Approximately 50% of the burden of disease worldwide is a result of chronic conditions as compared to 39% by communicable diseases and 13% from injury.

Chronic diseases cause disability, often for several decades of a person’s life.

The most widely used summary measure of the burden of disease is the disability adjusted life year (DALY) which combines the number of years of healthy life lost to premature death with the time spent in less than full health. One daily can be thought of as one lost health life year.

Chart reference: 

WHO (2005). Preventing chronic diseases: A vital investment. Available at http://www.who.int/chp/chronic_disease_report/full_report.pdf