Environment and Breast Cancer: Science Review

Evidence From Humans
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Cancer deaths in a cohort of Japanese barbers in Aichi Prefecture
Sugiura, S., Yagyu, K., Obata, Y., Lin, Y., Tamakoshi, A., Ito, H., Matsuo, K., Tajima, K., Aoki, K., Kikuchi, S. Asian Pac J Cancer Prev. 2009. 10:2, 307-10.
Topic area
Environmental pollutant - Occupation
Study design
Prospective cohort
Funding agency
Not reported
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
No analysis based on menopausal status
Number in Cohort
Cohort: 3,686
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
The cohort includes 8,360 people (3,686 women) from the Barbers’ Union of Aichi Prefecture in Japan, enrolled in 1976 and followed through death certificates sent to the Barbers' Union through 2002, with comparison to Aichi Cancer Registry. Individuals who left the Barbers’ Union or moved out of Aichi Prefecture during the follow-up period were treated as censored cases (363 women). Individuals who could not be identified by name, address, or other information were excluded from the study.
Exposures investigated
Employment as a barber
How exposure was measured
Questionnaire, self-administered
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Gender, age
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
Female breast cancer mortality, compared to Japanese general population: SMR 0.90 (95% CI 0.74-1.06)
Author address
Department of Public Health, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan.
Reviewers Comments
Members of the cohort were mostly young (<20) when they started working. Seventy-five percent of female barbers reported occupational hair dye use at baseline. Breast cancer mortality is not a sensitive measure of breast cancer risk. Because the general population was chosen as the comparison population, these results may be biased downward due to a healthy worker effect. Differences between barbers and the general population regarding important breast cancer risk factors such as reproductive history and SES may have introduced additional bias.