According to the World Health Organization (WHO), 1.1 billion people or 2% of the world's population live in areas with an increased risk of filariasis. The WHO estimates that 120 million people have the condition and 30% show signs of lymphedema.
The highest incidence of upper extremity lymphedema occurs after breast cancer surgery, especially if followed by radiation therapy. It has been estimated that 10-40% of these patients develop lymphedema. Lymphedema affects 0.13% of the population and this number increases by 0.5% for people over the age of 65.
Lymphedema of the lower extremities is the most common at 80%. It affects any age and in 65% of cases it affects both lower limbs. It usually starts at the foot end and progressively progresses centrally (Ryan et al, 2003).