High sodium, low potassium intake ups hypertension risk by middle age

A recent study has stressed the importance of reducing dietary sodium and increasing potassium intake among young adults to prevent hypertension.

The authors assessed the relationships of urinary sodium and potassium excretions with blood pressure (BP) trends and incident hypertension among 1,007 participants (mean age 30.2 years, 53 percent Blacks, 57 percent women) of the Coronary Artery Risk Development in Young Adults study, who had at least two 24-hour urine samples collected at year 5 examination, in the subsequent 25 years.

Participants were classified according to sex-specific medians for averaged 24-hour urinary excretions: lower sodium and higher potassium (Na-Lo-K-Hi); higher sodium and lower potassium (Na-Hi-K-Lo); and others.

The adjusted generalized estimating equation model showed a marked increase in systolic (SBP) and diastolic BP (DBP) in the Na-Hi-K-Lo group (n=185) relative to the Na-Lo-K-Hi group (n=185), with statistically significant BP differences at year 20, 25, and 30 (mean SBP: 3.93, 4.94, and 4.88 mm Hg, respectively; mean DBP: 4.70, 4.95, and 4.59 mm Hg, respectively).

Among 926 participants without prevalent hypertension by year 5, 381 (41.1 percent) developed the disease during 25-year follow-up. In the adjusted Cox proportional hazard model, participants in the Na-Hi-K-Lo group had a 45-percent higher risk of incident hypertension (hazard ratio, 1.45, 95 percent confidence interval, 1.00–2.10) compared with those in the Na-Lo-K-Hi group.

The association with incident hypertension was most robust among Black and White women (race–sex interaction: p=0.03). Furthermore, sodium-to-potassium ratio and sodium excretion positively correlated with incident hypertension, but potassium excretion showed an inverse association (p_trend<0.05 for all).