Study objective: To assess the association between sleep-disordered breathing and cognitive functioning in an elderly cohort of Japanese-American men.
Design: Cross-sectional study.
Setting: The Honolulu-Asia Aging Study of Sleep Apnea, Oahu, Hawaii.
Participants: 718 men between 79 and 97 years of age examined in 1999 and 2000.
Measurements: Apnea-hypopnea index from in-home overnight polysomnography, performance on the Cognitive Abilities Screening Instrument, body mass index, neck circumference, Epworth Sleepiness Scale, snoring, Center for Epidemiologic Studies Depression 11-item depression scale, physical disability, and history of heart disease, stroke, hypertension, diabetes, and dementia.
Results: Less than 30% of the men had no sleep-disordered breathing (apnea-hypopnea index < 5) and nearly one-fifth (19%) had severe sleep-disordered breathing (apnea-hypopnea index > or = 30). Severe sleep-disordered breathing was associated with higher body mass index, habitual snoring, and daytime drowsiness. No association was found between sleep-disordered breathing and cognitive functioning, including measures of memory function, concentration, and attention.
Conclusions: Sleep-disordered breathing was associated with more drowsiness but not with poor performance on standardized cognitive tests used to screen for Alzheimer disease and other dementias in older persons. Because a healthy-participant effect may have contributed to this finding, more extensive cognitive testing may be necessary to reveal more subtle deficits from sleep-disordered breathing.