Which of the following is NOT a known risk factor for dementia?

High intelligence is considered to be a protective factor rather than a risk factor for dementia. Research suggests that individuals with higher cognitive abilities may have a "cognitive reserve," which can help them better cope with the changes associated with brain aging and reduce the risk of developing dementia. This means that higher levels of education and engagement in intellectually stimulating activities may contribute to better brain health over time.

On the other hand, age is the most significant known risk factor for dementia, as the likelihood of developing the condition increases significantly as people grow older. Gender also plays a role, as women are generally at a higher risk for Alzheimer's disease and other forms of dementia than men, particularly in older age groups. Obesity has been linked to an increased risk of developing several chronic diseases, including dementia, as it can contribute to hypertension, diabetes, and cardiovascular issues, which are further factors associated with an elevated risk of dementia.