Disease susceptibility refers to an individual's likelihood of developing a disease based on various factors, including genetics, environment, and lifestyle. Some people may inherit genes that make them more prone to certain conditions, while others may be affected by their surroundings, such as exposure to toxins or pathogens. Additionally, lifestyle choices like diet, exercise, and smoking can influence disease susceptibility. For example, a poor diet may weaken the immune system, making it harder for the body to fight off infections. Understanding these factors can help in developing strategies for prevention and treatment of diseases.