Dietary Approaches to Stop Hypertension (DASH)-Style Dietary Pattern and 24-Hour Ambulatory Blood Pressure in Elderly Chinese with or without Hypertension

Background It is unknown whether the Dietary Approaches to Stop Hypertension (DASH) dietary pattern is associated with other blood pressure (BP) variables, beyond mean systolic blood pressure (SBP) and diastolic blood pressure (DBP). Objectives The study aimed to study the associations between the DASH dietary pattern and daytime and nighttime mean BPs and BP variance independent of the mean (VIM). Methods A sample of 324 Chinese adults aged >= 60 y who were not on BP-lowering medications were included in the analysis. The DASH score was calculated using data collected by a validated FFQ. The 24-h ambulatory BP was measured and the mean and VIM SBP and DBP were calculated for both the daytime (06:00-21:59) and nighttime periods (22:00-05:59). Multivariable linear models were constructed to assess associations between the DASH dietary pattern and daytime and nighttime BP outcomes, adjusting for sociodemographic factors, lifestyle, BMI, and hypertension (clinic SBP >= 140 mm Hg or DBP >= 90 mm Hg), and sleep parameters (only for nighttime BP outcomes). An interaction term between DASH score and hypertension status was added to explore the potential differential association in normotensive and hypertensive individuals. Results Every 1-unit increase in the DASH score was associated with a 0.18-unit (95% CI: -0.34, -0.01 unit) and a 0.22-unit (95% CI: -0.36, -0.09 unit) decrease in nighttime VIM SBP and nighttime VIM DBP, respectively. DASH score was not associated with any daytime BP outcomes, nighttime mean SBP, or nighttime mean DBP. A significant interaction (DASH score x hypertension status) was detected for VIM SBP (P-interaction = 0.04), indicating a differential association between DASH score and nighttime VIM SBP by hypertension status. Conclusions Independently of sleep parameters and other factors, the DASH dietary pattern is associated with lower nighttime BP variability in elderly adults.