It's not contracted through autologous blood transfusions, as has been pointed out to you many times.
What we know about doping in Spain and Portugal, makes it much more likely that a 5000m runner at that time from those countries, who then dies from an illness at age 32 whose main cause is repeated blood doping, was blood doping. There is NO circumstantial evidence that Coe doped (apart from being 'pretty fast for a white boi').
Leitao died in his fifties. I am not really sure that he would have been taking blood transfusions for performance enhancement at that age. My understanding was that he retired young due to injuries.
There was a Spanish marathon runner, Diego Garcia who won a silver medal in the marathon at the 1994 Euro champs who died around the age of 40 on a training run (sudden cardiac death). I don't know if that sort of thing can be caused by previous blood doping. If we assume that a lot of the Spanish elites in the 1990s were blood doping or using EPO then it is hard to say for sure whether this really impacted their long-term health. Martin Fiz is still running at the masters level today in his mid fifties and setting some world records, so there is likely a certain amount of individual variation in how health is impacted.