Table 5.
Modifications of associationa between 24-year mean road traffic noise Lden (per 10 dB) and incidence of breast cancer by menopausal status, HT use, obesity, night work, and residential area in 22,466 nurses from the Danish Nurse Cohort
| Breast cancer with receptor status N = 611 |
ER+ N = 494 |
PR+ N = 393 |
ER+/PR+ N = 384 |
|||||
|---|---|---|---|---|---|---|---|---|
| Number of cases | HR (95% CI) | Number of cases | HR (95% CI) | Number of cases | HR (95% CI) | Number of cases | HR (95% CI) | |
| Menopausal status | ||||||||
| Premenopausal | 334 | 1.16 (0.97–1.38) | 272 | 1.25 (1.02–1.52) | 231 | 1.17 (0.95–1.45) | 226 | 1.19 (0.96–1.48) |
| Postmenopausal | 277 | 1.18 (0.97–1.43) | 222 | 1.21 (0.97–1.51) | 162 | 1.26 (0.97–1.63) | 158 | 1.23 (0.94–1.59) |
| p value for interaction** | 0.9069 | 0.7135 | 0.6767 | 0.8909 | ||||
| HT use | ||||||||
| Never | 390 | 1.16 (0.99–1.36) | 319 | 1.21 (1.01–1.45) | 256 | 1.18 (0.97–1.44) | 254 | 1.19 (0.97–1.45) |
| Previous | 57 | 0.98 (0.64–1.50) | 44 | 1.12 (0.68–1.85) | 33 | 1.03 (0.58–1.84) | 31 | 0.99 (0.55–1.80) |
| Current | 164 | 1.26 (0.96–1.65) | 131 | 1.33 (0.99–1.80) | 104 | 1.34 (0.96–1.88) | 99 | 1.34 (0.95–1.89) |
| p value for interaction** | 0.4685 | 0.6047 | 0.5697 | 0.6012 | ||||
| Obesity (BMI > 30 kg/m2) | ||||||||
| No | 572 | 1.18 (1.03–1.35) | 459 | 1.25 (1.07–1.45) | 367 | 1.22 (1.03–1.45) | 358 | 1.22 (1.03–1.46) |
| Yes | 39 | 1.03 (0.65–1.65) | 35 | 1.04 (0.63–1.71) | 26 | 1.03 (0.59–1.78) | 26 | 1.03 (0.59–1.78) |
| p value for interaction** | 0.9805 | 0.9489 | 0.7553 | 0.7704 | ||||
| Night work* | ||||||||
| No | 473 | 1.16 (1.00–1.35) | 386 | 1.21 (1.02–1.43) | 317 | 1.22 (1.02–1.47) | 1.23 (1.02–1.48) | |
| Yes | 24 | 1.86 (0.97–3.57) | 17 | 3.36 (1.48–7.63) | 9 | 1.88 (0.59–6.00) | 310 | 3.04 (0.80–11.60) |
| p value for interaction** | 0.3754 | 0.0477* | 0.3000 | 8 | 0.1585 | |||
| Residential area | ||||||||
| Urban | 77 | 1.30 (0.81–2.10) | 67 | 1.24 (0.74–2.07) | 50 | 0.95 (0.52–1.75) | 49 | 0.96 (0.52–1.77) |
| Provincial | 299 | 1.21 (0.98–1.51) | 234 | 1.43 (1.12–1.83) | 192 | 1.57 (1.19–2.06) | 185 | 1.57 (1.19–2.08) |
| Rural | 235 | 1.12 (0.94–1.33) | 193 | 1.12 (0.92–1.35) | 151 | 1.06 (0.85–1.31) | 150 | 1.06 (0.86–1.32) |
| p value for interaction** | 0.6460 | 0.2610 | 0.0811 | 0.0893 | ||||
aModel adjusted for birth cohort, urbanization (urban, provincial, rural), body mass index (underweight, normal, overweight, obese), leisure time physical activity (low, medium, high), alcohol consumption (low, moderate, heavy), age at menarche (≤ 12 years of age, > 12 years of age), parity (nulliparous, parous), number of births, age at first birth, menopausal status (premenopausal, postmenopausal), use of hormone therapy (never, past, current), use of oral contraceptives (never, ever) and smoking status
Traffic noise was entered as a continuous variable in all models as the 24-year running mean preceding diagnosis. Model adjusted for birth cohort, urbanization (urban, provincial, rural), body mass index (underweight, normal, overweight, obese), leisure time physical activity (low, medium, high), alcohol consumption (low, moderate, heavy), age at menarche (≤ years of age, > 12 years of age), parity (nulliparous, parous), number of births, age at first birth, menopausal status (premenopausal, postmenopausal), use of hormone therapy (never, past, current), use of oral contraceptives (never, ever) and smoking status. However, there was no adjustment for the stratification variable
HT hormone therapy, BMI body mass index, ER estrogen receptor, PR progesterone receptor
*Only available for 17,545 nurses
**Test of the null hypothesis that the linear trends are identical, for Wald’s test for interaction