It follows that, as the prevalence of obesity among people with type 1 diabetes mellitus (T1DM) increases, so would the incidence of nonalcoholic fatty liver (NAFL), as it does in type 2 diabetes.
Dr. Erika B. Parente
However, researchers in Finland report that the incidence of NAFL in T1DM is much lower, and that the use of the waist-to-height ratio to calculate midsection girth could be a low-cost alternative to MRI and computed tomography to more precisely diagnose NAFL in T1DM.
In a cross-sectional analysis of 121 adults with T1DM in the Finnish Diabetic Nephropathy study, known as FinnDiane, researchers from the University of Helsinki report in Diabetes Care that a waist-to-height ratio of 0.5 showed a relatively high rate of accuracy for identifying NAFL that was statistically significant (P = .04).
Lead author Erika B. Parente, MD, PhD, a researcher at the Folkhälsän Research Center in Helsinki, noted that the findings do not identify any causality between what the researchers called visceral adiposity and NAFL. “As long as they have accumulation of fat in the center of body and they can develop this low-grade inflammation that also goes to insulin-load sensitivity, people with T1DM can accumulate fat in the liver as do people with T2DM and the general population,” she said in an interview.
These findings build on her group’s previous work published in Scientific Reports showing a strong relationship between waist-to-height ratio and visceral fat percentage in adults with T1DM. The most recent FinnDiane analysis found no similar relationship between NAFL and fat tissue in the hips, arms and legs, and total adipose tissue.
Better than BMI as a measure
“We also found that waist-to-height ratio is better than body mass index to identify those individuals at higher risk of having NAFL,” Dr. Parente said. However, it’s not possible to predict which patients referred to imaging evaluation after being screened by waist-to-height ratio of 0.5 will surely have NAFL, she added.
That answer, she said, would require a longitudinal and cost-effectiveness study with larger population.
The waist-to-height ratio cutoff of 0.5 showed an 86% sensitivity and 55% specificity for NAFL, whereas BMI of 26.6 kg/m2 showed an 79% sensitivity and 57% specificity.
“The most important message from our research is that health care professionals should be aware that individuals with T1DM can have NAFL, and waist-to-height ratio may help to identify those at higher risk,” she said.
The prevalence of NAFL among the adults with T1DM in the study was 11.6%, which is lower than the prevalence other studies reported in T2DM – 76% in a U.S. study – and in the general population – ranging from 19% to 46%. This underscores, Dr. Parente noted, the importance of using waist-to-height ratio in T1DM patients to determine the status of NAFL.
She said that few studies have investigated the consequences of NAFL in T1DM, pointing to two that linked NAFL with chronic kidney disease and cardiovascular disease in T1DM (Diabetes Care. 2014;37:1729-36; J Hepatol. 2010;53:713-8). “Most of the studies about the consequences of NAFL included people with T2DM,” she said. “From our research, we cannot conclude about the impact of NAFL in cardiovascular or kidney complications in our population because this is a cross-sectional study.”
That question may be answered by a future follow-up study of the ongoing FinnDiane study, she said.
Dr. Jeanne Marie Clark
The study is a “good reminder” that people with central adiposity and metabolic syndrome can develop NAFL disease, said Jeanne Marie Clark, MD, MPH, of Johns Hopkins University, Baltimore. “Even patients we may not think of having insulin resistance, such as those with T1DM.”
However, Dr. Clark added, “I do not think we can really determine which measure of central adiposity is best.” She noted that the study was “pretty small” with only 14 patients who had NAFL disease. “Waist-to-height ratio is certainly a reasonable option,” she added. “Waist circumference alone is known to be a strong predictor. I would say some measure is better than none, and it should be more routine in clinical practice.”
Dr. Parente disclosed financial relationships with Eli Lilly, Abbott, AstraZeneca, Sanofi, and Boehringer Ingelheim. Two of eight coauthors disclosed financial relationships with AbbVie, Astellas, AstraZeneca, Bayer, Boehringer Ingelheim, Eli Lilly, Elo Water, Fresenius, GE Healthcare, Medscape, Merck Sharpe and Dohme, Mundipharma, Novo Nordisk, Peer-Voice, Sanofi, and Sciarc. The remaining coauthors had no disclosures.
Dr. Clark had no disclosures.