The most common chronic illness characteristics are: - Complex causes - Many risk factors - Long latency periods - Long illness - Functional impairment or even disability Many chronic illnesses do not fix themselves and need help from healthcare professionals. While many illnesses can be considered chronic, there are 12 major chronic conditions that are significant burdens, they are: - Heart disease - Stroke - Lung cancer - Colorectal cancer - Depression - Type 2 diabetes - Arthritis - Osteoporosis - Asthma - Chronic obstructive pulmonary disease (COPD) - Chronic kidney disease - Oral disease