Table 2.

The Newcastle–Ottawa Scale for assessing the quality of cohort studies reviewed.

Study	Representativeness of the Exposed Cohort a	Selection of the Non-Exposed Cohort a	Ascertainment of Exposure a	Demonstration that Outcome of Interest was Not Present at Start of Study a	Comparability of Cohorts b	Assessment of Outcome a	Follow-up Duration a	Follow-up Adequacy a
Pasco, 2010 (Study 2) [14]	*	*	*	*	**	*	*	*
Veronese, 2018 [17]	*	*	*	*	**	*	*	*
Williams, 2016 (Study 2) [21]	*	*	*	*	**	*	*	*

^a A study can be awarded a maximum of one star. ^b A maximum of two stars can be given for comparability.