Associations of hip osteoarthritis with history of recurrent exposure to manual handling of loads over 20 kg and work participation: a population-based study of men and women.

Objectives: We reviewed work histories of manual handling of loads >20 kg in relation to hip osteoarthritis by age, exposure and work participation.

Methods: A nationally representative sample of 3110 Finnish men and 3446 women aged 30-97 was recruited. Diagnosis of hip osteoarthritis was based on standardised clinical examination by trained physicians. Previous exposure to physically loading work was evaluated through interviews. Logistic regression was used to estimate associations between work factors and hip osteoarthritis.

Results: 1.9% of men and 2.1% of women had hip osteoarthritis. Almost half the men and a quarter of the women had recurrently handled heavy loads at work. Subjects who had manually handled loads >20 kg had a 1.8-fold increased risk of hip osteoarthritis compared to non-exposed references, when age, body mass index, traumatic fractures and smoking were accounted for. Results were similar for men (OR 2.0; 95% CI 1.0 to 4.0) and women (1.8; 1.1 to 2.8). In a sub-analysis of subjects with hip replacement, the OR was 1.7 (1.0 to 2.9). Risk increased first after 12 years' exposure: among men it was 2.2 (0.8 to 5.9) for 13-24 years' exposure, and 2.3 (1.2 to 4.3) for >24 years' exposure. Among women it was 3.8 (1.7 to 8.1) for 13-24 years' exposure. Work participation among men aged <60 years with hip osteoarthritis was 20% lower compared with subjects without osteoarthritis.

Conclusions: A work history of manual handling of loads >20 kg showed a strong association with hip osteoarthritis in all age groups except the youngest.