In Alzheimer's disease, patients often suffer from disorientation problems. This is why we can think that professions which require good abilities to find their way in space are less affected by this pathology.
Researchers from Brigham and Women's Hospital and Massachusetts General Hospital wanted to study this hypothesis using national statistical data on deaths. They thus assessed the risk of death due to Alzheimer's disease in 443 different professions, between January 1, 2020 and December 31, 2022.
They then found that taxi and ambulance drivers had a lower rate of death from Alzheimer's disease than other occupations (1). Of nearly 9 million people included in the study across all professions, 3.88% (348,328) died of Alzheimer's disease. But among taxi drivers only 1.03% (171/16,658) died from Alzheimer's disease, while among paramedics this rate was 0.74% (10/1348)! After adjusting for other factors, ambulance drivers (0.91%) and taxi drivers (1.03%) had the lowest proportion of deaths from Alzheimer's disease among all occupations examined.
Why taxi drivers and paramedics are less affected by Alzheimer's
The reduction in the risk of death from Alzheimer's was not observed in other transportation-related occupations, such as bus drivers (3.11%) or airplane pilots (4.57%). This can be explained by the fact that these two professions have less need to process spatial information and make navigation decisions in real time: their routes vary little.
Mortality from Alzheimer's disease in different transport-related occupations.
According to Patel et al, BMJ 2024.
In a statement, Vishal Patel, a physician in the department of surgery at Brigham and Women's Hospital, explained the results: “The same part of the brain that is involved in creating cognitive spatial maps – which we use to navigate the world around us – is also involved in the development of Alzheimer's disease. »
Indeed, the hippocampus, which plays an important role in spatial memory and navigation, is one of the first regions of the brain to atrophy in Alzheimer's disease. Previous research, based on brain MRIs, had highlighted particularities in the hippocampus of London taxi drivers, compared to the general population (2).
Of course, this is an observational study and therefore it is not possible to draw definitive conclusions regarding the cause and effect relationship. The authors also acknowledge limitations, including that people at high risk of developing Alzheimer's disease may be less likely to enter or remain in memory-demanding occupations, such as driving taxis or ambulances. But they say this is unlikely given that symptoms of Alzheimer's disease usually develop when patients have finished their professional careers.
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In a commentary, Professor Tara Spires-Jones, neuroscience researcher at the University of Edinburgh, highlights other weaknesses in this study: “The age of death for taxi and ambulance drivers in this study was approximately 64-67 years, while it was 74 years for all other occupations. This is an important limitation of the study, because the age of onset of Alzheimer's disease is generally after 65 years.she notes. Similarly, the proportion of women among taxi and ambulance drivers was 10-22%, while it was 48% in all other professions. This is important because women are more likely to develop Alzheimer's disease than men. »
