Which type of diabetes, type 1 (T1D) diabetes or type 2 (T2D) diabetes, has a higher incidence of non-alcoholic fatty liver disease (NAFLD)?

Type 2 Diabetes Has Substantially Higher Incidence of Fatty Liver Disease

Type 2 diabetes is associated with a dramatically higher prevalence of fatty liver disease compared to type 1 diabetes, with over 70% of type 2 diabetes patients having NAFLD versus only 8.8% of type 1 diabetes patients when measured by gold-standard MRI. 1

Prevalence Comparison

Type 2 Diabetes

• Over 70% of people with type 2 diabetes have NAFLD, representing the vast majority of this population 1, 2, 3
• More than half of type 2 diabetes patients with NAFLD progress to develop NASH (the inflammatory form) 1, 2
• Between 12-20% already have clinically significant fibrosis (≥F2) at diagnosis 1, 2
• Using gold-standard MRI measurement, 68% of type 2 diabetes patients demonstrate hepatic steatosis 1

Type 1 Diabetes

• Only 8.8% prevalence of steatosis when measured by gold-standard MRI in populations with low obesity prevalence 1, 2
• Prevalence ranges from 12-52.4% in adults across various studies, but this wide variation reflects methodological differences and obesity rates 1
• In children with type 1 diabetes, prevalence ranges from 0-4.7%, which is actually lower than healthy controls of similar age and BMI 1
• Type 1 diabetes is not independently associated with increased hepatic steatosis when controlling for BMI 4

Why the Dramatic Difference

The fundamental pathophysiologic distinction explains this disparity:

• Type 2 diabetes is intrinsically linked to insulin resistance and metabolic syndrome, the primary drivers of NAFLD development 1
• Type 1 diabetes lacks these metabolic features unless obesity is present as a comorbid condition 1
• When NAFLD does occur in type 1 diabetes, it is primarily driven by concurrent obesity rather than the diabetes itself 1, 4

Clinical Implications for Screening

For Type 2 Diabetes Patients

• All adults with type 2 diabetes should be screened for clinically significant fibrosis using FIB-4 index, even with normal liver enzymes 1, 2
• Do not wait for elevated aminotransferases—clinically significant fibrosis frequently occurs with levels below 40 units/L 1, 2
• This represents a universal screening recommendation given the >70% prevalence 1, 2

For Type 1 Diabetes Patients

• Screening should only be performed when additional risk factors are present: obesity, incidental hepatic steatosis on imaging, or elevated aminotransferases 1, 2
• The low baseline prevalence (8.8%) does not justify universal screening in the absence of these risk factors 1

Important Caveats

The obesity epidemic is changing the landscape of type 1 diabetes. Approximately one-third of type 1 diabetes patients in the U.S. now have obesity, which increases their NAFLD risk substantially 1. When type 1 diabetes patients develop obesity, they acquire the same metabolic dysfunction that drives NAFLD in type 2 diabetes 1.

The variability in reported type 1 diabetes NAFLD prevalence (12-52.4%) across studies reflects differences in measurement techniques (ultrasound vs. MRI) and obesity rates in the studied populations 1. Studies using gold-standard MRI consistently show much lower rates in type 1 diabetes compared to type 2 diabetes 1.