[The correlation between blood pressure response to cold pressor test and long-term blood pressure changes]

Objective: The aim of the study was to investigate the correlation between blood pressure response to cold pressor test (CPT) and follow-up blood pressure after 8 years in subjects, and to evaluate the predictive value of CPT for long-term blood pressure levels. Methods: A total of 365 individuals from eight natural villages were enrolled by stratified cluster sampling from Mei County, Shaanxi Province in 2004. Baseline characteristics of subjects were collected and CPTs were conducted. Subjects were followed up in 2009 and 2012, respectively. According to the maximal change of systolic response (SR), the area under the curve (AUC) of systolic blood pressure change (AUC-SBP), the maximal change of diastolic response (DR) and the AUC of diastolic blood pressure change (AUC-DBP) in CPT, the individuals were divided into four quartile groups by above parameters, respectively: group Ⅰ (P(25)), group Ⅱ (P(50)), group Ⅲ (P(75)) and group Ⅳ (P(100)). The correlation between blood pressure response to CPT and the follow-up blood pressure was analyzed. Results: (1) There were no significant differences in baseline blood pressure levels and prevalence of hypertension among four quartile groups no matter it was grouped on SR, DR, AUC-SBP or AUC-DBP. (2) The prevalence of hypertension in each group from lowest (P(25)) to highest (P(100)) in 2012 was 25.64%, 30.67%, 38.03%, 55.74% on SR grouping (P<0.01), and 27.5%, 29.17%, 38.46%, 57.35% on AUC-SBP grouping (P<0.05), respectively. (3) There were no significant differences in the prevalence of hypertension among four groups in 2012 (P>0.05) either on DR or on AUC-DBP grouping. (4) The random effects model analysis showed that the correlation coefficient between SR, AUC-SBP and long-term systolic blood pressure increase were 1.91 (P<0.05) and 1.44 (P<0.05), respectively, and the correlation coefficient between DR, AUC-DBP and long-term diastolic blood pressure increase were 0.82 (P<0.05) and 0.78 (P>0.05), respectively. Age, male, body mass index, and fasting blood glucose were independent risk factors for long-term blood pressure elevation, and age, body mass index and fasting blood glucose positively correlated with changes in long-term blood pressure (all P<0.05). Conclusion: Individual systolic blood pressure response to CPT can be used as a predictor of long-term hypertension.

Effect of salt intake and potassium supplementation on brachial-ankle pulse wave velocity in Chinese subjects: an interventional study

Accumulating evidence has suggested that high salt and potassium might be associated with vascular function. The aim of this study was to investigate the effect of salt intake and potassium supplementation on brachial-ankle pulse wave velocity (PWV) in Chinese subjects. Forty-nine subjects (28-65 years of age) were selected from a rural community of northern China. All subjects were sequentially maintained on a low-salt diet for 7 days (3.0 g/day NaCl), a high-salt diet for an additional 7 days (18.0 g/day NaCl), and a high-salt diet with potassium supplementation for a final 7 days (18.0 g/day NaCl+4.5 g/day KCl). Brachial-ankle PWV was measured at baseline and on the last day of each intervention. Blood pressure levels were significantly increased from the low-salt to high-salt diet, and decreased from the high-salt diet to high-salt plus potassium supplementation. Baseline brachial-ankle PWV in salt-sensitive subjects was significantly higher than in salt-resistant subjects. There was no significant change in brachial-ankle PWV among the 3 intervention periods in salt-sensitive, salt-resistant, or total subjects. No significant correlations were found between brachial-ankle PWV and 24-h sodium and potassium excretions. Our study indicates that dietary salt intake and potassium supplementation, at least in the short term, had no significant effect on brachial-ankle PWV in Chinese subjects.