Depressed young adults face twice the risk of fatty liver disease, Seoul study finds

Study analyzes 7,831 young Korean adults aged 19–44

Link stronger in those with obesity or dyslipidemia

(From left) Heo Yeon of the Department of Family Medicine at Catholic University of Korea Seoul St. Mary's Hospital, Oh Sang-hun of the Department of Psychiatry at Uijeongbu Eulji University Hospital, and Nam Ga-eun of the Department of Family Medicine at Korea University Guro Hospital. [Seoul St. Mary's Hospital]

Young Korean adults with depressive symptoms face roughly twice the risk of developing fatty liver disease compared with those without such symptoms, and the risk grows as the severity of depression increases, according to a new study.

Catholic University of Korea Seoul St. Mary's Hospital announced Tuesday that a research team — led by Heo Yeon of its Department of Family Medicine (co-first author), Oh Sang-hun of the Department of Psychiatry at Uijeongbu Eulji University Hospital (co-first author), and Nam Ga-eun of the Department of Family Medicine at Korea University Guro Hospital (corresponding author) — had published the findings.

The team drew on data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted between 2014 and 2022. Starting with 10,955 adults aged 19 to 44, the researchers excluded those who tested positive for hepatitis B or C or reported moderate or higher alcohol consumption, arriving at a final sample of 7,831 participants whose depressive symptoms and fatty liver status were then analyzed.

Depressive symptoms were assessed using the PHQ-9, a widely used international screening tool. Fatty liver was defined using the Hepatic Steatosis Index (HSI).

Fatty liver disease is the most common chronic liver condition worldwide, affecting roughly one in four overweight or obese adults. Beyond the simple accumulation of fat in the liver, it carries the risk of progressing to cirrhosis, liver failure and liver cancer.

Among participants with depressive symptoms — defined as a PHQ-9 score of 10 or above — the prevalence of fatty liver was 33.9 percent, significantly higher than the 23.8 percent recorded among those without depressive symptoms. Even after adjusting for a range of socioeconomic factors, lifestyle habits and comorbidities, those with depressive symptoms remained about twice as likely to have fatty liver disease.

Depressive symptoms and the Hepatic Steatosis Index. [Seoul St. Mary's Hospital]

The data also showed a dose-response pattern: compared with those reporting minimal depressive symptoms (PHQ-9 score of 0–4), participants with moderate symptoms (PHQ-9 10–14) were about 1.95 times more likely to have fatty liver disease, while those with severe symptoms (PHQ-9 15 or above) were about 2.41 times more likely.

The research team identified several mechanisms through which depressive symptoms may promote the onset and progression of fatty liver disease: elevated stress hormones and inflammation, insulin resistance, oxidative stress, metabolic side effects of some antidepressants, and physical inactivity combined with unhealthy eating habits.

The study also found a statistically significant interaction effect: among young adults with obesity or dyslipidemia, the association between depressive symptoms and fatty liver was even stronger — suggesting that metabolically vulnerable youth are disproportionately affected when depression is present.

Most prior research on the link between depression and fatty liver has focused on middle-aged and older populations, Western subjects, or specific high-risk groups, leaving a gap in knowledge about young Asians — a group in whom metabolic abnormalities can appear relatively early and in whom lifestyle interventions offer a higher chance of recovery.

The study is the first to examine the association between depressive symptoms and fatty liver in a nationally representative sample of young Korean adults, the researchers said, filling that gap in the existing literature.

"This research grew out of frequently encountering, in clinical practice, cases where chronic diseases that emerged in youth went on to affect health outcomes in old age," said Heo Yeon, professor of family medicine at Catholic University of Korea Seoul St. Mary's Hospital. "Our findings confirm that depressive symptoms are closely linked not only to mental health but also to metabolic conditions such as fatty liver disease. That means young people presenting with depressive symptoms need integrated care that also addresses their metabolic health."

Nam Ga-eun, professor of family medicine at Korea University Guro Hospital, said fatty liver in young adulthood can lead to increased risks of liver disease and cardiovascular disease later in life, making early identification and management of depressed young adults essential. "Future prospective studies will be needed to establish the causal relationship between depressive symptoms and fatty liver disease," she added.

woo@heraldcorp.com