Abstract: Objective To exposure the association of oxygen saturation of arterial hemoglobin (SaO2) with late-onset hypertension in the Chinese Han population located at the Daxinganling area. Methods A total participants were selected by convenience sampling methods from the Daxinganling area. All data were obtained from each person by the questionnaire and standard physical examinations as well as biochemical index measuring. SaO2 was measured noninvasively with finger pulse oxymetry, the reported SaO2 is the average of three readings taken 10 seconds apart. Results The results showed there are significant differences for SaO2 within the population of individuals, the mean SaO2 values was 97.71%±6.14%, with region from 88% to 100%(n=2128). There were association of SaO2 with sex, BMI and age. SaO2 level declined with BMI and age increasing. Particularly, it was found that the risk increasing to hypertension is marked association with SaO2 rapid drop. During the period from 40-50 years of age, SaO2 declined from 97.85% to 97.64%, The risk to hypertension increased more than 10 times (p<0.001). That implicated hypoxia might involve in the etiology of hypertension. Conclusion The preliminary results demonstrated the rapid decline of SaO2 with lapse of age may be one of the major risk factors to hypertension, it may be helpful to explain late-onset hypertension to some extent at least.

Key words: Oxygen Saturation of arterial hemoglobin (SaO2), essential hypertension, late-onset, sex difference, age-dependent.