Table 2.

Summary of risk of bias assessment based on Newcastle–Ottawa Quality Assessment Scale. Two reviewers who had content and methodological expertise independently and in duplicate assessed and graded the risk of bias for the included studies with an adapted version of the Newcastle–Ottawa scale (NOS), which has been described elsewhere [8]. The assessments were compared and conflicts resolved by agreement between the two reviewers. The maximum score was 8, the minimum score 0. It was decided a priori that a score of 7 was reflective of high methodological quality (e.g., low risk of bias), a score of 5 or 6 indicated moderate quality, and a score of 4 or less indicated low quality (e.g., high risk of bias). A filled blue star indicates that a star has been awarded, and a blank star indicates that no star has been awarded and the study has been graded as poor quality in that category [8]. Wells GA (2010) The Newcastle–Ottawa Scale (NOS) For Assessing The Quality Of Non Randomised Studies In Meta-Analyses. Ottawa (ON): Ottawa Health Research Institute.

Study	Selection			Control		Outcomes			Overall Quality
	Representativ eness of the T1DM patients	Selection of the non-T1DM subjects	Properly IL1b quantification	Glycemic control	Control of confounding factors	Assessment of T1DM progression	Appropriate follow up period	Adequacy of follow up
Pérez-Bravo et al. (2004)									High
Lo et al. (2004)									High
Holm et al. (2006)									High
Dogan et al. (2006)									High
Arabi et al. (2007)									High
Duarte et al. (2007)									High
Salvi et al. (2010)									High
Meyers et al. (2010)									High
Gabbay et al. (2012)									Moderate
Svensson et al. (2012)									High
Ururahy et al. (2012)									High
Fartushok et al. (2012)									High
Koskela et al. (2013)									High
Allam et al. (2014)									High
Farhan et al. (2014)									Moderate
Aguilera et al. (2015)									High
Aravindhan et al. (2015)									Moderate
Alnek et al. (2015)									High
Mohamed et al. (2016)									High
Fatima et al. (2016)									Moderate
Talaat et al. (2016)									High
Duque et al. (2017)									Moderate
Abdel-Latif et al. (2017)									High
Leiva-Gea et al. (2018)									High
Ziaja et al. (2018)									Moderate
Thorsen et al. (2019)									High