AlewiJn Ott and Monique Bretler of Erasmus University, Rotterdam, have concluded that people who smoke are twice as likely to develop senile dementia as compared to those who have never smoked. The study was conducted over a period of two years on 6,870 people above 55 years of age. They found that as many as 145 of them developed dementia, and there were 104 cases of Alzheimer's disease. Even those who quit smoking were 50 per cent more likely to be affected than non-smokers (New Scientist, Vol 154, No 2078).