Participant attrition and perinatal outcomes in prenatal vitamin D-supplemented gestational diabetes mellitus patients in Asia: A meta-analysis

Table 2 Risk of bias assessment of respective trial included in the review[23]

Ref.	Random sequence generation (selection bias)	Allocation concealment (selection bias)	Blinding of participants and personnel (performance bias); All outcomes	Blinding of outcome assessment (detection bias); All outcomes	Incomplete outcome data (attrition bias); All outcomes	Selective reporting (reporting bias)	Other bias
Jamilian et al[37], 2016	Low	Unclear; Comment: Precise mechanism unclear	Unclear; Comment: Precise mechanism unclear	Low	Low	Low	Low
Jamilian et al[17], 2017	Low	Unclear; Comment: Precise mechanism unclear	Unclear; Comment: Precise mechanism unclear	Unclear	Low	Low	Low
Jamilian et al[33], 2019a	Low risk	Unclear risk; Comment: Precise mechanism unclear	Low risk	Low risk	Low risk	Low risk	Low risk
Jamilian et al[36], 2019b	Low risk	Unclear risk; Comment: Precise mechanism unclear	Low risk	Low risk	Low risk	Low risk	Low risk
Asemi et al[31], 2014a	Low risk	Unclear risk; Comment: Precise mechanism unclear	Low risk	Low risk	Low risk	Low risk	Low risk
Asemi et al[16], 2014b	Low	Low	Low	Low	Low	Low	Low
Karamali et al[32], 2016	Low risk	Unclear risk; Comment: Precise mechanism unclear	Low risk	Low risk	Low risk	Low risk	Low risk
Karamali et al[14], 2018	Low	Unclear; Comment: Precise mechanism unclear	Unclear; Comment: Precise mechanism unclear	Low	Low	Low	Low
Razavi et al[35], 2017	Low risk	Unclear risk; Comment: It’s unclear if the bottles were sequentially numbered and identical in appearance	Low risk	Low risk	Low risk	Low risk	Low risk
Valizadeh et al[34], 2016	Low risk	Unclear risk	High risk; Comment: Both investigators and participants were not blinded		Low risk	Low risk	Low risk
Yazdchi et al[15], 2016	Low	Unclear	Unclear	Low	Low	Low	Low
Zhang et al[38], 2016	Low	Unclear; Comment: Precise mechanism unclear	Unclear; Comment: Precise mechanism unclear	Unclear; Comment: Precise mechanism unclear	Low	Low	Low
Li and Xing[13], 2016	Low	Unclear; Comment: Precise mechanism unclear	Unclear; Comment: Precise mechanism unclear	Low	Low	Low	Low