These factors include smoking94-98 and diabetes.99-102 Some studies propose that impaired glucose processing (a precursor to diabetes) may also increase risk for dementia.103-105 The age at which some risk factors develop appears to affect dementia risk. For example, midlife obesity,103,106-109 hypertension,103,110-114 prehypertension (systolic blood pressure from 120 to 139 mm Hg or diastolic pressure from 80 to 89 mm Hg)114 and high cholesterol115-116 are associated with an increased risk of dementia. Regarding hypertension, evidence from a large-scale clinical trial suggests that intensive medical treatment to reduce blood pressure may safely decrease the occurrence of MCI and dementia.117 In contrast to mid-life, late-life obesity118 and hypertension onset after age 80119 are associated with decreased risk of dementia. It is possible that the disease causing dementia affects body mass and blood pressure rather than the reverse. More research is needed to understand why the effects of some modifiable risk factors may change with age. Building on the connection between heart health and brain health, researchers have found that factors that protect the heart may also protect the brain and reduce the risk of developing Alzheimer’s or other dementias. Physical activity120-130 appears to be one of these factors. Although researchers have studied a wide variety of exercises, they do not yet know which specific types of exercises, what frequency of exercise or what duration of activity may be most effective in reducing risk. In addition to physical activity, emerging evidence suggests that consuming a heart-healthy diet may be associated with reduced dementia risk.131-135 A heart-healthy diet 15 emphasizes fruits, vegetables, whole grains, fish, chicken, nuts and legumes while limiting saturated fats, red meat and sugar. A systematic review136 of the use of supplements, including vitamins C, D and E, omega-3 fatty acids and ginkgo biloba, found little to no benefit in preventing cognitive decline, MCI or Alzheimer’s dementia. Researchers have begun studying combinations of health factors and health behaviors (for example, blood pressure as a health factor and physical activity as a health behavior) to learn whether combinations of risk factors better identify Alzheimer’s and dementia risk than individual risk factors. They are also studying whether intervening on multiple risk factors simultaneously is more effective at reducing risk than addressing a single risk factor. Indeed, one such study,137 the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER), found that a multidomain intervention was associated with beneficial effects on cognitive function in older adults at high risk for cognitive decline and dementia. The success of FINGER has led to the launch of multidomain intervention studies in other countries, including the Alzheimer's Association’s U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.S. POINTER).138 Education People with more years of formal education are at lower risk for Alzheimer’s and other dementias than those with fewer years of formal education.75,139-143 Some researchers believe that having more years of education builds “cognitive reserve.” Cognitive reserve refers to the brain’s ability to make flexible and efficient use of cognitive networks (networks of neuron-to-neuron connections) to enable a person to continue to carry out cognitive tasks despite brain changes.144-145 The number of years of formal education is not the only determinant of cognitive reserve. Having a mentally stimulating job and engaging in other mentally stimulating activities may also help build cognitive reserve.146-149 It is important to note that the underlying reason for the relationship between formal education and reduced Alzheimer’s risk is unclear. It is possible that the generally higher socioeconomic status of individuals with more years of formal education is a protective factor. Having fewer years of formal education is associated with lower socioeconomic status.150 This in turn may increase one’s likelihood of experiencing poor nutrition; decrease one’s ability to afford health care or medical treatments, such as treatments for cardiovascular disease risk factors that are so closely linked to brain health; and limit one’s access to physically safe housing and employment.