P103 Associations between sleep regularity, OSA and hypertension in a middle-aged community population

Little is known about the association of irregular sleep patterns with obstructive sleep apnoea (OSA) and hypertension. This study examined whether irregular sleep patterns determined by the sleep regularity index (SRI) were associated with OSA and hypertension, and whether SRI modified the known association between OSA and hypertension. 635 adults (age mean[range]=57[42-77]years, female=58.6%) from the community-based Raine Study who were not current shift workers were assessed for OSA (in-laboratory polysomnography, AHI ≥5events/hour; time spent with oxygen saturation <90% (T90) ≥median), hypertension (doctor diagnosed or systolic BP ≥140mmHg and/or diastolic ≥90mmHg) and sleep (maximum 7 days of wrist actigraphy). The SRI was calculated from actigraphy (≥4 days) based on variation in usual sleep and wake times. Participants were categorised as regular sleepers (first tertile), average sleepers (second tertile), or irregular sleepers (third tertile). Logistical regression models examined the independent and combined associations between SRI, OSA and hypertension. Covariates included age, sex, body mass index, actigraphy sleep duration, insomnia, depression, activity, alcohol, smoking and anti-hypertensive medication. Compared to regular sleepers, irregular sleepers had increased odds of OSA defined by the AHI (OR 1.77 95% CI 1.10-2.83) and T90 (OR 1.69 95% CI 1.10-2.61) but not hypertension. There was no difference in hypertension odds for regular and irregular sleepers when the data were stratified by participants with and without OSA. Individuals with OSA are more likely to have irregular sleep patterns, which might exacerbate associated adverse health outcomes. However, irregular sleep patterns do not appear to modify the association between OSA and hypertension.