The Relationship between Health-Related Fitness and Quality of Life in Nonalcoholic Fatty Liver Disease

Background: It is well known that patients with nonalcoholic fatty liver disease (NAFLD) suffer from impaired quality of life (QoL) and decreased health-related fitness. Studies on the relationship between them have been scarce. Methods: A cross-sectional survey was performed in 104 NAFLD patients. Liver fat content and fibrosis were assessed using transient elastography. Health-related fitness was measured by fitness test. VO(2)max was determined by YMCA submaximal cycle ergometer test. Body composition was tested by bioimpedance analysis. QoL was evaluated using the 36-item Short Form Health Survey Questionnaire (SF-36). Results: Most patients had severe liver steatosis without significant fibrosis. Most of them exhibited poor health-related fitness. Multiple linear regression analyses demonstrated that body compositions (waist circumference, hip circumference, percent body fat, percent skeletal muscle, visceral fat area) dependently contributed to QoL (health transition, role limitation due to physical problem, general health, physical functioning and vitality). VO(2)max was positively related with physical functioning. Conclusion: For NAFLD patients, decreased health-related fitness was associated with impaired QoL both in the physical and mental dimension. Our results indicate that visceral fat together with muscle mass and VO(2)max could serve as individual exercise intervention targets to improve QoL.