This article from Neurobiological Aging reports that users of anti-inflammatory drugs not only have a reduced incidence of Alzheimer’s disease, but also show significantly less age-related brain atrophy, suggesting inflammation may be one of the causes of the cognitive decline commonly seen in the elderly.

Examples of anti-inflammatory substances include the Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), such as aspirin, ibuprofen, and naproxen, and other substances like EPA and DHA from fish oil.

Anti-inflammatory drugs reduce age-related decreases in brain volume in cognitively normal older adults.

Neurobiol Aging. 2009 Apr 20. PMID: 19386384

Walther K, Bendlin BB, Glisky EL, Trouard TP, Lisse JR, Posever JO, Ryan L.
Cognition and Neuroimaging Laboratories, Department of Psychology, University of Arizona, Tucson, AZ, 85721, USA.

Previous studies have indicated a decreased risk for developing Alzheimer’s disease in anti-inflammatory (AI) drug users. Yet few studies have determined whether AI drug use provides a protective effect against normal age-related changes in the brains of older adults. Regional volume changes in gray and white matter were assessed cross-sectionally using optimized voxel-based morphometry in 36 females taking AI drugs as arthritis or pain medication and 36 age- and education-matched female controls. Although mean gray and white matter volume differences between AI drug users and the non-AI group were small, AI drug use interacted with age, such that the non-AI group showed significantly greater age-related volume changes in regions of both gray and white matter compared to the AI drug users. These regions included the superior and medial frontal gyri, middle and inferior temporal gyri, fusiform and parahippocampal gyri, and occipital gray matter as well as temporal, parietal, and midbrain white matter. The results are consistent with the notion that AI drugs provide protection against age-related changes in brain volume. It is possible that inflammation plays a role in volume decreases associated with normal aging, and that suppressing the inflammatory response moderates this decrease.