Table S1. Levels of evidence and grades of the recommendations based on the Oxford Centre for Evidence-Based Medicine.

Strength of recommendation	Quality of evidence	Description
A	1a	Systematic review (SR) with homogeneity of randomized controlled trials (RCTs)
	1b	Individual RCT (with narrow confidence interval)
	1c	All or none
B	2a	SR (with homogeneity) of cohort studies
	2b	Individual cohort study (including low-quality RCT; for example, <80% follow-up)
	2c	“Outcomes” research; ecological studies
	3a	SR with homogeneity of case-control studies
	3b	Individual case-control study
C	4	Case series (and poor-quality cohort and case-control studies)
D	5	Expert opinion without explicit critical appraisal, or based on physiology, bench research, or “first principles”