World Osteoporosis Day is observed annually on 20 October, and launches a year-long campaign dedicated to raising global awareness of the prevention, diagnosis and treatment of osteoporosis and metabolic bone disease. Organized by the International Osteoporosis Foundation (IOF), World Osteoporosis Day involves campaigns by national osteoporosis patient societies from around the world with activities in over 90 countries. World Osteoporosis Day was launched on 20 October 1996 by the United Kingdom’s National Osteoporosis Society and supported by the European Commission. Since 1997, the day has been organised by the International Osteoporosis Foundation. In 1998 and 1999, the World Health Organization acted as co-sponsor of World Osteoporosis Day. The day also marks the launch of a year-long campaign to raise awareness of osteoporosis and metabolic bone disease. Since 1999 these campaigns have featured a specific theme.