Reference values and associated factors of controlled attenuation parameter and liver stiffness in adults: a cross-sectional study

Background & aims: The utilization of non-invasive techniques for liver fibrosis and steatosis assessment has gained acceptance as a viable substitute for liver biopsy in clinical practice. This study aimed to establish normative data for the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) by age and gender, as well as to explore the relationship between anthropometric measures, clinical status, and biochemical profile according to the 90th percentile cut-off values for CAP/LSM in a U.S. adult population. Methods and results: In this cross-sectional analysis, 7.522 US adults aged 20¿80 years from the National Health and Nutrition Examination Survey (NHANES 2017¿2020) were included. CAP and LSM were quantified using the FibroScan® 502-v2 device. A comprehensive range of data was collected, including sociodemographic, anthropometric, biochemical, lifestyle, and clinical conditions. Participants were segmented by sex and age. The median ± standard deviation (SD) for CAP was significantly lower in women (258.27 ± 61.02 dB/m) than in men (273.43 ± 63.56 dB/m), as was the median ± SD for LSM (women: 5.50 ± 4.12 kPa, men: 6.36 ± 5.63 kPa). Although median CAP and LSM values displayed an upward trend with age, statistical significance was not achieved. Notably, higher liver CAP values (above the 90th percentile) correlated with more pronounced clinical and biochemical profile differences compared to lower CAP values (below the 90th percentile) (p < 0.001). Conclusions: Our study provides age- and sex-stratified standard values for CAP and LSM in a sizeable, nationally representative cohort of adults. The evidence of sex-specific variations in TE test results from our study sets the stage for future research to further corroborate these findings.