Flavonoid intake and incident dementia in the Danish Diet, Cancer, and Health cohort

Abstract

Introduction Prospective studies investigating flavonoid intake and dementia risk are scarce. The aims of this study were to examine associations between flavonoid intake and the risk of incident dementia and to investigate whether this association differs in the presence of lifestyle risk factors for dementia. Methods We examined associations in 55,985 participants of the Danish Diet, Cancer, and Health Study followed for 23 years. The Phenol‐Explorer database was used to estimate flavonoid intakes. Information on incident dementia and dementia subtypes was obtained using Danish patient and prescription registries. Hazard ratios (HRs) were calculated using restricted cubic splines in multivariable‐adjusted Cox proportional hazards models. Results For incident dementia, moderate compared to low intakes of flavonols (HR: 0.90 [0.82, 0.99]), flavanol oligo+polymers (HR: 0.87 [0.79, 0.96]), anthocyanins (HR: 0.84 [0.76, 0.93]), flavanones (HR: 0.89 [0.80, 0.99]), and flavones (HR: 0.85 [0.77, 0.95]) were associated with a lower risk. For vascular dementia, moderate intakes of flavonols (HR: 0.69 [0.53, 0.89]) and flavanol oligo + polymers (HR: 0.65 [0.51, 0.83]) were associated with lower risk. Flavonoid intakes were not significantly associated with Alzheimer's disease or unspecified dementia. The inverse association between total flavonoid intake and incident dementia was stronger in “ever” smokers than in “never” smokers and in those without hypercholesterolemia versus those with hypercholesteremia. Furthermore, the inverse association of vascular dementia with a moderate total flavonoid intake was stronger in “ever” smokers and those who were “normal” to “overweight” versus “never” smokers or those who were “obese,” respectively. Conclusion A moderate intake of flavonoid‐rich foods may help to reduce dementia risk.

Change in habitual intakes of flavonoid-rich foods and mortality in US males and females

“…There is more evidence for a protective role of flavonoids in the development of neurological diseases [ 41 ] with mechanisms including a reduction in reactive oxygen species and amyloid beta-protein production [ 42 ]. Recent data also suggest that higher intake of flavonoids and flavonoid-rich foods are associated with a lower risk of Alzheimer’s, dementia, and Parkinson’s disease [ 43 – 46 ] but our data are the first to suggest that increasing intakes in mid-life can reduce risk of neurological death. Although we include a lag time of 2 years, we cannot discount the possibility that observed associations may be attributed to reverse causation, in particular, that a higher risk of neurological death may be linked to a decrease in intakes of flavonoid-rich foods.…”

Flavonoid intakes inversely associate with COPD in smokers

“…The primary aim of this study was to investigate the associations between intakes of 1) total flavonoids, 2) flavonoid subclasses and 3) key flavonoid compounds within respective subclasses with incident COPD in the Danish Diet, Cancer and Health cohort. In our previous work, a consistent finding was that associations between flavonoid intake and a range of chronic diseases (including cardiovascular disease, dementia and diabetes [ 15 , 16 ]) were stronger in current and former smokers. Given the importance of smoking as a risk factor for COPD, the purported antioxidant and anti-inflammatory properties of flavonoids, and that there is evidence of sex-related differences in COPD risk and outcomes [ 17 ], secondary aims were to explore interactions between flavonoid intakes and risk factors for COPD, namely sex and smoking.…”

Dietary (Poly)phenols and Cognitive Decline: A Systematic Review and Meta‐Analysis of Observational Studies

“…A total of 1823 studies were identified through the search strategy ( Figure 1 ). Out of these, after examination of the title ( n = 1303) and abstract ( n = 521) and full texts ( n = 487), 37 articles [ 15–51 ] were included in this review. The main characteristics of the included studies are presented in Table S2, Supporting Information.…”

“…Interestingly, this association was stronger in smokers (Q3 vs Q1 of flavanones, HR = 0.89, 95% CI: 0.80, 0.99) and significant for vascular dementia (Q3 vs Q1 of flavonols, HR 0.64, 95% CI: 0.48, 0.84), but no association was observed for Alzheimer's disease or unspecified dementia risk. [ 49 ] In a prospective study of 1329 participants of the Three Cities (3C) Bordeaux Cohort with a 12‐year follow‐up, authors analyzed different patterns of (poly)phenol consumption in association with risk of Alzheimer: compared to lowest exposure, individuals in the highest quintile of a high‐(poly)phenol pattern score had 50% lower probability of developing dementia (HR = 0.50, 95% CI: 0.32, 0.80) and 48% lower risk of Alzheimer's disease (HR = 0.52, 95% CI: 0.29, 0.93). [ 50 ] Finally, in a recent report from the JPHC including 8991 men and 22 456 women followed for an average of 9.4 years, the incidence risk of disabling dementia (defined as dementia that required care) was unrelated to intake of isoflavones in both men and women (Q5 vs Q1, HR = 1.05, 95% CI: 0.90, 1.24 and HR = 0.98, 95% CI: 0.86, 1.12, respectively).…”