TABLE 2.

Newcastle–Ottawa Scale (NOS) score of all eligible articles

Included study	Selection				Comparability	Exposure/outcome			Total scores
	Is the case definition adequate?/ascertainment of exposure	Representativeness of the cases/exposed cohort	Selection of controls/the non‐exposed cohort	Definition of controls/demonstration that outcome of interest was not present at start of study	Comparability of both groups/cohorts on the basis of the design or analysis	Ascertainment of exposure/assessment of outcome	same method of ascertainment for both groups/was follow‐up long enough for outcomes to occur	Non‐response rate/adequacy of follow up of cohorts
M. Montopoli	*	*	*	*	—	*	*	—	6
Lennard Y W Lee	*	*	*	*	*	*	*	*	8
Mengyuan Dai	*	*	*	*	*	*	*	*	8
Jia Luo	*	*	*	*	*	*	*	*	8
Fan Yang	*	*	—	*	—	*	*	*	6
Jianbo Tian	*	*	*	*	**	*	*	*	9
Kunyu Yang	*	*	*	—	—	*	*	*	6
Nicole M Kuderer	*	*	*	*	**	*	*	*	9
Jacobo Rogado	*	*	*	*	—	—	*	*	6
Perrine Vuagnat	*	*	*	—	—	*	*	*	6
Vikas Mehta	*	*	*	*	*	—	*	*	7
Elisa Maria Stroppa	*	*	*	*	**	*	*	*	9
J. Rogado	*	*	*	*	—	—	*	*	6
Giorgio Bogani	*	*	*	*	—	*	*	—	6
Jia Luo	—	*	*	*	*	*	*	*	7
Russell B	*	*	*	*	—	*	*	*	7