Fatty Liver Disease and Air Pollution Link: Study

Metabolic-associated fatty liver disease (MAFLD) is a growing global health problem. To understand the possible causes a large-scale epidemiologic study was recently conducted. The results identified links between long-term exposure to ambient air pollution and MAFLD. Adding to the problem, scientists say, these links are exacerbated by unhealthy diet/lifestyles and the presence of obesity.

Backstory

“The incidence of MAFLD has increased steadily since the 1980s, currently affecting a quarter of the global population and a majority of patients with adult-onset diabetes and poses a substantial global burden. In Asia, MAFLD increased to 40% between 2012 and 2017. Formerly known as nonalcoholic fatty liver disease (NAFLD), it may progress to end-stage liver diseases such as cirrhosis and liver cancer, liver transplantation and liver-related death.

Accumulating animal studies have shown that breathing air pollutants may increase the risk of MAFLD. For instance, fine particulate matter exposure may trigger a nonalcoholic steatohepatitis (NASH)-like phenotype, impair hepatic glucose metabolism, and promote hepatic fibrogenesis.”

Toxins in the air as a possible culprit

“A growing number of studies have suggested that ambient air pollution, which is the biggest environmental problem caused by industrialization, may increase the risk of metabolic disorders such as insulin resistance and dyslipidemia, and related diseases such as type 2 diabetes mellitus and metabolic syndrome. However, epidemiologic evidence for the association was limited, so we conducted this research to improve our understanding of the effects of air pollution on human health and also to help reduce the burden of MAFLD.”

-Xing Zhao, PhD, lead investigator, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan, China

Study overview

“Investigators conducted an epidemiologic study on the potential role of ambient air pollution in the risk of MAFLD in approximately 90,000 adults in China based on the baseline survey of the China Multi-Ethnic Cohort (CMEC), a prospective cohort that enrolled nearly 100,000 participants in southwest China from 2018 to 2019. The CMEC collected participant information including sociodemographics, lifestyle habits, and health-related history through verbal interviews performed by trained staff and subsequently assessed anthropometrics, biosamples (blood, urine, and saliva), and imaging data.”

Results overview

“The researchers found that long-term exposure to ambient air pollution may increase the odds of MAFLD, especially in individuals who are male, smokers, and alcohol drinkers, and those who consume a high fat diet. Unhealthy lifestyle behaviors and an excess accumulation of fat in the abdominal area may exacerbate the harmful effects.

Takeaway

“The investigators propose that air pollution should be recognized as a modifiable risk factor for MAFLD. Populations at high risk should be aware of the air quality in the areas where they live and plan their activities to minimize their exposures to air pollution.”


Journal Reference:  Bing Guo, Yuming Guo, Qucuo Nima, Yuemei Feng, Ziyun Wang, Rong Lu, Baimayangji, Yue Ma, Junmin Zhou, Huan Xu, Lin Chen, Gongbo Chen, Shanshan Li, Huan Tong, Xianbin Ding, Xing Zhao. Exposure to air pollution is associated with an increased risk of metabolic dysfunction-associated fatty liver disease. Journal of Hepatology, 2021; DOI: 10.1016/j.jhep.2021.10.016


Eric