BMI modifies the association of obstructive sleep apnea with morning blood pressure in East Asian adults.

BACKGROUND

Obstructive sleep apnea is strongly linked to hypertension, yet most evidence derives from Western populations in whom obesity is common. Because East Asian adults frequently develop obstructive sleep apnea at lower body mass index, it remains unclear whether body mass index modifies the association between obstructive sleep apnea severity and morning blood pressure in this population.

METHODS

A total of 1849 adults aged 18-92 years underwent overnight, in-hospital polysomnography. Morning brachial blood pressure was measured twice in the seated position after 5 minutes of rest. Obstructive sleep apnea severity was quantified using the apnea-hypopnea index. Generalized linear models evaluated independent and interactive associations of body mass index and apnea-hypopnea index with systolic and diastolic blood pressure, adjusting for relevant covariates, including antihypertensive medication use.

RESULTS

A significant body mass index × apnea-hypopnea index interaction was observed for both systolic and diastolic blood pressure (p < .01), indicating that the association between obstructive sleep apnea severity and morning blood pressure varied across body mass index, for example, a 20-unit increase in apnea-hypopnea index was associated with larger increases in systolic/diastolic blood pressure at lower body mass index (∼3/1.5 mmHg at body mass index 20 kg/m²) than at higher body mass index (∼1.1/0.1 mmHg at body mass index 30 kg/m²). In sensitivity analyses using nocturnal hypoxemia (T <90%), a body mass index-dependent association was observed for systolic but not diastolic blood pressure.

CONCLUSION

These findings suggest that the association between obstructive sleep apnea severity and morning blood pressure differs across the body mass index spectrum, underscoring the importance of considering both obstructive sleep apnea burden and body weight in cardiovascular risk assessment, particularly in East Asian populations.