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. 2021 Jul 26;15(6):773–788. doi: 10.4162/nrp.2021.15.6.773

Table 3. Characteristics of the included cohort studies (n = 13).

Author, Year [Reference] Study name Country Study design No. of subjects Male sex at enrollment (%) Baseline age Duration of follow-up (yrs) Exposure Comparisons Exposure assessment Outcome Confounders
Nutrients Demographics Anthropometrics Medical conditions Medications Lifestyles
Dorant, 1994 [32] The Netherlands Cohort Study Netherlands Case-cohort 484 cases, 3,123 controls 54.2% Range, 55–69 Mean, 3.3 Garlic supplements Use vs. no use 150-item semiquantitative FFQ Lung cancer X X X X
Giovannucci, 1994 [25] The Health Professional Follow-up Study Cohort U.S. Cohort 205 cases, 47,949 total 100% Range, 40–75 Mean, 6 Garlic intake ≥ 2 servings vs. 0 servings per week Semiquantitative FFQ Colon cancer X X X X X X
Steinmetz, 1994 [26] The Iowa Women's Health Study U.S. Cohort 212 cases, 35,216 total 0 Mean, 61.7 Mean, 5 Garlic intake 0, 0.5, ≥ 1.0 serving per week The Willett semiquantitative FFQ Colon cancer, proximal colon cancer, distal colon cancer X X
Dorant, 1995 [33] The Netherlands Cohort Study Netherlands Case-cohort 468 cases, 1,812 controls 0 Mean, 61.5 3.3 Garlic supplements Use vs. no use 150-item semiquantitative FFQ Breast cancer X X X X X X
Dorant, 1996 (a) [27] The Netherlands Cohort Study Netherlands Case-cohort 478 cases, 3,346 controls 49.58% Range, 55–69 Mean, 3.3 Garlic supplements Use vs. no use; 150-item semiquantitative FFQ Colon cancer; rectal cancer X X X X
Use vs. other supplements
Dorant, 1996 (b) [34] The Netherlands Cohort Study Netherlands Case-cohort 155 cases, 3,346 controls 36.59% Range, 55–69 Mean, 3.3 Garlic supplements Use vs. no use; 150-item semiquantitative FFQ Stomach cancer X X X X
Use vs. other supplements
Sellers, 1998 [28] The Iowa Women's Health Study U.S. Cohort 241 cases, 35,216 total 0 Mean, 61.7 Mean, 10 Garlic intake 0, ≤ 1, > 1 servings per week 127-item FFQ Colon cancer X X
Satia, 2009 [29] The VITAL (VITamins And Lifestyle) cohort U.S. Cohort 665 lung cancer cases, 428 colorectal cancer cases, 77,719 total Lung: 48.04%; Mean ± SD, Lung: 67.2 ± 6.6; Colon: 66.3 ± 6.7; No disease: 61.9 ± 7.4 Mean ± SD, 5.0 ± 1.01 Garlic supplements Use (any use in the past 10 years) vs. no use Questionnaire Lung cancer, colorectal cancer X X X X X
Colon: 48.01%
Brasky, 2011 [35] The VITAL (VITamins And Lifestyle) cohort U.S. Cohort 1,602 cases, 35,239 total 100% Range, 50–79 Median, 6.1 Garlic supplements Use vs. no use Questionnaire Prostate cancer X X X X
Walter, 2011 [36] The VITAL (VITamins And Lifestyle) cohort U.S. Cohort 588 cases, 66,227 total 49.20% Mean ± SD, 61.5 ± 7.4 Mean ± SD, 6.5 ± 1.8 Garlic supplement (from single supplements (and mixtures other than multivitamins) plus multivitamins) High use vs. low use vs. no use A 24-page self-administered, sex-specific questionnaire Hematologic malignancy X X X X
McCullough, 2012 [30] The Cancer Prevention Study II Nutrition Cohort U.S. Cohort 1,130 cases, 99,700 total 42.95% Mean range, 66.9–70.7 Mean, 7 Garlic intake; garlic supplements < 1 clove per month, 1 clove per month, > 1 clove per month; continuous garlic intake (each clove/week); use vs. no use 152-item modified Willett FFQ Colorectal cancer X X X X X X
Meng, 2013 [31] The Nurses' Health Study and the Health Professionals Follow-Up Study U.S. Cohort 1,339 colorectal cancer cases, 1,054 colon cancer cases, 634 proximal colon cancer cases, 397 distal colon cancer cases, 285 rectal cancer cases, 121,700 total in NHS; 1,029 colorectal cancer cases, 811 colon cancer cases, 345 proximal colon cancer cases, 314 distal colon cancer cases, 218 rectal cancer cases, 51,529 total in HPFS 0 in NHS, 100% in HPFS 30–55 in NHS; 40–75 in HPFS 24 in NHS, 22 in HPFS Garlic intake; garlic supplements < 1 clove per month, 1–3 cloves per month, 1 clove per week, 2–4 cloves per week, 5–6 cloves per week, ≥ 1 clove per day; use vs. no use Semiquantitative FFQ with up to 130 foods Colorectal cancer, colon cancer, proximal colon cancer, distal colon cancer, rectal cancer X X X X X X
Kim, 2018 [37] The Nurses' Health Study and the Health Professionals Follow-Up Study U.S. Cohort 292 cases in NHS and HPFS, 121,700 total in NHS; 51,529 total in HPFS 0 in NHS, 100% in HPFS 30–55 in NHS; 40–75 in HPFS 30 in both NHS and HPFS Garlic intake 0–1 clove per week, 1–4 cloves per week, ≥ 5 cloves per week Semiquantitative FFQ Gastric cancer X X X X X X

FFQ, food frequency questionnaire; NHS, Nurses' Health Study; HPFS, Health Professionals Follow-up Study.