Numerous studies supported the close association between excess dietary salt and hypertension. However, salt intake was assessed without adjustment for body weight in previous studies and most guidelines recommend salt restriction without considering body weight despite the assumption that salt intake increases along with food intake. The present study was designed to test the hypothesis that body weight-adjusted as well as total salt intake has clinical significance in managing blood pressure and subclinical organ damage in the general population.Design and Method:
This was a cross-sectional study to assess the relationships of body weight-adjusted salt intake with blood pressure, electrocardiogram (ECG) voltage (SV1+RV5), estimated glomerular filtration rate (eGFR), urinary albumin, and other cardiovascular risk factors. Participants in our yearly physical checkup program (n = 7,629, male = 4,798, mean age = 56.3 years) were enrolled in the present study. Salt intake was assessed using a spot urine test to estimate 24-hour urinary salt excretion.Results:
Total salt intake increased with increasing body weight. Both total and body weight-adjusted salt intakes were increased with age (p < 0.0001). In analyses where participants were divided into quintiles according to their salt intake, systolic blood pressure was increased with increasing body weight-adjusted as well as total salt intake after adjustment for important factors (p < 0.0001). Similarly, eGFR decreased and urinary albumin increased with increasing total salt intake or body weight-adjusted salt intake (p < 0.0001), while ECG voltage showed no significant association with salt intake. Multivariable regression analysis demonstrated that body weight-adjusted salt intake independently correlated with systolic blood pressure, eGFR, ECG voltage, and urinary albumin.Conclusions:
Excessive body weight-adjusted salt intake could be related to an increase in blood pressure and hypertensive organ damage in the general population. Adjustment for body weight might therefore provide clinically important information when assessing individual salt intake.