Sleep disturbances : Consequences and comorbidities

Sammanfattning: Background: Sleep disorders are common in the general population, with insomnia and sleep-related breathing disorders being the most common disorders. Since sleep has many important functions, such as a role in consolidation of memories and learning, energy conservation, cardiovascular and immune system regulation, it is not surprising that the disruption of normal sleep may lead to negative health effects and various comorbidities.  Aim: The overall aim of this thesis was to investigate the impact of disturbed sleep on various consequences and comorbidities. Methods and results: Papers I and II were based on the Sleep and Health in Women (SHE), a population-based prospective study of women, where a questionnaire was sent to women in 2000 and 2010. In paper I, the study cohort comprised 4,320 women <67 years of age who answered both questionnaires and had worked during the follow-up period. In women, having a long history of insomnia symptoms was associated with an increased risk of self-reported occupational accidents.In paper II, the 4,882 participants who answered the questions regarding nocturnal gastroesophageal reflux and snoring in both questionnaires were included in the study cohort. Women with nocturnal gastroesophageal reflux and snoring were at an increased risk of developing daytime sleepiness and to involuntarily fall asleep during the day. Paper III was based on the RHINE-cohort with participants from seven Northern European centers. The study cohort in paper III comprised the 2,568 smokers in the baseline study that also reported being smokers or former smokers in the follow-up study. It was found that having insomnia symptoms or excessive daytime sleepiness decreases the chance of long-term smoking cessation, and that smoking increases the risk of incident difficulties inducing sleep. Paper IV was the population-based, cross-sectional GA2LEN-survey which was conducted in four major Swedish cities. Paper IV included the 25,901 participants who answered questions regarding both snoring and insomnia symptoms. The combination of snoring and insomnia symptoms was associated with an increased risk of hypertension, asthma, chronic obstructive pulmonary disease, and daytime sleepiness. Conclusions: Disturbed sleep, due to varying causes, influences the risk of occupational accidents, on the chance of successful smoking cessation, on the risk of daytime sleepiness, hypertension, and obstructive lung disease. In clinical consultation, it is important to always inquire about disturbed sleep as it can have an impact on many aspects of health.