Objectives: To project the national burdens of low back, hip, and knee pains in Japan from 2005 to 2055 in terms of quality adjusted life years (QALYs).
Methods: The age- and sex-specific prevalence rates of low back, hip, and knee pains in the questionnaire survey (3048 men and 1885 women) were multiplied by the corresponding age- and sex-specific Japanese population projections. The losses of QALYs associated with low back, hip, and knee pains were calculated as the projected numbers of men and women with pain at each site multiplied by the corresponding sex-specific mean differences of EQ-5D scores between those who reported pain at each site and those who reported no musculoskeletal pain in the questionnaire survey.
Results: Among a total of 87.9 million Japanese people aged 30 years or older in 2005, 21.4 million (24.3%), 3.2 million (3.7%), and 9.1 million (10.4%) were estimated to have low back, hip, and knee pains, respectively. The prevalence rates of low back, hip, and knee pains will gradually increase in subsequent years, reaching 26.5%, 4.4%, and 12.9%, respectively by 2055. Consequently, the losses of QALYs associated with low back, hip, and knee pains per 1000 population will increase from 17.2, 3.8, and 8.9, respectively in 2005 to 18.8, 4.5, and 11.2, respectively by 2055.
Discussion: Due to population aging, the national burden of musculoskeletal pain in Japan is projected to increase in the next 50 years. Musculoskeletal pain has not been counted among national healthcare priorities. However, the control of musculoskeletal pain should not be bypassed to improve QOL and extend healthy life expectancy.