Does "susceptibility" explain the weak epidemiological relationship between dietary sodium and blood pressure?

It is often suggested that the weak epidemiological relationship between dietary sodium and blood pressure may reflect a stronger relationship within a susceptible subgroup. The evidence in favour of this explanation is reviewed, and found to be insubstantial. A more consistent explanation of the available data is that there is a weak general effect of dietary sodium on blood pressure acting on the general population. This conclusion has important practical implications for food and health policies.