Gut microbiota changes associated with frailty in older adults: A systematic review of observational studies

Table 3 The Newcastle-Ottawa Scale assessment for the cohort studies

Ref.	Selection				Comparability		Exposure			Scores
	Representativeness of selection of the non- exposed cohort	Selection of the non-exposed cohort	Ascertainment of exposure	Demonstration that outcome of interest was not present at start of study	Comparability of cohort on the basis of the design or analysis	Ascertainment of outcome	Ascertainment of outcome	Was follow-up long enough for outcomes to occur	Adequacy of follow-up of cohorts
Haran et al[24], 2018	Yes	Yes			Yes	Yes, Yes				5
Haran et al[23], 2021	Yes	Yes				Yes, Yes		Yes	Yes	6
Larson et al[25], 2020	Yes	Yes			Yes	Yes, Yes				5

Yes is one point, the total number of stars represents a number of points.