Miia Kivipelto (Aging Research Centre, Karolinska Institutet, Sweden) and colleagues randomly selected 1449 people aged 65-79 who had been surveyed about their leisure-time physical activity in 1972, 1977, 1982, and 1987 to take part in the study. The investigators re-examined the participants in 1998 and found that individuals participating in leisure-time physical activity at least twice a week had a 60% lower odds of AD compared to sedentary people (individuals participating in physical activity less than twice a week). The active group had 50% lower odds of dementia compared to the sedentary group. The researchers also found that in individuals who are genetically susceptible to AD (carriers of the gene variant APOE Î4), physical activity had more pronounced effects against developing dementia or AD in later life.

The authors state that interventions that could postpone the onset of AD even modestly would have a major public health impact, as the proportion of old people is increasing.

Dr Kivipelto states: "These findings may have wide implications for preventive healthcare; if an individual adopts an active lifestyle in youth and at midlife, this may increase their probability of enjoying both physically and cognitively vital years later in life".