Inclusion: 212 patients with colorectal cancer will be investigated before surgery and 100 of them will also be investigated in the same manner after surgery. Due to drop-outs we calculate a need of inviting at least 250 patients.
Controls: 597 individuals from a previous population based study will serve as controls to the prevalence of sleep apnea in the general population.
Exclusion: Dementia, CPAP treated sleep apnea investigations: Patients are investigated with lung function, blood-gas samples, questionnaires, overnight polysomnographic sleep apnea recordings including oro-nasal airflow, thoraco-abdominal respiration belts, chin-EMG, EOG, EEG, ECG (V5) and body position.
Controls: Men and women from two population-based cohort studies the "Sleep and health in women" and the "Men in Uppsala: A Study of Sleep, Apnea and Cardiometabolic Health" and older men and women from a local senior organization.
Outcomes: Prevalence of sleep apnea and hypoxia, sleep quality, and lung function, blood gas, STOP-BANG, Epworth sleepiness scale, Mallampati score, symptoms of sleep apnea, surgical complications, mortality, cancer severity.
