Modifying health and lifestyle factors may lower the risk of dementia for individuals already genetically predisposed to low or intermediate dementia risk, according to a study published this week in Nature Medicine.
The exact causes of dementia remain unclear, but both genetic and lifestyle factors - such as a lack of regular exercise - are considered to be the main drivers of this complex disease. Previous studies have mostly focused on one individual protective factor, yet the combination of multiple factors may yield more beneficial effects than the sum of their parts.
To examine the combined influence of lifestyle factors and genetic predisposition on dementia risk, Silvan Licher and colleagues analysed data from more than 6,000 individuals aged 55 and over from the Rotterdam Study. The authors assigned a score to each participant based on favourable health and lifestyle factors, such as regular physical activity, healthy diet, limited alcohol consumption, and abstention from smoking. The authors found that among individuals with low genetic predisposition, a favourable lifestyle score was associated with a further lowering of risk for dementia. Conversely, those with an unfavourable lifestyle score were shown to have elevated dementia risk, even participants with low genetic dementia risk. They also found that neither favourable nor unfavourable lifestyles seem to modify dementia risk among people who already have elevated genetic predisposition.
The authors note that while the study benefits from a large, longitudinal design, the findings will need to be confirmed in independent population analyses.