Only a limited amount of data exists regarding the association between body mass index (BMI), non-alcoholic fatty liver disease (NAFLD), and adverse outcomes. It is known that obesity is a significant risk factor for NAFLD and its associated intra- and extrahepatic complications. However, NAFLD also affects patients with normal BMI. These individuals suffer from what is termed lean NAFLD (LN).
Recently, a select number of emerging studies have challenged obesity’s status as a risk factor for NAFLD-associated adverse outcomes. These studies highlight the potential protective effects conferred by obesity, as well as its link with improved survival.
This study aimed to examine the relationship between BMI and NAFLD outcomes in a prospective cohort in China. Study participants were divided into LN, obese NAFLD (ON), obese non-NAFLD (ONN), and lean non-NAFLD (LNN) groups.
Patients with obesity and NAFLD (ON group) had the highest cardiovascular disease (CVD) risk compared to the LNN group. Nevertheless, patients with LN also had a higher risk of death: a positive association was found between the LN group and all-cause mortality, especially liver-related mortality. A positive relationship was also found between LN and digestive system cancers, as well as between LN and obesity-related colorectal and esophageal cancers. This study also concluded that LN patients with hypertension had an increased risk of adverse outcomes, suggesting that this may be a high-risk phenotype clinicians should monitor.