TY - JOUR
T1 - High mammographic density in long-term night-shift workers
T2 - DDM-Spain/var-DDM
AU - Pedraza-Flechas, Ana María
AU - Lope, Virginia
AU - Sanchez-Contador, Carmen
AU - Santamarina, Carmen
AU - Pedraz-Pingarron, Carmen
AU - Moreo, Pilar
AU - Ederra, María
AU - Miranda-García, Josefa
AU - Vidal, Carmen
AU - Llobet, Rafael
AU - Aragones, Nuria
AU - Salas-Trejo, Dolores
AU - Pollan, Marina
AU - Perez-Gomez, Beatriz
N1 - Publisher Copyright:
© 2017 American Association for Cancer Research.
PY - 2017/6/1
Y1 - 2017/6/1
N2 - Background: Night-shift work (NSW) has been suggested as a possible cause of breast cancer, and its association with mammographic density (MD), one of the strongest risk factors for breast cancer, has been scarcely addressed. This study examined NSW and MD in Spanish women. Methods: The study covered 2,752 women aged 45-68 years recruited in 2007-2008 in 7 population-based public breast cancer screening centers, which included 243 women who had performed NSW for at least one year. Occupational data and information on potential confounders were collected by personal interview. Two trained radiologist estimated the percentage ofMD assisted by a validated semiautomatic computer tool (DM-scan). Multivariable mixed linear regression models with random screening center-specific intercepts were fitted using log-transformed percentage ofMDas the dependent variable and adjusting by known confounding variables. Results: Having ever worked in NSW was not associated with MD =eb:0.96; 95% confidence interval (CI), 0.86-1.06]. However, the adjusted geometric mean of the percentage of MD in women with NSWfor more than 15 years was 25%higher than that of those without NSW history (MD>15 years:20.7% vs. MDnever:16.5%;eb:1.25; 95% CI,1.01-1.54). This association was mainly observed in postmenopausal participants (eb:1.28; 95% CI, 1.00-1.64). Among NSW-exposed women, those with 2 night-shifts per week had higher MD than those with 5 to 7 nightshifts per week (eb:1.42; 95% CI, 1.10-1.84). Conclusions: Performing NSW was associated with higherMD only in women with more than 15 years of cumulated exposure. These findings warrant replication in futures studies. Impact: Our findings suggest that MD could play a role in the pathway between long-term NSW and breast cancer.
AB - Background: Night-shift work (NSW) has been suggested as a possible cause of breast cancer, and its association with mammographic density (MD), one of the strongest risk factors for breast cancer, has been scarcely addressed. This study examined NSW and MD in Spanish women. Methods: The study covered 2,752 women aged 45-68 years recruited in 2007-2008 in 7 population-based public breast cancer screening centers, which included 243 women who had performed NSW for at least one year. Occupational data and information on potential confounders were collected by personal interview. Two trained radiologist estimated the percentage ofMD assisted by a validated semiautomatic computer tool (DM-scan). Multivariable mixed linear regression models with random screening center-specific intercepts were fitted using log-transformed percentage ofMDas the dependent variable and adjusting by known confounding variables. Results: Having ever worked in NSW was not associated with MD =eb:0.96; 95% confidence interval (CI), 0.86-1.06]. However, the adjusted geometric mean of the percentage of MD in women with NSWfor more than 15 years was 25%higher than that of those without NSW history (MD>15 years:20.7% vs. MDnever:16.5%;eb:1.25; 95% CI,1.01-1.54). This association was mainly observed in postmenopausal participants (eb:1.28; 95% CI, 1.00-1.64). Among NSW-exposed women, those with 2 night-shifts per week had higher MD than those with 5 to 7 nightshifts per week (eb:1.42; 95% CI, 1.10-1.84). Conclusions: Performing NSW was associated with higherMD only in women with more than 15 years of cumulated exposure. These findings warrant replication in futures studies. Impact: Our findings suggest that MD could play a role in the pathway between long-term NSW and breast cancer.
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U2 - 10.1158/1055-9965.EPI-16-0507
DO - 10.1158/1055-9965.EPI-16-0507
M3 - Research Article
C2 - 28336582
AN - SCOPUS:85020233110
SN - 1055-9965
VL - 26
SP - 905
EP - 913
JO - Cancer Epidemiology Biomarkers and Prevention
JF - Cancer Epidemiology Biomarkers and Prevention
IS - 6
ER -