Inadequate Sleep May in Itself Up Odds of Diabetes Onset

Marlene Busko

July 15, 2013

Troubled sleep, short sleep, and sleep apnea predicted the onset of type 2 diabetes, independent of mental-health disorders, in a prospective study of young, healthy military personnel.

This is the first study to clearly show that lack of a good night's sleep may be an independent risk factor for subsequent diabetes, rather than merely a surrogate marker for a mental-health disorder such as depression or posttraumatic stress disorder (PTSD), the researchers say.

"Since mental-health conditions and sleep disorders seem to be independently related to diabetes, [this research suggests that] there could be different pathways leading to diabetes," lead author Edward J. Boyko, MD, from the Department of Veterans Affairs Puget Sound Health Care System in Seattle, Washington, told Medscape Medical News.

However, since this was an observational study, it is too early to establish a causal relationship between inadequate sleep and incident diabetes, he cautioned, adding that further research is needed.

The paper was published online July 8 in Diabetes Care.

Sleep-Deprived Citizens, Diabetes Epidemic

In the United States, the incidence of diabetes has risen dramatically over the past 30 years, while the average hours of nightly sleep have declined over that time, the authors report. A recent study showed that close to a third of full-time workers in the United States get 6 or fewer hours of sleep each night, they note. Poor sleep, depression, and PTSD have all been reported to predict a higher risk for type 2 diabetes, but it was unclear whether sleep disturbances merely reflected mental-health disorders.

The researchers examined data from 47,093 members of the US military service who enrolled in the Millennium Cohort Study in 2001 to 2003 and replied to survey questions 3 years and 6 years later.

The population was "younger [and healthier] than a population you would typically study for risk of diabetes; [at baseline] the mean age was only 34.9 years, and they were only slightly overweight, with an average [body mass index] BMI of 26," Dr. Boyko noted.

The participants replied to questions asking about the average number of hours they slept each day, whether they often had trouble falling or staying asleep, and whether they had been told by a doctor that they had sleep apnea.

From baseline to year 3, there were 383 cases of new, self-reported diabetes, and from year 3 to year 6 there were 488 cases of newly occurring diabetes.

Compared with individuals who did not develop new-onset diabetes, those who did were more likely to be nonwhite and older (age 42.6 vs 36.6 years) and have a higher mean BMI (29.4 vs 26.3) at baseline. They were also significantly more likely to have reported mental-health and sleep disorders at baseline.

Percentage of Participants With Baseline Mental-Health and Sleep Disorders, No Diabetes Onset vs Diabetes Onset (Within 6 Years)*

Baseline Characteristic No Diabetes Onset (n = 46,710) With Diabetes Onset (n = 871)
Depression 2.6 5.1
Panic disorder 1.2 3.4
Other anxiety disorder 1.8 4.1
PTSD 3.7 8.4
Sleep apnea 2.6 10.3
Trouble sleeping 23.4 31.9
Sleeping < 5 hours a night 14.7 19.8

*P < 0.01 for all

After adjustment for demographic and mental health characteristics, measures of inadequate sleep were still linked with a 1.21-fold to a 1.78-fold increased risk of being diagnosed with type 2 diabetes.

Sleep-Related Risk Factors for Incident Type 2 Diabetes

Risk Factor Odds Ratio (95% CI)
Trouble sleeping 1.21 (1.03–1.42)
Sleep apnea 1.78 (1.39–2.28)
Sleeping < 5 hours a night* 1.52 (1.09–2.14)
Sleeping 5 hours a night* 1.28 (1.01–1.62)

*Compared with sleeping 7 hours a night

Although the survey looked at military personnel, "I think the results really apply to a working population of younger individuals," Dr. Boyko said.

Based on these outcomes, "it is unlikely that sleep simply serves as a surrogate marker for associated mental-health conditions previously shown to predict diabetes risk," according to the authors.

"Confirmation of these findings through further analyses may advance our understanding of diabetes pathophysiology and create new opportunities for prevention," they conclude.

The study was supported by the Department of Defense. The Millennium Cohort Study is funded through the Military Operational Medicine Research Program of the US Army Medical Research and Materiel Command. The Department of Veterans Affairs Puget Sound supported Dr. Boyko's involvement in this research. The authors have reported no relevant financial relationships.

Diabetes Care. Published online July 8, 2013. Abstract


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