Objective Pain that interferes with daily activities is the dominant cause of locomotor disability in older people. The objective of this study was to determine the influence of different trajectories of life-course socio-economic position (SEP) on pain interference in a population of older adults.

Design Prospective cohort study.

Setting General population in North Staffordshire, UK.

Participants All patients aged 50+ registered with three different general practices were sent a baseline postal questionnaire. Responders consenting to further contact were followed up twice. Ethical approval was granted for all stages of the study.

Main Outcome Pain interference measured using an SF-36 item, asking how much pain interfered with normal work and housework during the last 4 weeks. Response categories dichotomised into having pain interference (extremely, quite a bit, moderately) and having no pain interference (a little bit, not at all).

Life-Course SEP Measures (1) Age left school (young adulthood SEP): those who left school at ≤ the minimum school leaving age assigned low SEP; those who left school at > the minimum school leaving age assigned high SEP, (2) Longest job (adult working life SEP) and (3) Current/recent job (most recent adult SEP): using the National Statistics Socio-economic Classification, Routine and manual occupations were assigned low SEP; Intermediate and Managerial and professional occupations were assigned high SEP. Life-course SEP trajectories were constructed for each respondent from the three measures.

Other Measures BMI, HADS, health locus of control, adequacy of income.

Analysis Confined to participants who provided data at three SEP time-points (n=2535). Association of pain interference with each SEP trajectory (High, High, High (HHH) as reference trajectory) was calculated by logistic regression and adjusted for age, gender and BMI. Forward stepwise logistic regression was used to adjust for potential confounding psychosocial and social factors. Latent class analysis identified any clustering in SEP trajectories.

Results Adjusted response to the three stages of the survey was 71–85%. The LLL SEP trajectory was significantly associated with pain interference compared to HHH (OR 2.73; 95% CI 2.16 to 3.45); this association was not altered by age or gender. Adjustment for the remaining factors reduced the association but it remained significant (OR 2.05; 95% CI 1.56 to 2.70). Latent class analysis identified two clusters of SEP trajectories: those that started Low remained Low, those starting High remained High.

Conclusion In this study, adults with a consistently low SEP throughout their life-course were more likely to report pain interference in later life.