Table 3.

RR (95% CI) for the association between genital talc use and ovarian cancer risk in the NECC and the NHS

NECC*
NHS*
Pooled
Cases (%)Controls (%)RR (95% CI)Cases (%)Controls (%)RR (95% CI)RR (95% CI)
Total epithelial ovarian cancer:
N1,1751,202210600
Regular genital talc use (once a week or more)
    No859 (73.2)957 (79.7)1.00 (reference)138 (70.8)414 (76.0)1.00 (reference)1.00 (reference)
    Yes314 (26.8)244 (20.3)1.40 (1.15-1.70)57 (29.2)131 (24.0)1.24 (0.83-1.83)1.36 (1.14-1.63)
Frequency of genital talc use
    Never832 (70.9)916 (76.3)1.00 (reference)120 (61.5)352 (64.6)1.00 (reference)1.00 (reference)
    Less than once a week27 (2.3)41 (3.4)0.72 (0.43-1.19)18 (9.2)62 (11.4)0.98 (0.54-1.79)0.82 (0.55-1.20)
    1-6 times a week123 (10.5)96 (8.0)1.33 (1.00-1.79)22 (11.3)61 (11.2)1.01 (0.57-1.79)1.26 (0.97-1.63)
    Daily191 (16.3)148 (12.3)1.41 (1.10-1.79)35 (18.0)70 (12.8)1.44 (0.88-2.37)1.41 (1.14-1.76)
    Ptrend§0.0020.18<0.001
Serous invasive ovarian cancer:
N4501,20293263
Regular genital talc use (once a week or more)
    No310 (69.0)957 (79.7)1.00 (reference)60 (68.2)177 (73.8)1.00 (reference)1.00 (reference)
    Yes139 (31.0)244 (20.3)1.62 (1.26-2.09)28 (31.8)63 (26.3)1.48 (0.82-2.68)1.60 (1.26-2.02)
Frequency of genital talc use
    Never299 (66.6)916 (76.3)1.00 (reference)54 (61.4)151 (62.9)1.00 (reference)1.00 (reference)
    Less than once a week11 (2.4)41 (3.4)0.65 (0.32-1.33)6 (6.8)26 (10.8)0.79 (0.29-2.11)0.70 (0.39-1.24)
    1-6 times a week56 (12.5)96 (8.0)1.56 (1.08-2.26)12 (13.6)25 (10.4)1.64 (0.71-3.79)1.58 (1.12-2.21)
    Daily83 (18.5)148 (12.3)1.61 (1.18-2.20)16 (18.2)38 (15.8)1.34 (0.65-2.76)1.56 (1.17-2.08)
     Ptrend§<0.0010.29<0.001
  • * Unconditional (NECC) and conditional (NHS) logistic regression adjusted for age, study center (NECC only), duration of oral contraceptive use (months), parity (continuous), tubal ligation, BMI (kg/m2, continuous), and duration of PMH use (months).

  • P values for tests for heterogeneity comparing the NECC and NHS results were all >0.38.

  • Frequencies do not add up to total N due to missing data on talc use.

  • § Weighted by the midpoint of each category of genital talc use frequency and calculated using the Wald test.