Short Sleep, not Insomnia Alone Associated With Increased Risk for Comorbidities

Man with insomnia in the night.
Researchers conducted a systematic review and meta-analysis about the association of insomnia disorder characterized by objective sleep duration with hypertension, diabetes, and body mass index.

No significant differences of comorbidities for objective short sleep with or without insomnia were identified in a systematic review and meta-analysis, published in Sleep Medicine Reviews.

Researchers from The University of Sydney in Australia searched publication databases from 1995 through June of 2019 for studies of insomnia or insomnia disorders. A total of 15 articles (cross-sectional: n=11; cohort: n=4) were included in the qualitative analysis and 10 in the quantitative (cross-sectional: n=8; cohort: n=2).

Most studies (69.2%) used clinical or structured interviews to diagnose insomnia disorder. Although studies defined short sleep disorder differently, these investigators defined it as <6 hours of sleep.

Risk for hypertension was increased among individuals with insomnia with short sleep compared with insomnia with normal sleep (risk ratio [RR], 1.54; 95% CI, 1.30-1.82; P <.0001; I2, 48%), but not compared with objective short sleep (RR, 1.31; 95% CI, 0.98-1.74; P =.07; I2, 90%).

Type 2 diabetes mellitus was associated with insomnia with short sleep (RR, 1.63; 95% CI, 1.37-1.94; P <.0001; I2, 0%). Compared with objective short sleep disorder, no significant difference was observed (RR, 1.10; 95% CI, 0.61-1.98; P =.75; I2, 79%). No difference in BMI was identified among patients with short sleep with or without insomnia (RR, 0.11; 95% CI, -0.07 to 0.28; I2, 68%).

The investigators reanalyzed the associations without data from a study which based insomnia on an answer to a single question and found significant associations with insomnia with short sleep and hypertension (RR, 1.49; 95% CI, 1.23-1.80; P <.0001), type 2 diabetes (RR, 1.60; 95% CI, 1.34-1.92; P <.0001), and BMI (standardized mean difference, 0.21; 95% CI, 0.12-0.29; P <.0001) compared with insomnia with normal sleep.

This study was limited by the significant study heterogeneity and the varying definitions of insomnia.

These data indicated insomnia with short sleep was associated with increased risk for hypertension and type 2 diabetes but not different than objective short sleep.

Disclosure: An author declared affiliations with biotech, pharmaceutical, and/or device companies. Please refer to the original article for a full list of disclosures.


Johnson KA, Gordon CJ, Chapman JL, et al. The association of insomnia disorder characterised by objective short sleep duration with hypertension, diabetes and body mass index: A systematic review and meta-analysis. Sleep Med Rev. 2021;59:101456. doi:10.1016/j.smrv.2021.101456