To what extent are "DNA strand breaks", as measured in a blood sample, correlated with other health outcomes? Caffeine is a diuretic. The coffee group likely c

To what extent are "DNA strand breaks", as measured in a blood sample, correlated with other health outcomes? Caffeine is a diuretic. The coffee group likely consumed more total liquids in the course of the treatment. So the mechanism might be simply more flushing of damaged cells – possibly beneficial, but not unique to coffee. It's odd for the headline to highlight "dark roast" when lighter roasts weren't tested, for comparison.