We have a unique time-sensitive opportunity here to prospectively map the development of steatosis and fibrosis in young adults in the general population setting, nested within ALSPAC. Determining the prevalence of liver fibrosis will provide much needed normative data and help hepatologists understand the burden of this clinically relevant disease in this poorly phenotyped age group. By understanding the causal risk factors leading to the progression of fibrosis in young adults, it can inform prevention and precision public health policy to mitigate risk factors and target pathways to disease, including potentially screening targeted groups earlier than is currently advised. Furthermore, as antifibrotic drugs and those that reverse non-alcoholic steatohepatitis are developed, this study offers a window into a new potential target population. Previous public involvement and patient support work done with ALSPAC participants and liver disease patients (through the British Liver Trust) has reiterated the importance of work such as this. Ultimately, our aim is to reveal the true burden of liver disease in young adults and determine how we can identify young adults with reversible liver fibrosis who can benefit from early intervention, to prevent progression to cirrhosis and support patients. Regarding outputs, we anticipate at least 3 peer-reviewed publications, multiple international conference presentations, support and development for one doctoral researcher, and invaluable experience for myself in leading the scientific direction of important new data, which would aid in developing their fellowship and lectureship bids. This Rosetrees Trust intermediate project grant would provide the resources needed to gather vital new data and enable a new generation of investigators to lead the advancement of liver disease epidemiology.