A prospective cohort study of insomnia and chronic kidney disease in Japanese workers.

Purpose: The role of insomnia in chronic kidney disease (CKD) is controversial. To date, there have been no prospective studies investigating insomnia, CKD and the effect of shift work. We assessed insomnia and CKD risk in a prospective, occupational cohort study.

Methods: A total of 3600 participants with normal kidney function were followed for an average of 4.4 years. Insomnia was assessed using the Athens Insomnia Scale (AIS). CKD was defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m at the first health examination. Cox proportional hazard regression models were used to estimate hazard ratios with 95% confidence intervals of insomnia for CKD development.

Results: A total of 182 CKD cases were identified. After adjustment for potential confounders, we did not observe an association between insomnia (AIS score ≥6) and CKD. However, the AIS item of awakening during the night was associated with a significantly increased CKD risk (hazard ratio = 3.10, 95% confidence interval 1.68-5.30). In further analyses, having difficulty with sleep induction was associated with an increased CKD risk among shift workers (hazard ratio = 3.34, 95% confidence interval 1.22-8.31). This association was not present among non-shift workers.

Conclusions: Awakening during the night is associated with a moderately increased CKD risk.