Make Behavioral Changes for a Healthier Liver? Evidence from a liver function test in Japan

Health screening has gained increasing attention for promoting early detection of chronic diseases and lifestyle improvements. This study investigates the impacts of risk information obtained from a regular liver function test on individuals’ health behaviors. More specifically, we focus on a biomarker called aspartate aminotransferase (AST) reported from the test. Using rich longitudinal data on health screening and health insurance claims in Japan, we adopt a regression discontinuity design (RDD) approach to examine how individuals respond to the notification that their AST level was abnormally higher than the normal reference range. Our results suggest that, upon receiving an abnormal liver function test result, individuals tend to reduce the likelihood and amount of alcohol use. Furthermore, knowing one’s AST value has crossed 40U/I, the higher upper limit used for normal reference range, leads to a significant increase in the expenses on follow-up care such as abdominal ultrasound tests and a decrease in body mass index (BMI) and triglycerides. Some impacts of health signal appear greater among people with high metabolic syndrome risks.