Taxi driving shields against death from Alzheimer's?

A new study suggests that jobs demanding real-time navigational processing may reduce Alzheimer’s mortality risk

Taxi drivers endure gruelling hours, cramped seats and relentless traffic, making them prime candidates for health issues like back pain, hypertension, diabetes and insomnia. Yet, amid such challenges, a surprising twist emerges: Alzheimer’s disease, dreaded for its devastating effects on memory and identity, seems to spare them. A new study suggests that the nature of their work―navigating dynamic, real-world routes―might serve as an unexpected shield against death from Alzheimer’s.

Published in BMJ, the study investigated the occupations of deceased individuals to assess the risk of death from Alzheimer’s across 443 professions. The research, led by Vishal Patel, a resident physician in the department of surgery at Brigham and Women's Hospital in Boston, provides intriguing insights.

Deaths attributed to Alzheimer’s have doubled over the past three decades and are expected to rise as the population ages. The team hypothesised that occupations demanding real-time spatial and navigational processing, like taxi and ambulance driving, might reduce the risk of Alzheimer’s mortality compared with other jobs. This hypothesis stems from the fact that the brain region responsible for creating cognitive spatial maps, the hippocampus, is also implicated in Alzheimer’s development.

The researchers analysed death certificates from the National Vital Statistics System in the United States. Among 8.9 million deceased individuals with occupational data, 3.88 per cent (3,48,328) had Alzheimer’s listed as a cause of death. Interestingly, ambulance drivers (0.91 per cent) and taxi drivers (1.03 per cent) exhibited the lowest proportion of Alzheimer’s-related deaths among all occupations examined. In contrast, jobs that rely on predetermined routes, such as bus driving (3.11 per cent) or piloting aircraft (4.57 per cent), showed higher rates, likely due to reduced reliance on real-time navigational skills.

Notably, this trend was not observed for other types of dementia.

A landmark neuroimaging study from 2022 revealed that London taxi drivers displayed enhanced functional changes in the hippocampus. This brain region is also vulnerable to accelerated atrophy―a hallmark of Alzheimer’s. These findings influenced the researchers’ hypothesis for the current study.

The authors of the study point out that, while their findings suggest a possible connection between the demands of certain occupations and a lower risk of Alzheimer’s disease, the study cannot prove a direct cause-and-effect relationship. They emphasise that their results are not definitive but serve as a starting point for further research.

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