Growing old is associated with a greater risk of falls, reduced bone volume, vascular events, cognitive decline, and depression. Although it is relatively straightforward to study the effects of interventions on the physical risks associated with ageing, studying effects on cognitive function is more difficult. Age related cognitive impairment affects about 5% of people over 65 in the developed world, and about half of those affected have memory loss.1 In this week's BMJ, Kang and colleagues assess the impact of aspirin on cognitive function in a subgroup of elderly women enrolled in the women's health study2—a randomised controlled trial of the effect of aspirin on cardiovascular morbidity and cancer.

What is the evidence on interventions for delaying or preventing age related cognitive decline? Drugs for dementia produce transient symptomatic improvements by enhancing cholinergic neurotransmission but they do not delay progress to severe dementia. Molecular neurobiological and epidemiological studies suggest several interventions (such the possible neuroprotective effects of non-steroidal anti-inflammatory drugs 3) that may slow cognitive decline and postpone the onset of dementia. Many of …