Table 1.

Adjusted ORs and 95% CIs for associations between hormonal and reproductive factors and risk of bladder cancer among women in the Los Angeles–Shanghai Bladder Cancer Study

Los AngelesShanghai
Cases/controls (all women)All women OR (95% CI)aNever smokersEver smokersCases/controls (nonsmokers)Never smokers
OR (95% CI)bOR (95% CI)bOR (95% CI)c
Parity
 Nulliparous11/51.0 (ref)
 Parous102/1250.35 (0.11–1.08)
Number of children
 127/221.0 (ref)
 225/250.63 (0.23–1.74)
 317/280.47 (0.16–1.33)
 ≥433/500.56 (0.21–1.48)
Ptrend = 0.31
Pregnancy
 Never45/371.0 (ref)1.0 (ref)1.0 (ref)
 Ever304/3120.58 (0.33–0.98)0.30 (0.13–0.65)1.29 (0.71–2.35)
Total number of pregnancies
 144/321.0 (ref)1.0 (ref)1.0 (ref)
 264/850.41 (0.19–0.87)0.42 (0.14–1.22)0.71 (0.35–1.44)
 369/720.63 (0.29–1.34)0.42 (0.12–1.37)0.75 (0.37–1.51)
 ≥4127/1230.70 (0.35–1.39)0.79 (0.29–2.18)0.84 (0.43–1.62)
Ptrend = 0.73Ptrend = 0.82Ptrend = 0.93
OC use
 Never170/1701.0 (ref)1.0 (ref)1.0 (ref)95/1101.0 (ref)
 Ever177/1790.81 (0.55–1.19)1.40 (0.75–2.62)0.83 (0.55–1.24)18/200.82 (0.38–1.79)
Duration of OC use
 Nonuser170/1701.0 (ref)1.0 (ref)1.0 (ref)95/1101.0 (ref)
 <4 y84/860.74 (0.47–1.18)1.54 (0.70–3.36)0.76 (0.48–1.22)12/110.92 (0.36–2.37)
 ≥4 y88/930.79 (0.50–1.25)1.11 (0.53–2.32)0.88 (0.54–1.43)6/90.68 (0.22–2.16)
Ptrend = 0.28Ptrend = 0.51Ptrend = 0.54Ptrend = 0.54
Menopausal estrogen therapy use
 Never193/1941.0 (ref)1.0 (ref)1.0 (ref)
 Ever156/1540.96 (0.65–1.42)1.00 (0.54–1.86)1.03 (0.70–1.54)
Duration of estrogen use
 Nonuser193/1941.0 (ref)1.0 (ref)1.0 (ref)
 <4 y76/701.11 (0.69–1.80)1.02 (0.48–2.17)1.13 (0.69–1.86)
 ≥4 y80/840.86 (0.54–1.38)1.00 (0.47–2.14)0.96 (0.60–1.54)
Ptrend = 0.61Ptrend = 0.98Ptrend = 0.93
Hysterectomy
 Never233/2431.0 (ref)1.0 (ref)1.0 (ref)
 Ever116/1061.16 (0.79–1.69)0.83 (0.44–1.58)1.23 (0.82–1.86)
BMI
 16–19.970/392.25 (1.29–3.92)1.90 (0.78–4.64)1.84 (1.08–3.11)13/230.67 (0.31–1.47)
 20–24.9194/2071.0 (ref)1.0 (ref)1.0 (ref)67/871.0 (ref)
 25–29.954/660.72 (0.44–1.22)0.79 (0.36–1.75)0.82 (0.49–1.37)30/182.31 (1.14–4.47)
 ≥3030/361.46 (0.77–2.78)0.55 (0.23–1.33)2.73 (1.06–7.03)3/22.11 (0.33–13)
Ptrend = 0.12Ptrend = 0.10Ptrend = 0.52Ptrend = 0.008
  • aConditional logistic regression adjusted for age at reference year, race/ethnicity (non-Hispanic white, Hispanic white, or African American), smoking status (never, former, or current), pack-years of smoking, and BMI (<20, 20–24.9, 25–29.9, ≥30, unknown).

  • bUnconditional logistic regression adjusted for age at reference year, race/ethnicity (non-Hispanic white, Hispanic white, or African American), and BMI (<20, 20–24.9, 25–29.9, ≥30, unknown).

  • cUnconditional logistic regression adjusted for age at reference year and BMI (<20, 20–24.9, 25–29.9, ≥30, unknown).