[Association between long term systolic blood pressure variability index and cognitive function in middle-aged and elderly people].

OBJECTIVE

To investigate the association between different long term systolic blood pressure variability (SBPV) and cognitive function in middle-aged and elderly people.

METHODS

A total of 101 510 employees from the Tangshan Kailuan Group participated in the 2006-2007 annual physical examination, 5 440 cases were selected by simple randomly sampling method. After excluding participants who did not underwent 2012-2013 examination and without complete blood pressure and mini-mental state examination (MMSE) score, 3 002 participants (1 627 males, (50.86±9.93) years old) with integrated data were included into the study. The long term SBPV was calculated by standard deviation(SD), maximum-minimum difference(MMD), average real variability (ARV) of mean systolic blood pressure measured in 2006-2007, 2008-2009, 2010-2011 and 2012-2013. Participants were grouped by the quartile of the different SBPV index. Multiple linear regressions analysis was used to analyze the correlation between the long term SBPV and cognitive function status.

RESULTS

(1) The score of MMSE was 28.03±2.65. (2) The observation population was divided into four groups according to quartiles of different SBPV, respectively. The MMSE scores of SD<5.53 mmHg (1 mmHg=0.133 kPa)group, SD 5.53-8.90 mmHg group, SD 8.91-12.79 mmHg group and SD>12.79 mmHg group were 28.21±2.18, 28.26±3.09, 28.10±2.40 and 27.56±2.79, respectively(P<0.05). The MMSE scores of MMD<12.00 mmHg group, MMD 12.00-20.00 mmHg group, MMD 20.01-30.00 mmHg group and MMD>30.00 mmHg were 28.27±2.17, 28.25±3.09, 27.99±2.42 and 27.49±2.81, respectively(P<0.05). The MMSE scores of ARV<6.67 mmHg group, ARV 6.67-10.22 mmHg group, ARV 10.23-15.56 mmHg group and ARV>15.56 mmHg group were 28.27±2.20、28.28±3.20、28.00±2.42、27.57±2.65, respectively(P<0.05). (3) Adjusted for age, gender, baseline systolic blood pressure, body weight index, total cholesterol, fasting blood glucose, triglyceride, C reactive protein, smoke, drink, physical activity , the step-wise regressions analysis showed that SD(B=-0.129, P<0.05), MMD(B=-0.131, P<0.05), ARV(B=-0.125, P<0.05) had significant negative linear relationship with the MMSE score in the objects not taking the anti-hypertension drugs, and SD(B=-0.329, P<0.05), MMD(B=-0.314, P<0.05), but not ARV(B=-0.233, P>0.05), had significant negative linear relationship with the MMSE score in the objects taking the anti-hypertension drugs.

CONCLUSION

The long term SBPV indexes (SD, MMD, ARV ) are negatively correlated with the MMSE score in middle-aged and elderly people not taking the anti-hypertension drugs, and SD, MMD are negatively correlated with the MMSE score in people taking the anti-hypertension drugs. Clinical Trail Registry: Chinese Clinical Trail Registry, ChiCTRTNC-11001489.