World report on disability

A recent series of joint studies by the World Health Organization, Harvard School of Public Health, and John Hopkins School of Public Health show that low back disorders are the #1 cause of disability in the entire world, and neck disorders are #4.
Musculoskeletal conditions such as low back pain, neck pain and arthritis affect more than 1.7 billion people worldwide and have a greater impact on the health of the world population (death and disability) than HIV/AIDS, tropical diseases including malaria, the forces of war and nature, and all neurological conditions combined.
So, although these disorders are not going to directly kill anyone, they can severely mess up or destroy people's lives. This will become even more significant in the future as people continue to live longer.
World report on disability