The effect of age on the onset of pain interference in a general population of older adults: prospective findings from the North Staffordshire Osteoarthritis Project (NorStOP).

Pain that interferes with daily life appears to be strongly age-related in cross-sectional studies, although the nature of this relationship over time has not been established. We have investigated the onset and persistence of pain and pain interference over a 3-year period to determine their association with age in older people. A 3-year follow-up postal survey was conducted of adults aged 50 years and over (n=5366) who had previously been recruited as part of the North Staffordshire Osteoarthritis Project. Four thousand two-hundred and thirty-four completed questionnaires were received (adjusted response 84.7%). The occurrence of pain interference at 3 years was 19.7% in persons free of such pain at baseline, higher in females than males (6.0% difference; 95% CI: 2.6%, 9.3%), and showed a clear age-related trend with a more than twofold increase from 50 to 59 years (16.0%) to the 80+ years (35%). Any pain at follow-up was reported by 48% of those pain-free at recruitment, and this figure was similar for males and females, and across 10-year age-groups. Persistence of pain interference (72.1%) at 3 years was high. In adults aged 50 years and over, the onset of pain that interferes with life shows a clear gender difference and a consistent rise with age into the oldest age-group. This was in strong contrast to the onset of pain which showed no gender or age-related trends. The implications for public health, as for the treatment of the individual, are twofold, relating to efforts to prevent disabling pain from occurring and to understand the factors that accelerate the impact which pain has on everyday life when people reach the oldest ages.