In a 2-decade prospective population-based study from Sweden, Dr. Glans and colleagues investigated the association between adherence to conventional dietary recommendations or to a modified Mediterranean diet and subsequent risk of developing all-cause dementia, Alzheimer disease (AD), vascular dementia (VaD), or accumulation of AD-related β-amyloid pathology in the CSF, among 28,025 participants. They concluded that these dietary habits were not significantly associated with a reduced risk for developing all-cause dementia, AD dementia, VaD, or AD pathology. In response, Dr. Kawada cites a previous study that found significant interactions between dietary patterns and APOE-ε4 status in relation to incident dementia, with a healthy dietary pattern being associated with lower dementia incidence in ε4 noncarriers and a Western dietary pattern associated with higher dementia incidence in ε4 carriers. Dr. Kawada argues that studies examining the long-term effect of dietary patterns on incident dementia should consider the contribution of genetic factors. In another response, Dr. Hoffman notes that the researchers' use of a modified Mediterranean diet score does not explicitly measure for extra virgin olive oil (EVOO), which may be an important component for maintaining cognitive health, citing epidemiologic and animal studies in this regard. He contends that it is important to consider the role of EVOO as part of a Mediterranean diet for cognitive health to better inform the implementation of this diet in non-Mediterranean countries. Responding to these comments, the authors note that they did not find any significant interaction effects between conventional dietary recommendations or a modified Mediterranean diet and APOE-ε4 status with respect to subsequent dementia but do not comment about the role of extra virgin olive oil. Overall, this exchange highlights enduring uncertainties about the role of specific dietary factors in mitigating the long-term risk of dementia.

In a 2-decade prospective population-based study from Sweden, Dr. Glans and colleagues investigated the association between adherence to conventional dietary recommendations or to a modified Mediterranean diet and subsequent risk of developing all-cause dementia, Alzheimer disease (AD), vascular dementia (VaD), or accumulation of AD-related β-amyloid pathology in the CSF, among 28,025 participants. They concluded that these dietary habits were not significantly associated with a reduced risk for developing all-cause dementia, AD dementia, VaD, or AD pathology. In response, Dr. Kawada cites a previous study that found significant interactions between dietary patterns and APOE-ε4 status in relation to incident dementia, with a healthy dietary pattern being associated with lower dementia incidence in ε4 noncarriers and a Western dietary pattern associated with higher dementia incidence in ε4 carriers. Dr. Kawada argues that studies examining the long-term effect of dietary patterns on incident dementia should consider the contribution of genetic factors. In another response, Dr. Hoffman notes that the researchers' use of a modified Mediterranean diet score does not explicitly measure for extra virgin olive oil (EVOO), which may be an important component for maintaining cognitive health, citing epidemiologic and animal studies in this regard. He contends that it is important to consider the role of EVOO as part of a Mediterranean diet for cognitive health to better inform the implementation of this diet in non-Mediterranean countries. Responding to these comments, the authors note that they did not find any significant interaction effects between conventional dietary recommendations or a modified Mediterranean diet and APOE-ε4 status with respect to subsequent dementia but do not comment about the role of extra virgin olive oil. Overall, this exchange highlights enduring uncertainties about the role of specific dietary factors in mitigating the long-term risk of dementia.