Professor Tobias Kurth of Harvard University's School of Public Health and doctoral student Sophie Billioti de Gage of the University of Bordeaux in France, said the study -- participants were an average age of 78 -- were all free of dementia at the start of the trial, but over the next 20 years 253 developed dementia and 30 were benzodiazepine users, The Daily Telegraph reported.
The study, published in the British Medical Journal, found for every 100 people studied for a year -- 4.8 who had taken the drugs developed dementia compared with 3.2 who had not.
"Our data add to the accumulating evidence that use of benzodiazepines is associated with increased risk of dementia, which, given the high and often chronic consumption of these drugs in many countries would constitute a substantial public health concern," Billioti de Gage said in a statement. "Therefore, physicians should carefully assess the expected benefits of the use of benzodiazepines in the light of these adverse effects and, whenever possible, limit prescription to a few weeks as recommended by the good practice guidelines."
Tobias Kurth, who works jointly at Harvard University's School of Public Health and the University of Bordeaux, said one single study does not necessarily show everything that is going on, so there is no need to panic.