Mortality higher among lean than overweight, obese individuals with NAFLD

Among people with nonalcoholic fatty liver disease (NAFLD), those who are lean appear to be at higher risk of death than their overweight and obese counterparts despite having fewer metabolic comorbidities, a study has shown.

The retrospective study included 18,594 and 13,420 adults with NAFLD for cross-sectional and longitudinal analyses, respectively. Their median age was 51.0 years, and 54.6 percent were women.  

Of the participants, 11 percent were lean, 25 were overweight, 28 percent had class 1 obesity, and 35 percent had class 2–3 obesity. Lean individuals were more likely to be female, have active tobacco use, prior cerebrovascular accident, and have lower levels of liver enzymes, total cholesterol, low-density lipoprotein and triglycerides as well as higher level of high-density lipoprotein compared with overweight and obese individuals. Furthermore, lean individuals had a lower prevalence of metabolic abnormalities including diabetes, hypertension, dyslipidaemia, chronic kidney disease stage 3–5, and coronary artery disease than nonlean individuals.

Over a median follow-up of 49.3 months, lean individuals had a lower incidence of cirrhosis and diabetes than those who were overweight and obese. Also, there were no significant differences in the rates of cardiovascular disease and any cancer or obesity-related cancer.

However, lean individuals had significantly higher mortality, with an incidence rate of 16.67 per 1,000 person-years. The corresponding incidence rates in overweight, obesity class 1 and obesity class 2–3 groups were 10.11, 7.37, and 8.99 per 1,000 person-years.

The findings highlight the importance of paying increased attention to lean individuals with NAFLD.