Wednesday, June 12, 2013

Is Sleep Deprivation a Cause of Diabetes?

Nearly one-third of US adults sleep less than six hours per night and the average night's rest is 6.8 hours [1]. In other words, we're a tired, sleep-deprived country.

Speaking of country-wide health issues, 25.8 million Americans have diabetes with another 79 million diagnosed with prediabetes. As discussed in a previous post, our lifestyles can be the cause of type 2 diabetes. Considering that sleep habits make up a component of lifestyle, it's only logical to wonder if this sleep issue is contributing to the diabetes epidemic.

Fortunately, there are answers.

The Associations and Causes Between Sleep and Diabetes

A meta-analysis is a study that combines the results of several studies to develop comprehensive statistics that measure the relationship between several factors. The idea is to establish a more universal relationship or statistical effect.

A 2010 meta-analysis combined 10 studies that measured the connection between baseline sleep habits and diabetes development [2]. The follow-up periods for the studies averaged 9.5 years later, although the studies ranged from 4.2 to 32 years. Overall, this analysis included 107,756 people from the US, Japan, and Europe. In addition to average night's sleep. the studies also examined the risk of diabetes in relation to trouble falling asleep and trouble staying asleep.

Sleeping less than six hours a night, when compared to those who averaged six to eight hours, was associated with a 107% greater development with diabetes for men, but only a 7% greater development for women. People who had difficulty falling asleep or staying asleep had 57 and 84% greater risks for developing diabetes (men and women had similar results in these two cases).

Summarizing this data, diabetes is a much greater risk for men who sleep less than six hours per night and for men and women who have trouble initiating or maintaining sleep. However, these results are just associations. Other lifestyle factors could explain both the lack of sleep and development of diabetes.

A study of men in Boston looked at the relationship between initial sleep habits and rate of diabetes 15 years later [1]. In this study, the researchers adjusted the data to remove factors that could influence both sleep quantity and diabetes development. These factors were age, having high blood pressure, smoking status, self-rated health status, education, and waist circumference. When all of these factors were removed, men who slept a maximum of five hours per night developed diabetes at a 95% greater rate. Ouch.

But enough with associations - does sleep deprivation cause physiological changes that lead to diabetes? Researchers at the University of Chicago measured young men, 18 to 27 years old, on the last day of two six-day periods where sleep was intentionally limited or maximized [3]. The limitation period averaged three hours and 49 minutes. The max period averaged nine hours and three minutes.

Blood glucose and insulin were assessed frequently during each measurement day, with meals being consistent throughout. During sleep deprivation, post-meal blood glucose was 20 mg/dl higher, bringing the healthy young men to prediabetic levels. Clearing the excess blood glucose took about 40% more time. This is another sign of type 2 diabetes development.

Summarizing the Information

Here's what you should take from the information above. There's a high rate of diabetes in men who sleep less than six hours, and in men and women who struggle with falling or staying asleep. Young, healthy men who are intentionally sleep deprived can develop symptoms similar to prediabetes in just six days!

Based on the results of the meta-analysis and the University of Chicago study including men only, I can't say that sleep deprivation causes diabetes in women. It may, but this information cannot say for sure. However, men who are sleep deprived can quickly develop precursors for diabetes. 

In the battle of lifestyle versus diabetes, attaining six to eight hours of sleep should be a priority for men.

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