I recall that sodium intake has been shown to be irrelevant *unless* you already have problems with high blood pressure.
This seems to be stating the reverse.
Excess sodium upsets the K-Na osmotic balance your kidneys use to draw water out of your bloodstream. Excess sodium results in extra fluid retention, and that increases blood pressure. High blood pressure is one of the causes of kidney failure.
I have heard the same.
About 15% of people are “salt sensitive.” For the rest of us, studies showed that people getting under 3,000 mg or greater than 6,000 mg of sodium had a higher rate of death than those between 3,000 - 6,000.
I think it was referred to as a “U” or “V” shaped death curve.