Risk of cancer in patients with insomnia: Nationwide retrospective cohort study (2009-2018).

PURPOSE

To investigate the association between insomnia and the risk of various cancers using the Korean National Health Insurance Service database.

MATERIALS AND METHODS

Patients who underwent a national health examination in 2009 were followed-up until 2018. Newly-diagnosed cancers were collected one year after the baseline. Insomnia was defined as having a diagnosis of F510 or G470 within one year prior to enrollment. The incidence of various cancers was compared between patients with and without insomnia.

RESULTS

In the overall study population (N = 3,982,012), the risk for any type of cancer was not different between controls and insomnia patients (adjusted hazard ratio [aHR]: 0.990). However, it was different by age; insomnia increased the risk of any cancer in younger age groups (20-39y and 40-59y, aHR:1.310 and 1.139, respectively) but it significantly decreased the risk in the 60-79y age group (aHR: 0.939). In cancer type, colorectal cancer risk was lower (aHR: 0.872, P < 0.0001), whereas leukemia risk was higher (aHR: 1.402, P < 0.0001) in patients with insomnia than in those without it, regardless of sex. In men, the risk of stomach cancer was lower (aHR: 0.882, P = 0.0003), and the risks of lung (aHR:1.114, P = 0.0005), kidney (aHR 1.226, P = 0.0107), and prostate (aHR:1.101, P = 0.0028) cancers were higher in insomnia patients than in control patients. In women, insomnia patients compared to control patients showed a lower risk of ovarian cancer (aHR:0.856, P = 0.0344, respectively), while they had a higher risk of oral (aHR:1.616, P = 0.002), thyroid (aHR:1.072, P = 0.0192), and nerve (aHR: 1.251, P = 0.016) cancers.

CONCLUSION

Insomnia is associated with an increased or decreased risk of some cancers, depending on age, cancer type and sex.