Table 1. Characteristics of included studies in meta-analysis.
| First author, Year, Country | Study population | Study design | Sex, age, duration of follow-up | No. of cases/controls or cohort sizes | Exposure details | Highest vs. lowest analysis | RRs or ORs (95% CI) | NOS quality scores |
|---|---|---|---|---|---|---|---|---|
| Joh et al., 2013 (35), United States | NHS | Cohort study | Women, 30 to 55 years, 22 years of follow-up | 72051 | Dietary | Median 627 vs. 127 IU/d | 0.81 (0.54, 1.22) | 8 |
| Circulating | 80nmol/L vs. 56nmol/L | 0.60 (0.35, 1.02) | ||||||
| HPFS | Cohort study | Men, 40 to 75 years, 22 years of follow-up | 46380 | Dietary | Median 627 vs. 127 IU/d | 0.8 (0.5, 1.27) | ||
| Circulating | 70nmol/L vs. 50nmol/L | 0.66 (0.40 to 1.09) | ||||||
| Gallicchio et al., 2014, (23), in United States | VDPP | Nested case control | Men and women, 54 to 66 years, 2.2 to 10.9 years of follow-up | 775/775 | Circulating | ≥100nmol/L vs. <25nmol/L | 0.96 (0.43, 2.14) | 8 |
| Muller et al., 2014 (36), in France | EPIC | Nested case control | Men and women, 49 to 75 years, 6.7 years of follow-up | 555/1092 | Circulating | NA | 0.82 (0.68, 0.99) | 8 |
| Karami, et al., 2008 (28), in Central and Eastern Europe | Hospital based study | Case-control | Men and women, 20 to 88 years | 777/1035 | Dietary | High (>66%) vs. Low (<33%) | 0.81 (0.63, 1.3) | 5 |
| Wilson et al., 2009 (34), in Finland | ATBC | Cohort study | Men, 50 to 69 years, 3 years of follow-up | 29133 | Dietary | >6.8 vs. <3.5μg/day | 1.5 (1, 2.3) | 8 |
| Bosetti et al., 2006 (27), in Italy | 4 Italian areas | Case-control | Men and women, 24-79 years | 767/1534 | Dietary | Highest one vs. lowest one | Men: 0.92 (0.7, 1.21) Women: 0.6 (0.42, 0.88) Overall: 0.76 (0.57, 1.01) |
7 |
| Prineas et al., 1997 (38), in United States | LWHS | Cohort study | Women, 55-69 years, 8 years of follow-up | 35192 | Dietary | >476 vs. <3.5mg/day | 0.81 (0.45, 1.45) | 8 |
| Mellemgaard et al., 1996 (37), in Denmark | Born and living in Denmark | Case-control | Men and women, 20 to 79 years | 351/340 | Dietary | Men: >3.3 vs. <l.6fg Women: >2.6 vs. <1.3mg |
Men: 1.2 (0.6, 2.4) Women: 0.6 (0.3, 1.3) |
8 |
| Li et al.,, 2019 (39), in China | Hospital based study | Case-control | Men and women | 135/135 | Circulating | ≥30 vs. <20 | 0.30 (0.13, 0.72) | 8 |
NHS = Nurse's Health Study; HPFS = Health Professionals Follow-Up Study; VDPP = Vitamin D Pooling Project of Rarer Cancers; EPIC = EuropeanProspective Investigation into Cancer and Nutrition; ATBC = Alpha-Tocopherol Beta-Carotene Cancer Prevention Study; LWHS = Lowa Women's Health Study.