In a major development, a new study in The BMJ's Christmas edition,  researchers claimed that taxi and ambulance drivers, whose jobs require regular spatial and navigational tasks, have the lowest incidence of Alzheimer's disease death among all vocations. The findings suggest a relationship between memory-intensive employment and a lower risk of Alzheimer's disease death.

A team of US academics studied death certificates from 443 different occupations between January 2020 and December 2022. The dataset contained the cause of death, primary occupation (defined as the employment that an individual had for the majority of their working life), and other sociodemographic information, such as age, gender, race, and education level.

Alzheimer's disease accounted for 3.9% (348,328) of the approximately 9 million fatalities recorded with occupational information. Notably, taxi and ambulance drivers died at a lower rate from Alzheimer's disease than the general population and other professions.

Alzheimer's disease accounted for only 171 deaths (1.03%) among 16,658 taxi drivers, while ambulance drivers had an even lower rate of 0.74% (10 deaths out of 1,348). After accounting for age and other demographic characteristics, the researchers determined that taxi and ambulance drivers had the lowest Alzheimer's-related death rates—1.03% and 0.91%, respectively—compared to the overall population's rate of 1.69%.

The findings raise intriguing issues regarding how spatial and navigational processing affects brain health. Taxi and ambulance drivers must constantly activate their hippocampus, a brain region responsible for spatial memory and navigation but is also one of the most afflicted by Alzheimer's disease. This occupational strain may stimulate and strengthen hippocampus function, perhaps protecting against Alzheimer's-related cognitive decline.

Interestingly, the study discovered that this trend did not exist in other transportation-related vocations, such as bus drivers or airline pilots. The researchers suggest that this is due to the reliance on planned routes in these vocations, which may necessitate less active spatial processing than the ongoing navigational issues encountered by taxi and ambulance drivers.

However, the researchers stress that these findings are observational in nature and cannot establish causality. They also acknowledge certain limitations, such as the possibility that people who are susceptible to Alzheimer's may choose to avoid memory-intensive activities. Nonetheless, they suggest that this is unlikely to entirely explain the findings, given Alzheimer's disease symptoms often appear well after an individual's working years.

"We view these findings not as conclusive but as hypothesis-generating," the researchers concluded. "Further research is necessary to definitively conclude whether the spatial cognitive work required for these occupations affects the risk of death from Alzheimer's disease and whether any cognitive activities can be potentially preventive."

The findings pave the way for further investigation into the role of cognitive stimulation in Alzheimer's disease prevention. If spatial processing exercises prove advantageous, they may inspire interventions that stimulate similar brain activity, potentially lowering dementia rates in the general population.

The findings offer a promising glimpse into the connection between professional brain activity and long-term neurological health, especially for those in navigationally demanding jobs, even though more research is necessary.