TY - JOUR
T1 - Air pollution with NO2, PM2.5, and elemental carbon in relation to risk of breast cancer– a nationwide case-control study from Denmark
AU - Poulsen, Aslak Harbo
AU - Hvidtfeldt, Ulla Arthur
AU - Sørensen, Mette
AU - Pedersen, Julie Elbæk
AU - Ketzel, Matthias
AU - Brandt, Jørgen
AU - Geels, Camilla
AU - Christensen, Jesper H.
AU - Raaschou-Nielsen, Ole
PY - 2023/1/1
Y1 - 2023/1/1
N2 - Air pollution with particulate matter is an established lung carcinogen. Studies have suggested an association with breast cancer, but the evidence is inconsistent. Methods: From nationwide registers, we identified all breast cancer cases (n = 55 745) in Denmark between 2000 and 2014. We matched one control for each case on age and year of birth. We used a multi-scale dispersion model to estimate outdoor concentrations of particulate matter <2.5 μm (PM2.5), elemental carbon (EC) and nitrogen dioxide (NO2) as time-weighted average over all addresses up to 20 years prior to diagnosis. We calculated odds ratios (OR) and 95% confidence intervals (CI) by conditional logistic regression with adjustment for marital status, educational level, occupational status, personal income, region of origin, medication and area-level socio-economic indicators. Results: A 10 μg/m3 higher PM2.5 was associated with an OR for breast cancer of 1.21 (95% CI: 1.11–1.33). The corresponding ORs for EC (per 1 μg/m3) and NO2 (per 10 μg/m3) were 1.03 (95% CI: 1.00–1.07) and 1.03 (95% CI: 1.01–1.06), respectively. In multi–pollutant models, the OR for PM2.5 changed only little, whereas ORs for EC or NO2 approached the null. In an analysis of persons below 55 years, PM2.5 was associated with an OR of 1.32 (95% CI: 1.09–1.60) per 10 μg/m3 increase. Conclusion: We found evidence of an association between the investigated air pollutants and breast cancer, especially PM2.5. There were indications that the association differed by age at diagnosis. We were not able to include all potential confounders and thus, results should be interpreted with caution.
AB - Air pollution with particulate matter is an established lung carcinogen. Studies have suggested an association with breast cancer, but the evidence is inconsistent. Methods: From nationwide registers, we identified all breast cancer cases (n = 55 745) in Denmark between 2000 and 2014. We matched one control for each case on age and year of birth. We used a multi-scale dispersion model to estimate outdoor concentrations of particulate matter <2.5 μm (PM2.5), elemental carbon (EC) and nitrogen dioxide (NO2) as time-weighted average over all addresses up to 20 years prior to diagnosis. We calculated odds ratios (OR) and 95% confidence intervals (CI) by conditional logistic regression with adjustment for marital status, educational level, occupational status, personal income, region of origin, medication and area-level socio-economic indicators. Results: A 10 μg/m3 higher PM2.5 was associated with an OR for breast cancer of 1.21 (95% CI: 1.11–1.33). The corresponding ORs for EC (per 1 μg/m3) and NO2 (per 10 μg/m3) were 1.03 (95% CI: 1.00–1.07) and 1.03 (95% CI: 1.01–1.06), respectively. In multi–pollutant models, the OR for PM2.5 changed only little, whereas ORs for EC or NO2 approached the null. In an analysis of persons below 55 years, PM2.5 was associated with an OR of 1.32 (95% CI: 1.09–1.60) per 10 μg/m3 increase. Conclusion: We found evidence of an association between the investigated air pollutants and breast cancer, especially PM2.5. There were indications that the association differed by age at diagnosis. We were not able to include all potential confounders and thus, results should be interpreted with caution.
KW - Air pollution
KW - Breast cancer
KW - Cancer
KW - Case control
KW - Epidemiology
KW - Risk factors
U2 - 10.1016/j.envres.2022.114740
DO - 10.1016/j.envres.2022.114740
M3 - Journal article
C2 - 36356668
AN - SCOPUS:85141521819
SN - 0013-9351
VL - 216
JO - Environmental Research
JF - Environmental Research
M1 - 114740
ER -