Long sleep duration is associated with lower cognitive function among middle-age adults – the Doetinchem Cohort Study

Objectives In older adults, both short and long sleep duration are associated with lower cognitive function, suggesting an inverted U-shaped association between sleep duration and cognitive outcomes. This study examined whether sleep duration is associated with (changes in) cognitive function in a middle-aged population. Methods In the Doetinchem Cohort Study, the cognitive function of 2970 men and women aged 41–75 years at baseline (1995–2007) was examined 2–3 times, with 5-year time intervals. Global cognitive function and the domains memory, information processing speed, and cognitive flexibility were assessed. In multivariable linear regression models, (change in) self-reported sleep duration was studied in association with the level and change in cognitive function. In a subsample of the population (n = 2587), the association of sleep duration and feeling rested with cognitive function was studied. Results Sleep duration of 9 h and more was statistically significantly associated with lower global cognitive function (p < 0.01), memory (p = 0.02), and flexibility (p = 0.03), compared to a sleep duration of 7 or 8 h. Among adults feeling frequently not well rested, both short and long sleep duration were associated with a lower speed of cognitive function. An inverted U-shaped association between sleep duration and cognitive function was observed for speed, flexibility, and global cognitive function. Sleep duration was not associated with change in cognitive function. Conclusions Middle-age adults with long sleep duration had a lower cognitive function

Adherence to dietary guidelines and cognitive decline from middle age: the Doetinchem Cohort Study

BACKGROUND: Diet, in particular the Mediterranean diet, has been associated with better cognitive function and less cognitive decline in older populations. OBJECTIVES: To quantify associations of a healthy diet, defined by adherence to either the Mediterranean diet, the WHO guidelines, or Dutch Health Council dietary guidelines, with cognitive function and cognitive decline from middle age into old age. METHODS: From the Doetinchem Cohort Study, a large population-based longitudinal study, 3644 participants (51% females) aged 45-75 y at baseline, were included. Global cognitive function, memory, processing speed, and cognitive flexibility were assessed at 5-y time intervals up to 20-y follow-up. Adherence to the Mediterranean diet was measured with the modified Mediterranean Diet Score (mMDS), adherence to the WHO dietary guidelines with the Healthy Diet Indicator (HDI), and adherence to the Dutch Health Council dietary guidelines 2015 with the modified Dutch Healthy Diet 2015 index (mDHD15-index). The scores on the dietary indices were classified in tertiles (low, medium, high adherence). Linear mixed models were used to model level and change in cognitive function by adherence to healthy diets. RESULTS: The highest tertiles of the mMDS, HDI, and mDHD15-index were associated with better cognitive function compared with the lowest tertiles (P values <0.01), for instance at age 65 y equal to being 2 y cognitively younger in global cognition. In addition, compared with the lowest tertiles, the highest tertiles of the mMDS, HDI, and mDHD15-index were statistically significantly associated with 6-7% slower global cognitive decline from age 55 to 75 y, but also slower decline in processing speed (for mMDS: 10%; 95% CI: 2, 18%; for mDHD15: 12%; 95% CI: 6, 21%) and cognitive flexibility (for mDHD15: 10%; 95% CI: 4, 18%). CONCLUSIONS: Healthier dietary habits, determined by higher adherence to dietary guidelines, are associated with better cognitive function and slower cognitive decline with aging from middle age onwards

Mediterranean Style Diet and 12-Year Incidence of Cardiovascular Diseases: The EPIC-NL Cohort Study

Background: A recent meta-analysis showed that a Mediterranean style diet may protect against cardiovascular diseases (CVD). Studies on disease-specific associations are limited. We evaluated the Mediterranean Diet Score (MDS) in relation to incidence of total and specific CVDs. Methods: The EPIC-NL Study is a cohort of 40,011 men and women aged 20-70 years, examined between 1993 and 1997, with 10-15 years of follow-up. Diet was assessed with a validated food frequency questionnaire and the MDS was based on the daily intakes of vegetables, fruits, legumes and nuts, grains, fish, fatty acids, meat, dairy, and alcohol. Cardiovascular morbidity and mortality were ascertained through linkage with national registries. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) adjusted for age, sex, cohort, smoking, physical activity, total energy intake, and educational level. Results: In 34,708 participants free of CVD at baseline, 4881 CVD events occurred, and 487 persons died from CVD. A two unit increment in MDS (range 0-9) was inversely associated with fatal CVD (HR: 0.78; 95%CI: 0.69-0.88), total CVD (HR: 0.95 (0.91-0.98)), myocardial infarction (HR: 0.86 (0.79-0.93)), stroke (HR: 0.88 (0.78-1.00)), and pulmonary embolism (HR: 0.74 (0.59-0.92)). The MDS was not related to incident angina pectoris, transient ischemic attack and peripheral arterial disease. Conclusion: Better adherence to a Mediterranean style diet was more strongly associated with fatal CVD than with total CVD. Disease specific associations were strongest for incident myocardial infarction, stroke and pulmonary embolism