Skip to main content

Advertisement

Table 4 Adjusted RRs for the association between pregnancy-related conditions and breast CIS and invasive breast cancer

From: Pregnancy-related factors and the risk of breast carcinoma in situand invasive breast cancer among postmenopausal women in the California Teachers Study cohort

  Breast CIS Invasive breast cancer
  Observed Person-years Cases No. Adjusted RR (95% CI) Observed Person-years Cases No. Adjusted RR (95% CI) P for homogeneityb
Nausea or vomiting during pregnancy        
Ever experienced        
   No 108,269 124 Reference 111,618 620 Reference  
   Yes 224,001 270 1.05 (0.85 to 1.30) 230,499 1,174 0.92 (0.84 to 1.02) 0.29
Number of pregnancies during which participant experienced nausea or vomitinga        
   1 73,892 84 0.92 (0.70 to 1.22) 75,959 380 0.91 (0.80 to 1.03)  
   2 72,819 95 1.21 (0.91 to 1.61) 75,015 387 0.94 (0.82 to 1.07  
   3 43,520 53 0.99 (0.70 to 1.41) 44,783 238 0.94 (0.80 to 1.11)  
   ≥ 4 33,770 38 1.16 (0.76 to 1.77) 34,742 169 0.91 (0.75 to 1.11)  
   P trend    0.37    0.25 0.20
Ever needed treatment for nausea or vomiting during pregnancya        
   No 184,207 220 1.04 (0.83 to 1.30) 189,367 947 0.90 (0.81 to 1.00) 0.26
   Yes, for most recent pregnancy 19,436 24 1.09 (0.70 to 1.69) 20,092 114 1.07 (0.88 to 1.31) 0.96
   Yes, for other pregnancy(ies) 20,358 26 1.14 (0.74 to 1.74) 21,039 113 1.01 (0.83 to 1.24) 0.63
Preeclampsia        
Ever diagnosed with preeclampsia        
   No 304,969 361 Reference 314,176 1673 Reference  
   Yes, during most recent pregnancy 8,431 17 1.72 (1.05 to 2.81) 8,699 44 0.98 (0.73 to 1.33) 0.06
   Yes, during other pregnancy(ies) 12,379 13 0.93 (0.53 to 1.62) 12,648 51 0.77 (0.58 to 1.02) 0.57
  1. RRs for gravid postmenopausal women based on multivariable Cox proportional hazards regression models using age (in days) as the time metric and stratified by age (in years) with the adjustment for race, family history of breast cancer in a first degree relative, age at menarche, HT use, body mass index, pregnancy history (number full-term pregnancies: 1; 2; 3; ≥ 4; ever pregnant, but unknown whether full-term; ever been pregnant, but not full-term pregnancy). aCompared with gravid postmenopausal women who had never experienced nausea or vomiting during pregnancy. bHomogeneity in risk estimates between breast CIS and invasive breast cancer. Abbreviations: CIS, carcinoma in situ; RR, relative risk; CI, confidence interval; HT, hormone therapy