[Click! Health] Non-Alcoholic Fatty Liver Disease Patients Have a 67% Higher Risk of Death Compared to the General Population

The impact of the fatty liver index on overall and disease-specific mortality risk. Mortality risk increased linearly in proportion to the fatty liver index. Overall mortality risk was 19% higher in the intermediate group and 67% higher in the high group compared to the low group. (Adjustments were made for variables such as age, sex, smoking, alcohol consumption, BMI, and waist circumference)

[Asia Economy Reporter Chunhee Lee] It has been found that a high 'Fatty Liver Index,' a measure of non-alcoholic steatohepatitis (NASH), is associated with a 67% higher mortality risk compared to the general population. It was also revealed that the mortality risk increases particularly in underweight individuals.

According to Seoul National University Hospital on the 24th, a nationwide cohort study analyzing the association between NASH and cause-specific mortality was recently published by a joint research team led by Professor Soo-Jong Yoo of Seoul National University Hospital and Professor Kyung-Do Han of Soongsil University (first authors Go-Eun Jung from Gangnam Center and Soo-Min Jung, former professor at Samsung Seoul Hospital). The study involved 8,858,421 participants who underwent the national health screening in 2009.

NASH refers to a condition where an excessive amount of fat accumulates in the liver despite no alcohol consumption. It affects approximately one in four people worldwide. It is mainly accompanied by metabolic syndrome conditions such as obesity, diabetes, and hyperlipidemia. In 30% of patients, it can progress to hepatitis, cirrhosis, and fibrosis, requiring careful attention. Previous studies have shown that NASH patients have a higher risk of death compared to normal individuals. However, most of these studies were conducted in Western countries with limited sample sizes, so the association between NASH and mortality in Asian populations had not yet been established.

The research team used the Fatty Liver Index (FLI) to analyze the correlation between NASH and mortality. This index is one of the most validated measures for identifying fatty liver disease. It is calculated using body mass index, waist circumference, blood triglyceride levels, and gamma-glutamyl transferase levels.

Based on this, participants were divided into low (FLI <30), intermediate (30 ≤ FLI <60), and high (FLI ≥60) groups, and 8.85 million people were followed for 8.3 years. The results showed that the higher the fatty liver index group, the higher the mortality risk. After adjusting for variables, mortality rates from cardiovascular disease, cancer, respiratory disease, liver disease, and overall mortality all increased proportionally with the fatty liver index.

Next, the research team stratified the subjects by body mass index (BMI) into underweight, normal, overweight, and obese groups for further analysis. The results showed that in all BMI groups, a higher fatty liver index was associated with increased mortality risk. Notably, the mortality risk was greatest among those with a high fatty liver index who were underweight. In other words, the prognosis of NASH was worst in the underweight group.

Based on these results, the research team explained that NASH patients should be cautious not only about metabolic syndrome conditions such as obesity but also diseases that cause weight loss (sarcopenia and sarcopenic obesity).

Additionally, analysis of cause-specific cancer mortality revealed that as the fatty liver index increased, mortality rates from esophageal cancer, stomach cancer, colorectal cancer, lung and biliary tract cancer, breast cancer, and prostate cancer all increased linearly.

The research team emphasized that this study is significant because it comprehensively presents the association between NASH and mortality based on an analysis of the entire national population rather than a limited group.

Professor Soo-Jong Yoo of the Department of Gastroenterology at Seoul National University Hospital stated, “This study is the first to identify the association between NASH and mortality in the general Asian population,” adding, “Attention should be paid to the clinical importance of fatty liver, which can affect various diseases and mortality in the future.”

The study results were published online in the international journal Metabolism: Clinical and Experimental.