Relationship between inter-arm systolic blood pressure difference and carotid artery plaque in middle-aged and elderly adults

Objective To explore the relationship between inter-arm systolic blood pressure difference（sIAD） and carotid artery plaque in middle-aged and elderly adults. Methods Cross-sectional design was applied in the study. Using a random stratified sampling method, a total of 5 816 subjects aged 40 and over were selected from 101 510 workers in Kailuan Group who participated in the health examination from 2006 to 2007. Subsequently, 5 011 subjects who met the inclusion criteria and had complete data（regarding blood pressure on both arms and carotid ultrasound） in 2010-2011 were included in final analysis. Simultaneous systolic blood pressure measurements of both arms were recorded to calculate sIAD. The subjects were divided into sIAD＜10 and ≥10 mm Hg group. And the relationship between sIAD and carotid artery plaque were analysed. Results The detection rate of carotid artery plaque was 42.0% and 47.3% in the sIAD＜10 and ≥10 mm Hg group, respectively（χ~2=4.89, P=0.03）. In the subjects aged 40-＜60 years, the detection rate of carotid artery plaque in sIAD＜10 and ≥10 mm Hg group was 28.3% and 37.1%（χ~2=12.19, P＜0.01） respectively. And in the subjects aged 60 and above, the rate was 77.6% and 82.9%, respectively（χ~2=1.59, P=0.21）. Multiple logistic regression analysis showed that sIAD ≥10 mm Hg was an independent risk factor of carotid plaques（OR=1.33, 95%CI 1.06-1.67） after adjusting for confounding factors. In the subjects aged 40-＜60 years, the OR of carotid plaque with sIAD≥10 mm Hg was 1.31（95%CI 1.01-1.68）. In the subjects aged 60 and above, which was 1.48（0.84-2.62）. Conclusion sIAD≥10 mm Hg is an independent risk factor of carotid plaque in adults aged 40-＜60 years.