Abstract P261: Dietary Sodium, Potassium, and Blood Pressure in Normotensive Pregnant Women: The National Health and Nutrition Examination Survey

Abstract

Dietary sodium, potassium, and the sodium-to-potassium ratio are linearly associated with blood pressure in non-pregnant adults in a dose-response manner. Earlier investigations suggested null or inverse associations of sodium and blood pressure during normotensive pregnancy, but this finding has not been confirmed in a large, racially diverse group while accounting for counteractive effects of dietary potassium. Our purpose was to determine associations of blood pressure with sodium, potassium and the sodium-to-potassium ratio in normotensive pregnant women. We used cross-sectional blood pressure measurements and dietary data from 984 normotensive pregnant women in multiple cycles of the National Health and Nutrition Examination Survey (mean age=27.6 ± 0.2 years). We used Kruskal-Wallis tests to determine differences in blood pressure across quartiles of sodium intake and linear regression to test for associations of sodium, potassium, and the sodium-to-potassium ratio with systolic and diastolic blood pressure. Adjustment variables included: age, race, education, marital status, body mass index, smoking, and month of pregnancy. Average duration of pregnancy was 5.6 ± 0.1 months with no difference between quartiles of sodium intake. There was no difference in unadjusted systolic or diastolic blood pressures across quartiles of sodium intake; Quartile 1: 106/56; Quartile 2: 106/55; Quartile 3: 107/57; Quartile 4: 107/56, p>0.60 for all, and no difference in age and race-adjusted systolic or diastolic blood pressures across quartiles of dietary intake, Figure 1. In adjusted regression analyses, sodium ( b =0.16, 95%CI: -0.20, 0.52) and potassium ( b =0.18, 95%CI: -0.24, 0.60) intake and the sodium-to-potassium ratio ( b = -0.54, 95%CI: -1.55, 0.47) were not associated with systolic or diastolic blood pressure in normotensive pregnant women. Results were similar in analyses stratified by race/ethnicity. Blood pressure may be insensitive to sodium and potassium intake during normotensive pregnancy.