Insomnia and diabetes mellitus: what is the link?

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  • Risk for type 2 diabetes increased as exposure to insomnia symptoms accumulates during many years, but common risk factors play important role.

Why this matters

  • In this study, marginal structural models (MSMs) are used to effectively control for time-varying confounders, these are known to yield results closer to those of randomised experiments.
  • Future research should be focused on other potential modifiable causes where there is stronger observational evidence for a causal link.

Study design

  • This analysis included 996 respondents from the Twenty-07 Study 1950s cohort who participated in both the baseline and the final interview and were free of diabetes at baseline.
  • Funding: None disclosed.

Key results

  • Insomnia showed significant association with type 2 diabetes mellitus (OR, 1.34; P=.015).
  • Association between insomnia and type 2 diabetes incidence was non-significant in MSMs adjusted for past covariates (OR, 1.20; P=.079) and both past and present covariates (OR, 1.08; P=.554).


  • Blood samples for HbA1c only available in the final wave of the study.
  • Baseline data on diabetes was patient reported.