Kate Johnson

June 14, 2011

June 14, 2011 (Minneapolis, Minnesota) — Chronic sleep deprivation in people susceptible to developing type 2 diabetes results in increased insulin resistance and compensatory hyperinsulinemia, a new study suggests.

The results were presented here at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies.

The findings suggest that sleep curtailment in these young, otherwise healthy individuals "may further amplify their pre-existing metabolic risk and potentially make them a valuable target for lifestyle intervention," reported Plamen Penev, MD, PhD, from the University of Chicago, Illinois.

'Short' vs 'Usual' Sleepers

The study included 47 healthy participants (26 female), with a normal body mass index (average, 23.8 kg/m2) and average age of 26 years. All participants were at increased risk of developing type 2 diabetes on the basis of a family history in which 1 or both parents had the disease, he reported.

The study divided the participants into 2 groups according to their natural sleep duration: short sleepers, who slept less than 6 hours (average, 319 minutes per night; n = 19), and usual sleepers, who slept 6 or more hours (average, 409 minutes per night; n = 28).

Baseline overnight laboratory polysomnography was done to ensure that short sleepers did not have a sleep disorder.

"They slept just as well as the usual sleepers," said Dr. Penev. "If anything they had more consolidated sleep patterns, with fewer arousals, which suggested to us that they had chronic sleep deprivation — with a sleep duration about an hour and a half shorter than the usual sleepers."

At baseline, participants were also assessed for glucose tolerance by using a 75-g oral glucose tolerance test and fasting blood glucose, as well as for insulin sensitivity (insulin sensitivity index and homeostasis model assessment–insulin resistance) and β-cell function (corrected insulin response).

Physical activity was monitored for 2 weeks by using wrist and waist actigraphy.

Multivariate regression analysis controlling for differences in daily physical activity, age, body mass index, sex, and ethnicity showed that short sleepers had significantly higher insulin resistance (insulin sensitivity index score, 7.7 vs 11.4; P = .013).

However, "β-cell function was able to keep up with the increased insulin demand at this young stage, when they're still lean and healthy, and accordingly their measures of glucose tolerance were quite comparable — they remained normoglycemic," said Dr. Penev.

Although not a predefined outcome of the study, 2 weeks of physical activity monitoring by wrist and waist actigraphy showed that participants in the lowest tertile of sleep duration had significantly decreased activity compared with usual sleepers (122 vs 164 minutes per day; P = .040), suggesting that "people with familial risk who become obese or sedentary amplify their risk for diabetes in the future," said Dr. Penev.

Sleep Duration and Quality

"This is something that people at risk for type 2 diabetes need to take into consideration, that their sleep duration and quality may influence their potential to actually develop the disease down the road and it could be pushed forward if they don't get enough sleep," said Matthew Thimgan, PhD, moderator of the session and staff scientist at Washington University in St. Louis, Missouri.

"There are many different factors that can influence whether or not someone is getting enough sleep. If you think about a healthy young adult, many times it's lifestyle factors or environment — depending on socioeconomic factors," he said.

"At this point in their lives the subjects showed lower insulin sensitivity, but they were able to produce enough insulin to compensate. But, eventually they may not be able to do that, and if they don’t get enough sleep that may occur sooner."

The study was supported by National Institutes of Health grants R01- HL089637, CTSA-RR 024999, and P60-DK020595. Dr. Penev and Dr. Thimgan have disclosed no relevant financial relationships.

The 25th Anniversary Meeting of the Associated Professional Sleep Societies. Abstract #O111. Presented June 13, 2011.

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