The importance of metabolic factors for the increasing prevalence of fatty liver in Shanghai factory workers

Background and Aim: To evaluate changes in the prevalence rates of ultrasonographic fatty liver (FL) in a specific population. Methods: An analysis of the medical records of BaoSteel Group (Shanghai, China) employees was done to evaluate the prevalence of FL in this population, in which health examinations were performed biennially between 1995 and 2002. Results: The study reviewed a database of 59 131 employees, of which 27.1% received medical check-ups four times within the study period, 26.6% three times, and 24.0% twice. The prevalence rates of obesity and metabolic disorders were high at baseline and increased significantly with time. The prevalence of ultrasonographic FL increased from 3.87% to 14.04% in the overall population, while there was an increase from 4.44% to 14.64% in men and 1.56% to 11.37% in women over the 6-year study period. Increased rates of FL were also noted, from 25.88% to 51.39%, among patients with elevated serum alanine aminotransferase (ALT) levels (> 40 U/L). The highest overall prevalence rates of FL were found in individuals aged 50-60 years, with all age-associated prevalence significantly higher in males than females. Conclusion: The prevalence of FL increased rapidly over the study period with increased rates of obesity and metabolic disorders; FL is becoming a major cause of abnormal ALT levels in the specific population.