Table 2.

Methodological quality assessment for the FEM studies (Newcastle-Ottawa scale)

Group	First author (year)	Selection			Comparable		Exposure/outcome			Total stars (out of 9)
		Validation of case definition or cohort exposure	Representative sample	Selection of controls or non-exposed cohort	Definition of controls or non-exposed cohort	Groups comparable in design and analysis	Assessment of exposure or outcome	Same method used for both groups or adequate follow-up period	Non-response rate or loss to follow-up
Acute	Fleck et al. (2008)	*	*	−	*	**	−	−	−	5
	Lebowitz et al. (2001)	*	−	−	−	**	−	*	−	4
	Strakowski et al. (2008)	−	−	*	*	**	−	*	*	6
Remission	Elshahawi et al. (2011)	−	−	−	*	**	−	*	−	4
	Hellvin et al. (2012)	*	*	*	*	**	−	*	−	7
	Lopez-Jaramillo et al. (2010)	*	*	−	*	**	−	*	−	6
	Torres et al. (2010)	−	*	*	*	**	−	*	−	6

*criteria was met; **criteria was met and awarded two stars (comparability only); −criteria was not met.