Table 1

Summary of the dose-response associations (ORs) observed between folate and cervical dysplasia, cervical carcinoma in situ, and invasive cervical carcinoma in case-control studies

First author (year) (ref. no.)No. of cases/no. of controlsCategories of dietary intakeCategories of circulating concentrationsAdjusted forb
1 = lowa2341 = lowa234
Dysplasia
Van Eenwyk (1992) (5)100 /1001.00.80.70.41.00.91.10.3 (serum)A–G, J, K
1.00.50.60.1 (RBC)
Liu (1993) (6)257 /1331.00.931.330.67A–D, H–J
Buckley (1992) (7)42 /581.00.590.30Nothing
Butterworth (1992) (8)294 /1701.01.00.71— (RBC)B–D, H, I
Kanetsky (1998) (9)32 /1131.01.400.281.00.131.50— (serum)A, C, E, G, I, L
1.01.30.7— (RBC)
Carcinoma in situ
Brock (1988) (10)117 /1961.01.80.91.3A–E, L
Ziegler (1991) (11)229 /5021.00.930.790.73A–G
Invasive cervical carcinoma
Ziegler (1990) (12)271 /5021.00.861.021.18A–D, F, G
Verreault (1989) (13)189 /2271.00.61.30.8A–G, L
Herrero (1991) (14)748 /14111.00.991.000.95A, B, E, G–I
Potischman (1991) (15)330 /5651.01.011.061.05 (serum)A, B, E, G–I
  • a Referent category.

  • b A, age; B, sexual activity; C, smoking; D, contraceptive use; E, socioeconomic status; F, history of genital infection; G, time since last Pap smear or frequency of Pap smears; H, parity; I, HPV infection (HPV-16 and/or HPV-18); J, race; K, body mass index; L, total energy.