Smoking can contribute to dementia
25 February 2011
A study has found evidence of a link between heavy and prolonged smoking tobacco and dementia. The researchers point to a strong association between the time and amount of smoking exposure, but not with current or past smoking status.
Dr Cleusa Ferri, a Researcher from the Institute of Psychiatry (IoP) at King’s who led the study, said: ‘Tobacco smoke includes thousands of compounds many of which are associated with brain toxicity. So far, the mechanisms by which smoking would increase the risk of dementia aren’t clear.’
The paper recognises that smokers are more likely to have cardiovascular and cerebrovascular disorders, which also increase the risk of dementia. Another consideration is that smokers are more likely to have poorer health in adulthood in general, including poor nutrition, being more likely to drink harmful levels of alcohol or undertake less exercise. Dr Ferri considered self-reported heart disease, alcohol intake before the age of 65 and physical exercise in the analysis, which reduced the possibility of some of these mechanisms distorting the findings.
The study was conducted on survey data from over 15,000 older aged adults from China, India and Latin America, and is part of a wider international collaborative program on ageing and health in low and middle income countries (10/66 Dementia Research Group –www.alz.co.uk/1066) led by Professor Martin Prince.
Dr Cleusa Ferri said: ‘These findings are important in that they provide the first tentative evidence that the increased risk for dementia and Alzheimer’s disease, observed in studies conducted in high income countries, may also extend to middle income countries in Latin America and Asia, where the smoking epidemic is yet to peak. Although it strengthens the view that tobacco smoking can contribute to the development of dementia, it’s not possible to make a clear statement about cause, because the studies were cross-sectional, with dementia diagnosis and smoking history ascertained at the same time.’
The 10/66 group are anticipating the opportunity to better understand these associations using a recently completed three - five year follow-up of the same participants.
‘Tobacco use and dementia: evidence from the 1066 dementia population-based surveys in Latin America, China and India’ is published in this month’s Geriatric Psychiatry. To read the paper in full, please follow the link.