Objectives: To determine whether poor cognitive performance was associated with symptoms related to the sleep apnea syndrome, snoring, and breathing stoppage during sleep.
Design: Cross-sectional analysis of data collected at baseline in the EVA Study, a 4-year cohort study.
Setting: The city of Nantes in western France.
Sample: A total of 1389 persons, aged 60 to 70 years, recruited from the electoral rolls of the city of Nantes.
Measurements: Demographic characteristics and data on drug use and tobacco and alcohol consumption were collected using a standardized questionnaire. Weight and height were measured. Individuals completed a previously validated sleep questionnaire about nocturnal sleep characteristics, snoring, breathing stoppage during sleep, and day-time sleepiness. Trained psychologists administered eight neuropsychological tests: The Mini-Mental State Examination, Trail Making Test, Digit Symbol Substitution Test of the WAIS-Revised, Benton Visual Retention Test, Paced Auditory Serial-Addition Task, Auditory Verbal Learning Test, Raven Progressive Matrices, and Word Fluency Test. Depressive symptomatology was assessed by the Center for Epidemiologic Studies-Depression scale.
Main results: In this older sample, 49.5% of subjects reported snoring, and 10.8% reported breathing stoppage during sleep. Both respiratory disorders were associated significantly with male gender and high body mass index. In men, prevalence of snoring was increased significantly in those with alcohol consumption greater than 40 mL per day. Breathing stoppage during sleep was associated with depressive symptoms in women. Logistic regression models adjusted for age, gender, educational level, tobacco status and alcohol consumption, depressive symptomatology, and number of medications found that both snoring and breathing stoppage were associated with low scores (< or = 10th percentile) in tests requiring visual attention skills, the Trail Making Test (OR = 2.14, 95% CI = 1.24-3.69 and OR = 1.88, 95% CI = 1.04-3.39, respectively), and the Digit Symbol Substitution Test (OR = 1.80, 95% CI = 1.09-2.99 and OR = 1.58, 95% CI = .87-2.89, respectively). These relationships were significant only when either snoring or breathing stoppage was associated with daytime sleepiness.
Conclusions: This cross-sectional analysis suggested that in community-dwelling individuals 60 to 70 years of age, snoring and breathing stoppage during sleep associated with daytime sleepiness were risk factors for low cognitive performance in tests requiring visual attention skills.