Author response: Dietary flavonols and risk of Alzheimer dementia
Thomas M.Holland, MD, MS, Faculty, College of Health Sciences, Rush University Post-Doctoral Fellow, Rush Institute for Healthy Aging, RUMC
PujaAgarwal, PhD, Rush University Medical Center, Rush Institute for Healthy Aging
YaminWang, PhD, Rush Institute for Healthy Aging
Sarah L.Booth, PhD, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University (Boston, MA)
Submitted May 22, 2020
We thank Tomoyuki Kawada for the thoughtful comments on our recently published article.1 In this longitudinal prospective analysis, we concluded that higher dietary intake of flavonols may reduce the risk of developing Alzheimer’s dementia. We agree with Dr. Kawada that prospective cohort study designs like ours—Engelhardt et. al.,2 Devore et. al.,3 and Root et al.4 in middle-aged adults—cannot confer causality. Further, we recognize that co-morbidities—as well as other lifestyle factors—have an impact on Alzheimer's dementia risk. To mitigate this, our basic models were adjusted for potential confounders, including demographic, lifestyle, and genetic risk factors that are related to Alzheimer's dementia. To add strength to our findings, we further adjusted for cardiovascular type co-morbidities, BMI, depression, and other nutrient intake, and we found no material difference. Due to the combination of potential for changes in either dietary habits or the ability to accurately self-report diet due to pre-clinical changes in cognitive function in combination with the relatively short follow-up time, the reported associations cannot establish the temporal relationship between the exposure (flavonols) and the outcome. A future prospective randomized control trial is needed to establish causality.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
Holland TM, Agarwal P, Wang Y, et al. Dietary flavonols and risk of Alzheimer dementia. Neurology 2020;94:e1749–e1756.
Engelhart MJ, Geerlings MI, Ruitenberg A, et al. Dietary intake of antioxidants and risk of Alzheimer disease. JAMA 2002;287:3223–3229.
Devore EE, Kang JH, Breteler MMB, Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol 2012;72:135–143.
Root M, Ravine E, Harper A. Flavonol intake and cognitive decline in middle-aged adults. J Med Food 2015;18:1327–1332.
We thank Tomoyuki Kawada for the thoughtful comments on our recently published article.1 In this longitudinal prospective analysis, we concluded that higher dietary intake of flavonols may reduce the risk of developing Alzheimer’s dementia. We agree with Dr. Kawada that prospective cohort study designs like ours—Engelhardt et. al.,2 Devore et. al.,3 and Root et al.4 in middle-aged adults—cannot confer causality. Further, we recognize that co-morbidities—as well as other lifestyle factors—have an impact on Alzheimer's dementia risk. To mitigate this, our basic models were adjusted for potential confounders, including demographic, lifestyle, and genetic risk factors that are related to Alzheimer's dementia. To add strength to our findings, we further adjusted for cardiovascular type co-morbidities, BMI, depression, and other nutrient intake, and we found no material difference. Due to the combination of potential for changes in either dietary habits or the ability to accurately self-report diet due to pre-clinical changes in cognitive function in combination with the relatively short follow-up time, the reported associations cannot establish the temporal relationship between the exposure (flavonols) and the outcome. A future prospective randomized control trial is needed to establish causality.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References