SALT LAKE CITY – Increased caffeine intake was associated with better cognitive functioning in patients with obstructive sleep apnea, according to the results of a small study.
In 42 patients with untreated obstructive sleep apnea, a statistically significant inverse relationship was found between caffeine intake and a global deficit score that was derived from an aggregate measure of neuropsychological functioning, Dr. Daniel Norman reported at the annual meeting of the Associated Professional Sleep Societies.
The association persisted after controlling for body mass index and apnea-hypopnea index, said Dr. Norman of the University of California, San Diego.
Patients had a mean apnea-hypopnea index of 63 episodes per hour, indicating severe sleep apnea. The neuropsychological assessment battery included tests of speed of information processing, executive functioning, memory skills, verbal skills, and attention and working memory domains.
Caffeine intake was assessed using a detailed instrument that has been shown to characterize usual caffeine consumption based on 24-hour recall.
Daily caffeine intake in cognitively impaired patients was one-sixth that of non-cognitively impaired patients (30 mg vs. 180 mg), Dr. Norman said. Previous findings that obstructive sleep apnea patients consume three times the caffeine of nonapneic individuals on a daily basis led to speculation that those with sleep apnea were self-medicating with caffeine to counteract daytime sleepiness. Caffeine has been shown to enhance cognition, and the findings of the current study suggest this is an additional effect experienced by those who use caffeine for that purpose.