Sleep Duration and Snoring in Relation to Biomarkers of...

Sleep Duration and Snoring in Relation to Biomarkers of Cardiovascular Disease Risk Among Women With Type 2 Diabetes

Sleep Duration and Snoring in Relation to Biomarkers of Cardiovascular Disease Risk Among Women With Type 2 Diabetes
Published online February 23, 2007
Catherine J. Williams, MPH1, Frank B. Hu, MD, PHD2,3, Sanjay R. Patel, MD4 and Christos S. Mantzoros, MD1
Diabetes Care

© 2007 by the American Diabetes Association

Cardiovascular and Metabolic Risk
Original Article

1 Department of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
2 Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, Massachusetts
3 Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
4 Pulmonary and Critical Care Medicine, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, Ohio

Address correspondence and reprint requests to Dr. Christos Mantzoros, Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Ave., ST816, Boston, MA 02115. E-mail: cmantzor@bidmc.harvard.edu

ABSTRACT

OBJECTIVE—Sleep habits have been associated with risk of cardiovascular disease (CVD) and metabolic disturbances, but the mechanisms underlying these associations have yet to be fully elucidated. We aim to determine whether sleep duration and/or snoring are associated with biomarkers of CVD in women with type 2 diabetes.

RESEARCH DESIGN AND METHODS—We studied 935 women aged 43–69 years enrolled in the Nurses’ Health Study cohort with type 2 diabetes who had no history of documented coronary heart disease or stroke in 1990. Information on sleep duration and snoring frequency was collected in 1986 from mailed questionnaires, and biomarkers of CVD were measured from blood samples taken in 1989–1990.

RESULTS—Longer sleep duration was associated with increased levels of C-reactive protein after adjusting for age, BMI, lifestyle factors, family history of diabetes, glycemic control, and medication use (P = 0.05). HDL was decreased with short and long sleep duration among normotensive (P = 0.02) but not hypertensive women. More frequent snoring was directly associated with triglycerides (P = 0.02) and inversely associated with HDL cholesterol (0.03) and adiponectin (P = 0.03) in multivariate-adjusted analyses.

CONCLUSIONS—The associations of sleep duration and snoring with lipid profile, hormone measures, and/or inflammatory markers may partially explain the previously reported relationship between sleep habits and cardiovascular and metabolic disorders.

Abbreviations: CRP, C-reactive peptide • CVD, cardiovascular disease • NHS, Nurses’ Health Study • OSA, obstructive sleep apnea • sICAM-1, soluble intercellular adhesion molecule 1 • TNF, tumor necrosis factor • WHR, waist-to-hip ratio

INTRODUCTION

Mounting evidence from epidemiologic research indicates that sleeping habits may play an important role in human health. According to the National Sleep Foundation, mean sleep duration of Americans is estimated at 6.9 h/day (1), and data from 2-week sleep diaries of healthy subjects suggest that sleep duration on weekends is about half an hour longer than on weekdays, possibly indicating compensation for sleep debt (2). Of added concern, the National Sleep Foundation also reports that 56% of Americans snore at least three nights per week, with 24% snoring nearly every night. Of all participants surveyed, 8% had symptoms consistent with a diagnosis of obstructive sleep apnea (OSA) (1). These data underline the high prevalence of sleep deprivation and/or poor quality of sleep in today's society.

Both short (<5 h/day) and long (>9 h/day) duration of sleep have been associated with higher risk of all-cause mortality (3), coronary heart disease (4), and hypertension (5,6). Several large prospective cohort studies, including the National Health and Nutrition Examination Survey (NHANES I) and the Nurses’ Health Study (NHS) (7–9), have demonstrated an increased risk of obesity with habitual sleep deprivation. Sleep-disordered breathing has been associated with greater risk of insulin resistance and type 2 diabetes prospectively in NHS (10) and in several smaller cross-sectional studies (11–14), as well as with increased rates of hypertension, stroke, and acute coronary events (15–19). These observational results are consistent with unfavorable changes in glucose tolerance and increases in sympathetic activation demonstrated in experimental sleep deprivation studies (20). However, the biological mechanisms underlying these associations have yet to be fully elucidated, and only a limited number of studies have examined the relationship between sleep habits and established biomarkers of cardiovascular disease (CVD) (8,21–24). Thus, we obtained information on sleep duration and frequency of snoring and measured plasma concentrations of biomarkers of CVD. The objective of our investigation was to determine whether short and/or long sleep duration and, in a separate analysis, snoring are associated with increased total or LDL cholesterol, triglycerides, leptin, or inflammatory markers C-reactive protein (CRP), lipoprotein(a), soluble E-selectin, soluble intercellular adhesion molecule-1 (sICAM-1), and soluble tumor necrosis factor (TNF)-{alpha} receptor II and/or decreased HDL cholesterol or adiponectin levels.

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