Alzheimer's 'less likely to kill people' who hold two jobs, breakthrough study finds

These figures stand in stark contrast to the overall average of 3.88 per cent across 443 different occupations.

Researchers believe the mental exercise of planning routes in drivers' heads could be key to protecting against the disease.

The findings point to the importance of the hippocampus, a brain region crucial for both memory and navigation skills.

Dr Anupam Jena, a physician at Massachusetts General Hospital, said: "Frequent navigational and spacial processing tasks may be associated with some protection."

Previous research from University College London found that London black cab drivers have particularly well-developed hippocampi.

The trend did not extend to other transport roles that don't require active navigation, such as pilots who saw a 4.5 per cent death rate from Alzheimer's, or ship captains at 2.7 per cent.

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Scientists believe that constantly strengthening connections in this part of the brain might make it more resilient against Alzheimer's.

The study examined death records across the United States, revealing striking differences in Alzheimer's mortality between occupations.

Chief executives ranked in the middle range, with about four per cent dying from Alzheimer's.

Some occupations showed much higher rates, with researchers noting that in certain jobs, almost eight per cent of deaths were attributed to Alzheimer's disease.

However, the study authors did not specify which professions had the highest rates.

Experts have urged caution in interpreting these findings.

Professor Tara Spires-Jones of the UK Dementia Research Institute pointed out a crucial detail about age differences in the data.

"The age at death of taxi and ambulance drivers in this study was around 64 to 67 years, while for all other occupations, it was 74," she said. "They might have gone on to develop Alzheimer's if they lived longer."

Professor Robert Howard from University College London offered another perspective, suggesting that people with better navigational skills might naturally gravitate towards driving careers.

He said: "It is just as likely that individuals with better navigational and spatial skills flourish in these jobs."