Table 1.
Characteristics of case-control studies included in the systematic review and meta-analysis (vs.).
| Study | Country | Study Name | Controls (M/F) | Cancer Type | Cases (M/F) | Vitamin D Intake | Vitamin D Source | Age (Years) | Quality a |
|---|---|---|---|---|---|---|---|---|---|
| Peters et al. 1992 [15] | USA | 746 | CC | 746 (419/327) | Continuous | Dietary | 45–69 | GOOD | |
| Ferraroni et al. 1994 [19] | Italy | 2024 (1189/835) | CRC CC RC |
CRC: 1326 (711/615) CC: 828 RC: 398 |
Q5 vs. Q1 | Dietary | 20 to 74 | FAIR | |
| Olsen et al. 1994 [20] | Denmark | 759 (438/321) | CRC | 49 | T3 vs. T1 | Dietary | 45 to 74 | GOOD | |
| Boutron et al. 1996 [21] | France | 309 (159/150) | CRC | 171 (109/62) | Q5 vs. Q1 | Dietary | 30 to 75 | GOOD | |
| Pritchard et al. 1996 [22] | Sweden | 512 (276/236) | RC CC |
RC: 217 (107/110) CC: 352 (189/163) |
Qu4 vs. Qu1 b | Dietary | 67.7 (9.0) | FAIR | |
| La Vecchia et al. 1997 [17] | Italy | Case control study Italy | 4154 (2073/2081) | CRC CC c RC c |
CRC 1953 (1125/818) CC: 1225 RC: 728 |
Q5 vs. Q1 | Dietary | 23 to 74 | GOOD |
| Marcus et al. 1998 [23] | USA | 678 F | CC RC |
CC: 348 F RC: 164 F |
Q5 vs. Q1 | Dietary Supplemental Total |
<75 | FAIR | |
| Kampman et al. 2000 [24] | USA | 2400 (1114/1286) | CC | 1993 (1095/888) | Q5 vs. Q1 | Dietary Supplemental (Ever vs. Never) |
30 to 79 | GOOD | |
| Levi et al. 2000 [25] | Switzerland | 491 (211/280) | CRC | 223 (142/81) | T3 vs. T1 | Dietary | 27 to 74 | GOOD | |
| Slattery et al. 2004 [26] | USA | KPMCP and the state of Utah |
1197 (672//525) | RC | RC: 946 (556/390) | Four categories (highest vs. lowest) d | Dietary | 30 to 79 | GOOD |
| Mizoue et al. 2008 [27] | Japan | Fukuoka Colorectal Cancer Study |
861 (327/534) | CRC CC RC |
CRC: 836 (502/334) CC: 476 RC: 354 |
Q5 vs. Q1 | Dietary | 20 to 74 | GOOD |
| Theodoratou et al. 2008 [28] | UK | SOCCS | 2793 (1591/1202) | CRC | 2070 (1185/885) | Q5 vs. Q1 | Dietary Total |
16 to 79 | GOOD |
| Lipworth et al. 2009 [29] | Italy | 4154 (2073/2081) | CC RC |
CC: 1225 (688/537) RC: 728 (437/291) |
D10 vs. D1 | Dietary | 20–74 | GOOD | |
| Jenab et al. 2010 [30] | Europe e | EPIC | CRC CC RC |
CRC: 1248 (620/628) CC: 785 (369/416) RC: 463 (251/212) |
Q5 vs. Q1 | Dietary | 30 to 77 | GOOD | |
| Key et al. 2011 [31] | UK | UK Dietary Cohort Consortium | 1951 (980/971) | CRC | 565 (266/299) | Four categories (highest vs. lowest) | Dietary | 62.2 (9.2) | GOOD |
| Sun et al. 2011 [32] | Canada | NL and ON cohorts | NL: 488 ON: 1830 |
CRC | NL: 651 ON: 1272 |
Q5 vs. Q1 | Supplemental | 20 to 74 | GOOD |
| Banqué et al. 2012 [33] | Spain | 490 (312/178) | CRC | 245 (156/89) | T3 vs. T1 | Dietary | 30 to 80 | GOOD | |
| Sun et al. 2012 [34] | Canada | NL and ON cohorts | 2481 (1357/1124) | CRC | 1760 (935/825) | Q5 vs. Q1 | Dietary Total |
20 to 74 | GOOD |
| Vallès et al. 2018 [16] | Spain | MCC-Spain | 3950 (2018/1932) | CRC | 2140 (1365/445) | Continuous | Dietary | 20 to 85 | FAIR |
| Hosseinzadeh et al. 2019 [35] | Iran | 201 (108/93) | RC | 162 (94/68) | Adequate vs. low intake | Dietary | 40 to 80 | GOOD | |
| Zhang et al. 2020 [36] | China | 2389 | CRC CC RC |
CRC: 2380 (1356/1924) CC: 1476 RC: 828 |
Qu4 vs. Qu1 b | Dietary | 30 to 75 | GOOD |
a assessed by the Study Quality Assessment Tools from the National Heart, Lung and Blood Institute for case-control studies. b, includes combined results for men and women, and separated results. c, continuous. d, includes separated results for men and women. e, includes Denmark, France, Greece, Germany, Italy, the Netherlands, Norway, Spain, Sweden, and the United Kingdom. Results from Sun et al. 2011 regarding dietary and total vitamin D are included as the combination of both NL and ON cohorts in Sun et al. 2012. Funding source for all the studies is agency. Abbreviations: CC, colon cancer; CRC, colorectal cancer; D, decile; EPIC, European Prospective Investigation Into Cancer and Nutrition; F, females; FFQ, food frequency questionnaire (self-administered); KPMCP, Kaiser Permanente Medical Care Program of Northern California; M, males; MCC, multicenter case-control; NA, not applicable; NL, Newfoundland and Labrador subjects; ON, Ontario subjects; Qu, quartile; Q, quintile; RC, rectal cancer; SOCCS, Study of Colorectal Cancer in Scotland; T, tertile; wk, week.