Evidence-based strategies to prevent cognitive decline in older people.

A helpful method to understand cognitive decline in older people is to consider this entity as increasing cognitive frailty caused by a number of interacting pathological processes. Over the last 20 years, multiple lifestyle, environmental and constitutional factors have been linked to the development of cognitive decline. For two interventions based on these factors, increasing physical activity and the control of hypertension, there is class 1 evidence for benefit. Other interventions based on these factors do not have the support of high-level evidence for the alteration of cognitive decline, but their other benefits would argue for their implementation. These interventions include increasing education, smoking cessation, avoiding head injuries, decreasing exposure to air pollution and increased social connections. As cognitive decline is experienced almost universally with ageing, and serious cognitive decline is experienced by substantial numbers of low-risk individuals, whole-of-population intervention strategies are the most effective and efficient. For other interventions to help prevent cognitive decline there is not sufficient evidence for their implementation to be recommended. These include alteration of alcohol ingestion, correction of hearing loss, treatment of depression, dietary interventions, menopausal hormone treatment and monoclonal antibodies directed against amyloid-β.