Table 3. The main characteristics of included studies on vitamin D intake and pancreatic cancer risk.

Article	Country	Year	Study design	Age (years)	Smoking	BMI	Ethnicity (white/black)	Sample (M/F)	Adjusted variables	Study quality
Waterhouse	USA	2015	Case-control study	Median:65	Ever:6525; never:4948	BMI<25:4491;BMI:25-30:4148; BMI:30-35:1422; BMI≥35:585	9159/408	11490(6165/5325)	Age, sex, smoking status, total daily energy intake and other cohort-specific confounders (alcohol intake, BMI, history of diabetes, history of pancreatitis, family history of pancreatic cancer, education, race, total calcium intake, dietary calcium intake, total retinol intake, dietary retinol intake, total vitamin A intake, study centre and extent of proxy use)	7
Genkinger	USA	2014	Cohorts	Range:15-107;most:≥40	NR	NR	NR	862680(319732/542948)	Smoking habits, personal history of diabetes, alcohol intake, BMI, energy intake, age in years and year of questionnaire return	6

BMI: body mass index; M/F: male/female; NR: not reported; USA: the United States of America.