[Sportschosun, Jang Jong-ho] A large-scale study has found that smoking increases the risk of fatty liver disease in young adults in their 20s and 30s. The study also showed that smoking raises the risk regardless of obesity or heavy drinking, underscoring once again the need for early smoking cessation among younger age groups.
A joint research team led by Professor Jiyongho of the Advanced Biomedical Research Institute at Ewha Womans University Seoul Hospital, a co-first author, and Professor Shin Hyun-young of the Department of Gastroenterology at The Catholic University of Korea Seoul St. Mary's Hospital, the corresponding author, announced the findings.
Using big data from NHIS health screenings, the team tracked the incidence of fatty liver disease through 2022 in 3,496,144 Korean adults aged 20 to 39 who underwent health checkups between 2004 and 2007. The analysis used the Fatty Liver Index, which combines Body Mass Index (BMI), waist circumference, triglycerides, and Gamma-Glutamyl Transferase (GGT), to assess fatty liver.
The Fatty Liver Index is calculated on a scale of 0 to 100, and a score of 60 or higher is considered to indicate a high likelihood of fatty liver.
The results showed that among men, smoking 20 or more cigarettes a day increased the risk of fatty liver by 41%, while smoking for 10 to 19 years raised the risk by 15%. Among women, smoking rates were lower overall, but those who had smoked for 10 to 19 years saw a 55% increase in fatty liver risk, a larger rise than that seen in men.
The association was more pronounced in groups with a BMI below 25 or daily alcohol intake below 25 grams. By contrast, the link weakened in groups with obesity or higher alcohol consumption.
The research team explained that smoking is known to worsen insulin resistance and disrupt lipid metabolism, promoting fat accumulation in the liver. It also triggers systemic inflammation, oxidative stress, and tissue hypoxia, while nicotine-induced sympathetic nervous system stimulation may also affect the progression of fatty liver and liver fibrosis.
Professor Jiyongho said, "This study is meaningful because it is a large-scale, long-term follow-up of healthy young adults using NHIS screening data." He added, "Going forward, we will examine the combined effects of lifestyle factors such as smoking, obesity, and drinking on liver health in young adults, and develop predictive models and prevention strategies that can enable early intervention during health screenings."
The study was supported by the NRF under the Ministry of Science and ICT and was published in the international journal Journal of Gastroenterology and Hepatology. Co-authors included Lee Seon-ju, associate research fellow at the NHIS Artificial Intelligence Division, and Jeon Ho-su, professor of Gastroenterology at Ewha Womans University Seoul Hospital.
Jang Jong-ho, bellho@sportschosun.com
This article has been translated by GripLabs Mingo AI.
