O4‐05‐01: Caloric intake, but not the Mediterranean diet, is associated with cognition and mild cognitive impairment

The Mediterranean diet (MeDi) has been shown to be associated with lower cognitive decline, decreased risk of dementia and MCI, and increased longevity. However, not all studies have been able to replicate these findings. It may be that other factors associated with the MeDi in some cultural contexts are responsible for, or at least modulate, its effects. The aim of this study was to examine in an Australian context the associations between the MeDi and cognitive decline over 8 years, or transition to MCI and to investigate the role of caloric intake in cognitive decline. Prospective narrow cohort study of 1367 participants (60-64 years) from Canberra, Australia, randomly selected from the electoral roll, and free from dementia or MCI with an 8-year follow-up. Dietary intake was measured using a validated Food Frequency Questionnaire. Adherence to the MeDi was computed following the methodology used by Scarmeas et al. (2006, 2009). Excess caloric intake was computed based on MHMRC recommendations for gender, age, height and activity level. Global cognition was computed based on five tasks assessing immediate and delayed recall, executive function, speed of processing and verbal fluency. MCI diagnoses were based on a full neuropsychological battery and reviewed by expert clinicians. Predictors were assessed using linear and Cox regressions. After adjusting for gender, age, education,stroke, diabetes, BMI, hypertension, physical activity, APOE e4 genotype, andcaloric intake the MeDi was neither associated with global cognition (b = −0.003,n.s.) nor transition from normal cognition to MCI (HR 1.07,95%CI 0.85-1.35, n.s.). In contrast, caloric intake exceeding the recommendation of the NHMRC was significantly associated with increased cognitive decline (b = −0.302,p = .007) and increased risk of MCI (HR 3.53, 95%CI1.33-9.38, p = .012). In this large community-based sample the MeDi was not associated with cognitive decline or MCI. It may be that dietary or other cultural differences associated with the MeDi vary in different cultural contexts and modulate, mediate, or are responsible for the associations found between the MeDi and cognition in previous research. In contrast, excessive caloric intake was associated with an increased risk of both cognitive decline and of conversion to MCI over eight years.