Effect of low vs. high dietary sodium on blood pressure levels in a normotensive Indo-Asian population.
BACKGROUND
Hypertension is a major modifiable risk factor, and while sodium restriction in hypertensive patients appears effective, its role in normotensive individuals remains unclear. We assessed the effect of a low vs. high-sodium diet on blood pressure in normotensive Indo-Asian adults.


METHODS
A randomized, controlled, crossover trial was conducted on 200 normotensive subjects randomly selected from the general population in Karachi, Pakistan. Participants were randomized to either a low (20 mEq/day) or a high-sodium diet (220 mEq/day) for 1 week, followed by 1 week of washout, then the alternate diet for 1 week. The primary outcome was difference in systolic blood pressure (SBP) measured at the end of each phase in the overall population.


RESULTS
Mean (95% confidence interval) decline in 24-h urinary sodium excretion was 81.0 (69.6-92.4) mEq/day (P < 0.001), and in SBP was 1 (0-3)mm Hg (P = 0.17) between high and low-sodium phase. A significant interaction was detected (P = 0.001) between dietary sodium and baseline SBP with a greater adjusted mean (95% confidence interval) decline in SBP (6 (2-9)mm Hg) among participants with high-normal SBP (130-139 mm Hg) and no significant change (-1(-2 to 1)) in those with normal baseline SBP (<130 mm Hg), respectively.


CONCLUSIONS
Reducing sodium intake has a beneficial effect on blood pressure in Indo-Asians with high-normal SBP, at least in the short term. Given the ubiquity of high-normal blood pressure (BP), and frank hypertension in this population, we argue that primary prevention strategies, targeted at use of discretionary sodium, should now be designed and evaluated.
Jessani
Saleem
S
Clinical Epidemiology Unit, Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan.
Hatcher
Juanita
J
Chaturvedi
Nish
N
Jafar
Tazeen H
TH
D000328:Adult; D044466:Asian People; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D002318:Cardiovascular Diseases / Q000208:ethnology / Q000503:physiopathology / Q000517:prevention & control; D018592:Cross-Over Studies; D004039:Diet, Sodium-Restricted; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006973:Hypertension / Q000208:ethnology / Q000503:physiopathology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D010154:Pakistan; D012964:Sodium / Q000652:urine; D012982:Sodium, Dietary / Q000494:pharmacology*
D012982:Sodium, Dietary; D012964:Sodium