Table 3.

Adjusted HRs (95% CI) of breast cancer–specific death for a 10 μg/m3 increase in post-diagnosis PM stratified by stage at diagnosis

PM2.5PM2.5-10PM10Events/Person–Years
NHS
 Model 3a:
  Stage I1.60 (1.05–2.45)0.95 (0.66–1.35)1.12 (0.89–1.41)293/52,795
  Stage II0.83 (0.54–1.28)0.85 (0.60–1.20)0.89 (0.71–1.11)329/22,457
  Stage III1.18 (0.73–1.93)1.13 (0.79–1.61)1.11 (0.86–1.42)277/6,192
Pinteraction0.290.290.21
 Model 4b:
  Stage I1.50 (0.97–2.32)0.93 (0.65–1.33)1.09 (0.86–1.38)293/52,795
  Stage II0.82 (0.52–1.28)0.86 (0.60–1.22)0.89 (0.70–1.12)329/22,457
  Stage III0.98 (0.59–1.63)1.06 (0.73–1.53)1.02 (0.79–1.33)277/6,192
Pinteraction0.270.460.42
NHSII
 Model 3a:
  Stage I2.12 (0.90–5.02)1.43 (0.81–2.52)1.46 (0.96–2.21)94/15,004
  Stage II1.03 (0.46–2.30)1.24 (0.74–2.07)1.14 (0.77–1.69)112/9,484
  Stage III1.45 (0.59–3.57)0.96 (0.48–1.92)1.09 (0.68–1.74)106/3,403
Pinteraction0.030.180.04
 Model 4b:
  Stage I2.41 (0.98–5.93)1.40 (0.78–2.51)1.50 (0.97–2.32)94/15,004
  Stage II1.13 (0.51–2.52)1.18 (0.69–2.03)1.13 (0.75–1.69)112/9,484
  Stage III1.59 (0.58–4.30)1.07 (0.52–2.20)1.17 (0.70–1.95)106/3,403
Pinteraction0.0470.140.03
Pooled estimates
 Model 3a:
  Stage I1.69 (1.16–2.47)1.09 (0.74–1.61)1.20 (0.96–1.50)387/67,799
  Stage II0.87 (0.60–1.28)0.97 (0.69–1.38)0.95 (0.76–1.18)441/31,941
  Stage III1.24 (0.81–1.90)1.09 (0.80–1.50)1.10 (0.89–1.38)383/9,595
 Model 4b:
  Stage I1.64 (1.11–2.43)1.07 (0.73–1.56)1.21 (0.90–1.61)387/67,799
  Stage II0.88 (0.60–1.30)0.94 (0.70–1.27)0.94 (0.76–1.16)441/31,941
  Stage III1.08 (0.69–1.70)1.06 (0.76–1.48)1.05 (0.83–1.33)383/9,595
  • Abbreviations: BMI, body mass index; ER, estrogen receptor; HR, hazard ratio; MET, metabolic equivalent; NHS, Nurses' Health Study; PM, particulate matter.

  • aModel 3 adjusted for age, diagnosis date, race/ethnicity, region of residence at diagnosis, Census-tract median income, pre-diagnostic physical activity and BMI, and the following clinical factors: ER status, treatment, hormones, and grade.

  • bModel 4 adjusted for age, diagnosis date, race/ethnicity, region of residence at diagnosis, Census-tract median income, ER status, treatments, hormones, grade, pre- to post-diagnosis weight change categories, post-diagnostic physical activity, and post-diagnostic aspirin use.