Nocturnal awakenings and difficulty resuming sleep: their burden in the European general population.

OBJECTIVES: To (1) define the prevalence and importance of nocturnal awakenings (NA) in the general population, and (2) investigate its associations with daytime impairment, physical diseases, and psychiatric disorders.
METHODS: This is a cross-sectional telephone study conducted in the general population of France, United Kingdom, Germany, Italy, and Spain. A representative sample consisting of 22,740 non-institutionalized individuals aged 15 or over was interviewed regarding sleeping habits, health, sleep and mental disorders. Nocturnal awakenings were evaluated according to their frequency per week and per night and their duration.
RESULTS: At the time of the interview, 31.2% (95% confidence interval: 30.6-31.8%) of the sample reported waking up at least 3 nights per week and 7.7% (7.4% to 8.0%) of the sample had difficulty resuming sleep (DRS) after they woke up. Duration of the symptom was longer than one year in 78.8% of the cases. DRS had greater impacts on daytime functioning than any other kind of NA or other insomnia symptoms with odds ratios five to seven times higher than individuals waking up once or twice within the same night. Individuals with painful physical condition or with a psychiatric disorder were more than four times more likely to have DRS. Other significant factors associated with NA were hypertension, cardio-vascular disease, upper airway disease, diabetes, and heavy caffeine consumption.
CONCLUSIONS: Nocturnal awakenings are highly prevalent in the general population and strongly associated with various physical diseases and psychiatric disorders. There is also a dose response effect in the associations: odds ratios increased with the number of awakenings during the same night and the difficulty resuming sleep once awakened. The study shows that nocturnal awakenings are complex and should be assessed systematically.