Sir, The study led by Sir Denis Pereira Gray does not demonstrate that “seeing the same family doctor cuts the risk of dying early by up to 53 per cent” (report, June 29). It found evidence that seeing the same family doctor is associated with an up to
53 per cent lower risk of early death. Association is not causation.

Healthier people are at reduced risk of early death, and they are more likely to be able to wait to see their own doctor. Those who are more ill need to see whoever is available at the earliest opportunity. Perhaps articulate and motivated people work the system better in order to see the doctor of their choice, and they may be at reduced risk of…