Background : Physical job demands (PJD), age, disability and lifestyle may influence the risk of occupational injury.Aim : To assess the relationships between PJD, lifestyle and injury in workers of various ages.Methods A total of 2888 randomly selected workers from northeastern France, aged ≥15, completed a postal questionnaire. The PJD score was defined as the total number of the following reported job demands: using pneumatic tools, other vibrating hand tools, hammers, machine tools or vibrating platforms and exposure to manual handling tasks, awkward postures, high pace of work, high physical workload, work at heights, work in adverse climates or exposure to noise, cold or heat. Data were analysed using logistic regression.Results Nine per cent of subjects reported an injury during the previous 2 years. The PJD score was related to the injury rate for workers aged ≥45: crude odds ratio (OR) 3.5 (95% confidence interval = 1.5-8.0) for PJD = 1, 5.0 (2.2-11.3) for PJD = 2-3 and 14.5 (6.5-32.2) for PJD ≥4, versus PJD = 0. Lower ORs were found for those aged <30 (1.4, 4.2 and 9.9, respectively) and 30-44 (1.5, 4.4 and 6.5, respectively). The differences between age groups remained when controlling for all factors studied. Obesity, smoking and musculoskeletal disorders were associated with injury risk in workers aged ≥45 (adjusted ORs 1.7-2.6). Smoking was also an injury risk factor for workers aged <30.Conclusions PJD and lifestyle have a higher impact on injury rates among older workers than among younger ones. Injury prevention should address reducing PJD and improving relevant lifestyle factors, especially for older workers.