NAFLD linked with reduced physical work capacity

In adolescents, non-alcoholic fatty liver disease correlated with decreased cardiorespiratory fitness, irrespective of BMI, according to recently published results.

“The relationship between transferrin saturation and (physical work capacity [PWC]) in adolescents with NAFLD indicates that functional iron deficiency might contribute to reductions in cardiorespiratory fitness,” Tim Mitchell, MBBS, from the department of gastroenterology at the Fiona Stanley Fremantle Hospital Group in Perth, Australia, and colleagues wrote.

Mitchell and colleagues gathered data from 390 girls and 458 boys from the Raine Study, which included weight-adjusted, submaximal physical work capacity, ultrasound-determined hepatic steatosis, iron indices, and hematologic and metabolic parameters. Researchers used X² and linear regression analyses to compared patient characteristics according to NAFLD status at age 17 years.

Investigators found 14% of patients had NAFLD. These adolescents saw a significant reduction in physical work capacity vs. those without NAFLD. Results showed iron bioavailability was inversely associated with BMI in adolescents with NAFLD but not in adolescents without NAFLD. Mean corpuscular volume and mean corpuscular hemoglobin were associated with physical work capacity, independent of NAFLD status.

The data showed reduced physical work capacity correlated with lower transferrin saturation in adolescents who had NAFLD (reduction of 0.012 W/kg per unit decrease in transferrin saturation; P = .007), whereas no association was seen in adolescents without NAFLD (reduction of 0.001 W/kg), adjusted for sex. Researchers said this correlation was independent of mean corpuscular volume and mean corpuscular hemoglobin.

“Future therapies aiming to modify the inflammatory milieu of NAFLD may increase iron bioavailability and as such improve physical fitness and engagement in exercise programs,” Mitchell and colleagues wrote.