass index, estimated glomerular filtration rate, urinary potassium excretion value, total score on the salt check-sheet, and presence of inadequate blood pressure control were associated with high urinary salt excretion (≥10.2 g/day). In conclusion, hypertensive outpatients with high urinary salt excretion values estimated using Tanaka's formula or with high scores on the salt check sheet may be candidates for more intensive salt reduction guidance.

Assessment of Foods Associated with Sodium and Potassium Intake in Japanese Youths Using the Brief-Type Self-Administered Diet History Questionnaire

The identification of sodium and potassium intake in youths is an important step to preventing the increase of blood pressure in childhood. We examined food intake and estimated mineral intake using a brief-type self-administered diet history questionnaire (BDHQ) to test its validity as a comparison with urinary excretion in Japanese youths. The subjects were 5th and 8th graders (n = 2377), who completed the BDHQ and permitted the use of their overnight urine specimens. Sodium intake was poorly associated with sodium excretion (Rho = 0.048), and the coefficients of dietary potassium and a sodium-to-potassium molar ratio were 0.091–0.130. Higher soybean paste (miso) intake and pickles were significantly associated with higher sodium excretion (p ≤ 0.005). However, these foods were positively associated with potassium excretion (p = 0.002–0.012), and not associated with an excreted sodium-to-potassium ratio. Fruits and dairy products were positively associated (p ≤ 0.048), whereas beverages were negatively associated with potassium excretion (p ≤ 0.004). The association of the sodium-to-potassium ratio was opposite to that of potassium (p ≤ 0.001). The choice of foods, potassium, and the sodium-to-potassium ratio assessed using the BDHQ are available as part of health education for youths, but the assessment of sodium intake in population levels should be carefully conducted.

Intervention study of the effect of insulation retrofitting on home blood pressure in winter: a nationwide Smart Wellness Housing survey

OBJECTIVE

The WHO's Housing and health guidelines (2018) listed 'low indoor temperatures and insulation' as one of five priority areas, and indicated insulation retrofitting to help mitigate the effect of low indoor temperatures on health. However, there is still not enough evidence for the effect of insulation retrofitting based on an objective index.

METHODS

We conducted a nonrandomized controlled trial comparing home blood pressure (HBP) between insulation retrofitting (942 households and 1578 participants) and noninsulation retrofitting groups (67 households and 107 participants). HBP and indoor temperature were measured for 2 weeks before and after the intervention in winter. To examine the influence of insulation retrofitting on HBP, we used multiple linear regression analysis.

RESULTS

The analyses showed that indoor temperature in the morning rose by 1.4°C after insulation retrofitting, despite a slight decrease in outdoor temperature by 0.2°C. Insulation retrofitting significantly reduced morning home SBP (HSBP) by 3.1 mmHg [95% confidence interval (95% CI): 1.5-4.6], morning home DBP (HDBP) by 2.1 mmHg (95% CI: 1.1-3.2), evening HSBP by 1.8 mmHg (95% CI: 0.2-3.4) and evening HDBP by 1.5 mmHg (95% CI: 0.4-2.6). In addition, there was a dose-response relationship between indoor temperature and HBP, indicating the effectiveness of a significant improvement in the indoor thermal environment. Furthermore, there was heterogeneity in the effect of insulation retrofitting on morning HSBP in hypertensive patients compared with normotensive occupants (-7.7 versus -2.2 mmHg, P for interaction = 0.043).

CONCLUSION

Insulation retrofitting significantly reduced HBP and was more beneficial for reducing the morning HSBP of hypertensive patients.

Estimated 24-hour urinary sodium excretion and sodium-to-potassium ratio among Japanese elementary school teachers and school lunch cooks

Background:Dietary salt intake is largely responsible for increase in blood pressure that is commonly seen with aging. In our previous study carried out in 2015, we calculated the 24-hour urinary sodium excretion and sodium-to-potassium (Na/K) ratio among elementary school children. In the present study, we aimed to examine the same items among the school children's teachers and lunch cooks.Methods:Of 153 recruited participants, urine samples were collected from 129 subjects (84.3%), and 124 subjects (81.0%; 37 male teachers, 65 female teachers, and 22 female cooks) whose dietary habits were confirmed were included in the final study analysis.Results: The median estimated 24-hour urinary salt excretion (g/day) was 8.2 in male teachers, 7.4 in female teachers, and 8.9 in cooks. The median urinary Na/K ratio (mEq/mEq) was 4.1 in male teachers, 3.6 in female teachers, and 4.0 in cooks. In both male and female teachers and cooks, no association was found between urinary salt excretion or urinary Na/K ratio and an awareness of the need to restrict salt intake. The proportion of subjects with both a urinary salt excretion and Na/K ratio above the median was high in male teachers and cooks, whereas the proportion of subjects who scored below the median in both tests was high in female teachers.Conclusion:It should be considered that elementary school teachers and cooks who have been provided with the results of their own salt excretion could realize the importance of reducing salt consumption from early childhood and the continuous salt intake reduction education for children.

Impact of indoor temperature instability on diurnal and day-by-day variability of home blood pressure in winter: a nationwide Smart Wellness Housing survey in Japan

Home blood pressure (HBP) variability is an important factor for cardiovascular events. While several studies have examined the effects of individual attributes and lifestyle factors on reducing HBP variability, the effects of living environment remain unknown. We hypothesized that a stable home thermal environment contributes to reducing HBP variability. We conducted an epidemiological survey on HBP and indoor temperature in 3785 participants (2162 households) planning to have their houses retrofitted with insulation. HBP was measured twice in the morning and evening for 2 weeks in winter. Indoor temperature was recorded with each HBP observation. We calculated the morning-evening (ME) difference as an index of diurnal variability and the standard deviation (SD), coefficient of variation (CV), average real variability (ARV) and variability independent of the mean (VIM) as indices of day-by-day variability. The association between BP variability and temperature instability was analyzed using multiple linear regression models. The mean ME difference in indoor/outdoor temperature (a decrease in temperature overnight) was 3.2/1.5 °C, and the mean SD of indoor/outdoor temperature was 1.6/2.5 °C. Linear regression analyses showed that the ME difference in indoor temperature was closely correlated with the ME difference in systolic BP (0.85 mmHg/°C, p < 0.001). The SD of indoor temperature was also associated with the SD of systolic BP (0.61 mmHg/°C, p < 0.001). The CV, ARV, and VIM showed similar trends as the SD of BP. In contrast, outdoor temperature instability was not associated with either diurnal or day-by-day HBP variability. Therefore, residents should keep the indoor temperature stable to reduce BP variability.

Screening tool for identifying adults with excessive salt intake among community-dwelling adults: a population-based cohort study

BACKGROUND

Excessive salt intake is widely known to be a cause of hypertension, cardiovascular events, and so on. However, simple tools for screening excessive salt intake are lacking.

OBJECTIVE

We aimed to develop a simple screening tool to identify community-dwelling adults with excessive salt intake.

METHODS

The present study involved participants who received health check-ups in Fukushima, Japan, in 2016 and 2017. We defined data from the 2016 check-up as the derivation set, and data from those who received check-ups in 2017 but not 2016 as the validation set. The outcome measure was excessive salt intake, defined as the estimated daily salt intake of 1 SD or more. Candidate predictors associated with the outcome were extracted using the Delphi method by an expert panel and narrowed down with clinical expertise and stepwise backward selection. The screening tool was developed using a coefficient-based multivariable scoring method and externally validated.

RESULTS

A total of 1101 participants were included in the derivation set and 249 in the validation set. At the conclusion of the deviation process, 8 predictors were selected and scored. The areas under the receiver operating characteristic curve for derivation and external validation were 0.70 (95% CI: 0.67, 0.74) and 0.71 (95% CI: 0.62, 0.80), respectively. The calibration slope and intercept for external validation were 1.16 and -0.03, respectively.

CONCLUSION

We developed a screening tool to identify adults with excessive salt intake. By extracting groups with excessive salt intake, target populations needing intervention for salt reduction can be highlighted efficiently.

Cross-Sectional Analysis of the Relationship Between Home Blood Pressure and Indoor Temperature in Winter

Mortality due to cardiovascular disease rises sharply in winter. Known as excess winter mortality, this phenomenon is partially explained by cold exposure-induced high blood pressure. Home blood pressure, especially in the morning, is closely associated with cardiovascular disease risk. We conducted the first large nationwide survey on home blood pressure and indoor temperature in 3775 participants (2095 households) who intended to conduct insulation retrofitting and were recruited by construction companies. Home blood pressure was measured twice in the morning and evening for 2 weeks. The relationship between home blood pressure and indoor temperature in winter was analyzed using a multilevel model with 3 levels: repeatedly measured day-level variables (eg, indoor ambient temperature and quality of sleep), nested within individual-level (eg, age and sex), and nested within household level. Cross-sectional analyses involving about 2900 participants (1840 households) showed that systolic blood pressure in the morning had significantly higher sensitivity to changes in indoor temperature (8.2 mm Hg increase/10°C decrease) than that in the evening (6.5 mm Hg increase/10°C decrease) in participants aged 57 years (mean age in this survey). We also found a nonlinear relationship between morning systolic blood pressure and indoor temperature, suggesting that the effect of indoor temperature on blood pressure varied depending on room temperature range. Interaction terms between age/women and indoor temperature were significant, indicating that systolic blood pressure in older residents and women was vulnerable to indoor temperature change. We expect that these results will be useful in determining optimum home temperature recommendations for men and women of each age group.

Clinical Trial Registration—

URL: http://www.umin.ac.jp/ctr/index.htm . Unique identifier: UMIN000030601.

Practical and personal education of dietary therapy in hypertensive patients

The guidelines for the management of hypertension by the Japanese Society of Hypertension (JSH2019) defined blood pressure (BP) levels of 130-139/80-89 mmHg as "elevated blood pressure". The JSH2019 also revised the target level of BP control to a lower level. Thus, lifestyle modifications are quite important regardless of the use of antihypertensive drugs. Among the lifestyle modifications, salt reduction is most important, especially among East Asian people, who still consume a significant amount of salt. Since the awareness of salt reduction may not necessarily lead to actual salt reduction, the assessment of individual salt intake is essential when members of the medical staff provide practical guidance regarding salt reduction. The evaluation methods of salt intake are classified as the assessment of dietary contents and the measurement of urinary sodium (Na) excretion. Since highly reliable methods, such as the measurement of 24-h urinary Na excretion, are not convenient in practical clinical settings, the combination of the assessment of dietary contents using questionnaires and the estimation of salt intake using spot urine is recommended as a practical evaluation procedure. Repeated assessment of salt intake and practical guidance from dieticians are useful for long-term adherence to salt reduction. The Japanese Society of Hypertension Salt Reduction Committee began to certify flavorful foods as being low in salt content in 2013. More than 200 products have been certified as of April 2019. The utilization of these products is expected to aid in the salt reduction of hypertensive individuals as well as the Japanese general population.

Usefulness of a salt check sheet for elementary school and junior high school children

There are no known methods to easily evaluate the dietary salt intake of children. We hypothesized that the salt check sheet, for which validity has been confirmed in both hypertensive outpatients and in the general population, can be used to assess dietary salt intake in children. We enrolled 188 healthy schoolchildren (mean age 11.2 ± 1.1 years, 53.2% boys) and asked them to answer both the salt check sheet and a brief self-administered dietary history questionnaire for Japanese schoolchildren aged 6-18 years (BDHQ15y). The mean total salt check-sheet score was 12.7 ± 4.0 points (range: 4-24 points), and the estimated daily salt intake from the BDHQ15y was 12.1 ± 3.7 g (range: 4.7-27.2 g). The total check-sheet score was significantly positively correlated with the estimated daily salt intake from the BDHQ15y (r = 0.408, P < 0.001). Thirty-one study participants were assigned to the "low" salt group (total score on the salt check sheet was 0-8 points), 78 participants to the "medium" salt group (9-13 points), and 79 participants to the "high and very high" salt group (≥14 points), and a comparison estimating daily salt intake from the BDHQ15y among the three groups was performed. Daily salt-intake levels tended to increase as the group of total check-sheet scores increased: "low" vs "medium" vs "high and very high" salt group levels were 9.5 ± 3.1 vs 11.6 vs 13.5 ± 3.9, respectively (P < 0.001). This demonstrates that the salt check sheet is a useful tool to easily assess dietary salt intake in children.

A self-monitoring urinary salt excretion level measurement device for educating young women about salt reduction: A parallel randomized trial involving two groups

To prevent and treat hypertension, it is important to restrict salt in one's diet since adolescence. However, an effective salt-reduction education system has yet to be established. Besides accurate evaluation, we believe that the frequent usage of a measurement device may motivate individuals to avoid high salt intake. The present study evaluated the use of a urinary salt excretion measurement device for salt-reduction education in a parallel randomized trial of two groups. The sample comprised 100 university students who provided consent to participate. A survey with 24-hour home urine collection and blood pressure measurement was conducted. Participants in the self-monitoring group measured their own urinary salt excretion level for 4 weeks, using the self-measurement device. Analyses were conducted on 51 participants in the control group and 49 in the self-monitoring group. At baseline, there was no significant difference between the two groups in terms of their characteristics and 24-hour urinary salt excretion levels. After intervention, 24-hour urinary sodium/potassium ratio showed no change in the control group [baseline score: 4.1 ± 1.5; endline score: 4.2 ± 2.0; P = 0.723], but it decreased significantly in the self-monitoring group [baseline score: 4.0 ± 1.7; endline score: 3.5 ± 1.4; P = 0.044]. This change was significant even after adjusting for baseline and endline differences between groups using analysis of covariance (P = 0.045). The self-monitoring urinary salt excretion measurement device improved the 24-hour urinary sodium/potassium ratio. The device is a useful and practical tool for educating young individuals about dietary salt reduction.

Self-monitoring of urinary salt excretion as a method of salt-reduction education: a parallel, randomized trial involving two groups

OBJECTIVE

The present study aimed to evaluate salt-reduction education using a self-monitoring urinary salt-excretion device.

DESIGN

Parallel, randomized trial involving two groups. The following parameters were checked at baseline and endline of the intervention: salt check sheet, eating behaviour questionnaire, 24 h home urine collection, blood pressure before and after urine collection.

SETTING

The intervention group self-monitored urine salt excretion using a self-measuring device for 4 weeks. In the control group, urine salt excretion was measured, but the individuals were not informed of the result.

SUBJECTS

Seventy-eight individuals (control group, n 36; intervention group, n 42) collected two 24 h urine samples from a target population of 123 local resident volunteers. The samples were then analysed.

RESULTS

There were no differences in clinical background or related parameters between the two groups. The 24 h urinary Na:K ratio showed a significant decrease in the intervention group (-1·1) compared with the control group (-0·0; P=0·033). Blood pressure did not change in either group. The results of the salt check sheet did not change in the control group but were significantly lower in the intervention group. The score of the eating behaviour questionnaire did not change in the control group, but the intervention group showed a significant increase in eating behaviour stage.

CONCLUSIONS

Self-monitoring of urinary salt excretion helps to improve 24 h urinary Na:K, salt check sheet scores and stage of eating behaviour. Thus, usage of self-monitoring tools has an educational potential in salt intake reduction.

The SONG (Salt intake and OrigiN from General foods) Study - A Large-scale Survey of the Eating Habits and Dietary Salt Intake in the Working-age Population

Objective Dietary salt reduction is important for the prevention and treatment of lifestyle-related diseases, including hypertension. Thus, in order to follow a strict low-salt diet, it is necessary to assess one's salt intake and to become aware of the importance of salt reduction. Methods More than 2,000 employees of a company, who received a periodic health checkup, participated in the present study. They assessed their day-to-day diet-related lifestyle, using the Salt Check Sheet, and we analyzed the correlations among the Salt Check Sheet scores, the daily salt intake (as estimated by a spot urine sample), and the results of the periodic health checkup. Results In the overall survey population, we only found a weak correlation between the salt check scores and the salt intake. In a subgroup analysis, significant correlations between these two variables were observed among untreated hypertensive participants, but not among treated hypertensive participants. We examined the association between 13 individual questionnaire items and the estimated daily salt intake using a multivariate linear regression model and found that only 5 of the 13 questionnaire items were correlated with the daily salt intake. Conclusion We found that a Salt Check Sheet composed of the 5 items that showed a strong correlation with the salt intake might be more useful for periodic health checks of the working-age population.