Is the Association between Sleep Disordered Breathing and Night and Morning Blood Pressure Modified by Sleep Quality?: Toon Health Study
Methods:Participants of this study is 2,033 men and women aged 30-79 who participated in Toon Health Study between 2009 and 2012. We excluded 98 persons due to the missing information of sleep quality, severity of SDB and home blood pressure (BP), and enrolled 1,935 for analysis. Sleep quality in the last month was evaluated by Pittsburgh Sleep Quality Index (PSQI) with seven components of 21 as full score. We defined ≥6 as sleep quality deteriorated. Severity of SDB was measured by flow-respiratory disturbance index (flow-RDI) and graded according to normal to mild (0-9.9), moderate (10.0-19.9), and severe (≥20.0). Morning BP was monitored for a week, and morning BP >135/85mmHg and hypertensive medication use were defined as morning hypertension. Logistic regression model was used to calculate age-adjusted and multivariable-adjusted odds ratio (OR) of morning hypertension for severity of SDB according to sleep quality status.
Results:Severity of SDB was associated with morning hypertension, and the association was kept after multivariable adjustment. When stratified by sleep quality status, this association was found only for those with deteriorated sleep quality. Respective multivariable-adjusted OR of morning hypertension was 0.94 (0.69-1.28) and 1.14 (0.78-1.68) for moderate and severe SDB for PSQI<6, and 1.93 (1.30-2.86) and 1.84 (1.13-3.01), respectively for PSQI≥6. (p for interaction was 0.01 for moderate SDB).
Conclusions:The association between SDB and morning hypertension was modified by sleep quality. Persons with deteriorated sleep quality together with SDB may have higher possibility of having hypertension.