Which of the following is a leading cause of liver dysfunction?

Substance abuse is a leading cause of liver dysfunction because it directly impacts liver health through various means. Alcohol, specifically, is a well-known hepatotoxin that can lead to conditions such as fatty liver, alcoholic hepatitis, fibrosis, and cirrhosis. The liver is responsible for metabolizing substances, and when it is overloaded with harmful agents, it can become damaged. Drugs can also cause liver damage by inducing inflammation or directly harming liver cells.

Other factors that contribute to liver dysfunction, such as high blood pressure or genetic disorders, can influence liver health but are not as direct in causing liver issues as substance abuse. Obesity, while a significant concern related to liver health, often manifests its effects through mechanisms such as fatty liver disease, which can be secondary to other lifestyle choices, including substance use. Thus, substance abuse represents a more direct and immediate risk factor for liver dysfunction.