Hi Dolores:

If blood pressure dropped ten times more than 4.7 times, it could be
dangerously low, right? Perhaps you mean 5 to 10 points more.

Here's the way that the authors worded it in the meta-analysis:

"The effects are comparable to those achieved with blood-pressure
lowering medications. At the population level, a reduction of 4 to 5
millimeters of mercury in systolic blood pressure and 2-3 millimeters
of mercury in diastolic blood pressure would be expected to
substantially reduce the risk of stroke (by about 20 percent) and all-
cause mortality by 8 percent."

D.