Lifetime occupation is not associated with radiographic osteoarthritis of the first metatarsophalangeal joint in a cohort study of UK women

OBJECTIVE: The study aim was to determine whether lifetime occupation was associated with the presence of radiographic osteoarthritis (ROA) of the first metatarsophalangeal joint (MTPJ) in women. METHOD: Data were collected from the prospective, population-based Chingford 1000 Women study. This cohort of women, aged 45–64 years at inception, was established in 1989 from a single general practice in Chingford, UK. Data has subsequently been collected repeatedly. Data from baseline, year six and year ten was used for the purposes of this cross-sectional study. The primary outcome was the presence of dorsal view ROA of the first MTPJ. The main exposure was lifetime occupation, categorised according to levels of occupation previously defined via international consensus: 1. Sedentary, 2. Light, 3. Light manual, 4. Heavy manual. Logistic regression analyses were conducted to quantify the relationship between lifetime occupation type and the presence of ROA of the first MTPJ, adjusting for age, body mass index and lifetime high-heeled footwear use as potential interactive variables for each decade. RESULTS: Data for 209 women were included within this study. The mean (SD) age was 57 (±5.2) years. Predominant lifetime occupation was reported as sedentary by 51.7%, as light by 0%, as light manual by 33.5% and as heavy manual by 14.8% of participants. There were no statistical associations between lifetime occupation type and the presence of ROA of the first MTPJ in either the unadjusted (OR = 0.99, CI = 0.78–1.26,P = 0.96) partially adjusted (for age and BMI; OR = 1.00, CI = 0.78–1.29, P = 0.99) or fully adjusted models (for age, BMI and lifetime high heel footwear use for each decade of working life (OR = 1.02, CI = 0.79–1.31, P = 0.91); high-heel footwear use up to 20s (OR = 0.83, CI = 0.71–1.31, P = 0.83); high-heel footwear use in 20–30s (OR = 1.00, CI = 0.75–1.3, P = 0.98); high-heel footwear use in 30–40s (OR = 1.00, CI = 0.70–1.42, P = 0.99); high-heel footwear use in 40–50s (OR = 0.90, CI = 0.58–1.40, P = 0.65); high-heel footwear use in 50s (OR = 0.63,CI = 0.36–1.09, P = 0.10). CONCLUSIONS: The findings suggest that lifetime occupation is not associated with the presence of ROA of the fist metatarsophalangeal joint. There does not appear to be any interactive effect between lifetime occupation, lifetime high-heel footwear use, age or BMI and ROA of the first MTPJ. In later life a positive trend towards increased ROA in those who reported lifetime high-heel footwear use was noted and this may be worthy of further research.