Methodological quality of included studies.

For case-control studies: (Ia) cases with independent validation; (Ib) consecutive or representative cases; (Ic) community controls; (Id) controls with no history of pancreatitis; (IIa) study controls were comparable for age and gender; (IIb) study controls were comparable for all additional factor(s) reported; (IIIa) the same method of ascertainment was used for cases and controls; (IIIb) assessment of exposure was from a secure record; and (IIIc) the non-response rate was similar for both groups. For cohort studies: (Ia) the exposed cohort was representative of the population; (Ib) the non-exposed cohort was drawn from the same population; (Ic) the exposure ascertainment was from secure records or a structured interview; (Id) pancreatitis was not present at start of the study; (IIa) the cohorts were comparable for age and gender; (IIb) the cohorts were comparable for all additional factor(s) reported; (IIIa) cases were assessed from a secure record; (IIIb) follow-up was long enough for pancreatitis to occur; and (IIIc) follow-up was complete. NOS: Newcastle-Ottawa score. Methodological quality of included studies.