Indeed the Sykes data is long-term history, and I think of a middle-class sample. But it does teach us that received wisdom was badly wrong there, which should

Indeed the Sykes data is long-term history, and I think of a middle-class sample. But it does teach us that received wisdom was badly wrong there, which should make us less confident of the same wisdom elsewhere. The bone marrow study was 2012, and no class has a monopoly on Leukemia. I would not be surprised if there were a class gradient, but an average of under 2% doesn't leave room for a very big underclass to be scoring 20% or 30%. These are England and Germany, things could be different elsewhere, I don't know whether there is good data.