Up to 40 per cent of dementia cases could be prevented or delayed, according to a report published last week calling for urgent action on risk factors from excessive drinking to air pollution. The number of people around the world living with dementia is expected to soar from around 50 million today to over 150 million by 2050. But experts in a commission for the journal The Lancet said that a range of policy actions could dramatically reduce or delay cases, in updated research based on analysis of a wide variety of international studies. The report said a lack of education in childhood, midlife hearing loss and smoking in older age accounted for 7 per cent, 8 per cent and 5 per cent of dementia cases respectively. 9 tips on avoiding Alzheimer’s It also identified three new risks – head injuries and excessive alcohol consumption in middle age and exposure to air pollution later in life – which together are associated with 6 per cent of all cases. “Our report shows that it is within the power of policymakers and individuals to prevent and delay a significant proportion of dementia, with opportunities to make an impact at each stage of a person’s life,” said lead author Gill Livingston of University College London. Recommendations include healthy lifestyles , policies to tackle pollution and prevent head injuries in high-risk occupations, and initiatives such as providing hearing aids. Dementia is caused when the brain is damaged by diseases , such as Alzheimer’s or stroke, and can affect people’s memory, moods and their ability to perform daily tasks. Beyond the challenges it poses to individuals and families, experts estimate its economic cost at about US$1 trillion every year. The number of people living with dementia has surged as the global population expands and people live longer. Some two-thirds of people with dementia are now living in low- and middle- income countries. The authors said tackling risk factors in these nations and among deprived communities in richer countries would have the greatest impact. [Sixty per cent of dementia cases] are to the best of our knowledge caused by things people cannot control like their genes – so I hope that this report will not lead to people feeling like having dementia is their ‘fault’ Tara Spires-Jones of the UK Dementia Research Institute But co-author Adesola Ogunniyi of the University of Ibadan in Nigeria called for more research in these societies, with nearly all the evidence for dementia currently from studies in high-income countries. Other factors identified in the report were hypertension in midlife (2 per cent), obesity in middle age (1 per cent), depression (4 per cent), social isolation (4 per cent), physical inactivity (2 per cent) and diabetes (1 per cent). Reacting to the study, Tara Spires-Jones, of the UK Dementia Research Institute at the University of Edinburgh in Scotland, said it provided an important set of practical measures that people can take to reduce their risk of dementia. But she noted that the study suggests 60 per cent of cases “are to the best of our knowledge caused by things people cannot control like their genes – so I hope that this report will not lead to people feeling like having dementia is their ‘fault’”. She also cautioned that the data used “does not prove causation”, adding there was evidence that brain changes in early dementia cause depression. Last year a report by the University of Glasgow in Scotland found that former soccer players are around three-and-a-half times more likely to die from neurodegenerative diseases than the general population, focusing attention on the way players’ head injuries are treated.