Association between coffee consumption and periodontal diseases: a systematic review and meta-analysis

BMC Oral Health

Table 4 GRADE method for the primary outcome

Outcome	Quality assessment
	Required domains					Additional domains			Grade
	Study limitations	Consistency	Directness of evidence	Precision	Reporting bias	Dose–response association	Plausible confounding that would decrease observed effect	Strength of association (magnitude of effect)	Grade
Periodontitis	High^a	Inconsistent^b	Indirect	Precise^c	Unevaluable^d	Undetected	Present^e	Weak^f	⨁◯◯◯ Very low
Tooth loss	High^a	Inconsistent^b	Indirect	Precise^c	Unevaluable^d	Undetected	Present^e	Weak^f	⨁◯◯◯ Very low

^aAll-included studies are observational design
^bConsiderable heterogeneity (I² > 50%)
^cSample size over 4000
^dDue to small number of included studies
^eAll-included studies are observational design, and all analyses were based on unadjusted estimates
^fOR < 2.0

ISSN: 1472-6831