Effect of sodium intake on renin level: Analysis of general population and meta-analysis of randomized controlled trials.
BACKGROUND
We evaluated the association between sodium intake and plasma renin levels in the cross sectional study and meta-analysis of randomized controlled trials, whether there is a persistent elevation of plasma renin by longer-term sodium intake restriction.


METHODS
Plasma renin activity (PRA) and 24-h urine sodium (24HUNa) excretion were measured from individuals randomly selected from a community. Simple and multiple linear regression analyses adjusted for age, 24-h systolic blood pressure, 24-h average heart rate, fasting blood glucose and gender were performed. For meta-analysis, 74 studies published from 1975 to mid-2014 were identified in a systematic literature search using EMBASE, CINAHL, and MEDLINE. Random effects meta-analyses and a meta-regression analysis were performed.


RESULTS
Among the 496 participants recruited, 210 normotensive and 87 untreated hypertensive subjects were included in the analysis. There was no significant association between PRA and 24HUNa in the total population, or hypertensive and normotensive individuals. In the meta-analysis, the standard mean difference (SMD) of renin level by sodium intake reduction was 1.26 (95% CI: 1.08 to 1.44, Z=12.80, P<0.001, I(2)=87%). In the meta-regression analysis, an increase in a day of intervention was associated with a fall in SMD by -0.04 (95% CI: -0.05 to -0.02, Z=-5.27, P<0.001, I(2)=86%), indicating that longer duration of reduced sodium intake would lead to lesser SMD of renin level.


CONCLUSIONS
The present population based cross-sectional study and meta-analysis suggests that prolonged reduction in sodium intake is very unlikely associated with elevation of plasma renin levels.
Department of Social Welfare, Soongsil University, Seoul, Republic of Korea.
O J
OJ
Rhee
Cardiovascular Center, Dongguk University Ilsan Hospital, Goyang, Republic of Korea. Electronic address: mooyong_rhee@dumc.or.kr.
M Y
MY
Rhee
Department of Family Medicine, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
S W
SW
Oh
Division of Nephrology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
S J
SJ
Shin
Department of Clinical Pharmacology and Therapeutics, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
N
N
Gu
Division of Cardiology, Department of Internal Medicine, College of Medicine, Dongguk University, Gyeongju, Republic of Korea.
D Y
DY
Nah
Department of Statistics, Survey and Health Policy Research Center, Dongguk University, Seoul, Republic of Korea.
S W
SW
Kim
Department of Thoracic and Cardiovascular Surgery, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
J H
JH
Lee
D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003430:Cross-Sectional Studies; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis / Q000652:urine; D011159:Population Surveillance / Q000379:methods; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D012083:Renin / Q000097:blood*; D012964:Sodium / Q000652:urine*; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*
D017673:Sodium Chloride, Dietary; D012964:Sodium; D012083:Renin
General population; Meta-analysis; Renin; Sodium intake