Evolution of Sleep-Disordered Breathing across the Adult Years

The prevalence of obstructive sleep apnea (OSA) increases with aging in the adult, but the precise prevalence estimates depend on how OSA is defined, with variability stemming from the definition of hypopnea, the number of events per hour that qualify as disease, and whether associated daytime symptoms are required. Aging is associated with several changes to upper airway physiology and neurophysiology that likely contribute to the increased prevalence of OSA with aging, including reduced slow wave sleep, reduced arousal threshold, increased pharyngeal collapsibility, and increased pharyngeal resistance. Additionally, in women, the loss of sex hormones stemming from menopause leads to both increased fat mass and fat redistribution favoring the trunk, as well as reduced peak phasic and tonic genioglossus tone, all of which can contribute to the onset or worsening of OSA. Although daytime sleepiness is a very common consequence of OSA, sleepiness is less common in elderly individuals versus young and middle-aged individuals with equivalent OSA severity. Depression and cardiovascular disease, broadly defined, are risks associated with OSA in middle age. With further aging into late adulthood, specific risk for coronary vascular disease from OSA appears to diminish, whereas risk for cerebrovascular disease remains elevated. In late life, OSA is associated with increased accumulation of beta-amyloid and tau, pathogenic proteins in Alzheimer disease, and may accelerate the pace of cognitive decline.