Incidence of Diabetes in Middle-Aged Men Is Related to ...

Incidence of Diabetes in Middle-Aged Men Is Related to Sleep Disturbances

Incidence of Diabetes in Middle-Aged Men Is Related to Sleep Disturbances
Received for publication February 13, 2004. Accepted for publication June 10, 2004.
Peter M. Nilsson, MD, PHD1, Mattias Rööst, MD1, Gunnar Engström, MD, PHD2, Bo Hedblad, MD, PHD2 and Göran Berglund, MD, PHD1
Diabetes Care

© 2004 by the American Diabetes Association, Inc.

Metabolic Syndrome/Insulin Resistance Syndrome/Pre-Diabetes
Original Article

1 Department of Medicine, University Hospital, Malmö, Sweden
2 Department of Community Medicine, University Hospital, Malmö, Sweden

Address correspondence and reprint requests to Peter M. Nilsson, MD, PhD, Department of Medicine, University Hospital, S-205 02 Malmö, Sweden. E-mail: peter.nilsson@medforsk.mas.lu.se

ABSTRACT

OBJECTIVE—Sleep deprivation in healthy men has been experimentally found to result in disturbances in glucose metabolism and in sympathovagal imbalance. The aim of the present study was to investigate whether sleep disturbances and elevated resting heart rate are associated with increased risk of developing diabetes.

RESEARCH DESIGN AND METHODS—A group of 6,599 initially healthy, nondiabetic men aged 44.5 ± 4.0 years took part in a prospective, population-based study in Malmö, Sweden. The incidence of diabetes during a mean follow-up of 14.8 ± 2.4 years was examined in relation to self-reported difficulties in falling asleep and resting heart rate at baseline. Diabetes was assessed at follow-up in all subjects by questionnaire and in a subgroup of 1,551 men by blood glucose measurement.

RESULTS—A total of 615 (9.3%) subjects reported either difficulties in falling asleep or regular use of hypnotics (seen as markers of sleep disturbances), and 158 (2.4%) subjects reported both of these. Altogether, 281 (4.3%) of the men developed diabetes during the follow-up period. Logistic regression models showed difficulties in falling asleep or regular use of hypnotics (odds ratio [OR] 1.52 [95% CI 1.05–2.20]) and resting heart rate (OR per 10 bpm 1.13 [0.99–1.30]) to be associated with development of diabetes when full adjustments were made for baseline age, biological risk factors, lifestyle, family history of diabetes, and social class.

CONCLUSIONS—The results suggest that sleep disturbances and, possibly, elevated resting heart rate, in middle-aged men, are associated with an increased risk of diabetes.

Abbreviations: HPA, hypothalamopituitary adrenal • MDC, Malmö Diet and Cancer • MPP, Malmö Preventive Project • OGTT, oral glucose tolerance test • OSA, obstructive sleep apnea • SNA, sympathetic nervous activation

INTRODUCTION

Sleep problems are common in the adult population according to several epidemiological studies (1), as the amounts of hypnotics prescribed reflect as well (2). Although long-term sleep loss is often secondary to somatic or psychiatric illness (3), it appears that insomnia may also play a more central role in the pathogenesis of somatic illness and metabolic dysregulation (4).

Divergent sleep duration, either excessively long or excessively short, has been shown (5), together with self-reported poor sleep quality (6), to be a predictor of overall mortality. Sleep disturbances are associated with increased levels of cardiovascular risk factors and coronary artery disease mortality (7,8). The sleep cycle is closely related to endocrine and metabolic functioning and to sympathovagal balance, with sleep deprivation having negative consequences for these systems. Sleep disturbances are associated with an increased concentration of cortisol and such indicators of increased sympathetic activity as elevations in pulse rate, body temperature, and epinephrine secretion (9,10). Experimentally, sleep deprivation has been shown to negatively affect glucose metabolism and to enhance variables associated with type 2 diabetes (11). An elevated heart rate is a risk marker for cardiovascular disease and may, like sleep problems, reflect increased psychosocial stress.

A clinical study has shown sleep disorders to be much more common in patients with diabetes than in control subjects (12). Studies of the obstructive sleep apnea (OSA) syndrome have indicated it to be associated with both insulin resistance and type 2 diabetes, with the causality being unclear, but it has been proposed that they are independently associated with it (13,14).

The aim of the present study was to investigate, in a large sample of middle-aged urban men taken from a prospective population-based study, to what extent sleep disturbances and increased resting heart rate, both of which are established cardiovascular risk markers, are also independently associated with the risk of diabetes.

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