This study prospectively assessed the importance of individual conditions and computer use during school or work and leisure time as risk factors for self-reported generally reduced productivity due to musculoskeletal complaints among young adults with musculoskeletal symptoms in the neck or upper extremities. METHODS: A cohort of 2914 young adults (18-25 years, vocational school and college or university students) responded to an internet-based questionnaire concerning musculoskeletal symptoms related to individual conditions and computer use during school or work and leisure time that possibly affected general productivity. Prevalence ratios (PR) were used to assess prospective risk factors for generally reduced productivity. RESULTS: The selected study sample (N=1051) had reported neck or upper-extremity symptoms. At baseline, 280 of them reported reduced productivity. A follow-up of the 771 who reported no reduced productivity was carried out after 1 year. Risk factors for self-reported generally reduced productivity for those followed-up were symptoms in two or three locations or dimensions for the upper back or neck and the shoulders, arms, wrists, or hands [PR 2.30, 95% confidence interval (95% CI) 1.40-3.78], symptoms persisting longer than 90 days in the shoulders, arms, wrists, or hands (PR 2.50, 95% CI 1.12-5.58), current symptoms in the shoulders, arms, wrists, or hands (PR 1.78, 95% CI 1.10-2.90) and computer use 8-14 hours/week during leisure time (PR 2.32, 95% CI 1.20-4.47). A stronger relationship was found if three or four risk factors were present. For women, a relationship was found between generally reduced productivity and widespread and current symptoms in the upper extremities. CONCLUSIONS: The main risk factors for generally reduced productivity due to musculoskeletal symptoms among young adults in this study were chronic symptoms in the upper extremities and widespread symptoms in the neck and upper extremities.