The relationship between sodium concentrations in spot urine and blood pressure increases: a prospective study of Japanese general population: the Circulatory Risk in Communities Study (CIRCS).

BACKGROUND: Although several cross-sectional and intervention studies showed that sodium intake or excretion was associated with blood pressure levels, no prospective study has examined the long-term association between sodium excretion in spot urine and blood pressure changes. METHODS: We conducted a prospective study of 889 normotensive subjects (295 men and 594 women, mean age 57.3 years) who underwent the baseline survey including spot urine test in 2005 and the follow-up survey in 2009 to 2011 (mean follow-up period: 5.8 years). We examined the association between sodium concentration in spot urine, a validated index of sodium excretion occurring over 24-h, and blood pressure changes between baseline and follow-up survey in all, non-overweight (body mass index(BMI) ≤ 25 kg/m(2)) and overweight normotensives. RESULTS: For all subjects, sodium concentrations in spot urine were not associated with either systolic or diastolic blood pressure changes. When stratified by BMI at baseline survey, sodium concentrations were positively associated with systolic blood pressure changes in non-overweight subjects, but not in overweight subjects. After adjustment for age, sex, BMI, alcohol intake status, current smoking and estimated glomerular filtration rate, the multivariable-adjusted mean values of the systolic blood pressure change among non-overweight subjects was +7.3 mmHg in the highest quartiles of sodium concentrations, while it was +3.9 mmHg in the lowest quartile (P for difference = 0.021, P for trend = 0.040). After further adjustment of baseline blood pressure levels, the association was slightly weakened; the multivariable-adjusted mean values of the systolic blood pressure changes were +7.0 mmHg and +4.2 mmHg (P for difference = 0.047, P for trend = 0.071). CONCLUSIONS: High sodium concentrations in spot urine were associated with subsequent systolic blood pressure increases among non-overweight normotensive individuals. (272 words).

Blood pressure levels and risk of cardiovascular disease mortality among Japanese men and women: the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study).

OBJECTIVE: To examine the association of blood pressure (BP) with cardiovascular mortality in real-world settings and investigate whether that association varied by use of antihypertensive medication at baseline. METHODS: Data from 27 728 Japanese men and women, aged 40-79 years, free of stroke, coronary heart disease, cancer, and kidney disease at entry (1988-1990) were used in this study. Mortality surveillance was completed through 2009, resulting in 449 800 person-years of follow-up. Hazard ratios for cardiovascular mortality were analysed by BP category (based on 2018 European guidelines) at admission. RESULTS: There were 1477 deaths from cardiovascular diseases (CVDs). Relative to high-normal BP at admission, the multivariable hazard ratios (95% confidence intervals) of CVD were 0.85 (0.69-1.04) for optimal BP; 0.96 (0.81-1.15) for normal BP; 1.26 (1.09-1.46) for Grade 1 hypertension; and 1.55 (1.31-1.84) for Grade 2-3 hypertension. A similar linear association was observed among persons not taking antihypertensive medication at admission. Among patients treated for hypertension, a U-shaped association with CVD mortality was observed; hazard ratios = 2.31 (1.25-4.27), 1.68 (1.05-2.69), 1.56 (1.10-2.22), and 1.63 (1.13-2.36), respectively. Similar patterns were observed for stroke and coronary heart disease, although not always statistically significant. CONCLUSION: BP categories at baseline were linearly and positively associated with CVD mortality overall and also among participants not taking antihypertensive medication. A higher risk of mortality from CVD was observed among patients already treated for hypertension with optimal and normal BPs than those with high-normal BP, suggesting the importance of careful monitoring of BP and comorbidities of such patients.

Urea nitrogen concentrations in spot urine, estimated protein intake and blood pressure levels in a Japanese general population.

BACKGROUND: An inverse association between total protein intake and blood pressure has been reported in Western countries. Such evidence is limited in the Japanese population, however, whose major protein sources are plants and seafood. METHODS: We conducted a population-based cross-sectional study of 986 men and 1,636 women, aged 40-74 years, in a Japanese rural community to examine the association between blood pressure levels and urea nitrogen concentrations in spot urine. RESULTS: The concentration of urea nitrogen in spot urine, an indicator of total protein intake that was validated by 24-h urea nitrogen excretion and 24-h dietary research, was inversely associated with systolic blood pressure levels for men: a 238 mg/dl increase in urea nitrogen concentration was associated with a 2.1 mm Hg lower mean systolic blood pressure. For women, a weaker and nonsignificant inverse association was observed. There was no association between urea nitrogen concentrations and diastolic blood pressure levels in either sex. Total protein intake estimated from spot urine was also inversely associated with systolic blood pressure levels for men: a 19.2 g/day increase in estimated protein intake was associated with a 1.5 mm Hg lower mean systolic blood pressure. CONCLUSION: A urinary biomarker for total protein intake was inversely associated with systolic blood pressure levels for men in a Japanese general population.