Table 3. Newcastle-Ottawa Quality Assessment Scale – Cohort Studies.

	Representativeness of the exposed cohort	Selection	Ascertainment of exposure	Demonstration that outcome of interest was not present at start of study	Comparability	Assessment of outcome	Outcome	Adequacy of follow up of cohorts	Total
		Selection of the non-exposed cohort			Comparability of cohorts on the basis of the design or analysis (study adjusts for age*, sex*)		Was follow-up long enough for outcomes to occur
Festa et al. (2002)9	*	*	*	*	**	*	*	—	8
Eliasson et al. (2003)10	*	*	*	*	**	*	*	—	8
Kanaya et al. (2006)12	*	*	*	*	**	*	*	*	9
Davidson et al. (2006)24	—	*	*	*	**	*	—	—	6
Meigs et al. (2006)23	*	*	*	*	**	*	*	—	8