A new study raises the possibility that jobs that require frequent spatial processing—such as figuring out a taxi route or the best way to navigate to a hospital—could lead to lower rates of death from Alzheimer's disease. Researchers from Mass General Brigham investigated this possibility by using national data on the occupations of people who had died to evaluate risk of death from Alzheimer's disease across 443 professions.

They found that taxi driving and ambulance driving were associated with a lower rate of death from Alzheimer's disease compared to other professions. Results are published in the BMJ.

"The same part of the brain that's 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," said lead author Vishal Patel, MD, MPH, a resident physician in the Department of Surgery at Brigham and Women's Hospital.

"We hypothesised that occupations such as taxi driving and ambulance driving, which demand real-time spatial and navigational processing, might be associated with a reduced burden of Alzheimer's disease mortality compared with other occupations."

Patel and colleagues at Brigham and Women's Hospital and Massachusetts General Hospital analysed death from the National Vital Statistics System for adults from 443 different occupations between January 1, 2020 and December 31, 2022.

The team looked at sociodemographic information, including age, sex, race, ethnicity, and educational attainment, in addition to the occupation that the person engaged in for most of their working life.

Of nearly 9 million people included in the study from across all occupations, 3.88% (348,328) died from Alzheimer's disease. Among taxi drivers, 1.03% (171/16,658) died from Alzheimer's disease, while among ambulance drivers, the rate was 0.74% (10/1348).

After adjustment, ambulance drivers (0.91%) and taxi drivers (1.03%) had the lowest proportion of deaths due to Alzheimer's disease of all occupations examined. This trend was not observed in other transportation related jobs that use predetermined routes, such as bus drivers (3.11%) or aircraft pilots (4.57%), who are less reliant on real-time spatial and navigational processing. The trend was not seen for other types of dementia.

"Our results highlight the possibility that neurological changes in the hippocampus or elsewhere among taxi and ambulance drivers may account for the lower rates of Alzheimer's disease," said senior author Anupam B. Jena, MD, Ph.D., a physician in the Department of Medicine at Massachusetts General Hospital.

The authors note that this is an observational study, so no firm conclusions can be drawn about cause and effect. And the authors acknowledge limitations, including that individuals who are at higher risk of developing Alzheimer's disease may be less likely to enter or remain in memory intensive driving occupations such as taxi and ambulance driving.

However, they say this is unlikely given that Alzheimer's disease symptoms typically develop after working age.

"We view these findings not as conclusive, but as hypothesis-generating," said Jena. "But they suggest that it's important to consider how occupations may affect risk of death from Alzheimer's disease and whether any cognitive activities can be potentially preventive."