Dementia prevention is a global public health priority because of the high societal cost of the condition. The incidence of dementia can be reduced by identifying and targeting modifiable risk factors through personal or public health interventions. One such risk factor is diet, which can be targeted to prevent dementia and reduce risk. Studies have reported that healthy dietary patterns, such as the Mediterranean diet (MedDiet), would be an important strategy for reducing dementia risk. Recent reviews indicated that higher adherence to MedDiet was associated with lower cognitive decline. However, additional investigations are needed because most of the previous studies were conducted in small cohorts with limited dementia cases.
A healthy diet can also reduce an individual’s genetic risk for dementia. However, previous studies that analyzed diet-gene interactions are limited, and their results are inconsistent. Polygenic risk scores have been reported to be important for predicting all causes of dementia and can be used in in-depth exploration of potential diet-gene interactions.
A new study in the journal BMC Medicine It aimed to analyze the relationship between dementia incidence and MedDiet adherence as well as to assess the interaction between genetic risk and diet for dementia.
The study Adherence to a mediterranean diet is associated with a lower risk of dementia, regardless of genetic predisposition: findings from the UK biobank prospective cohort study. Image credit: Marian Wu/Shutterstock
about studying
The study involved recruiting participants who were included in the UK Biobank study and were 60 years of age or older, who were reported to be British, Irish or other white, and who had accurate genetic and dietary data. Dietary assessment was performed using Oxford WebQ, a web-based diet assessment tool. Adherence to MedDiet was determined using the MedDiet PYRAMID score and the MedDiet Aditation Screener score (MEDAS). MEDAS is a 14-point score widely used in observational studies and trials, while PYRAMID is a 15-point score widely used in epidemiological studies.
Polygenic risk scores were used to estimate the genetic risk of dementia. All cases of incident dementia were confirmed using hospital inpatient records and death records. The International Classification of Diseases (ICD) coding system was used to record the diagnoses. Sensitivity analyzes were performed to assess the strength of associations between dementia incidence and MedDiet adherence.
Results
The results indicated that a total of 882 cases of dementia of all causes were included in the study. Participants who had higher adherence to MedDiet as measured by an ongoing MEDAS score were reported to be primarily female, had a BMI within a healthy range, were more physically active, and had a higher level of education. The mean continuous MEDAS score was reported to be 6.1 ± 1.7, and the PYRAMID score was 7.5 ± 1.8.
Higher MedDiet adherence has been reported to be associated with a 4.2 to 6.9 percent lower risk of dementia for continuous MEDAS and PYRAMID scores. In addition, a higher polygenic risk score has been reported to be associated with dementia risk. The results of the sensitivity analysis also confirmed that higher adherence to MedDiet was associated with a lower incidence of dementia.
Therefore, the current study showed that higher MedDiet adherence was associated with a lower risk of dementia. However, the evidence for interaction with genetic risk was unclear. This study indicates the importance of nutritional interventions in developing dementia prevention strategies in the future, regardless of genetic predisposition.
determinants
The first limitation of the study is that its observational design prevents it from drawing causal inferences. Second, low adherence to MedDiet can be a consequence and not cause of dementia. Third, the calculated MedDiet results may not fully represent the participant’s usual dietary intake. Fourth, the number of dementia cases was obtained from hospital records and death records only, which may miss some cases. Finally, participants in the UK biobank had a higher socioeconomic status and were healthier compared to the general UK population.