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. Author manuscript; available in PMC: 2023 Jan 1.
Published in final edited form as: Environ Res. 2021 Aug 11;203:111863. doi: 10.1016/j.envres.2021.111863

Table 3.

Multivariable-adjusted associations of permanent hair dye use and characteristics of use with breast tumor clinicopathologic features in the overall study sample of breast cancer casesa, N=2,998

Regular hair dye useb Duration of hair dye useb
 Typical hair dye applicationc
 Typical hair dye shaded
≤10 Years >10 Years Home Kit Combination Medium Dark
Tumor feature OR (95% CI) OR (95%CI) OR (95%CI) OR (95% CI) OR (95% CI) OR (95% CI) OR (95% CI)
Tumor grade
 Well differentiated 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF)
 Moderately differentiated 1.04 (0.81–1.34) 0.94 (0.70–1.25) 1.26 (0.88–1.82) 1.25 (0.79–1.99) 1.61 (0.97–2.67) 1.04 (0.64–1.68) 0.76 (0.47–1.23)
 Poorly differentiated 1.07 (0.82–1.38) 0.90 (0.67–1.21) 1.46 (1.00–2.11) 1.41 (0.87–2.29) 2.27 (1.36–3.82)* 0.95 (0.59–1.55) 0.59 (0.36–0.97)
Ptrend = 0.46 Ptrend = 0.43 Ptrend = 0.75 Ptrend = 0.23 Ptrend = 0.13 Ptrend = 0.89 Ptrend = 0.77
Tumor size
 <1.0 cm 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF)
 1.0–2.0 cm 1.09 (0.91–1.30) 1.13 (0.92–1.38) 1.03 (0.80–1.34) 1.37 (0.97–1.95) 1.41 (0.98–2.03) 0.94 (0.67–1.32) 0.95 (0.67–1.34)
 >2.0 cm 0.86 (0.71–1.04) 0.80 (0.63–1.00) 1.02 (0.77–1.35) 1.08 (0.72–1.63) 1.10 (0.72–1.68) 0.92 (0.62–1.36) 0.91 (0.61–1.34)
Ptrend = 0.59 Ptrend = 0.32 Ptrend = 0.78 Ptrend = 0.11 Ptrend = 0.054 Ptrend = 0.76 Ptrend = 0.96
ER status
 Negative 0.96 (0.80–1.15) 0.99 (0.80–1.22) 0.92 (0.70–1.21) 0.76 (0.51–1.10) 0.73 (0.49–1.07) 0.86 (0.60–1.24) 0.76 (0.53–1.08)
 Positive 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF)
Ptrend = 0.46 Ptrend = 0.025
HER2 status
 Negative 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF)
 Positive 1.09 (0.88–1.35) 1.24 (0.98–1.58) 0.78 (0.56–1.07) 0.99 (0.64–1.53) 1.05 (0.67–1.64) 1.11 (0.72–1.70) 1.00 (0.66–1.51)
Ptrend = 0.078 Ptrend = 0.034
Lymph node status
 Negative 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF)
 Positive 0.85 (0.70–1.03) 0.97 (0.78–1.21) 0.63 (0.47–0.84)* 1.12 (0.75–1.67) 0.77 (0.50–1.18) 1.21 (0.83–1.76) 0.83 (0.56–1.21)
Ptrend = 0.56 Ptrend <0.001
Tumor subtype
 Luminal A 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF) 1.00 (REF)
 HER2-positive 1.11 (0.89–1.39) 1.28 (1.00–1.65) 0.79 (0.56–1.10 0.85 (0.54–1.35) 0.94 (0.59–1.50) 1.01 (0.64–1.58) 0.83 (0.54–1.29)
 Triple-negative 0.99 (0.78–1.25) 1.04 (0.79–1.35) 0.93 (0.66–1.30) 0.74 (0.46–1.19) 0.62 (0.37–1.02) 0.85 (0.54–1.35) 0.65 (0.41–1.03)
Ptrend = 0.15 Ptrend = 0.017
a

The multivariable-adjusted model included the following covariates: 1) family history of breast cancer, 2) oral contraceptive use, 3) education, 4) BMI, 5) age, 6) race, and 7) mode of detection.

b

Never-users of hair dye composed the referent group.

c

Those reporting salon application as the typical application of hair dyes composed the referent group.

d

Those reporting typical use of light hair dye shades composed the referent group.

*

Significant after correction for multiple comparisons (Bonferroni correction, P <0.01).