In people with type 2 diabetes, having nonalcoholic fatty liver disease (NAFLD) is linked to a higher risk for severe hypoglycemia (low blood glucose), according to a new study published in the journal JAMA Network Open.
NAFLD is a condition in which the liver contains elevated levels of fat, which can lead to diminished liver function and even liver failure and death if it goes unrecognized and untreated. Unfortunately, studies suggest that large numbers of people with type 2 diabetes have undiagnosed NAFLD. There are steps you can take to prevent or even reverse NAFLD, including losing excess body weight, getting enough physical activity, making healthy dietary choices, and optimizing blood glucose control. Studies suggest that both the Mediterranean diet and the Dietary Approach to Stop Hypertension (DASH) diet may help reduce the risk for NAFLD. Of course there are some risk factors for NAFLD that you can’t control, such as a family history of diabetes — but having a family predisposition to NAFLD may make it even more important to take steps to reduce your risk.
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For the latest study, researchers were interested in looking at whether NAFLD is related to episodes of hypoglycemia in people with type 2 diabetes. To do this, they looked at data from a general health study that included over 1.9 million adults ages 20 and older in South Korea who were diagnosed with type 2 diabetes between January 2009 and December 2012. People who consumed large amounts of alcohol were excluded from the study, because the researchers were interested only in how liver disease not linked to alcohol was related to hypoglycemia. NAFLD was measured using a formula called the fatty liver index (FLI) that combined various measurements, while severe hypoglycemia was based on records from hospital admissions and emergency department visits.
NAFLD linked to increased risk of severe hypoglycemia
Participants were followed through December 2015, for a median of 5.2 years. During this period, about 45,000 participants, or 2.3%, experienced one or more episodes of severe hypoglycemia. Compared with participants who didn’t experience severe hypoglycemia, those who did were more likely to be older, with an average age of 67.9 compared with 57.2. They also tended to have a lower body-mass index (BMI, a measure of body weight that takes height into account) — with an average BMI of 24.2 compared with 25.1. Without taking BMI into consideration, participants with NAFLD tended to have fewer cases of hypoglycemia — not surprising by itself, since people with NAFLD tended to have a higher BMI. But once the researchers adjusted for a number of factors including age and BMI, they found that people with NAFLD were about 26% more likely overall to experience severe hypoglycemia.
But the relationship between NAFLD and severe hypoglycemia wasn’t exactly straightforward — it followed what researchers often call a J-shaped curve. This means that in people with a higher fatty liver index (indicating more liver fat), the risk for severe hypoglycemia went down at first, but then went up again in people with an even higher fatty liver index. Compared with the overall study population, participants whose fatty liver index score fell in the fifth decile — meaning the group of 10% of participants whose scores were fifth lowest out of all ten groups — were 14% less likely to have NAFLD, even though their fatty liver index scores were close to the average of the group. But members of the ninth decile — those with the second-highest range of fatty liver index scores — were 2% more likely to experience severe hypoglycemia, and those in the tenth decile were 29% more likely to experience severe hypoglycemia.
“In this study, NAFLD was associated with a higher risk of severe hypoglycemia in patients with type 2 diabetes independent of obesity status,” the researchers concluded. “Presence of NAFLD should be considered when evaluating vulnerability to hypoglycemia in patients with type 2 diabetes.”
Want to learn more about protecting your liver? Read “Diabetes and NAFLD” and “Preventing Fatty Liver (NAFLD).”