Mild-to-moderate sleep apnea is associated with incident hypertension: age effect

Mild-to-moderate obstructive sleep apnea (OSA) is highly prevalent in the general population; however, previous studies on its association with incident hypertension are mixed. We examined the association between mild and moderate OSA and incident hypertension in a large random general population sample.

From 1741 adults of the Penn State Cohort, 744 adults without hypertension or severe OSA (i.e. apnea/hypopnea index [AHI] ≥ 30 events/hour) were followed-up after 9.2 years. Mild OSA was defined as an AHI of 5 to 14.9 events/hour (n = 71), while moderate OSA as an AHI of 15 to 29.9 events/hour (n = 32). Incident hypertension was defined by a self-report of receiving antihypertensive medication and/or history of a diagnosis since their baseline study.

After adjusting for multiple potential confounders, mild-to-moderate OSA was significantly associated with increased risk of incident hypertension (overall hazard ratio [HR] = 2.94, 95% confidence interval (CI) = 1.96-4.41; HR = 3.24, 95% CI = 2.08-5.03 for mild OSA and HR = 2.23, 95% CI = 1.10-4.50 for moderate OSA). Importantly, this association was modified by age (p-interaction < 0.05); while strong in young and middle-aged adults (HR = 3.62, 95% CI = 2.34-5.60), the association was lost in adults older than 60 years (HR = 1.36 95% CI = 0.50-3.72). Furthermore, the association of mild-to-moderate OSA with components of metabolic syndrome was strongest in young and middle-aged adults.

Mild-to-moderate OSA, even when asymptomatic, is associated with increased risk of incident hypertension, but the strength of association significantly decreases with age. Although older participants with asymptomatic mild-to-moderate OSA are not at significant risk of developing hypertension, early detection and intervention, including improving metabolic indices, is especially warranted in young and middle-aged adults.