Effects of dietary patterns and sodium intake on blood pressure variability: results from the DASH and DASH-sodium trials.

The DASH diet did not significantly differ from the Control diet in week-to-week systolic blood pressure variability in pooled analyses.

• Difference in systolic VIM (variation independent of mean) between DASH and Control diet groups: 0.49
• 95% CI: -0.05 to 1.03, which crosses zero and is therefore not statistically significant
• Analysis pooled data from both the DASH and DASH-Sodium trials
• Week-to-week office BP variability was the primary outcome measure

The DASH diet did not significantly differ from the Control diet in 24-hour ambulatory systolic blood pressure variability.

• Difference in 24-h systolic VIM between DASH and Control diet groups: 0.37
• 95% CI: -0.13 to 0.87, which crosses zero and is therefore not statistically significant
• 24-h ambulatory BP measurements were used to quantify ambulatory BPV
• BPV was quantified using variation independent of the mean (VIM) as the primary metric

Higher versus lower sodium intake did not produce significant differences in blood pressure variability in the DASH-Sodium trial.

• Difference in VIM for week-to-week systolic BP between higher and lower sodium levels: 0.31
• 95% CI: -0.10 to 0.72, which crosses zero and is therefore not statistically significant
• Analysis was conducted within the DASH-Sodium trial specifically
• Both office and 24-h ambulatory BPV were assessed across sodium levels

No significant combined or interactive effects of dietary pattern and sodium level on blood pressure variability were observed.

• Interactive effects between dietary patterns and sodium intake were assessed using multivariate linear regression models
• Neither combined nor interactive effects reached statistical significance
• This finding held for both week-to-week office BPV and 24-h ambulatory BPV measures

Blood pressure variability was quantified using variation independent of the mean (VIM) as the primary analytical method in both trials.

• VIM was used because it is independent of the mean BP level, allowing fair comparison across groups with different absolute BP levels
• Both week-to-week office BPV and 24-h ambulatory BPV were quantified using VIM
• Between-group comparisons were performed using t-tests
• The study utilized data from two separate trials: the DASH trial and the DASH-Sodium trial

The study concluded that BP-related cardiovascular benefits of the DASH diet and sodium reduction likely result from reducing absolute BP rather than reducing BPV.

• In observational studies, BPV has been independently associated with adverse cardiovascular disease outcomes
• The DASH diet and sodium reduction are known to lower absolute BP and cardiovascular risk
• Despite lowering absolute BP, neither intervention significantly affected BPV
• This dissociation suggests the mechanism of cardiovascular benefit operates through absolute BP reduction rather than BPV reduction