Incidence of sleep apnea syndromes in general patients at a hospital for internal medicine.

Incidence of sleep apnea syndromes in the general population in Japan is unknown. To investigate this incidence in Japan, sleep apnea syndromes were carefully diagnosed for all patients who visited a private hospital located in Naka Ward, Nagoya, from November 1, 1983, until April 30, 1985. A total of 9132 patients were examined by four doctors. Insomnia, heavy snoring, daytime hypersomnia, shortthick neck, hypertrophied tonsils, obesity, and micrognathia were considered important clues for diagnosis of sleep apnea syndromes. Patients with signs and symptoms of possible sleep apnea syndromes underwent either an ear-oximeter test or a recording of snoring. Final diagnosis was determined by polysomnography. Sleep apnea syndromes were diagnosed in 26 (23 males and 3 females) out of 9132 patients, the percentage among general patients being 0.285%. The percentage was specifically high (0.785%) in male patients between the age of 40 and 69; and 19 out of all 26 patients with sleep apnea syndromes were in this age group. Among the 26 sleep apnea patients, 17 had hypertension, 9 had diabetes mellitus, and 5 suffered from depression. The percentage of patients with sleep apnea syndromes in this study might actually have been higher because there were more than six patients with suspicious symptoms, whose diagnostic work-up could not be completed.