Insomnia Is an Independent Risk Factor for Type 2 Diabetes, Study Says

Previous research identified a link between the sleep disorder and type 2 diabetes, but the new study suggests there is a causal relationship.

Everyday Health Archive
woman tired in bed
Not making sleep a priority may make it more likely you will develop type 2 diabetes.iStock; Everyday Health

New research that examined the DNA of nearly 900,000 people is the first to identify insomnia as a novel risk factor for developing type 2 diabetes. According to the study, published in the September 2020 issue of Diabetologia, insomnia raises the risk for type 2 diabetes by 17 percent.

This finding is novel because researchers used a method known as Mendelian randomization (MR). MR uses genetic variants to determine whether an observational association between a risk factor and an outcome signals an actual cause-and-effect relationship, according to an article published in November 2017 in the JAMA Guide to Statistics and Methods.

RELATED: Too Little (or Too Much) Sleep Linked to Earlier Death in People With Diabetes

Modern Life May Be Disrupting Sleep, Contributing to More Diabetes Cases

“We are continuing to see the prevalence of diabetes rise so much, says Diana Isaacs, PharmD, CDCES, of Cleveland Clinic in Ohio, who was not involved in the new research. According to the Centers for Disease Control and Prevention (CDC), 9.4 percent of Americans (about 30.3 million U.S. adults) have diabetes, and most of these cases are type 2 diabetes.

There are also 84.1 million American adults have prediabetes, the precursor to type 2 diabetes, per the CDC. When a person has prediabetes, the cells in the body don’t respond to insulin the way they should, which leads to the pancreas making more insulin in an effort to get the cells to respond. Eventually, the pancreas can’t make enough insulin to keep up, causing the blood sugar to rise — and over time, this can lead to diabetes, according to the American Diabetes Association (ADA).

The increase in diabetes prevalence is tied to the disintegration of self-care, says Minisha Sood, MD, an endocrinologist at Fifth Avenue Endocrinology in New York City, who was not involved in the new research. “As a society we push our bodies to the brink of what we are capable of doing without really keeping in good touch of what’s healthiest for them,” says Dr. Sood.

“In my practice, I find that people are sleeping later, they have more screen time, they’re more sedentary, and they’re not being exposed to the outdoors as much,” Sood says. All those factors can shift the cues that the brain gets and can contribute to overall sleep disruption, which includes sleep duration and sleep quality. That definitely translates into higher blood sugars and increased risk for higher blood sugars and obesity,” adds Sood.

RELATED: Obesity Ties to Higher Type 2 Diabetes Risk Even Without Genetic Predisposition

Study Examined the DNA of Nearly 900,000 People to Determine Type 2 Diabetes Risk Factors

Researchers started by looking through the database of studies about type 2 diabetes and identified 1,360 relevant articles and 97 possible risk factors to investigate. The DNA data came from the Diabetes Genetics Replication and Meta-Analysis Consortium (DIAGRAM) and consisted of 74,124 participants with type 2 diabetes and 824,006 without the disease, who served as the control group.

The mean age of the subjects was 55, 51.8 percent were men, and the majority were of European descent.

Investigators then checked the potential causes of type 2 diabetes to see if they could be replicated in a separate independent cohort, using the FinnGen consortium, which contained 11,006 people with type 2 diabetes and 82,655 controls.

RELATED: How Type 2 Diabetes and Heart Disease Are Connected

Researchers found 34 causal associations, 19 risk factors, and 15 protective factors with type 2 diabetes. They pinpointed insomnia as a new risk factor and estimated that people with insomnia were 17 percent more likely to develop type 2 diabetes than those without the disorder.

Because being overweight and having obesity impacts many other risk factors, researchers then looked at the risk and protective factors after controlling for adulthood body mass index (BMI). Eight risk factors remained statistically significant, suggesting that these factors independently impact the risk of type 2 diabetes. In addition to insomnia, systolic blood pressure, lifetime smoking, and levels of liver enzyme were among those factors. Protective factors included total cholesterol, HDL or “good” cholesterol, and sex hormone levels.

“This is one of the first studies to show an association with insomnia and increased risk of diabetes, and I’m not fully surprised,” says Marilyn Tan, MD, endocrinologist and chief of the Stanford Endocrine Clinic at Palo Alto, California. “We do know that poor sleep and stress can affect insulin resistance and one’s response to insulin,” she says.

An example of this is untreated obstructive sleep apnea (OSA), she says. “We know that sleep apnea increases cardiovascular risk and may also affect insulin resistance.” (Prior research published in Atherosclerosis and CHEST back this up.)

Though these factors have been explored before, the new study is important because it identifies a causal relationship, Dr. Isaacs says. “Just because two things are happening more often it doesn’t automatically mean they’re related to each other,” Isaacs adds.

RELATED: Why Sleep Quality Matters When Managing Type 2 Diabetes

Improving Sleep Could Be an Attainable First Step to Reducing Risk for Type 2 Diabetes

Although identifying insomnia as a risk factor is a new finding, the most important risk factor for type 2 diabetes is still obesity, says coauthor Susanne Larsson, PhD, associate professor at the Karolinska Institutet in Stockholm.

Obesity is a known risk factors and a big part of what’s driving the increase of type 2 diabetes, Isaac agrees, adding, “It’s modifiable risk factor, but it’s so hard to actually implement changes in that area.”

Improving sleep is also a modifiable risk factor, and one that may be easier to tackle than losing weight, she says. “Losing weight is very important, but it’s really hard for many people. Improving sleep may be something that is easier to change first, and if you improve your sleep quality it could make it easier to lose weight,” says Isaac.

RELATED: 6 Easy Ways to Lose Weight to Improve Diabetes Management and Heart Health

Health Expert Tips on How to Sleep Better

The first step to improving sleep is making it a priority, says Isaac. “Often we have so much to do we don’t devote the time that’s needed to have quality sleep. Sleep shouldn’t be an afterthought.”

Here are some other ways to catch more z’s:

  • Move more. Get the recommended amount of exercise, says Isaac. “Exercise doesn’t always lead to weight loss, but it does improve sleep and mood,” she says. “There are so many benefits to getting the recommended amount of physical activity, which is at least 30 minutes five days a week.”
  • Respect your body’s natural rhythm. “The body’s natural circadian rhythm is important,” says Sood. “We’re designed to have bedtime before 11 p.m., probably closer to 9 or 10 p.m., and wake early in the morning,” she says.

This is good rule of thumb, though it may not work for people who are naturally night owls, adds Sood.

  • Remove distractions. Try to adopt a good self-care routine where you try to relax for an hour before you go to sleep, suggests Isaac. “Try to remove distractions such as cell phones and televisions in your bedroom,” she says.
  • Don’t eat right before bedtime. Try to finish up eating about three hours before your intended bedtime so that your body can wind down and not have to work hard at digestion as your trying to sleep, says Sood.

It’s a good idea to avoid a meal high in fat right before bed so that you don’t get indigestion, adds Tan.

  • Watch your fluid intake. Hydration is good, but make sure you aren’t drinking too much before bedtime, says Isaac. “You don’t have to want to get up and have to use the bathroom,” she adds.
  • Stay consistent. “A lot of times people sleep very few hours during the weekdays and then try to make up for it by sleep a lot on the weekends — that can be confusing for the body,” says Tan.