To determine whether the extent of multiple-site lower extremity joint pain contributes to disability in middle and old age and describe patterns of severity in site-specific measures amongst those with multiple-site pain.
Population-based, cross-sectional postal survey. Adults aged 50 years and over registered with three general practices and reporting pain lasting one month or longer in the previous year in at least one hip, knee, or foot were included. Respondents completed a generic measure of physical function and site-specific measures of severity for each relevant joint pain.
Of 2429 eligible participants, 1801 reported multiple-site lower limb joint pain. Lower limb joint pain count was independently associated with reduced physical function after adjusting for a range of covariates. The severity of pain and disability attributed to each site increased as the number of painful sites increased.
Many older people with joint pain in the lower limb have more than one joint affected. Generic and site-specific measures of disability both show the same pattern of reduced physical function. Treatment targeted at a single joint may have only a marginal effect on reducing disability in individuals with multiple joint involvement unless treatment is also conferring benefit at other sites.