Impact of obstructive sleep apnea on long-term blood pressure variability in Japanese men: a cross-sectional study of a work-site population.

Blood pressure variability (BPV) has been shown to be associated with cardiovascular diseases. The effects on long-term BPV of obstructive sleep apnea (OSA) are not yet known. We evaluated a total of 1653 Japanese male workers (18-69 years) at a work site to diagnose OSA, and we divided them into three groups: non-OSA (apnea-hypopnea index (AHI): < 5, n = 1414), mild-to-moderate OSA (5 ≤ AHI < 30: n = 131) and severe OSA (AHI ≥ 30: n = 108). The standard deviation and coefficient of variation of the subjects' BPV were calculated by using their annual blood pressure measurements at routine physical examinations from 2012 to 2015 (four measurements). The multivariable-adjusted BPV of systolic blood pressure (SBP) was significantly higher in the severe-OSA group compared to the non-OSA group. A multiple regression analysis also revealed that OSA was positively associated with BPV of SBP. We focused on the mild-to-moderate OSA group to evaluate the association of OSA treatment with BPV, because most of the severe-OSA subjects were being treated with continuous positive airway pressure or an oral appliance. The BPV of both systolic and diastolic blood pressure was significantly decreased in the treated subjects. These findings suggest that OSA is associated with increases in long-term BPV which was improved by the treatment of OSA in Japanese men of a work-site population.