248)Background: The links between diet and the risk of dementia have never been studied taking into account the possibility of protopathic bias (i.e., reverse causation). Objective:We aimed to examine the relationship between consumption frequency of meat, fish, fruits and vegetables and long-term risk of dementia and Alzheimer's disease (AD), by taking into account this possibility. Methods:We analysed data of 5934 volunteers aged 65 and over from the Three-city study who were followed every 2 to 4 years for 12 years. Dietary habits were assessed at inclusion using a brief food frequency questionnaire. The presence of symptoms of dementia was investigated at each follow-up visit. To limit the risk of protopathic bias, a 4-year lag window between exposure and disease assessment was implemented by excluding from the analyses all dementia cases that occurred during the first four years after inclusion. Analyses were performed using a Cox proportional hazard model and were adjusted for socio-demographic, lifestyle and health factors. Results:The average follow-up time was 9·8 years. During this period, 662 cases of dementia, including 466 of AD, were identified. After adjustment, only low meat consumption (≤ 1time/week) was associated with an increased risk of dementia and AD compared with regular consumption (≥4times/week) (HR=1·58 95%CI=[1·17-2·14], HR=1·67 95%CI=[1·18-2·37], respectively). No association was found between the consumption of fish, raw fruits, or cooked fruits and vegetables and the risk of dementia or AD. Conclusion:These findings suggest very low meat consumption increases the long-term risk of dementia and AD, and that a protopathic bias could have impacted finding from previous studies. 4

BackgroundAlthough several studies highlighted an association between occupational exposure and Dupuytren’s contracture (DC), they were often limited by the highly selected population. We aimed to study this association using a job-exposure matrix (JEM) and self-reported exposure in a large cohort.MethodsFrom CONSTANCES, a French population-based prospective cohort, we retrieved sex, age, social position, alcohol/tobacco intake and diabetes. Lifetime exposures were assessed by two different methods: with the biomechanical JEM ‘JEM Constances’, we assessed exposure to vibration and/or forearm rotation for participants whose work history was available, and from a self-administered questionnaire, we retrieved self-reported exposure to arduous work and/or carrying heavy loads. Surgery for DC was collected from the French Health Administrative database from 2009 to 2016. Multivariate logistic regression models adjusted for confounders were built to assess association between surgery for DC and occupational exposures.ResultsWork history was retrieved for 23 795 subjects among whom 98 underwent surgery for DC. Adjusted OR (aOR) was 2.08 (1.03–4.2) for being ever exposed to vibration and/or forearm rotation for subjects <60 years and 1.20 (0.69–2.08) for subjects ≥60 years. Data for self-reported exposure were available for 81 801 participants among whom 367 underwent surgery for DC. aOR for being exposed more than 20 years to arduous work and/or carrying heavy loads was 2.01 (1.32–3.04) for subjects <60 years and 1.04 (0.7–1.54) for subjects ≥60.ConclusionsManual work is associated with surgery for DC among younger subjects. Monitoring exposed workers is important to prevent future functional limitations.