LAUSR

Objectives: This study aimed to investigate the influence factor of orthostatic hypotension (OH) in plateau region, and the difference between plateau and plain region among middle-aged and older adults. Methods: A total of 445 plateau residents aged 63.39 ± 8.37 years form Jiulong County, Ganzi at altitude 2950m and 418 plain residents aged 64.02 ± 8.06 years from Jingyang Community, Chengdu at altitude 500m were included in this study. OH was defined as a decline in systolic BP and/or diastolic BP of at least 20/10 mm Hg at either 30 s or 2 min from supine to upright posture. Results: Of 39% the plateau residents were male, 65.8% had hypertension. The prevalent of OH was 9%. The participants with OH had older age, higher prevalent of hypertension, higher baPWV and CIMT. There were no significant difference between two groups in race, lifestyle, oxygen saturation, hematocrit, spot urinary sodium and centarl BP. The logistic regression analysis showed that only baPWV and IMT were influencing factors of OH. Further compared with plain residents, there was no significance difference in age, gender and systolic BP, however the plateau residents had higher prevalent of OH and baPWV (9.0% vs 4,1% P = 0.004; 19.16 ± 5.33 vs 17.51 ± 3.59 P = 0.001). Combined with plateau and plain residents as a whole, the participants with OH had older age, higher prevalent of hypertension, total cholesterol and baPWV. Logistical regression analysis showed BaPWV was the only risk factor of OH. Further logistical regression analysis identified PWV as dependent variable showed plateau was risk factor of baPWV. Conclusion: Increased arterial stiffness was the main influence factor of OH whether on the plateau or plain region. Higher arterial stiffness on the plateau region may contribute to higher prevalent of OH.