NATURAL EVOLUTION OF SLEEPINESS - A 5-YEAR FOLLOW-UP-STUDY IN A MIDDLE-AGED POPULATION

The prevalence and natural evolution of sleepiness were investigated i n a 5-year follow-up study in a middle-aged population in Finland. In the original study a structured sleep questionnaire was completed by 1 190 subjects and a 5-year follow-up questionnaire was returned by 626. The prevalence of sleepiness, meaning here an unintentional tendency to fall asleep weekly in the course of everyday living, was 9.6% in th e first survey and 10.6% 5 years later in the same cohort; 3.7% had be en sleepy in both surveys. Sleep fragmentation, leg jerking and awaken ings during sleep were common findings among sleepy subjects in both s urveys. Shift-workers and those who had irregular working hours ran a risk of chronic sleepiness. Sleepiness was also associated with poor s ubjective health, obesity, depression, nervousness and tension. In par ticular, chronically sleepy subjects had an increased risk of sleepine ss-related traffic accidents and premature retirement. Contrary to com mon findings from sleep laboratories, neither snoring nor self- or spo use-reported breathing pauses during sleep were significantly associat ed with long-term sleepiness in a non-selected middle-aged population. It is suggested that more attention should be paid to subjects suffer ing from excessive daytime sleepiness even if they do not have a histo ry of respiratory or other known organic sleep disorder. Eur J Neurol 5:355-363 (C) 1998 Lippincott-Raven Publishers.