title: Hair-coloring product use and risk of non-Hodgkin's lymphoma: a population-based case-control study in Connecticut.
abstract: A population-based case-control study was conducted in Connecticut in 1996-2002 to test the hypothesis that lifetime hair-coloring product use increases non-Hodgkin's lymphoma risk. A total of 601 histologically confirmed incident female cases and 717 population-based controls were included in the study. An increased risk of non-Hodgkin's lymphoma was observed among women who reported use of hair-coloring products before 1980 (odds ratio = 1.3, 95% confidence interval (CI): 1.0, 1.8). The odds ratios were 2.1 (95% CI: 1.0, 4.0) for those using darker permanent hair-coloring products for more than 25 years and 1.7 (95% CI: 1.0, 2.8) for those who had more than 200 applications. Follicular type, B-cell, and low-grade lymphoma generally showed an increased risk. On the other hand, the authors found no increased risk of non-Hodgkin's lymphoma overall and by subtype of exposure and disease among women who started using hair-coloring products in 1980 or later. It is currently unknown why an increased risk of non-Hodgkin's lymphoma was found only among women who started using hair-coloring products before 1980. Further studies are warranted to show whether the observed association reflects the change in hair dye formula contents during the past two decades or indicates that recent users are still in their induction and latent periods.
authors.affiliation: Department of Epidemiology and Public Health, Yale School of Medicine, New Haven, CT 06510, USA.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Theodore R
authors.initials: TR
authors.lastname: Holford
authors.forename: Brian
authors.initials: B
authors.lastname: Leaderer
authors.forename: Peter
authors.initials: P
authors.lastname: Boyle
authors.forename: Shelia Hoar
authors.initials: SH
authors.lastname: Zahm
authors.forename: Stuart
authors.initials: S
authors.lastname: Flynn
authors.forename: Geovanni
authors.initials: G
authors.lastname: Tallini
authors.forename: Patricia H
authors.initials: PH
authors.lastname: Owens
authors.forename: Tongzhang
authors.initials: T
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003237:Connecticut / Q000453:epidemiology; D005260:Female; D006202:Hair Dyes / Q000009:adverse effects* / Q000737:chemistry; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D013997:Time Factors
chemical_list: D006202:Hair Dyes