Relationship between nocturnal blood pressure and 24-h urinary sodium excretion in a rural population in Korea

Abstract

Background:The relationship between sodium intake and blood pressure (BP) is affected by many factors such as absolute level of sodium intake, salt sensitivity, and the accuracy or the timing of the BP measurement. There is no epidemiologic study using both ambulatory BP monitoring (ABPM) and 24-h urine sample in a middle-aged general population. Methods: In the rural area, Yeojoo County, Gyunggi Province in South Korea, 218 subjects with age between 30 and 59 years old were measured with ABPM and 24-h urine sample. ABPM device was TM2430, and the 24-h urine sample was collected using the aliquot cup. Metabolic syndrome (MetS) score was calculated by the sum of the number of abnormal criteria other than BP. Results: For both ABPM and 24-h urine sample, 148 subject data was acceptable for the analysis by the creatinine equation and/or the completeness of collection. Age was 47.4 ± 8.3 years (range 30 to 59 years), and female was 85 (57.4%). In multiple linear regression analysis, sodium intake was not an independent factor for casual BPs and daytime BPs whereas sodium intake was an independent factor for nighttime systolic BP (β = 1.625, p = 0.0026) and nighttime diastolic BP (β = 1.066, p = 0.0017). When compared to the lowest quartiles of sodium intake, daytime diastolic BP and nighttime BPs were in the higher three quartile groups. Conclusions: Sodium intake was associated not with casual BPs and daytime BPs but with increased nighttime BPs in the middle-aged general population in Korea.

Obesity masks the relationship between dietary salt intake and blood pressure in people of African ancestry: the impact of obesity on the relationship between sodium and blood pressure

“…To determine the masking effects of an increased BMI, we first investigated the relationship between 24–hour urinary sodium excretion and BP in the total population sample. Consistent with previous studies in this population 4 – 6 and in other population groups, 29 , 30 we found no relationship. In spite of the inconclusive results in this population, the relationship between sodium level and BP has been well established in a number of studies, 31 – 34 therefore our current findings require thorough scrutiny.…”

Association between urinary sodium-to-potassium ratio and home blood pressure and ambulatory blood pressure: the Ohasama study

“…Previous research has shown that multiple daily measurements of spot urinary Na/K ratio are strongly related to home hypertension [19]. Previous studies have indicated an association between urinary Na/K ratio and ambulatory BP indices alone [20][21][22]. As these results were derived from different cohorts, it remained unclear, which type of out-of-office BP was remarkably affected by urinary Na/K ratio.…”

“…A community-based cross-sectional study in Korea reported that urinary Na/K ratio was positively associated with night-time BP among individuals aged at least 55 years but not among those aged less than 55 years [20]. Another study among 148 Koreans showed that 24-h sodium excretion was an independent factor for night-time BP but not for daytime BP [22]. Meanwhile, a previous study among patients with diabetes in Australia reported that urinary Na/K ratio was not associated with dipping status [21].…”

“…An Asian community-based study showed that urinary Na/K ratio was significantly associated with home hypertension [19]. Few other studies have evaluated the association of urinary Na/K ratio only with ambulatory BP [20][21][22]. These studies cannot clarify the difference in the effect of urinary Na/K ratio on BP according to out-of-office BP measurements.…”

Erratum to: Relationship between nocturnal blood pressure and 24-h urinary sodium excretion in a rural population in Korea

“…After publication of the article [ 1 ] it was discovered that a citation error had occurred, resulting in different citation numbers in the PDF and HTML files. The correct citation of 20:9 has now been updated in all versions of the manuscript.…”