Feasibility and efficacy of sodium reduction in the Trials of Hypertension Prevention, phase I. Trials of Hypertension Prevention Collaborative Research Group.
Phase I of the Trials of Hypertension Prevention was a multicenter, randomized trial of the feasibility and efficacy of seven nonpharmacologic interventions, including sodium reduction, in lowering blood pressure in 30- to 54-year-old individuals with a diastolic blood pressure of 80 to 89 mm Hg. Six centers tested an intervention designed to reduce dietary sodium to 80 mmol (1800 mg)/24 h with a total of 327 active intervention and 417 control subjects. The intervention consisted of eight group and two one-to-one meetings during the first 3 months, followed by less-intensive counseling and support for the duration of the study. The mean net decrease in sodium excretion was 43.9 mmol/24 h at 18 months. Women had lower sodium intake at baseline and were therefore more likely to decrease to less than 80 mmol/24 h. Black subjects were less likely to decrease to less than 80 mmol/d, independent of sex or baseline sodium excretion. The mean (95% confidence interval) net decrease associated with treatment was -2.1 (-3.3, -0.8) mm Hg for systolic blood pressure and -1.2 (-2.0, -0.3) mm Hg for diastolic blood pressure at 18 months (both P < .01). Multivariate analyses indicated a larger systolic blood pressure effect in women (-4.44 versus -1.23 mm Hg in men), adjusted for age, race, baseline blood pressure, and baseline 24-hour urinary sodium excretion (P = .02). Dose-response analyses indicated an adjusted decrease of -1.4 mm Hg for systolic blood pressure and -0.9 mm Hg for diastolic blood pressure for a decrease of 100 mmol/24 h in 18-month sodium excretion. These results support the utility of sodium reduction as a population strategy for hypertension prevention and raise questions about possible differences in dose response associated with gender and initial level of sodium intake.
Kumanyika
S K
SK
Department of Epidemiology, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md.
Hebert
P R
PR
Cutler
J A
JA
Lasser
V I
VI
Sugars
C P
CP
Steffen-Batey
L
L
Brewer
A A
AA
Cameron
M
M
Shepek
L D
LD
Cook
N R
NR
D000328:Adult; D044383:Black People; D001794:Blood Pressure; D004039:Diet, Sodium-Restricted; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009318:Natriuresis; D010349:Patient Compliance; D012727:Sex Characteristics; D044465:White People