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Fatty liver increases diabetes risk for adults without obesity

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February 14, 2019

Nonalcoholic fatty liver disease is an independent risk factor for diabetes development in adults without obesity, according to findings published in Nutrition, Metabolism and Cardiovascular Diseases.

“Although it is very well-established that nonalcoholic fatty liver disease (NAFLD) occurs frequently in obese subjects, it is now becoming clear that NAFLD also occurs in a substantial proportion of nonobese individuals,” Ki-Chul Sung, MD, PhD, of the division of cardiology at Kangbuk Samsung Hospital in Seoul, South Korea, and colleagues wrote. “The mechanisms by which nonobese individuals develop NAFLD are not entirely clear, but differential distribution of visceral adipose tissue, recent increases in body weight, intake of a high cholesterol diet and genetic background are all thought to contribute to the pathogenesis of NAFLD in this group.”

Sung and colleagues recruited 70,303 adults aged at least 20 years with a BMI of less than 25 kg/m2 who had at least two health screenings at Kangbuk Samsung Hospital from 2007 to 2014. Each participant provided medical history via a self-administered questionnaire, and fatty liver was identified via abdominal ultrasonography. The researchers also calculated insulin resistance and liver fibrosis of each participant.

There were 852 incident cases of diabetes (mean age, 40.2 years; 33.6% women; mean BMI, 22.8 kg/m2) in the entire cohort after a mean follow-up of 3.32 years. Diabetes in this study was defined by the self-identification of diabetes, glucose-lowering medication use, an HbA1c level of at least 6.5% or a fasting glucose level of 126 mg/dL or more. The researchers noted that diabetes risk increased with each increasing quartile of insulin resistance (P < .001) and that the highest liver fibrosis quartile was linked to an increased risk for diabetes as well (HR = 1.36; 95% CI, 1.13-1.64).

Women with fatty liver alone were at increased risk for diabetes (HR = 2.86; 95% CI, 1.5-5.46) as were men (HR = 2.17; 95% CI, 1.56-3.03). The combination of fatty liver and insulin resistance increased diabetes risk in women (HR = 6.6; 95% CI, 3.05-14.27) and men (HR = 3.95; 95% CI, 2.64-5.9). According to the researchers, when a participant had fatty liver, the highest quartile of liver fibrosis and insulin resistance, they were also at increased risk for diabetes, particularly men (HR = 2.63; 95% CI, 1.41-4.92), whereas the association was nonsignificant in women (HR = 1.5; 95% CI, 0.32-6.95).

“Our data suggest that identifying fatty liver and insulin resistance in asymptomatic subjects, may identify a subgroup of nonobese individuals who are at increased risk of type 2 diabetes,” the researchers wrote. “In such subjects, implementation of lifestyle changes such as weight loss (if appropriate), or increases in physical activity, may reduce risk of type 2 diabetes.” – by Phil Neuffer

Disclosures: The authors report no relevant financial disclosures.

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