Association of Midlife Diet With Subsequent Risk for Dementia

Abstract

Importance Observational studies suggest that diet is linked to cognitive health. However, the duration of follow-up in many studies is not sufficient to take into account the long preclinical phase of dementia and the evidence from intervention studies is not conclusive. Objectives To examine whether midlife diet is associated with subsequent risk of dementia. Design, Setting and Participants Population-based cohort study established in 1985-1888, with dietary intake assessment in 1991-1993, 1997-1999 and 2002-2004; follow-up for incident dementia until March 2017. Exposures Food frequency questionnaire to derive the Alternate Healthy Eating Index (AHEI), an 11-component diet quality score (range=0-110), with higher scores indicating a healthier diet. Main Outcome and Measures Incident dementia ascertained through linkage to electronic health records. Results Among 8225 (mean age 50.2 (SD, 6.1) years; 5686, 69.1% men) dementia-free participants in 1991-1993 a total of 344 cases of incident dementia were recorded over a median follow-up of 24.8 (IQR, 24.2 to 25.1) years. No significant difference in incidence rate (IR) of dementia was observed in tertiles of AHEI exposure in 1991-1993, 1997-1999 (median follow-up 19.1 years) and 2002-2004 (median follow-up 13.5 years). Compared with IR of dementia of 1.76 (95% CI, 1.47-2.12) per 1000 person-years in the worst tertile of AHEI (lowest tertile of diet quality) in 1991-1993, the absolute rate differences for the intermediate and the best tertiles were, respectively, 0.03 (95 % CI, -0.43 to 0.49) and 0.04 (95% CI, -0.42 to 0.51) per 1000 person-years. In 1997-1999, the absolute rate differences in the intermediate and the best AHEI tertiles compared to the worst tertile (IR=2.06 (95% CI, 1.62-2.61) per 1000 person-years) were respectively 0.14 (95 % CI, -0.58 to 0.86) and 0.14 (95% CI, -0.58 to 0.85) per 1000 person-years. In 2002-2004, these absolute rate differences with the worst AHEI tertile (IR=3.12 (95% CI, 2.49-3.92) per 1000 person-years) were respectively -0.61 (95 % CI, -1.56 to 0.33) and -0.73 (95% CI, -1.67 to 0.22) per 1000 person-years in the intermediate and best AHEI tertiles. In multivariate analysis, HRs of dementia per 10-point AHEI increment were not significant as assessed in 1991-1993 (0.97, 95% CI, 0.87-1.08)), in 1997-1999 (0.97, 95% CI, 0.83-1.12)), or in 2002-2004 (0.87, 95% CI, 0.75-1.00)). Conclusion In this long-term prospective cohort study, diet quality assessed in midlife was not significantly associated with subsequent risk of dementia.

Dietary patterns are related to cognitive functioning in elderly enriched with individuals at increased risk for Alzheimer’s disease

“…These results are in line with population-based studies, which observed a positive association between adherence to the Mediterranean diet [43][44][45][46], or MIND diet and cognitive decline or dementia [15,16,18,20]. While not all cross-sectional [21,22] and longitudinal [47][48][49] studies did replicate these findings, a meta-analysis on the Mediterranean diet and a systematic review of the MIND diet 50,51]. Extending the evidence from these population-based studies, we here show that higher adherence to the Mediterranean diet and MIND diet are also associated with cognitive outcomes in a sample enriched with subjects who are either clinically or genetically at increased risk for AD.…”

“…The relationships between greater adherence to these diets and better cognition, slower cognitive decline and decreased risk for dementia could not always be replicated (e.g., e.g., [20][21][22]). Methodological challenges such as the sensitivity of outcome measures, the most sensitive time periods in life course and the true adherence of cultural diverse populations to the predefined diets might have contributed to these inconsistent findings [23].…”

Dementia prevention, intervention, and care: 2020 report of the Lancet Commission

“…A further prospective cohort study with three midlife dietary assessments in 8255 people, followed up for a mean of nearly 25 years, found neither healthy dietary pattern nor Mediterranean diet protected from dementia, except in those with cardiovascular disease, suggesting that diet might influence dementia risk by protecting from the excess risk of cardiovascular risk factors. 147 …”

The Effect of Healthy Diet on Cognitive Performance Among Healthy Seniors – A Mini Review

“…However, there are also research studies which disagree with these positive impacts. They claim that dietary interventions, especially dietary monotherapies, do not have any effect on the improvement of cognitive functions among healthy older population groups (Krause and Roupas, 2017;Akbaraly et al, 2019). But one thing is certain, the dietary approaches are non-invasive and have fewer or no side effects if compared to drug therapies (Klimova and Kuca, 2018).…”