To examine if the association with hypertension was different between individuals with and without insomnia symptoms.
This was a population-based, multiyear, cross-sectional study with data from the 2005–2008 United States National Health and Nutrition Examination Surveys (n = 12 643). Insomnia symptoms were considered if at least one of difficulty falling asleep, prolonged nocturnal awakening, or early morning awakening was reported, at least five times per month. Short sleep time (<6 h) was also considered in the insomnia definition. Ever doctor-diagnosed self-reported hypertension, self-reported current antihypertensive use, and objectively measured systolic and diastolic hypertension were examined.
There were generally no associations between insomnia symptoms and hypertension when sleep duration was not considered in the insomnia definition and after controlling for covariates. However, there were significantly increased odds of subjective hypertension measures among individuals with insomnia coupled with short sleep time compared to individuals without insomnia after controlling for covariates [e.g. among individuals with any insomnia: odds ratio (OR), 95% confidence interval (CI) of doctor-diagnosed hypertension 1.49, 1.19–1.88; OR, 95% CI of current antihypertensive medications 1.33, 1.04–1.70]. There were no significant associations though between insomnia symptoms accompanied by short sleep time and objective hypertension measures (e.g. among individuals with any insomnia: OR, 95% CI of measured systolic hypertension 1.32, 0.87–2.02; OR, 95% CI of measured diastolic hypertension 0.96, 0.52–1.75).
Insomnia symptoms coupled with short sleep time may be positively related to hypertension, but the lack of association with objective hypertension measures suggests that there may be no true relationship present.
aDivision of Respirology, Department of Medicine, St. Michael's Hospital, University of Toronto, Ontario
bDivision of Internal Medicine, Department of Medicine, Kingston General Hospital and Queen's University, Kingston, Ontario, Canada
Correspondence to Dr Nicholas Vozoris, MHSc, MD, FRCP(C), Division of Respirology, St Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada. Tel: +1 416 864 6026; fax: +1 416 864 5649; e-mail: firstname.lastname@example.org
Abbreviation: NHANES, National Health and Nutrition Examination Surveys
Received 5 October, 2012
Revised 21 December, 2012
Accepted 10 January, 2013