Sitting for too long such as watching television or working on the computer and other devices may increase the risk of non-alcoholic fatty liver disease, according to a new study.
A growing number of studies have suggested an association between sedentary behaviour and chronic diseases including obesity, diabetes, insulin resistance, metabolic syndrome, cardiovascular disease, cancer, and even death that is distinct from those related to a lack of physical activity.
However, the association between physical activity and non-alcoholic fatty liver disease (NAFLD) has been largely unexplored.
In the current study researchers examined the association of sitting time and physical activity level with NAFLD in nearly 140,000 Koreans who underwent a health examination between March 2011 and December 2013, to explore whether any observed associations were related to the amount of body fat.
Physical activity level and sitting time were assessed using the questionnaire. The presence of fatty liver was determined using ultrasonography.
Of the people studied, nearly 40,000 had NAFLD. The researchers found that both prolonged sitting time and decreased physical activity level were independently associated with increasing prevalence of NAFLD.
Remarkably, these associations were also observed in patients with a body mass index (BMI) of less than 23.
"We found that prolonged sitting time and decreased physical activity level were positively associated with the prevalence of NAFLD in a large sample of middle-aged Koreans," said lead investigator Seungho Ryu, of the Sungkyunkwan University School of Medicine in South Korea.
"Our findings suggest that both increasing participation in physical activity and reducing sitting time may be independently important in reducing the risk of NAFLD, and underlines the importance of reducing time spent sitting in addition to promoting physical activity," said co-author Yoosoo Chang, of Sungkyunkwan University.
"The message is clear, our chairs are slowly but surely killing us. Our body is designed to move and it is not surprising that sedentary behaviour, characterised by low muscle activity, has a direct impact on physiology," said Michael I Trenell, professor at Newcastle University in UK.
The study was published in the Journal of Hepatology.
