Environment and Breast Cancer: Science Review

Evidence From Humans
Print this page
Personal use of hair dye and cancer risk in a prospective cohort of Chinese women
Mendelsohn, J. B., Li, Q. Z., Ji, B. T., Shu, X. O., Yang, G., Li, H. L., Lee, K. M., Yu, K., Rothman, N., Gao, Y. T., Zheng, W., Chow, W. H. Cancer Sci. 2009. 100:6, 1088-91.
Topic area
Environmental pollutant - Consumer product chemicals
Study design
Prospective cohort
Funding agency
NIH Intramural Research Program of NIH
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Stratified analysis based on menopausal status (data not shown)
Number in Cohort
Cohort: 73,366
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
The Shanghai Women's Health Study is a population-based prospective cohort of 74,942 women who were recruited from seven communities of urban Shanghai from 1996-2000, between the ages of 40-70 years. Incident cases were identified through follow-up with cohort members and linkage to the Shanghai Cancer Registry through December 2005. Women who turned out to be younger than 40 or older than 70 at baseline and women who had a prevalent cancer at baseline were excluded from the analysis.
Exposure Investigated
Exposures investigated
Among women who had used hair dye within the past 3 years, frequency of use within the past year and overall duration of use were assessed.
How exposure was measured
Questionnaire, self-administered Questionnaire, in person
Exposure assessment comment
Classifying women who had not used hair dye in the past 3 years as "non-users" may have led to exposure misclassification.
Breast cancer outcome investigated
Primary incident breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
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.
5-year birth cohort, education, smoking status, family history of cancer, passive smoking, alcohol consumption, mean fruit and vegetable intake, mean energy expenditure, measured BMI, number of live births, HRT use, menopausal status, age at menarche, inc
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
Breast cancer risk associated with never/ever use of hair dye: aRR 0.93 (95% CI 0.78-1.09)

Duration of hair dye use:
1-2 years: aRR 0.90 (95% CI 0.72-1.12)
3-4 years: aRR 0.87 (95% CI 0.66-1.13)
5-9 years: aRR 0.91 (95% CI 0.65-1.29)
10+ years: aRR 1.00 (95% CI 0.67-1.50)
Results Comments
Authors report no association between hair dye use and breast cancer in pre- or postmenopausal women in stratified analyses (data not shown).
Author address
Division of Cancer Epidemiology and Genetics, National Cancer Institute (NCI), National Institutes of Health, Bethesda, MD, USA. mendelju@mail.nih.gov