The definition of a chronic illness is rather broad. Examples of chronic illness include: diabetes, heart disease, fibromyalgia, arthritis, lupus, and even cancer. If it affects you for more than a few months, it's often considered chronic. Despite the fact that the majority of theUS population looks rather healthy, statistics show that nearly 1 in 2 people have a chronic condition. This could be an illness like cancer or rheumatoid arthritis, or a condition such as arthritis, migraines or back pain from a car accident.