The Mediterranean diet (MD) has shown to reduce the occurrence of several chronic diseases. To evaluate its potential protective role on dementia incidence we studied 16,160 healthy participants from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Spain Dementia Cohort study recruited between 1992–1996 and followed up for a mean (±SD) of 21.6 (±3.4) years. A total of 459 incident cases of dementia were ascertained through expert revision of medical records. Data on habitual diet was collected through a validated diet history method to assess adherence to the relative Mediterranean Diet (rMED) score. Hazard ratios (HR) of dementia by rMED levels (low, medium and high adherence levels: ≤6, 7–10 and ≥11 points, respectively) were estimated using multivariable Cox models, whereas time-dependent effects were evaluated using flexible parametric Royston-Parmar (RP) models. Results of the fully adjusted model showed that high versus low adherence to the categorical rMED score was associated with a 20% (HR = 0.80, 95%CI: 0.60–1.06) lower risk of dementia overall and HR of dementia was 8% (HR = 0.92, 0.85–0.99, p = 0.021) lower for each 2-point increment of the continuous rMED score. By sub-types, a favorable association was also found in women for non-AD (HR per 2-points = 0.74, 95%CI: 0.62–0.89), while not statistically significant in men for AD (HR per 2-points = 0.88, 0.76–1.01). The association was stronger in participants with lower education. In conclusion, in this large prospective cohort study MD was inversely associated with dementia incidence after accounting for major cardiovascular risk factors. The results differed by dementia sub-type, sex, and education but there was no significant evidence of effect modification.

Background: Dementia has become a public health priority as the number of cases continues to grow worldwide. Objective: To assess dementia incidence and determinants in the EPIC-Spain Dementia Cohort. Methods: 25,015 participants (57% women) were recruited from three Spanish regions between 1992-1996 and followed-up for over 20 years. Incident cases were ascertained through individual revision of medical records of potential cases. Crude and age-adjusted incidence rates (IR) of dementia and sub-types (Alzheimer’s disease (AD), and non-AD) were calculated by sex. Neelson-Aalen cumulative incidence estimates at 10, 15, and 20 years were obtained for each sex and age group. Multivariate Royston-Parmar models were used to assess independent determinants. Results: Global IR were higher in women for dementia and AD, and similar by sex for non-AD. IR ranged from 0.09 cases of dementia (95% confidence interval: 0.06–0.13) and 0.05 [0.03–0.09] of AD per 1000 person-years (py) in participants below 60 years, to 23.2 (15.9–33.8) cases of dementia and 14.6 (9.1–33.5) of AD (per 1000 py) in those ≥85 years. Adjusted IR were consistently higher in women than men for overall dementia and AD. Up to 12.5% of women and 9.1% of men 60–65 years-old developed dementia within 20 years. Low education, diabetes, and hyperlipidemia were the main independent predictors of dementia risk, whereas alcohol showed an inverse association. Conclusion: Dementia incidence increased with age and was higher among women, but showed no geographical pattern. Dementia risk was higher among subjects with lower education, not drinking alcohol, and presenting cardiovascular risk factors.

Background: Cohort studies generally focus on a particular disease, although they offer the possibility of evaluating different outcomes with minimal additional investment. The objective of this study was to describe the methodology used to assess dementia in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Murcia study. Methods: The EPIC-Murcia cohort consists of 8,515 healthy participants (68% women, aged 30–70 years), recruited between 1992 and 1996 and followed up for over 20 years. Incident cases were ascertained by a 2-step protocol: a record linkage with health databases to identify potential events and a review of medical records of potential cases to validate incident cases. Results: Overall, 1,202 potential cases were identified, and 275 dementia cases were validated. Medical reports were the source of information in 243 cases, with complete neurological information in 227, and a high degree of certainty of the diagnosis in 229 cases. P70 (dementia code) and/or antidementia drugs and/or ICD codes identified 259 cases (sensitivity: 94.2%, 95% CI 90.7–96.6; specificity: 98.1%, 95% CI 97.8–98.4). Conclusion: Ascertainment of incident dementia in the EPIC-Murcia cohort study was feasible using information from medical records. This systematic 2-step validation protocol is proposed as a feasible way to ascertain dementia in cohort studies originally designed for other endpoints.